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Author SHA1 Message Date
Jeuk Kim
92a885576f NFSv4/flexfiles: support loosely coupled data servers
A flexfiles storage device is tightly coupled to the MDS only when the
decoded ds_versions[0].tightly_coupled flag is set (RFC 8435, sections
2.3 and 4.1). The client currently ignores that flag and treats every
data server as tightly coupled, which breaks I/O to loosely coupled DSes.

Two things force that assumption on an NFSv4.1+ DS:

  1) nfs4_set_ds_client() always sets NFS_CS_PNFS on the new client, so
     EXCHANGE_ID is sent with EXCHGID4_FLAG_USE_PNFS_DS.

  2) nfs4_init_ds_session() then calls is_ds_client() and returns -ENODEV
     if the reply does not carry EXCHGID4_FLAG_USE_PNFS_DS.

A loosely coupled DS is just a normal NFS server and does not act in the
pNFS DS role, so the client must not require it to advertise that role.

Thread the ds_versions[0].tightly_coupled flag from the flexfiles driver
down to the DS connect path. When it is false, skip both the NFS_CS_PNFS
flag and the is_ds_client() check. The file layout driver always passes
true because NFSv4.1 file layout data servers use the pNFS DS role.

Signed-off-by: Jeuk Kim <jeuk20.kim@samsung.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:08 -07:00
Jeuk Kim
2b03ebbf8d NFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers
flexfiles accepts NFSv4.0 data servers, but two NFSv4 code paths assume
the data server client has a session. Unlike NFSv4.1+, an NFSv4.0 client
has no session (clp->cl_session is NULL; it uses clp->cl_slot_tbl), so
I/O to a v4.0 flexfiles DS oopses:

  - nfs4_init_ds_session() dereferences clp->cl_session->session_state
    while seeding the DS lease. It also only seeds cl_lease_time when
    NFS4_SESSION_INITING is set; without a session that never happens, so
    cl_lease_time stays 0 and nfs4_renew_state() busy-loops, requeuing
    every 5 seconds. Seed the lease whenever there is no session and
    return before touching session state.

  - ff_layout_async_handle_error_v4() dereferences
    clp->cl_session->fc_slot_table on every DS I/O error. Fall back to the
    v4.0 transport slot table (clp->cl_slot_tbl) when there is no session.

Fixes: a7878ca140 ("nfs: flexfilelayout: remove v3-only data server limitation")
Signed-off-by: Jeuk Kim <jeuk20.kim@samsung.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:08 -07:00
Jia Zhu
8cb1ce7aa0 NFSv4: pin the superblock for active state owners
NFSv4 open state can outlive the file and dentry that created it. This
was observed in production when NFSv4 state recovery, such as after a
server reboot or lease expiration, raced with unmount.

The race requires recovery to hold an open state reference while the last
open file is closed and the filesystem is unmounted, allowing the
superblock's active reference to drop to zero between
refcount_inc(&state->count) and nfs4_put_open_state():

    state manager                    umount

    nfs4_run_state_manager()
      nfs4_do_reclaim()
        nfs4_reclaim_open_state()
          refcount_inc(&state->count)
          ...
                                      close last file
                                      generic_shutdown_super()
                                        "Busy inodes after unmount"
                                      nfs_free_server()
          nfs4_put_open_state()
            iput(inode)
              evict()
                nfs_clear_inode()
                  nfs_zap_acl_cache()

The "VFS: Busy inodes after unmount" warning is the visible symptom of
that lifetime mismatch: superblock teardown proceeds even though the NFS
open state still pins an inode. After umount has freed the server, the
state manager can then run nfs4_put_open_state() for the last open-state
reference. The resulting iput(inode) can evict an NFS inode with freed
server data, causing crashes at nfs_zap_acl_cache(). This can be
reproduced by delaying the reclaim path before nfs4_put_open_state(),
then closing the last file and unmounting the NFS mount.

Pin the superblock while a state owner is active, and drop the pin when
the owner becomes idle again, so the NFS server stays alive until all
open state associated with the owner has been released.

Assisted-by: Codex:GPT-5
Signed-off-by: Jia Zhu <zhujia.zj@bytedance.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:08 -07:00
Luxiao Xu
932a8cf6ab sunrpc: fix use-after-free in __rpc_clnt_handle_event and __rpc_clnt_remove_pipedir
Normal client creation goes through rpc_setup_pipedir(), which records
clnt->pipefs_sb, but the mount-event path in __rpc_clnt_handle_event()
calls rpc_setup_pipedir_sb() directly and never refreshes that field.
The umount path also removes the directory without clearing
clnt->pipefs_sb.

After a late pipefs mount or any remount, rpc_clnt_remove_pipedir()
compares the current superblock against a stale pipefs_sb pointer and
skips cleanup, leaving pipefs dentries whose inode private data still
points at a freed rpc_clnt, leading to a potential use-after-free during
subsequent rpc_info_open() or rpc_show_info() calls.

Fix this by properly updating clnt->pipefs_sb upon mount events and
clearing it during unmount or failure paths.

Fixes: bfca5fb4e9 ("SUNRPC: Fix RPC client cleaned up the freed pipefs dentries")
Cc: stable@vger.kernel.org
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Xin Liu <dstsmallbird@foxmail.com>
Reviewed-by: Ren Wei <enjou1224z@gmail.com>
Assisted-by: Codex:gpt-5.4
Signed-off-by: Luxiao Xu <rakukuip@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:08 -07:00
Mike Snitzer
3e05a62a97 NFS/localio: issue commit inline when not in a memory-reclaim context
Extend the memory-reclaim-context test used for LOCALIO reads and writes to
the commit (fsync) path.  As with data IO, bouncing every commit through the
dedicated !WQ_MEM_RECLAIM nfslocaliod_workqueue is only required when the
submitting context is a memory-reclaim context: nfs_local_run_commit() calls
vfs_fsync_range(), which may flush the underlying filesystem's own
!WQ_MEM_RECLAIM workqueue, and doing so from a WQ_MEM_RECLAIM worker or a
PF_MEMALLOC task trips check_flush_dependency().

The writeback path does exercise this: nfs_write_inode() (the ->write_inode
super_op) runs under wb_workfn on the WQ_MEM_RECLAIM bdi_wq and reaches
nfs_local_commit() via __nfs_commit_inode(), so that case must keep
deferring.  Application-context commits -- fsync (nfs_file_fsync), O_DIRECT
(nfs_direct), and copy/clone (nfs42) -- are not in a reclaim context and now
run the fsync inline via nfs_local_defer_io(), avoiding the per-commit
workqueue hop.

Completion (nfs_commit_release_pages -> nfs_commit_end) then runs
synchronously in the submitting context; higher layers already cope with
this, as __nfs_commit_inode() dispatches the commit async and waits for it
separately via wait_on_commit().

Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:08 -07:00
Mike Snitzer
b10c63dcf2 NFS/localio: remove dead FLUSH_SYNC handling from nfs_local_commit
nfs_local_commit() is reached only through nfs_initiate_commit(), and every
path that supplies its "how" argument has already cleared FLUSH_SYNC:
__nfs_commit_inode() strips it (how &= ~FLUSH_SYNC) before dispatch and does
its own waiting via wait_on_commit(), while the O_DIRECT path passes how=0.
filelayout issues its DS commit with a NULL localio, so it never enters
nfs_local_commit() at all.  The FLUSH_SYNC branch has therefore been dead
since it was introduced with commit 70ba381e1a ("nfs: add LOCALIO
support").

Remove the never-taken FLUSH_SYNC branch along with the completion plumbing
it was the sole user of: the struct nfs_local_fsync_ctx::done member, its
initialization, and the complete() call in nfs_local_fsync_work().  With the
branch gone the "how" parameter is unused, so drop it from nfs_local_commit()
and its callers.  No functional change.

Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Mike Snitzer
da729ddd4a NFS/localio: issue IO inline when not in a memory-reclaim context
Every LOCALIO read and write is currently bounced through the dedicated
!WQ_MEM_RECLAIM nfslocaliod_workqueue.  That bounce is only actually
required when the submitting context is a memory-reclaim context: LOCALIO
issues IO directly into a stacked local filesystem (e.g. XFS) which may in
turn flush its own !WQ_MEM_RECLAIM workqueue.  Doing that from a
WQ_MEM_RECLAIM worker (most importantly writeback's wb_workfn on bdi_wq) or
an explicit PF_MEMALLOC reclaim task trips check_flush_dependency() and
risks a forward-progress deadlock, which is why commit b9f5dd57f4
("nfs/localio: use dedicated workqueues for filesystem read and write")
introduced the intermediate workqueue.

Outside of reclaim context -- ordinary application/task submission such as
O_DIRECT or fsync-driven writeback -- the workqueue hop buys nothing and
merely adds a context switch and scheduling latency per IO while discarding
the NFS client's inherent application-context parallelism.

