This wasn't really needed before; the main place this could race is with
channel recovery, but (through potentially fragile means) shouldn't have
been possible.
However, a number of upcoming patches benefit from having better control
over subdev init, necessitating some improvements here.
- allows subdev/engine oneinit() without init() (host/fifo patches)
- merges engine use locking/tracking into subdev, and extends it to fix
some issues that will arise with future usage patterns (acr patches)
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
- NV_PMC_ENABLE still exists, but we don't touch anything in it yet
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Ampere needs different handling here, most of what we touch has moved.
We probably want to refactor these interfaces in general, but I'm not
yet sure how they should look, this will get the job done for now.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
- new-style handlers can now be used here too
- decent clean-up
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
- reads vectors from HW, rather than being hardcoded
- removes hacks to support routing via old interfaces
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
- switches ampere over now, and removes its hack mc implementation
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Initially for NV_USERMODE class, and Turing/Ampere's new interrupt tree.
v2. fixup for ga103 early merge
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
It's quite a lot of tedious and error-prone work to switch over all the
subdevs at once, so allow an nvkm_intr to request new-style handlers to
be created that wrap the existing interfaces.
This will allow a more gradual transition.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Turing adds a second top-level interrupt tree in HW, in addition to the
trees available via NV_PMC. Most of the interrupts we care about are
exposed in both trees, but not all of them, and we have some rather
nasty hacks to route the fault buffer interrupts.
Ampere removes the NV_PMC trees entirely.
Here we add some infrastructure to be able to handle all of this more
cleanly, as well as providing more explicit control over handlers.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Unifies the handling between PCI-based and Tegra GPUs, and makes more
explicit/obvious where device interrupts can be expected.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
We're going to want this information available earlier than it is now.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
The vblank and nonstall events have some annoying interactions with DRM
locking, and aren't able to do certain things as a result.
However, other uses of event notifications don't have such requirements,
and upcoming patches take advantage of this for various improvements.
Having separate classes for each nvkm_event's spinlocks allows lockdep
to distinguish between them and avoid false-positives.
v2: __always_inline + comment
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
This removes support for accelerated fbcon rendering, and fixes a number
of races/crashes/issues around suspend/resume/module unload etc.
Losing HW accelerated rendering isn't ideal, but it's been significantly
reduced in performance since the removal of accelerated scrolling in the
kernel anyway - not to mention, can be racey (skips cpu<->gpu sync) from
certain contexts.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This removes some now-unnecessary nesting of workqueues.
v2:
- use ?: (lyude)
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Also fixes vblank interrupts being left enabled when they're not meant
to be as a result of races/bugs in previous event handling code.
v2:
- use ?: (lyude)
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
This replaces the twisty, confusing, relationship between nvkm_event and
nvkm_notify with something much simpler, and less racey. It also places
events in the object tree hierarchy, which will allow a heap of the code
tracking events across allocation/teardown/suspend to be removed.
This commit just adds the new interfaces, and passes the owning subdev to
the event constructor to enable debug-tracing in the new code.
v2:
- use ?: (lyude)
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
This moves control of link retraining in response to HPD IRQ to the
KMS driver's HPD IRQ handler.
NVKM still handles checking link status for the moment, this can be
moved to the KMS driver when it takes explicit control of link rate
selection.
v2:
- skip source config on retrain (fixes some retrain failures)
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Will be moving the DP link status check / re-train here so it's safe
from racing with modeset routing changes.
MST message handling etc. will remain where it is.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
There's no good reason for this to be a mutex, and once the layers of
workqueues have been untangled, nouveau_connector_hpd() can be called
from IRQ context and won't be able to take a mutex.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
In case the LCDIFv3 is used to drive a 4k panel via i.MX8MP HDMI bridge,
the LCDIFv3 becomes susceptible to FIFO underflows, these lead to nasty
flicker of the image on the panel, or image being shifted by half frame
horizontally every second frame. The flicker can be easily triggered by
running 3D application on top of weston compositor, like neverball or
chromium. Surprisingly glmark2-es2-wayland or glmark2-es2-drm does not
trigger this effect so easily.
Configure the FIFO Panic threshold register and enable the FIFO Panic
mode, which internally boosts the NoC interconnect priority for LCDIFv3
transactions in case of possible underflow. This mitigates the flicker
effect on 4k panels as well.
Fixes: 9db35bb349 ("drm: lcdif: Add support for i.MX8MP LCDIF variant")
Signed-off-by: Marek Vasut <marex@denx.de>
Tested-by: Liu Ying <victor.liu@nxp.com> # i.MX8mp EVK
Reviewed-by: Liu Ying <victor.liu@nxp.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221101152629.21768-1-marex@denx.de
Add a blank line to make the sentence before the list render as a separate
paragraph, not a definition.
