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Darrick J. Wong 43f3b18679 xfs: fix freemap adjustments when adding xattrs to leaf blocks 
[ Upstream commit 3eefc0c2b7 ]

xfs/592 and xfs/794 both trip this assertion in the leaf block freemap
adjustment code after ~20 minutes of running on my test VMs:

 ASSERT(ichdr->firstused >= ichdr->count * sizeof(xfs_attr_leaf_entry_t)
					+ xfs_attr3_leaf_hdr_size(leaf));

Upon enabling quite a lot more debugging code, I narrowed this down to
fsstress trying to set a local extended attribute with namelen=3 and
valuelen=71.  This results in an entry size of 80 bytes.

At the start of xfs_attr3_leaf_add_work, the freemap looks like this:

i 0 base 448 size 0 rhs 448 count 46
i 1 base 388 size 132 rhs 448 count 46
i 2 base 2120 size 4 rhs 448 count 46
firstused = 520

where "rhs" is the first byte past the end of the leaf entry array.
This is inconsistent -- the entries array ends at byte 448, but
freemap[1] says there's free space starting at byte 388!

By the end of the function, the freemap is in worse shape:

i 0 base 456 size 0 rhs 456 count 47
i 1 base 388 size 52 rhs 456 count 47
i 2 base 2120 size 4 rhs 456 count 47
firstused = 440

Important note: 388 is not aligned with the entries array element size
of 8 bytes.

Based on the incorrect freemap, the name area starts at byte 440, which
is below the end of the entries array!  That's why the assertion
triggers and the filesystem shuts down.

How did we end up here?  First, recall from the previous patch that the
freemap array in an xattr leaf block is not intended to be a
comprehensive map of all free space in the leaf block.  In other words,
it's perfectly legal to have a leaf block with:

 * 376 bytes in use by the entries array
 * freemap[0] has [base = 376, size = 8]
 * freemap[1] has [base = 388, size = 1500]
 * the space between 376 and 388 is free, but the freemap stopped
   tracking that some time ago

If we add one xattr, the entries array grows to 384 bytes, and
freemap[0] becomes [base = 384, size = 0].  So far, so good.  But if we
add a second xattr, the entries array grows to 392 bytes, and freemap[0]
gets pushed up to [base = 392, size = 0].  This is bad, because
freemap[1] hasn't been updated, and now the entries array and the free
space claim the same space.

The fix here is to adjust all freemap entries so that none of them
collide with the entries array.  Note that this fix relies on commit
2a2b5932db ("xfs: fix attr leaf header freemap.size underflow") and
the previous patch that resets zero length freemap entries to have
base = 0.

Cc: <stable@vger.kernel.org> # v2.6.12
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2026-03-04 07:21:15 -05:00
arch arm64: dts: rockchip: Explicitly request UFS reset pin on RK3576 2026-03-04 07:21:13 -05:00
block block: decouple secure erase size limit from discard size limit 2026-03-04 07:19:38 -05:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: authencesn - reject too-short AAD (assoclen<8) to match ESP/ESN spec 2026-01-30 10:32:12 +01:00
Documentation ipv6: Move ipv6_fl_list from ipv6_pinfo to inet_sock. 2026-03-04 07:20:44 -05:00
drivers usb: host: tegra: Remove manual wake IRQ disposal 2026-03-04 07:21:14 -05:00
fs xfs: fix freemap adjustments when adding xattrs to leaf blocks 2026-03-04 07:21:15 -05:00
include mfd: tps65219: Implement LOCK register handling for TPS65214 2026-03-04 07:21:12 -05:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/timeout: annotate data race in io_flush_timeouts() 2026-03-04 07:19:36 -05:00
ipc ipc: don't audit capability check in ipc_permissions() 2026-02-26 14:59:19 -08:00
kernel Remove WARN_ALL_UNSEEDED_RANDOM kernel config option 2026-03-04 07:20:46 -05:00
lib Remove WARN_ALL_UNSEEDED_RANDOM kernel config option 2026-03-04 07:20:46 -05:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm, page_alloc, thp: prevent reclaim for __GFP_THISNODE THP allocations 2026-03-04 07:21:10 -05:00
net netfilter: nf_conntrack_h323: fix OOB read in decode_choice() 2026-03-04 07:20:52 -05:00
rust rust: cpufreq: always inline functions using build_assert with arguments 2026-03-04 07:19:37 -05:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2026-01-08 10:17:11 +01:00
scripts docs: kdoc: avoid error_count overflows 2026-03-04 07:21:10 -05:00
security apparmor: fix aa_label to return state from compount and component match 2026-02-26 14:59:42 -08:00
sound ASoC: SOF: ipc4-control: Keep the payload size up to date 2026-03-04 07:20:54 -05:00
tools selftests/mm/charge_reserved_hugetlb: drop mount size for hugetlbfs 2026-03-04 07:21:10 -05:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: Don't clobber irqfd routing type when deassigning irqfd 2026-02-11 13:41:44 +01:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap 8 hotfixes. 4 are cc:stable, 7 are against mm/. 2025-11-26 12:38:05 -08:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS soc: fixes for 6.18, part 4 2025-11-28 09:57:31 -08:00
Makefile Linux 6.18.15 2026-02-27 16:05:10 -05:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.