Add current_is_workqueue_mem_reclaim(), which reports whether %current is a
WQ_MEM_RECLAIM worker using the same predicate check_flush_dependency()
warns on.  Use it, together with the PF_MEMALLOC check, in the new
nfs_local_defer_io() helper to decide per-IO whether nfs_local_do_read()
and nfs_local_do_write() must defer to nfslocaliod_workqueue or may issue
the IO inline.  Buffered writeback continues to bounce (wb_workfn is a
WQ_MEM_RECLAIM worker); O_DIRECT and app-context submission now run inline.

Running nfs_local_call_write() inline is safe: it already saves and
restores current->flags around the PF_LOCAL_THROTTLE|PF_MEMALLOC_NOIO it
sets and scopes the file opener's creds.  The async O_DIRECT completion
path is likewise unaffected: when the underlying filesystem returns
-EIOCBQUEUED, the kiocb ki_complete callback (nfs_local_read_aio_complete /
nfs_local_write_aio_complete) can run in bottom-half context and so must
still defer the pgio completion (nfs_local_pgio_release -> rpc_call_done) to
nfsiod_workqueue via nfs_local_pgio_aio_complete().  That completion hop is
independent of how the IO was submitted, and this change leaves it as-is;
only the submission side stops unconditionally hopping through
nfslocaliod_workqueue.

Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Guangshuo Li
68c0375557 NFS: Fix delayed delegation return list handling
The delayed delegation return handling added a separate
delegations_delayed list to keep delegations whose return needs to be
retried later. The delayed list is then spliced back to
delegations_return by nfs_server_clear_delayed_delegations(), which also
causes the state manager to retry the delegation return.

However, nfs_end_delegation_return() still moves delayed delegations to
delegations_return instead of delegations_delayed. As a result, the new
delayed list is never populated, nfs_server_clear_delayed_delegations()
always returns false, and NFS4CLNT_DELEGRETURN is not set again to drive
a retry.

Move delayed delegations to delegations_delayed so that the delayed
return path can splice them back to delegations_return and schedule the
retry as intended.

Fixes: 4039fbedcb ("NFS: fix delayed delegation return handling")
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
ZhangGuoDong
3265f1998a NFS: Verify symlink inode before caching target
nfs_symlink() copies the symlink target into a folio before issuing the
SYMLINK RPC.  After a successful reply, it caches that folio in the
instantiated inode mapping and assumes that the dentry now names a
symlink.

If the dentry is instantiated with a non-symlink inode, the raw symlink
target folio can be inserted into the wrong mapping.  When that inode is
a directory, reclaim or unmount later calls nfs_readdir_clear_array()
through nfs_dir_aops and interprets the symlink target as a readdir
cache array, which can lead to invalid kfree() calls.

A vmcore from a 4.19-based kernel showed the crash when reclaiming a
directory mapping on unmount:

  Stack trace:
   nfs_readdir_clear_array+0x4d/0x70 [nfs]
   page_cache_free_page.isra.35+0x1a/0x90
   delete_from_page_cache_batch+0x1cf/0x2c0
   truncate_inode_pages_range+0x24d/0x910
   [...]
   nfs_evict_inode+0x15/0x30 [nfs]
   evict+0x115/0x2b0
   dispose_list+0x48/0x60
   evict_inodes+0x16c/0x1b0
   generic_shutdown_super+0x3f/0x120
   nfs_kill_super+0x1b/0x40 [nfs]
   deactivate_locked_super+0x3f/0x70
   cleanup_mnt+0x3b/0x80

The current code still has the same unchecked cache insertion pattern,
so it may be susceptible to the same failure mode.

Verify that the instantiated inode is a symlink before caching the
target folio.  If the type is wrong, drop the suspect dentry and skip
the cache insertion while preserving the successful SYMLINK result.

Co-developed-by: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: ZhangGuoDong <zhangguodong@kylinos.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Jiangshan Yi
59075fb8b7 NFS: fix folio dereference before NULL check in nfs_inode_remove_request()
nfs_inode_remove_request() obtains the folio for the head request via
nfs_page_to_folio(), which returns NULL when the PG_FOLIO flag is not
set on req->wb_head.

The presence of the "if (likely(folio))" check shows the code already
assumes folio can be NULL. However, folio was dereferenced before that
check:

        folio = nfs_page_to_folio(req->wb_head);
        mapping = folio->mapping;                       /* deref */

        spin_lock(&mapping->i_private_lock);
        if (likely(folio)) {                            /* too late */

folio->mapping is read (and mapping->i_private_lock is taken, and
folio_end_dropbehind(folio) is called outside the check) before folio
is validated, so a NULL folio would crash before the guard is ever
reached, rendering the check useless.

Move the folio->mapping read, the i_private_lock section and the
folio_end_dropbehind() call inside the "if (likely(folio))" block so
the folio is only dereferenced after it has been confirmed non-NULL.
The behaviour is unchanged when folio is non-NULL.

Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Mike Snitzer
b4dd7f8159 nfs4.2: open UNCACHEABLE_FILE_DATA files with O_DIRECT
Honor the per-file UNCACHEABLE_FILE_DATA attribute by transparently
opening such regular files with O_DIRECT, so reads and writes bypass the
page cache as the attribute requires, without the application having to
request O_DIRECT itself.

This follows the model the specification describes: the attribute is
"similar in intent to O_DIRECT" and clients "retain flexibility in how
they satisfy the requirements" (draft-ietf-nfsv4-uncacheable-files
Section 4.4, "Relationship to Direct I/O"), and its Implementation
Status (Section 6) describes a prototype Linux client that "treats the
attribute as an indication to use O_DIRECT-like behavior for file
access".

Introduce an NFS_CONTEXT_O_DIRECT open-context flag: nfs4_atomic_open()
sets it when the resolved inode has uncacheable_file_data set (and the
open is not O_APPEND), and the open paths nfs_atomic_open() and
nfs4_file_open() apply O_DIRECT to the file when the flag is set.

The I/O mode is thus selected at open time and is not changed for an
already-open file: a later change to the attribute takes effect on the
next open.  The specification permits this -- a client that has already
opened a file MAY continue with its existing caching behavior and apply
the updated attribute to subsequent operations (Section 5).

The delegation interaction in Section 4.3 was considered: it permits read
caching to remain when another NFSv4.2 mechanism, such as a delegation,
already ensures a consistent view of the file.  That relaxation is
optional ("may remain appropriate") and read-only -- it does not relax
write-behind suppression (Section 4.1) or the WRITE durability invariant
(Section 4.2).  This implementation deliberately does not take it: an
uncacheable file is opened O_DIRECT regardless of any delegation held,
which is compliant (read caching is simply suppressed more aggressively
than the Section 4.3 minimum) and avoids decoupling read vs write caching
behind a single open flag.  Relaxing reads under a delegation is left as
a possible future optimization.

Section 6 observes the benefit holds "for applications that issue
well-formed I/O requests".  That alignment caveat does not constrain the
Linux NFS client's over-the-wire path: the client readily issues
misaligned I/O using O_DIRECT over SunRPC to the remote NFS server.  The
only place a fallback from O_DIRECT to buffered I/O for misaligned I/O
applies is NFS LOCALIO (fs/nfs/localio.c), which detects non-DIO-aligned
I/O and falls back internally; that path is unaffected by this change.

Link: https://datatracker.ietf.org/doc/draft-ietf-nfsv4-uncacheable-files/

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Mike Snitzer
6f36ce3098 nfs4.2: request UNCACHEABLE_FILE_DATA only for regular files
The UNCACHEABLE_FILE_DATA attribute applies only to regular files
(NF4REG); per draft-ietf-nfsv4-uncacheable-files a server MUST reject a
query of it on any other object type with NFS4ERR_INVAL.  The previous
commit decodes and tracks the attribute but does not gate it: the bit
rides in the per-server attribute bitmask (server->attr_bitmask) and in
the generic getattr request bitmap (nfs4_fattr_bitmap), so it would be
requested for non-regular objects too -- e.g. a plain directory GETATTR,
a LOOKUP that resolves to a directory, or a CREATE (which only ever makes
non-regular objects).  A strict server would fail those compounds.

Gate the client accordingly:

 - Only set NFS_INO_INVALID_UNCACHEABLE_FILE_DATA on regular-file inodes.
   In particular, drop it from nfs4_update_changeattr_locked()'s
   force-revalidation aggregation: that helper only ever runs on
   directory inodes (its callers update a directory's change information
   after OPEN-create, REMOVE, RENAME and LINK), so it was setting the
   file-only bit on directories.

 - Gate the request by object type at the choke point
   nfs4_bitmap_copy_adjust(), which clears
   FATTR4_WORD2_UNCACHEABLE_FILE_DATA unless the target inode is a
   regular file (a NULL inode -- unknown object type -- clears it too).
   This already covers GETATTR, SETATTR and LINK; route LOOKUP, LOOKUPP
   and CREATE through it as well.