Link: https://lkml.kernel.org/r/20221107142255.4038811-1-glider@google.com
Fixes: 93858ae70c ("kmsan: add ReST documentation")
Signed-off-by: Alexander Potapenko <glider@google.com>
Suggested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A user could write a name of a file under 'damon/' debugfs directory,
which is not a user-created context, to 'rm_contexts' file. In the case,
'dbgfs_rm_context()' just assumes it's the valid DAMON context directory
only if a file of the name exist. As a result, invalid memory access
could happen as below. Fix the bug by checking if the given input is for
a directory. This check can filter out non-context inputs because
directories under 'damon/' debugfs directory can be created via only
'mk_contexts' file.
This bug has found by syzbot[1].
[1] https://lore.kernel.org/damon/000000000000ede3ac05ec4abf8e@google.com/
Link: https://lkml.kernel.org/r/20221107165001.5717-2-sj@kernel.org
Fixes: 75c1c2b53c ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: syzbot+6087eafb76a94c4ac9eb@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org> [5.15.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In RCU mode, the node limits were being updated to the last pivot which
may not be correct and would cause the metadata to be set when it
shouldn't. Fix this by not setting a new limit in this case.
Link: https://lkml.kernel.org/r/20221107163857.867377-1-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It is possible to confuse the depth tracking in the maple state by
searching the same node for values. Fix the depth tracking by moving
where the depth is incremented closer to where the node changes level.
Also change the initial depth setting when using the root node.
Link: https://lkml.kernel.org/r/20221107163814.866612-1-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When psi annotations were added to to btrfs compression reads, the psi
state tracking over add_ra_bio_pages and btrfs_submit_compressed_read was
faulty. A pressure state, once entered, is never left. This results in
incorrectly elevated pressure, which triggers OOM kills.
pflags record the *previous* memstall state when we enter a new one. The
code tried to initialize pflags to 1, and then optimize the leave call
when we either didn't enter a memstall, or were already inside a nested
stall. However, there can be multiple PageWorkingset pages in the bio, at
which point it's that path itself that enters repeatedly and overwrites
pflags. This causes us to miss the exit.
Enter the stall only once if needed, then unwind correctly.
erofs has the same problem, fix that up too. And move the memstall exit
past submit_bio() to restore submit accounting originally added by
b8e24a9300 ("block: annotate refault stalls from IO submission").
Link: https://lkml.kernel.org/r/Y2UHRqthNUwuIQGS@cmpxchg.org
Fixes: 4088a47e78 ("btrfs: add manual PSI accounting for compressed reads")
Fixes: 99486c511f ("erofs: add manual PSI accounting for the compressed address space")
Fixes: 118f3663fb ("block: remove PSI accounting from the bio layer")
Link: https://lore.kernel.org/r/d20a0a85-e415-cf78-27f9-77dd7a94bc8d@leemhuis.info/
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Thorsten Leemhuis <linux@leemhuis.info>
Tested-by: Thorsten Leemhuis <linux@leemhuis.info>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Sterba <dsterba@suse.com>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If a nilfs2 filesystem is downgraded to read-only due to metadata
corruption on disk and is remounted read/write, or if emergency read-only
remount is performed, detaching a log writer and synchronizing the
filesystem can be done at the same time.
In these cases, use-after-free of the log writer (hereinafter
nilfs->ns_writer) can happen as shown in the scenario below:
Task1 Task2
-------------------------------- ------------------------------
nilfs_construct_segment
nilfs_segctor_sync
init_wait
init_waitqueue_entry
add_wait_queue
schedule
nilfs_remount (R/W remount case)
nilfs_attach_log_writer
nilfs_detach_log_writer
nilfs_segctor_destroy
kfree
finish_wait
_raw_spin_lock_irqsave
__raw_spin_lock_irqsave
do_raw_spin_lock
debug_spin_lock_before <-- use-after-free
While Task1 is sleeping, nilfs->ns_writer is freed by Task2. After Task1
waked up, Task1 accesses nilfs->ns_writer which is already freed. This
scenario diagram is based on the Shigeru Yoshida's post [1].
This patch fixes the issue by not detaching nilfs->ns_writer on remount so
that this UAF race doesn't happen. Along with this change, this patch
also inserts a few necessary read-only checks with superblock instance
where only the ns_writer pointer was used to check if the filesystem is
read-only.