 - Type-gate nfs4_bitmask_set(), which translates
   NFS_INO_INVALID_UNCACHEABLE_FILE_DATA into a request for attr 87 in
   the getattr attached to WRITE, CLOSE and DELEGRETURN.  WRITE and
   CLOSE only ever pass regular files, but DELEGRETURN passes whatever
   object held the delegation -- with directory delegation support that
   includes directories -- so request attr 87 there only for S_ISREG
   inodes.

The bit is kept in server->attr_bitmask (it is server-supported, and OPEN
still requests it via its regular-file-only open_bitmap), so no bespoke
per-data-file bitmask plumbing is needed.  The remaining getattr-bearing
compounds are already safe: ACCESS and LAYOUTCOMMIT use
server->cache_consistency_bitmask (no word2 attributes); READDIR does not
encode the bit; and LOOKUP_ROOT, FSINFO, STATFS and PATHCONF use fixed
bitmaps without it.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Tom Haynes
86ff184279 nfs4.2: add UNCACHEABLE_FILE_DATA attribute support
Recognize the NFSv4.2 per-file UNCACHEABLE_FILE_DATA attribute (attr 87,
draft-ietf-nfsv4-uncacheable-files): decode it via GETATTR, track per-
exported-filesystem support, and record on the inode whether a regular
file's data must not be cached.  Acting on the attribute (opening such
files O_DIRECT) is done by a subsequent change.

If the NFSv4 server reports a regular file's UNCACHEABLE_FILE_DATA as
true, it indicates the file's data must not be cached; the client records
this in NFS_I(inode)->uncacheable_file_data for use by the I/O paths.

The UNCACHEABLE_FILE_DATA attribute applies only to regular files
(NF4REG); per the draft a server MUST reject a query of it on any other
object type with NFS4ERR_INVAL.  A subsequent commit gates the client
accordingly.

Link: https://datatracker.ietf.org/doc/draft-ietf-nfsv4-uncacheable-files/

Signed-off-by: Tom Haynes <loghyr@hammerspace.com>
[snitzer: adapt Tom's original code focused on metadata for ABE]
Co-developed-by: Mike Snitzer <snitzer@hammerspace.com>
Signed-off-by: Mike Snitzer <snitzer@hammerspace.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Benjamin Coddington
4a013b0e88 NFSv4/flexfiles: report cancelled I/O as a layout error
When a layout is recalled or revoked the client cancels its in-flight I/O
so the layout can be returned.  The metadata server needs to learn that
this I/O to the storage device did not complete, so that it can reconcile
the affected mirror instance (or, if none remains, take other action).

The cancellation completed with -EAGAIN, which ff_layout_io_track_ds_error()
does not recognise: it fell through the switch and recorded nothing, so no
error was reported to the server.

-EAGAIN is overloaded in the RPC layer, so rather than key the reporting on
it, cancel the I/O with -ECANCELED and map that to NFS4ERR_NXIO in
ff_layout_io_track_ds_error() -- the status the client already reports for
the transport errors that leave an in-flight write incomplete.  The
cancelled I/O is then reported to the server via LAYOUTERROR / LAYOUTRETURN.

Unlike a genuine transport error, though, we aborted the I/O ourselves and
have no evidence the device is at fault, so once the error is recorded we
skip marking the device unreachable and forcing a further layout return.

The retry disposition is unchanged from the original -EAGAIN cancellation:
both NFS4ERR_NXIO and -ECANCELED are no-ops in ff_layout_async_handle_error(),
which still resets the I/O to pNFS (or the MDS), so it is re-driven as before.

Signed-off-by: Benjamin Coddington <bcodding@hammerspace.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Benjamin Coddington
aceaa5991b pNFS: honor clora_changed when recalling a layout
When the metadata server recalls a layout with clora_changed FALSE, the
layout is not changing and the client may complete its modified writes to
the storage devices before returning the layout (RFC 8881, Section
20.3.3).  Only when clora_changed is TRUE -- the server is restriping, or
a storage device has failed -- should the client stop writing to the
storage devices and redirect through the metadata server.

Since commit b739a5bd9d ("NFSv4/flexfiles: Cancel I/O if the layout is
recalled or revoked") the client cancels in-flight I/O on every recall,
regardless of clora_changed.  For an unchanged recall this abandons
writes whose data may already have reached the storage device; such a
write can then land after the LAYOUTRETURN, which the server sees as a
write without a layout.

Pass the recall's clora_changed value through
pnfs_mark_matching_lsegs_return() and only cancel in-flight I/O when the
layout is actually changing.  When it is not, the existing deferred
return path waits for the in-flight writes to drain before sending the
LAYOUTRETURN.  Other callers, which are tearing down or returning the
layout for their own reasons, continue to cancel as before.

Signed-off-by: Benjamin Coddington <bcodding@hammerspace.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Benjamin Coddington
ba0f097418 pNFS: report clora_changed in the cb_layoutrecall_file tracepoint
A CB_LAYOUTRECALL carries the clora_changed flag (RFC 8881, Section
20.3.3), which tells the client whether the server is changing the
layout (and therefore whether the client should flush modified data to
the storage devices before returning, or stop writing to them and go
through the metadata server). The client decodes this into
cbl_layoutchanged, but it is otherwise invisible.

Give nfs4_cb_layoutrecall_file its own event definition and report
clora_changed, so the intent of a recall can be observed in a trace.

Signed-off-by: Benjamin Coddington <bcodding@hammerspace.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
ZhangGuoDong
c056f817e4 pnfs/blocklayout: Fix device leaks on parse failure
bl_parse_concat() and bl_parse_stripe() allocate a child device array and
then parse each child in turn.  If parsing a child fails, the failed child is
not counted in nr_children and the parent may be left with a children array
that bl_free_device() will not release when nr_children is zero.

Release the failed child and the already parsed children before returning the
error.  Also make bl_free_device() release the child array whenever the
children pointer is set, so that partially initialised concat or stripe
devices are cleaned up correctly.

bl_parse_scsi() can also fail after assigning d->bdev_file and dropping the
file reference.  Clear the pointer after fput() so that an outer cleanup path
does not put it again.

Fixes: 5c83746a0c ("pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing")
Signed-off-by: ZhangGuoDong <zhangguodong@kylinos.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Ruoyu Wang
d05c2007b3 NFSv4: remove callback IDR entry on client allocation failure
nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it
finishes setting up the client. If any later initialization step fails,
the error path frees the nfs_client directly with nfs_free_client(). That
bypasses nfs_put_client(), which is where the callback IDR entry is
removed during normal teardown.

A failed allocation can therefore leave cb_ident_idr pointing at a freed
nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the
stale pointer and take a reference to it.

Make the callback IDR removal helper callable by the allocation failure
path, and remove the callback identifier before freeing the client.

This was found by a local static-analysis checker for publish-before-free
lifetime bugs and confirmed by manual inspection.

Fixes: f4eecd5da3 ("NFS implement v4.0 callback_ident")
Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Arnaud Bonnet
187bfc974e nfs: refactor pNFS functions using clear_and_wake_up_bit
Commit 8236b0ae31 ("bdi: wake up concurrent wb_shutdown() callers.")
introduces the clear_and_wake_up_bit() helper as a wrapper for the
common clear -> barrier -> wake up bitops sequence.

The file pnfs.c has several helpers with identical contents. Thus they
are replaced with the more recent clean_and_wake_up_bit() global helper
which describes accurately its effects at the call and still specifies
the cleared bit. This also homogenizes the code with other subsystems.

Since the helpers are no longer used after this, they can be safely
removed.

Suggested-by: Agatha Isabelle Moreira <code@agatha.dev>
Link: https://kernelnewbies.org/Beginner%20Cleanup%20and%20Refactor%20Tasks%20by%20Agatha%20Isabelle%20Moreira#task_007
Fixes: d67ae825a5 ("pnfs/flexfiles: Add the FlexFile Layout Driver")
Signed-off-by: Arnaud Bonnet <abo@medichon.fr>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:02:07 -07:00
Arnaud Bonnet
61461050da nfs: replace atomic bitops sequence with clear_and_wake_up_bit helper
Commit 8236b0ae31 ("bdi: wake up concurrent wb_shutdown() callers.")
introduces the clear_and_wake_up_bit() helper as a wrapper for the
common clear -> barrier -> wake up bitops sequence.

Use the helper in nfs_clear_invalid_mapping as inode.c already relies
on functions from <linux/wait_bit.h> and to homogenize with other
subsystems.

Suggested-by: Agatha Isabelle Moreira <code@agatha.dev>
Link: https://kernelnewbies.org/Beginner%20Cleanup%20and%20Refactor%20Tasks%20by%20Agatha%20Isabelle%20Moreira#task_007
Fixes: d529ef83c3 ("NFS: fix the handling of NFS_INO_INVALID_DATA flag in nfs_revalidate_mapping")
Signed-off-by: Arnaud Bonnet <abo@medichon.fr>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-17 09:01:10 -07:00
Chuck Lever
220af23d86 NFS: Return a delegation the client fails to record
When an NFS server grants a delegation in an OPEN reply,
nfs_inode_set_delegation() records it on the client. However, three
of its error flows return without sending DELEGRETURN.

A delegation can be relinquished only by DELEGRETURN (RFC 8881
Section 20.2.4), so dropping one silently leaves the server believing
the client still holds it. If the server happens to recall that
delegation, the client answers CB_RECALL with NFS4ERR_BADHANDLE
because it has no record of the stateid. The server revokes the
delegation and moves it onto its cl_revoked list, because the client
never sends the FREE_STATEID that would drain it. Every subsequent
SEQUENCE reply then carries SEQ4_STATUS_RECALLABLE_STATE_REVOKED,
and the client's state manager loops issuing TEST_STATEID across its
delegations without ever clearing the condition.

The window is easy to reach now that a server offers a write
delegation on any write OPEN: a delegation recalled for one opener
races a re-open that the server answers with a fresh write
delegation.

Instead of dropping it, hand the delegation back during these error
flows.

Fixes: ade04647dd ("NFSv4: Ensure we honour NFS_DELEGATION_RETURNING in nfs_inode_set_delegation()")
Signed-off-by: Chuck Lever <cel@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-10 13:28:23 -04:00
Runyu Xiao
33930840b5 sunrpc: xprtsock: annotate shared socket callbacks with READ_ONCE/WRITE_ONCE
xprtsock replaces and restores sk->sk_data_ready and
sk->sk_write_space on live sockets with plain stores, and
xs_udp_do_set_buffer_size() invokes sk->sk_write_space via a plain
load. These callback pointers are shared with generic socket and
protocol paths that may read or invoke them concurrently, so xprtsock
needs the same READ_ONCE()/WRITE_ONCE() callback visibility contract
that the validated 4022 family applied elsewhere.

When SUNRPC takes over an AF_LOCAL, UDP, or TCP socket and later
restores the lower-socket callbacks during teardown, another CPU may
still hold an earlier callback snapshot. The plain replace/restore
pattern leaves the same visibility hole as the validated 4022 family,
so a stale snapshot can still invoke xs_data_ready() or
xs_udp_write_space() after the live callback fields have already been
restored to the lower-socket handlers.

Use WRITE_ONCE() for the shared sk_data_ready and sk_write_space
stores in xs_local_finish_connecting(), xs_udp_finish_connecting(),
xs_tcp_finish_connecting(), and xs_restore_old_callbacks(). Use
READ_ONCE() for the direct sk_write_space invocation in
xs_udp_do_set_buffer_size(). This matches the required callback
visibility contract while leaving adjacent sk_state_change and
sk_error_report handling unchanged.

Fixes: a246b0105b ("[PATCH] RPC: introduce client-side transport switch")
Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-10 13:28:23 -04:00
Weiming Shi
fd22370226 SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6
rpcb_register_inet4() and rpcb_register_inet6() store the result of
rpc_sockaddr2uaddr() into map->r_addr without checking it for NULL.
rpc_sockaddr2uaddr() returns NULL when its final kstrdup() fails, and
the unchecked NULL is then carried into the synchronous RPCBPROC_SET
encode path: rpcb_register_call() -> rpc_call_sync() ->
rpcb_enc_getaddr() -> encode_rpcb_string(), whose first statement is
strlen(string), dereferencing NULL and oopsing the kernel.

The crash reproduces under failslab on v6.12; with KASAN the NULL
dereference surfaces as a fault on the shadow of address zero:

 Oops: general protection fault, probably for non-canonical address
       0xdffffc0000000000 [#1] PREEMPT SMP KASAN
 RIP: 0010:strlen (lib/string.c:409)
 Call Trace:
  encode_rpcb_string (net/sunrpc/rpcb_clnt.c:890)
  rpcb_enc_getaddr (net/sunrpc/rpcb_clnt.c:910)
  rpcauth_wrap_req_encode (net/sunrpc/auth.c:745)
  call_encode (net/sunrpc/clnt.c:1966)
  __rpc_execute (net/sunrpc/sched.c:952)
  rpc_run_task (net/sunrpc/clnt.c:1243)
  rpc_call_sync (net/sunrpc/clnt.c:1272)
  rpcb_v4_register (net/sunrpc/rpcb_clnt.c:500)
  svc_generic_rpcbind_set
  nfsd_rpcbind_set
  svc_register
  svc_setup_socket
  svc_addsock
  write_ports
  nfsctl_transaction_write
  vfs_write

The crash is reachable when an in-kernel RPC service (nfsd, lockd,
nfs-callback) registers with the local rpcbind under enough memory
pressure for the small GFP_KERNEL kstrdup() in rpc_sockaddr2uaddr() to
fail. The asynchronous getport path already handles this exact failure
mode by returning -ENOMEM; only the two register helpers omit the check.

Mirror that handling: bail out with -ENOMEM when rpc_sockaddr2uaddr()
returns NULL, before the address is fed into the encoder.

Fixes: d77385f238 ("SUNRPC: Fix rpc_sockaddr2uaddr")
Reported-by: Xiang Mei <xmei5@asu.edu>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2026-08-10 13:28:23 -04:00
Linus Torvalds
db2ddb8714 Linux 7.2-rc7 v7.2-rc7 2026-08-09 14:54:50 -07:00
Linus Torvalds
b9b3e33b70 tracing fixes for 7.2:
- Fix use-after-free in eventfs_remove_rec()
 
   The freeing of the eventfs_inode children used list_for_each_entry() where
   the child is freed via srcu, but there's still a chance that it gets freed.
   It should be using list_for_each_entry_safe().
 
 - Fix eventfs_inode SRCU use of list in freeing
 
   The iterator uses an SRCU protected list walk on the eventfs inodes. The
   eventfs inode uses its "list" field in a union with the RCU list head.
   When the inode gets added to the SRCU list it immediately corrupts the
   list pointer and can cause an issue with the iterator. Move the RCU list
   head to be shared with the children list head which allows the iterator to
   check the parent inode if is freed before referencing the child. Have the
   iterator check the parent "is_freed" field and break out if it is set.
   Also add memory barriers to make sure the ordering is correct.
 
 - Fix various RCU synchronization issues with direct_functions
 
   Updates to direct_functions have some missing RCU protection and
   synchronization. Restructure the code a bit to make sure updates to the
   direct_functions are protected.
 
 - Remove an unneeded comma from a scope_guard()
 
   There's a spurious comma in a scope_guard(). Remove it.
 
 - Fix race in per CPU buffer swap in the ring buffer
 
   When a per CPU buffer swap happens, it must make sure that it doesn't
   occur while a writer is active. Instead it returns an -EBUSY. But there's
   a small race window when a writer moves from one sub-buffer to the next
   that it resets the "committing" counter. If a swap happens at that moment,
   the buffer used for the commit of an event will not match the buffer the
   event is actually on. Instead of using the "committing" counter, use the
   recursive detection counter that does not get reset when the writer
   crosses sub-buffers.
 
 - Fix off-by-one in ftrace_free_mem()
 
   The function ftrace_free_mem() gets an "end_ptr" as a parameter that is
   exclusive to the rang to be freed. But its value is used to search for the
   records that expects an inclusive value. Subtract one from the parameter
   to convert it to an inclusive range.
 
 - Disable resizing of the ring buffer for persistent buffers
 
   Resizing the persistent buffer has undefined behavior. Prevent it from
   being resized.
 
 - Disable changing ring buffer subbuf order when resizing is disabled
 
   The ring buffer subbuffer order can not be changed during resizing. Use
   that instead of just checking if the buffer is mapped as mapped buffers
   also have resizing disabled.
 
 - Initialize subbuf_order of reader pages when they are created
 
   In rb_allocate_cpu_buffer() the bpage->order is not updated to the current
   subbuf_order leaving it as zero. This value is used when the page is freed.
 
 - Fix test_ringbuffer() to test for ERR_PTR before calling kthread_stop()
 
   The rb_threads[] array is assigned the output of kthread_run_on_cpu()
   which could return an ERR_PTR. At the end of the test, all threads in the
   array are cleaned up by kthread_stop() passing in the value in the array
   if it isn't zero. But if the array contains an ERR_PTR, kthread_stop()
   will not be able to handle it properly.
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Merge tag 'trace-v7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix use-after-free in eventfs_remove_rec()

   The freeing of the eventfs_inode children used list_for_each_entry()
   where the child is freed via srcu, but there's still a chance that it
   gets freed. It should be using list_for_each_entry_safe().

 - Fix eventfs_inode SRCU use of list in freeing

   The iterator uses an SRCU protected list walk on the eventfs inodes.
   The eventfs inode uses its "list" field in a union with the RCU list
   head. When the inode gets added to the SRCU list it immediately
   corrupts the list pointer and can cause an issue with the iterator.
   Move the RCU list head to be shared with the children list head which
   allows the iterator to check the parent inode if is freed before
   referencing the child. Have the iterator check the parent "is_freed"
   field and break out if it is set. Also add memory barriers to make
   sure the ordering is correct.