Link: https://syzkaller.appspot.com/bug?id=79a4c002e960419ca173d55e863bd09e8112df8b
Link: https://lkml.kernel.org/r/20221103141759.1836312-1-syoshida@redhat.com [1]
Link: https://lkml.kernel.org/r/20221104142959.28296-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+f816fa82f8783f7a02bb@syzkaller.appspotmail.com
Reported-by: Shigeru Yoshida <syoshida@redhat.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is a case in exc_invalid_op handler that is executed outside the
irqentry_enter()/irqentry_exit() region when an UD2 instruction is used to
encode a call to __warn().
In that case the `struct pt_regs` passed to the interrupt handler is never
unpoisoned by KMSAN (this is normally done in irqentry_enter()), which
leads to false positives inside handle_bug().
Use kmsan_unpoison_entry_regs() to explicitly unpoison those registers
before using them.
Link: https://lkml.kernel.org/r/20221102110611.1085175-5-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
As pointed out by Peter Zijlstra, __msan_poison_alloca() does not play
well with IRQ code when PREEMPT_RT is on, because in that mode even
GFP_ATOMIC allocations cannot be performed.
Fixing this would require making stackdepot completely lockless, which is
quite challenging and may be excessive for the time being.
Instead, make sure KMSAN is incompatible with PREEMPT_RT, like other debug
configs are.
Link: https://lkml.kernel.org/r/20221102110611.1085175-4-glider@google.com
Link: https://lore.kernel.org/lkml/20221025221755.3810809-1-glider@google.com/
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
As pointed out by Masahiro Yamada, Kconfig picks up the first default
entry which has true 'if' condition. Hence, the previously added check
for KMSAN was never used, because it followed the checks for 64BIT and
!64BIT.
Put KMSAN check before others to ensure it is always applied.
Link: https://lkml.kernel.org/r/20221102110611.1085175-3-glider@google.com
Link: https://github.com/google/kmsan/issues/89
Link: https://lore.kernel.org/linux-mm/20221024212144.2852069-3-glider@google.com/
Fixes: 921757bc9b ("Kconfig.debug: disable CONFIG_FRAME_WARN for KMSAN by default")
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Make sure usercopy hooks from linux/instrumented.h are invoked for
copy_from_user_nmi(). This fixes KMSAN false positives reported when
dumping opcodes for a stack trace.
Link: https://lkml.kernel.org/r/20221102110611.1085175-2-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marco Elver <elver@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Without that, every call to __msan_poison_alloca() in NMI may end up
allocating memory, which is NMI-unsafe.
Link: https://lkml.kernel.org/r/20221102110611.1085175-1-glider@google.com
Link: https://lore.kernel.org/lkml/20221025221755.3810809-1-glider@google.com/
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The kernel test robot reported build failures with a 'randconfig' on s390:
>> mm/hugetlb_vmemmap.c:421:11: error: a function declaration without a
prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
core_param(hugetlb_free_vmemmap, vmemmap_optimize_enabled, bool, 0);
^
Link: https://lore.kernel.org/linux-mm/202210300751.rG3UDsuc-lkp@intel.com/
Link: https://lkml.kernel.org/r/patch.git-296b83ca939b.your-ad-here.call-01667411912-ext-5073@work.hours
Fixes: 30152245c6 ("mm: hugetlb_vmemmap: replace early_param() with core_param()")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mfill_atomic_install_pte() checks page->mapping to detect whether one page
is used in the page cache. However as pointed out by Matthew, the page
can logically be a tail page rather than always the head in the case of
uffd minor mode with UFFDIO_CONTINUE. It means we could wrongly install
one pte with shmem thp tail page assuming it's an anonymous page.
It's not that clear even for anonymous page, since normally anonymous
pages also have page->mapping being setup with the anon vma. It's safe
here only because the only such caller to mfill_atomic_install_pte() is
always passing in a newly allocated page (mcopy_atomic_pte()), whose
page->mapping is not yet setup. However that's not extremely obvious
either.
For either of above, use page_mapping() instead.
Link: https://lkml.kernel.org/r/Y2K+y7wnhC4vbnP2@x1n
Fixes: 153132571f ("userfaultfd/shmem: support UFFDIO_CONTINUE for shmem")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Matthew Wilcox <willy@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
virtio_pmem use devm_memremap_pages() to map the device memory. By
default this memory is mapped as encrypted with SEV. Guest reboot changes
the current encryption key and guest no longer properly decrypts the FSDAX
device meta data.
Mark the corresponding device memory region for FSDAX devices (mapped with
memremap_pages) as decrypted to retain the persistent memory property.
Link: https://lkml.kernel.org/r/20221102160728.3184016-1-pankaj.gupta@amd.com
Fixes: b7b3c01b19 ("mm/memremap_pages: support multiple ranges per invocation")
Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Anatoly Pugachev reported sparc64 breakage on the patch:
https://lore.kernel.org/r/20221021160603.GA23307@u164.east.ru
The sparc64 impl of pte_mkdirty() is definitely slightly special in that
it leverages a code patching mechanism for sun4u/sun4v on relevant pgtable
entry operations.