 - Fix various RCU synchronization issues with direct_functions

   Updates to direct_functions have some missing RCU protection and
   synchronization. Restructure the code a bit to make sure updates to
   the direct_functions are protected.

 - Remove an unneeded comma from a scope_guard()

   There's a spurious comma in a scope_guard(). Remove it.

 - Fix race in per CPU buffer swap in the ring buffer

   When a per CPU buffer swap happens, it must make sure that it doesn't
   occur while a writer is active. Instead it returns an -EBUSY. But
   there's a small race window when a writer moves from one sub-buffer
   to the next that it resets the "committing" counter. If a swap
   happens at that moment, the buffer used for the commit of an event
   will not match the buffer the event is actually on. Instead of using
   the "committing" counter, use the recursive detection counter that
   does not get reset when the writer crosses sub-buffers.

 - Fix off-by-one in ftrace_free_mem()

   The function ftrace_free_mem() gets an "end_ptr" as a parameter that
   is exclusive to the rang to be freed. But its value is used to search
   for the records that expects an inclusive value. Subtract one from
   the parameter to convert it to an inclusive range.

 - Disable resizing of the ring buffer for persistent buffers

   Resizing the persistent buffer has undefined behavior. Prevent it
   from being resized.

 - Disable changing ring buffer subbuf order when resizing is disabled

   The ring buffer subbuffer order can not be changed during resizing.
   Use that instead of just checking if the buffer is mapped as mapped
   buffers also have resizing disabled.

 - Initialize subbuf_order of reader pages when they are created

   In rb_allocate_cpu_buffer() the bpage->order is not updated to the
   current subbuf_order leaving it as zero. This value is used when the
   page is freed.

 - Fix test_ringbuffer() to test for ERR_PTR before calling
   kthread_stop()

   The rb_threads[] array is assigned the output of kthread_run_on_cpu()
   which could return an ERR_PTR. At the end of the test, all threads in
   the array are cleaned up by kthread_stop() passing in the value in
   the array if it isn't zero. But if the array contains an ERR_PTR,
   kthread_stop() will not be able to handle it properly.

* tag 'trace-v7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Fix crash passing ERR_PTR to kthread_stop()
  ring-buffer: Initialise reader page order in rb_allocate_cpu_buffer()
  ring-buffer: Prevent subbuf order change when resizing is disabled
  ring-buffer: Prevent resizing of persistent ring buffer
  ftrace: Fix off-by-one fentry site disable in ftrace_free_mem()
  ring-buffer: Use current_context for safe per-CPU buffer swap
  ftrace: Drop extra comma in trace_buffered_event_enable
  ftrace: Protect direct_functions in update_ftrace_direct_mod
  ftrace: Protect direct_functions in update_ftrace_direct_del
  ftrace: Protect direct_functions in ftrace_find_rec_direct
  eventfs: Use children field for rcu head and add memory barriers
  eventfs: Fix use-after-free in eventfs_remove_rec()
2026-08-09 08:47:31 -07:00
Linus Torvalds
b643e495ae s390 updates for 7.2-rc7
- Fix potential uninitialized memory reads and buffer overflows from
   malformed zcrypt CCA and EP11 requests by properly validating lengths
   and payloads
 
 - Fix possible out of bounds accesses in zcrypt EP11 domain handling by
   replacing fixed payload layout assumptions with parsing ASN.1 fields
   with bounds checks
 
 - Fix zcrypt CCA and EP11 request and reply buffer allocations missing
   required 4-byte padding, and scrub the full allocation on release
 
 - Fix zcrypt CCA and EP11 messages leaking up to 3 uninitialized bytes
   of memory by zeroing trailing alignment padding
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Merge tag 's390-7.2-7' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fixes from Vasily Gorbik:

 - Fix potential uninitialized memory reads and buffer overflows from
   malformed zcrypt CCA and EP11 requests by properly validating lengths
   and payloads

 - Fix possible out of bounds accesses in zcrypt EP11 domain handling by
   replacing fixed payload layout assumptions with parsing ASN.1 fields
   with bounds checks

 - Fix zcrypt CCA and EP11 request and reply buffer allocations missing
   required 4-byte padding, and scrub the full allocation on release

 - Fix zcrypt CCA and EP11 messages leaking up to 3 uninitialized bytes
   of memory by zeroing trailing alignment padding

* tag 's390-7.2-7' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/zcrypt: Pad trailing CCA or EP11 message with zeros
  s390/zcrypt: Improve EP11 CPRB domain handling with ASN.1 parsing
  s390/zcrypt: Improve EP11 CPRB length and overflow checks
  s390/zcrypt: Improve CCA CPRB length and overflow checks
  s390/zcrypt: Fix CPRB memory allocation in zcrypt misc code
2026-08-09 06:31:16 -07:00
Hui Su
91542863ab ring-buffer: Fix crash passing ERR_PTR to kthread_stop()
In test_ringbuffer()'s out_free cleanup loop, the check
`!rb_threads[cpu]` only catches NULL entries and misses entries that
hold an ERR_PTR.

rb_threads[] is static, so unassigned slots are NULL. But when
kthread_run_on_cpu() fails for a cpu, it stores ERR_PTR(-ENOMEM) (or
-EINTR) in rb_threads[cpu] before the creation loop jumps to out_free.
That entry is non-NULL, so the old `!ptr` check does not break, and the
cleanup proceeds to call kthread_stop() on the ERR_PTR. kthread_stop()
then dereferences the bogus pointer, crashing the kernel during the
late_initcall self-test.

crash logs:
  BUG: kernel NULL pointer dereference, address: 000000000000001c
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 1 Comm: swapper/0 Not tainted 7.2.0-rc6-dirty #7 PREEMPT(lazy)
  RIP: 0010:kthread_stop+0x2e/0x220
  RBX: fffffffffffffff4
  CR2: 000000000000001c
  Call Trace:
   <TASK>
   test_ringbuffer+0x1ec/0x650
   do_one_initcall+0x6c/0x2c0
   kernel_init_freeable+0x21d/0x420
   kernel_init+0x15/0x1c0
   ret_from_fork+0x21b/0x320
   </TASK>
  Kernel panic - not syncing: Fatal exception

Cc: stable@vger.kernel.org
Fixes: 64ed3a049e ("ring-buffer: make use of the helper function kthread_run_on_cpu()")
Link: https://patch.msgid.link/20260807154145.2846521-2-sh_def@163.com
Signed-off-by: Hui Su <sh_def@163.com>
Reviewed-by: Vincent Donnefort <vdonnefort@google.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:26:30 -04:00
Vincent Donnefort
6d014e44b6 ring-buffer: Initialise reader page order in rb_allocate_cpu_buffer()
In rb_allocate_cpu_buffer(), bpage->order was omitted, leaving it as 0.
This is an issue for a ring-buffer with subbufs bigger than PAGE_SIZE if
when freed: free_buffer_page() relies on this value. Align the value
with the actual allocation size (buffer::subbuf_order).

Cc: stable@vger.kernel.org
Fixes: f9b94daa54 ("ring-buffer: Set new size of the ring buffer sub page")
Link: https://patch.msgid.link/20260806211306.3704194-4-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:26:11 -04:00
Vincent Donnefort
bf98d7b0d5 ring-buffer: Prevent subbuf order change when resizing is disabled
Because ring_buffer_subbuf_order_set() frees buffer pages, we can't
allow it when resizing is disabled. A non-consuming reader is at risk of
use-after-free (rb_advance_iter()).

Return -EBUSY on resize_disabled, matching ring_buffer_resize()
behaviour.

Cc: stable@vger.kernel.org
Fixes: f9b94daa54 ("ring-buffer: Set new size of the ring buffer sub page")
Link: https://patch.msgid.link/20260806211306.3704194-3-vdonnefort@google.com
Reported-by: syzbot+e0cc44465d6bae735679@syzkaller.appspotmail.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:23:45 -04:00
Vincent Donnefort
7c727dfce6 ring-buffer: Prevent resizing of persistent ring buffer
Dynamically resizing a persistent ring buffer is not possible. Disable
the feature.

Cc: stable@vger.kernel.org
Fixes: be68d63a13 ("ring-buffer: Add ring_buffer_alloc_range()")
Link: https://patch.msgid.link/20260806211306.3704194-2-vdonnefort@google.com
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:23:18 -04:00
Josh Poimboeuf
8b8292d648 ftrace: Fix off-by-one fentry site disable in ftrace_free_mem()
When a module's init text is freed, do_init_module() calls
ftrace_free_mem() with a half-open [start, end) range.  However the
ftrace_cmp_recs() comparator treats the upper bound as inclusive, as all
its other users do, passing 'ip + size - 1'.  So ftrace_free_mem() can
delete a record sitting exactly at 'end', which is outside the freed
range.

For a kernel without CFI or IBT, the first record of a function is at
the function start, which for the first function in a module is also the
base of its text allocation.  As the module allocator packs its regions,
that address is often the 'end' passed by a neighboring module's
do_init_module(), causing the first function's ftrace location to get
disabled, preventing an attempt to livepatch it:

  livepatch: failed to find location for function 'pcspkr_probe'

Convert the exclusive end to the inclusive 'end - 1' the comparator
expects, and return early for an empty range to avoid the subtraction
from underflowing when the init text size is zero.

Cc: stable@vger.kernel.org
Fixes: 42c269c88d ("ftrace: Allow for function tracing to record init functions on boot up")
Link: https://patch.msgid.link/1b5ccfa8095bdb1277f84af1c2c2e2205aca03ae.1785992188.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:22:41 -04:00
Tengda Wu
f27bdc4307 ring-buffer: Use current_context for safe per-CPU buffer swap
The ring_buffer_swap_cpu() function currently checks the per-CPU
committing counter to determine if a buffer is actively being written to
before performing the swap. However, there exists a race window where
this check can be bypassed:

    ring_buffer_lock_reserve
        cpu_buffer = buffer->buffers[cpu];       // cpu_buffer_a
        rb_reserve_next_event
            rb_start_commit // inc committing
            if (unlikely(READ_ONCE(cpu_buffer->buffer) != buffer)) {...}
            __rb_reserve_next
                rb_move_tail
                    rb_end_commit(cpu_buffer);   // dec committing => 0
                    /* interrupt hits here, successfully swaps! */
                    local_inc(&cpu_buffer->committing);

    ring_buffer_unlock_commit
        cpu_buffer = buffer->buffers[cpu];      // cpu_buffer_b
        rb_commit
            rb_end_commit
            RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))
                                                // triggers warning

The committing counter can temporarily drop to 0 during a single write
operation (within rb_move_tail), creating a window where swap can
succeed even though the write is still in progress. This leads to
inconsistent buffer state and triggers the RB_WARN_ON in rb_commit().

Replace the committing counter check with current_context checks, which
are set at the entry of ring_buffer_lock_reserve() and remain valid
throughout the entire write operation, providing a reliable indicator of
buffer busy state during swap.

Cc: stable@vger.kernel.org
Fixes: 4239c38fe0 ("ring-buffer: Process commits whenever moving to a new page.")
Link: https://patch.msgid.link/20260803005640.2445666-2-wutengda@huaweicloud.com
Signed-off-by: Tengda Wu <wutengda@huaweicloud.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 22:22:06 -04:00
Linus Torvalds
06cf61899d - Fix MCE CMCI discovery initialization ordering bug
(Breno Leitao)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2026-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fix from Ingo Molnar:

 - Fix MCE CMCI discovery initialization ordering bug (Breno Leitao)

* tag 'x86-urgent-2026-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mce: Set up the polling timer before CMCI discovery
2026-08-08 16:43:07 -07:00
Linus Torvalds
d4eee3bdb8 - Fix race in futex_pivot_pending() during private hash resize
that can cause stuck tasks (Yao Kai)
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-urgent-2026-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull futex fix from Ingo Molnar:

 - Fix race in futex_pivot_pending() during private hash resize
   that can cause stuck tasks (Yao Kai)

* tag 'locking-urgent-2026-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Fix race in futex_pivot_pending() during private hash resize
2026-08-08 16:39:53 -07:00
Linus Torvalds
91a73db697 USB / Thunderbolt fixes for 7.2-rc7
Here are some small USB and Thunderbolt driver fixes for 7.2-rc7 that
 resolve some reported issues.  Included in here are:
   - new quirk for some broken USB devices
   - thunderbolt device fixes for reported issues
   - usb gadget driver fix
   - usb atm driver fix
   - xhci driver fixes.
   - other minor USB driver fixes
 
 All of these have been in linux-next this week with no reported issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'usb-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB / Thunderbolt fixes from Greg KH:
 "Here are some small USB and Thunderbolt driver fixes for 7.2-rc7 that
  resolve some reported issues. Included in here are:

   - new quirk for some broken USB devices

   - thunderbolt device fixes for reported issues

   - usb gadget driver fix

   - usb atm driver fix

   - xhci driver fixes.

   - other minor USB driver fixes

  All of these have been in linux-next this week with no reported
  issues"

* tag 'usb-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: xhci: use BIT_ULL for CRCR bits to fix incorrect 64bit mask
  usb: quirks: Add ShanWan gamepad to quirk list
  usb: hub: Split announce_device() to log device identity before enumeration
  usb: core: Add quirk for 255-bytes initial config read
  usb: atm: cxacru: properly kill rcv_urb on error in cxacru_cm()
  usb: misc: usbio: check ibuf_len against rxbuf_len in bulk msg
  usb: gadget: f_ncm: Use unsigned int for ndp_index
  usb: cdnsp: fix incorrect endian conversions for APB timeout register
  thunderbolt: Initialize ->domain_released completion before it is being used
  thunderbolt: icm: Preserve USB4 proxy data-valid bit
  thunderbolt: Bound the DROM dual link port number before indexing sw->ports
  thunderbolt: Fix bandwidth group reservation indexing
  thunderbolt: stream: Unmap buffers with mapped size
2026-08-08 16:33:04 -07:00
Linus Torvalds
e4836b67ba TTY / Serial / VT driver fixes for 7.2-rc7
Here are some small serial and vt tty driver fixes for 7.2-rc7 that
 resolve some reported problems.  Included in here are:
   - 2 vt core fixes
   - amba-pl011 serial driver fixes
   - 8250_of and 8250_dma driver fixes
   - qcom-geni serial driver fix
   - sc16is7xx serial driver fix
 
 All of these have been in linux-next this week with no reported issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty / serial / vt driver fixes from Greg KH:
 "Here are some small serial and vt tty driver fixes for 7.2-rc7 that
  resolve some reported problems. Included in here are:

   - two vt core fixes

   - amba-pl011 serial driver fixes

   - 8250_of and 8250_dma driver fixes

   - qcom-geni serial driver fix

   - sc16is7xx serial driver fix

  All of these have been in linux-next this week with no reported
  issues"

* tag 'tty-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: amba-pl011: synchronize DMA teardown
  serial: amba-pl011: cancel RS485 hrtimers after freeing IRQ
  serial: amba-pl011: fix indefinite RS485 post-send delay
  vt: add permission check for KDSKBMETA ioctl
  vt: stabilize tty reference in kbd_keycode with tty_port_tty_get
  serial: 8250_of: clear stuck empty-FIFO RX-timeout on LPC32xx
  serial: qcom-geni: fix TX DMA buffer flush
  serial: 8250_dma: Clear stale RX state on shutdown
  serial: sc16is7xx: enable THRI before filling TX FIFO
2026-08-08 16:31:15 -07:00
Linus Torvalds
e663f6deac Staging driver fixes for 7.2-rc7
Here are some more small staging driver fixes, just for the rtl8723bs
 driver, for some reported problems found with it now that people are
 starting to actually test the thing with "bad" networks.
 
 Nothing major, but good to have in the -final release.  All of these
 have been in linux-next for over a week with no reported problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'staging-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging

Pull staging driver fixes from Greg KH:
 "Here are some more small staging driver fixes, just for the rtl8723bs
  driver, for some reported problems found with it now that people are
  starting to actually test the thing with "bad" networks.

  Nothing major, but good to have in the -final release. All of these
  have been in linux-next for over a week with no reported problems"

* tag 'staging-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: rtl8723bs: validate monitor transmit frame lengths
  staging: rtl8723bs: fix missing shared-key auth challenge length check
  staging: rtl8723bs: fix OOB read in WMM_param_handler()
  staging: rtl8723bs: fix OOB read in rtw_get_wpa_ie()
2026-08-08 16:29:33 -07:00
Linus Torvalds
5668ba2304 Char / Misc and documentation fixes for 7.2-rc7
Here are some small char/misc and nvmem and documentation fixes for
 7.2-rc7 to resolve some reported issues.  Included in here are:
   - updates to the documentation for the kernel threat model and
     security bugs to get the LLMs to actually follow what we have been
     asking them to do (i.e. not claim security issues for things we do
     not consider security issues.)
   - nvmem driver fixes which required a tiny "layout" driver to be
     added.
   - fastrpc driver fixes
   - mei driver fix
   - counter driver fix
   - binder driver fix
 
 All of these have been in linux-next this week with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char / misc and documentation fixes from Greg KH:
 "Here are some small char/misc and nvmem and documentation fixes for
  7.2-rc7 to resolve some reported issues.  Included in here are:

   - updates to the documentation for the kernel threat model and
     security bugs to get the LLMs to actually follow what we have been
     asking them to do (i.e. not claim security issues for things we do
     not consider security issues.)

   - nvmem driver fixes which required a tiny "layout" driver to be
     added.