Before having a clue of why the sparc64 is special and caused the patch to
SIGSEGV the processes, revert the patch for now. The swap path of dirty
bit inheritage is kept because that's using the swap shared code so we
assume it'll not be affected.
Link: https://lkml.kernel.org/r/Y1Wbi4yyVvDtg4zN@x1n
Fixes: 0ccf7f168e ("mm/thp: carry over dirty bit when thp splits on pmd")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Tested-by: Anatoly Pugachev <matorola@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
A semaphore deadlock can occur if nilfs_get_block() detects metadata
corruption while locating data blocks and a superblock writeback occurs at
the same time:
task 1 task 2
------ ------
* A file operation *
nilfs_truncate()
nilfs_get_block()
down_read(rwsem A) <--
nilfs_bmap_lookup_contig()
... generic_shutdown_super()
nilfs_put_super()
* Prepare to write superblock *
down_write(rwsem B) <--
nilfs_cleanup_super()
* Detect b-tree corruption * nilfs_set_log_cursor()
nilfs_bmap_convert_error() nilfs_count_free_blocks()
__nilfs_error() down_read(rwsem A) <--
nilfs_set_error()
down_write(rwsem B) <--
*** DEADLOCK ***
Here, nilfs_get_block() readlocks rwsem A (= NILFS_MDT(dat_inode)->mi_sem)
and then calls nilfs_bmap_lookup_contig(), but if it fails due to metadata
corruption, __nilfs_error() is called from nilfs_bmap_convert_error()
inside the lock section.
Since __nilfs_error() calls nilfs_set_error() unless the filesystem is
read-only and nilfs_set_error() attempts to writelock rwsem B (=
nilfs->ns_sem) to write back superblock exclusively, hierarchical lock
acquisition occurs in the order rwsem A -> rwsem B.
Now, if another task starts updating the superblock, it may writelock
rwsem B during the lock sequence above, and can deadlock trying to
readlock rwsem A in nilfs_count_free_blocks().
However, there is actually no need to take rwsem A in
nilfs_count_free_blocks() because it, within the lock section, only reads
a single integer data on a shared struct with
nilfs_sufile_get_ncleansegs(). This has been the case after commit
aa474a2201 ("nilfs2: add local variable to cache the number of clean
segments"), that is, even before this bug was introduced.
So, this resolves the deadlock problem by just not taking the semaphore in
nilfs_count_free_blocks().
Link: https://lkml.kernel.org/r/20221029044912.9139-1-konishi.ryusuke@gmail.com
Fixes: e828949e5b ("nilfs2: call nilfs_error inside bmap routines")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+45d6ce7b7ad7ef455d03@syzkaller.appspotmail.com
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org> [2.6.38+
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is a memory leak reported by kmemleak:
unreferenced object 0xffff88817231ce40 (size 224):
comm "mount.cifs", pid 19308, jiffies 4295917571 (age 405.880s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
60 c0 b2 00 81 88 ff ff 98 83 01 42 81 88 ff ff `..........B....
backtrace:
[<ffffffff81936171>] __alloc_file+0x21/0x250
[<ffffffff81937051>] alloc_empty_file+0x41/0xf0
[<ffffffff81937159>] alloc_file+0x59/0x710
[<ffffffff81937964>] alloc_file_pseudo+0x154/0x210
[<ffffffff81741dbf>] __shmem_file_setup+0xff/0x2a0
[<ffffffff817502cd>] shmem_zero_setup+0x8d/0x160
[<ffffffff817cc1d5>] mmap_region+0x1075/0x19d0
[<ffffffff817cd257>] do_mmap+0x727/0x1110
[<ffffffff817518b2>] vm_mmap_pgoff+0x112/0x1e0
[<ffffffff83adf955>] do_syscall_64+0x35/0x80
[<ffffffff83c0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
The root cause was traced to an error handing path in mmap_region() when
arch_validate_flags() or mas_preallocate() fails. In the shared anonymous
mapping sence, vma will be setuped and mapped with a new shared anonymous
file via shmem_zero_setup(). So in this case, the file resource needs to
be released.
Fix it by calling fput(vma->vm_file) and unmap_region() when
arch_validate_flags() or mas_preallocate() returns an error in the shared
anonymous mapping sence.
Link: https://lkml.kernel.org/r/20221028073717.1179380-1-lizetao1@huawei.com
Fixes: d4af56c5c7 ("mm: start tracking VMAs with maple tree")
Fixes: c462ac288f ("mm: Introduce arch_validate_flags()")
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