   - fastrpc driver fixes

   - mei driver fix

   - counter driver fix

   - binder driver fix

  All of these have been in linux-next this week with no reported
  problems"

* tag 'char-misc-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  docs: security-bugs: clarify some mandatory steps for AI reports
  docs: coding-assistant: explain important steps when looking for bugs
  docs: security-bugs: clarify what counts as a valid version
  docs: threat-model: move fake devices out of "non production use"
  docs: threat-model: clarify "security bug" vs "vulnerability"
  counter: microchip-tcb-capture: Fix DT channel validation
  mei: pull kvfree out of spinlock
  rust_binder: do not query current thread for all ioctls
  nvmem: layouts: Add fixed-layout driver
  nvmem: apple-spmi-nvmem: wrap regmap calls to satisfy CFI
  misc: fastrpc: fix memory leak in fastrpc_channel_ctx_free
  misc: fastrpc: fix channel ctx ref leak when session alloc fails
  misc: fastrpc: take fl->lock when moving mmaps on interrupted invoke
  misc: fastrpc: Remove buffer from list prior to unmap operation
  misc: fastrpc: Fix initial memory allocation for Audio PD memory pool
2026-08-08 16:25:59 -07:00
Leon Hwang
48f2fd0d93 ftrace: Drop extra comma in trace_buffered_event_enable
Drop the extra comma in "scoped_guard()" to cleanup the code.

Link: https://patch.msgid.link/20260730150411.88667-5-leon.hwang@linux.dev
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 11:21:32 -04:00
Leon Hwang
092f8ec7db ftrace: Protect direct_functions in update_ftrace_direct_mod
Fix accessing the __rcu pointer direct_functions with RCU protection.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-4-leon.hwang@linux.dev
Fixes: e93672f770 ("ftrace: Add update_ftrace_direct_mod function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 11:21:27 -04:00
Leon Hwang
f26e5fa75f ftrace: Protect direct_functions in update_ftrace_direct_del
Fix accessing the __rcu pointer direct_functions with RCU protection.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-3-leon.hwang@linux.dev
Fixes: 8d2c1233f3 ("ftrace: Add update_ftrace_direct_del function")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 11:21:23 -04:00
Leon Hwang
63444b7617 ftrace: Protect direct_functions in ftrace_find_rec_direct
Fix accessing the __rcu pointer direct_functions with RCU protection.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730150411.88667-2-leon.hwang@linux.dev
Fixes: d05cb47066 ("ftrace: Fix modification of direct_function hash while in use")
Acked-by: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 11:21:04 -04:00
Linus Torvalds
a7c7074b58 fbdev core fixes for 7.2-rc7:
A few patches for the core fbdev layer which stabilize or fix potential
 issues with text font rendering after screen rotation or after user
 initiated font changes and locking fixes for sysfb during modifications
 of the graphics mode database.
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Merge tag 'fbdev-for-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev

Pull fbdev fixes from Helge Deller:
 "A few patches for the core fbdev layer which stabilize or fix
  potential issues with text font rendering after screen rotation or
  after user initiated font changes and locking fixes for sysfb during
  modifications of the graphics mode database"

* tag 'fbdev-for-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
  fbdev: bitblit: bound-check glyph index in bit_cursor()
  fbdev: Fix out-of-bounds access when rotating console after font resize
  fbdev: core: Fix pointer desynchronization in fb_io_read()
  fbdev: serialize mode sysfs access with lock_fb_info()
  fbdev: clear fb_info->mode before deleting a videomode
  fbdev: bound mode sysfs output to the sysfs buffer
2026-08-08 07:47:52 -07:00
Steven Rostedt
f0ece16ffc eventfs: Use children field for rcu head and add memory barriers
When an eventfs inode is freed, it sets ei->is_freed and then uses its
ei->list to add it to the srcu link list as the list field is a union with
the rcu list head. As the ei->list is used to iterate over an SRCU
protected list without taking the eventfs_mutex, there's nothing stopping
the iteration over that list to see the ei->rcu instead of the ei->list
and it will read a corrupt target.

To fix this, change the union of the rcu list head with the children list.
On freeing the eventfs inode, set the is_free and execute a smp_wmb()
before adding the eventfs inode to the SRCU list.

On iteration of the ei->children list, at the start, execute a smp_rmb()
and then read the is_freed of the ei to see if the children list is still
valid. If is_freed is set, then the ei_child read is not valid and the
loop should exit immediately.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260808094215.4252430d@robin
Fixes: 704f960dbe ("eventfs: Read ei->entries before ei->children in eventfs_iterate()")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260806022719.375354-1-shuangpeng.kernel%40gmail.com
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 10:36:05 -04:00
Shuangpeng Bai
fd73b69170 eventfs: Fix use-after-free in eventfs_remove_rec()
eventfs_remove_rec() recursively removes the child at the current loop
position. After the recursive call returns, list_for_each_entry() advances
by reading list.next from the removed child.

If free_ei() drops the final reference, release_ei() reuses the list/rcu
union to queue an SRCU callback. The child may be freed before that read.
The eventfs_mutex serializes list updates, but it does not keep the removed
child alive or prevent the SRCU callback from running.

Use list_for_each_entry_safe() to save the next sibling before recursively
removing the current child.

Cc: stable@vger.kernel.org
Fixes: 43aa6f97c2 ("eventfs: Get rid of dentry pointers without refcounts")
Link: https://patch.msgid.link/20260806022719.375354-1-shuangpeng.kernel@gmail.com
Signed-off-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2026-08-08 10:35:33 -04:00
Linus Torvalds
361efac9e9 Driver core fixes for 7.2-rc7
- Fix Rust build failure on s390 by gating ioremap() / iounmap() helpers
   and the io::mem module on CONFIG_HAS_IOMEM; gate affected doctests as
   well.
 
 - Add missing kernel-doc for show_const / store_const union members in
   struct device_attribute.
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Merge tag 'driver-core-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core

Pull driver core fixes from Danilo Krummrich:

 - Fix Rust build failure on s390 by gating ioremap() / iounmap()
   helpers and the io::mem module on CONFIG_HAS_IOMEM; gate affected
   doctests as well.

 - Add missing kernel-doc for show_const / store_const union members in
   struct device_attribute.

* tag 'driver-core-7.2-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core:
  rust: io: gate ioremap doctests on CONFIG_HAS_IOMEM
  rust: io: gate ioremap/iounmap on CONFIG_HAS_IOMEM
  driver core: add missing kernel-doc for union members
2026-08-08 07:13:29 -07:00
Linus Torvalds
7d8c681eef Input updates for v7.2-rc6
- Fixes for information leaks and OOB accesses across several drivers,
   including evdev, focaltech, edt-ft5x06, iforce, and cs40l50-vibra
 
 - Improvements to the synaptics-rmi4 driver to properly handle F54
   worker errors and prevent buffer overflows
 
 - Input validation fixes in the hynitron_cstxxx touchscreen driver to
   prevent issues with invalid finger IDs and touch counts
 
 - Fixes for use-after-free and initialization bugs in the byd mouse
   and psxpad-spi drivers
 
 - New quirks for the atkbd driver to make keyboard work on HONOR and
   Xiaomi laptops
 
 - Support for the ZENAIM LEVERLESS controller in the xpad driver.
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Merge tag 'input-for-v7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

Pull input updates from Dmitry Torokhov:

 - Fixes for information leaks and OOB accesses across several drivers,
   including evdev, focaltech, edt-ft5x06, iforce, and cs40l50-vibra

 - Improvements to the synaptics-rmi4 driver to properly handle F54
   worker errors and prevent buffer overflows

 - Input validation fixes in the hynitron_cstxxx touchscreen driver to
   prevent issues with invalid finger IDs and touch counts

 - Fixes for use-after-free and initialization bugs in the byd mouse and
   psxpad-spi drivers

 - New quirks for the atkbd driver to make keyboard work on HONOR and
   Xiaomi laptops

 - Support for the ZENAIM LEVERLESS controller in the xpad driver.

* tag 'input-for-v7.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: evdev - sanitize event type index when fetching event masks
  Input: synaptics-rmi4 - propagate F54 worker errors to V4L2 queue
  Input: synaptics-rmi4 - block s_input when F54 queue is busy
  Input: synaptics-rmi4 - bound the F54 report size to the allocated buffer
  Input: synaptics-rmi4 - zero report size on F54 work error
  Input: synaptics-rmi4 - fix F55 transmitter electrode count typo
  Input: hynitron_cstxxx - validate touch count and finger IDs
  Input: evdev - fix information leak in evdev_pass_values()
  fixp-arith: convert comments to kernel-doc format
  Input: focaltech - fix array out-of-bounds in focaltech_process_rel_packet
  Input: atkbd - skip deactivate for HONOR ZQC-P
  Input: atkbd - skip deactivate for Xiaomi Book Pro 14's internal keyboard
  Input: iforce - validate input packet lengths
  Input: psxpad-spi - set driver data before use
  Input: cs40l50-vibra - validate custom data from user space
  Input: xpad - add support for ZENAIM LEVERLESS
  Input: edt-ft5x06 - ignore contacts with an out-of-range slot id
  Input: byd - synchronize timer deletion before freeing private data
2026-08-08 07:09:35 -07:00
Linus Torvalds
afe80aebd3 powerpc fixes for 7.2 #4
- Couple of fixes for mem leak and underflow case
 
 Thanks to: George Wilson, R Nageswara Sastry
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Merge tag 'powerpc-7.2-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Madhavan Srinivasan:

 - A couple of fixes for a memory leak and a underflow case

Thanks to George Wilson and R Nageswara Sastry

* tag 'powerpc-7.2-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/pseries: lparcfg - fix kbuf[] underflow
  powerpc/pseries: pci - logic bug
  powerpc/pseries: papr-phy-attest - validate cmd.length, plug mem leak
2026-08-08 07:03:59 -07:00
Rik van Riel
e033cbf397 fbdev: bitblit: bound-check glyph index in bit_cursor()
bit_cursor() fetches the glyph under the cursor with

	c = scr_readw(vc_pos);
	src = vc_font.data + ((c & charmask) * w * height);

where charmask is 0x1ff when vc_hi_font_mask is set. The screen buffer
value comes directly from scr_readw() and may be larger than the current
font's glyph count.

Syzkaller triggers this via vcs_write(). The Call Trace shows
vcs_write() in vc_screen.c writing an arbitrary 16-bit value with
writev() to /dev/vcsa, which vcs_write_buf() in vc_screen.c stores via
vcs_scr_writew() without checking charcount. The stored value is later
read in bit_cursor() in bitblit.c.

When the font is changed from a font with 512 glyphs to a font with
256 glyphs, the screen buffer can retain characters with the high
bit set from the previous mode, which could also produce the same
out-of-bounds access.

  BUG: KASAN: global-out-of-bounds in soft_cursor+0x378/0x6bc drivers/video/fbdev/core/softcursor.c:70
  Read of size 16 at addr ffff800086c57970

  Call Trace:
   soft_cursor+0x378/0x6bc drivers/video/fbdev/core/softcursor.c:70
   bit_cursor+0xa90/0x1108 drivers/video/fbdev/core/bitblit.c:365
   fbcon_cursor+0x344/0x498 drivers/video/fbdev/core/fbcon.c:1427
   hide_cursor+0xdc/0x2d0 drivers/tty/vt/vt.c:883
   update_region+0x100/0x18c drivers/tty/vt/vt.c:669
   vcs_write+0x8ec/0xaf0 drivers/tty/vt/vc_screen.c:685

bit_putcs_aligned() and bit_putcs_unaligned() already clamp the glyph
index to vc_font.charcount. Apply the same clamp in bit_cursor() after
extracting the attribute and masking, before indexing fontdata.

The fix completes the bounds checking started in commit 18c4ef4e76
("fbdev: bitblit: bound-check glyph index in bit_putcs*"), which missed
the cursor path.

This change should be safe because the clamp reuses the existing
contract from fbcon: charcount is maintained under console_lock in
con_font_set() and fbcon_font_set(), and hi_font_mask is cleared when
switching from 512 to 256 glyphs. When stale screen data with high bits
remains after a font switch, or when vcs_write() stores an arbitrary
value, clamping the index to 0 prevents the out-of-bounds read without
changing cursor semantics — the same fallback bit_putcs uses.

Reported-by: syzbot+61b1db46218109869c14@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=61b1db46218109869c14
Link: https://lore.kernel.org/all/6a75205c.01d0871a.3a0d52.0032.GAE@google.com/
Fixes: 18c4ef4e76 ("fbdev: bitblit: bound-check glyph index in bit_putcs*")
Cc: stable@vger.kernel.org
Assisted-by: Hermes:muse-spark-1.2 syzkaller
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-08-08 08:08:58 +02:00
Zizhi Wo
ef7656e85f fbdev: Fix out-of-bounds access when rotating console after font resize
[BUG]
Recently, we encountered a KASAN warning as follows:

BUG: KASAN: slab-out-of-bounds in ccw_putcs+0x8bd/0xa80
Read of size 1 at addr ff11000110067100 by task bash/1209
CPU: 10 UID: 0 PID: 1209 Comm: bash Not tainted 7.2.0-rc3 #69 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014
 Call Trace:
  <TASK>
  ...
  kasan_report+0xf0/0x120
  ? ccw_putcs+0x8bd/0xa80
  ccw_putcs+0x8bd/0xa80
  ? __pfx_ccw_putcs+0x10/0x10
  fbcon_putcs+0x338/0x410
  ? __pfx_ccw_putcs+0x10/0x10
  do_update_region+0x21d/0x450
  invert_screen+0x29d/0x5e0
  ? __kmalloc_noprof+0x493/0x640
  ? vc_do_resize+0x17c/0xe50
  clear_selection+0x4c/0x60
  vc_do_resize+0xaee/0xe50
  fbcon_modechanged+0x2bd/0x640
  rotate_all_store+0x298/0x380
  ...

reproduce:
1) issue two ioctls: first a KDFONTOP ioctl with op.op = KD_FONT_OP_SET,
op.width = 1 and op.height = 1, then a TIOCL_SETSEL ioctl
2) echo 2 > /sys/devices/virtual/graphics/fbcon/rotate_all
3) issue two ioctls: first a KDFONTOP ioctl with op.op = KD_FONT_OP_SET,
op.width = 8 and op.height = 1, then a TIOCL_SETSEL ioctl
4) echo 3 > /sys/devices/virtual/graphics/fbcon/rotate_all

[CAUSE]
The root cause is that fbcon_modechanged() first sets the current rotate's
corresponding ops. Subsequently, during vc_resize(), it may trigger
clear_selection(), and in fbcon_putcs->ccw_putcs[rotate=3], this can result
in an out-of-bounds access to "src". This happens because par->rotated.buf
is reallocated in fbcon_rotate_font():
1) When rotate=2, its size is (width + 7) / 8 * height
2) When rotate=3, its size is (height + 7) / 8 * width

And the call to fbcon_rotate_font() occurs after clear_selection(). In
other words, the fontbuffer is allocated using the size calculated from the
previous rotation 2, but before reallocating it with the new size,
con_putcs is already using the new rotation 3:

rotate_all_store
 fbcon_rotate_all
  fbcon_set_all_vcs
   fbcon_modechanged
    set_blitting_type
    ...
     par->bitops = &ccw_fbcon_bitops
    vc_resize
    ...
     clear_selection
      highlight
      ...
       do_update_region
	fbcon_putcs
	...
	 image.dy = vyres - ((xx + count) * vc->vc_font.width) [1]  // overflow!
	 ccw_putcs_aligned
	  // old buf size is still being used during the read!
	  src = par->rotated.buf + (scr_readw(s--) & charmask) * cellsize
	  fb_pad_aligned_buffer----[src KASAN!!!]	[2]
	  info->fbops->fb_imageblit(info, image)
	   sys_imageblit
	    fb_imageblit
	     fb_address_forward
	      // offset: image->dy * bits_per_line + image->dx * bpp
	      unsigned int bits = (unsigned int)adr->bits + offset
	      adr->address += (bits & ~(BITS_PER_LONG - 1u)) / BITS_PER_BYTE	[3]
	     fb_bitmap_imageblit
	     ...
	      fb_read_offset	// page fault!	[4]
    update_screen
     redraw_screen
     ...
      ccw_cursor
       soft_cursor
        memcpy(src, image->data, dsize)----[src KASAN again!!!]	[5]
     fbcon_switch
      fbcon_rotate_font
       font_data_rotate
	dst = kmalloc_array(charcount, d_cellsize, GFP_KERNEL)
       // the new size is allocated only here!
       par->rotated.buf = buf	[6]

[FIX]
A fairly obvious approach is to follow fbcon_switch(): in
fbcon_modechanged(), call rotate_font() before vc_resize() so that a
correctly sized buffer is allocated in time, as done in [6]. This fix is
necessary, but it is not sufficient on its own.

In [1] it causes an image.dy overflow (ccw_putcs: vyres = 768,
image.dy = 4294967040), because vc_cols has not been updated in time at
this point (it is likewise only updated after clear_selection()). This
allows (xx + count) * width to exceed vyres, causing image.dy to overflow.
Subsequently, address in [3] is incremented by an even larger amount, which
triggers a page fault at [4].

Therefore, a second fix is required in combination with the first: move
clear_selection() earlier, before set_blitting_type() in
fbcon_set_all_vcs(), to prevent the out-of-bounds access. fbcon_rotate()
has a similar problem, so add the same clear there. Since vc_is_sel() is
not exported, the fbdev side is currently forced to call clear_selection()
unconditionally, causing the global selection to be cleared prematurely.
And this will not cause any other significant impact.

Signed-off-by: Zizhi Wo <wozizhi@huawei.com>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-08-08 08:08:58 +02:00