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Filename Latest commit message Latest commit date
Ryusuke Konishi 7d0544bacc nilfs2: do not force clear folio if buffer is referenced
commit ca76bb226bf47ff04c782cacbd299f12ddee1ec1 upstream.

Patch series "nilfs2: protect busy buffer heads from being force-cleared".

This series fixes the buffer head state inconsistency issues reported by
syzbot that occurs when the filesystem is corrupted and falls back to
read-only, and the associated buffer head use-after-free issue.

This patch (of 2):

Syzbot has reported that after nilfs2 detects filesystem corruption and
falls back to read-only, inconsistencies in the buffer state may occur.

One of the inconsistencies is that when nilfs2 calls mark_buffer_dirty()
to set a data or metadata buffer as dirty, but it detects that the buffer
is not in the uptodate state:

 WARNING: CPU: 0 PID: 6049 at fs/buffer.c:1177 mark_buffer_dirty+0x2e5/0x520
  fs/buffer.c:1177
 ...
 Call Trace:
  <TASK>
  nilfs_palloc_commit_alloc_entry+0x4b/0x160 fs/nilfs2/alloc.c:598
  nilfs_ifile_create_inode+0x1dd/0x3a0 fs/nilfs2/ifile.c:73
  nilfs_new_inode+0x254/0x830 fs/nilfs2/inode.c:344
  nilfs_mkdir+0x10d/0x340 fs/nilfs2/namei.c:218
  vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257
  do_mkdirat+0x264/0x3a0 fs/namei.c:4280
  __do_sys_mkdirat fs/namei.c:4295 [inline]
  __se_sys_mkdirat fs/namei.c:4293 [inline]
  __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4293
  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
  entry_SYSCALL_64_after_hwframe+0x77/0x7f

The other is when nilfs_btree_propagate(), which propagates the dirty
state to the ancestor nodes of a b-tree that point to a dirty buffer,
detects that the origin buffer is not dirty, even though it should be:

 WARNING: CPU: 0 PID: 5245 at fs/nilfs2/btree.c:2089
  nilfs_btree_propagate+0xc79/0xdf0 fs/nilfs2/btree.c:2089
 ...
 Call Trace:
  <TASK>
  nilfs_bmap_propagate+0x75/0x120 fs/nilfs2/bmap.c:345
  nilfs_collect_file_data+0x4d/0xd0 fs/nilfs2/segment.c:587
  nilfs_segctor_apply_buffers+0x184/0x340 fs/nilfs2/segment.c:1006
  nilfs_segctor_scan_file+0x28c/0xa50 fs/nilfs2/segment.c:1045
  nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1216 [inline]
  nilfs_segctor_collect fs/nilfs2/segment.c:1540 [inline]
  nilfs_segctor_do_construct+0x1c28/0x6b90 fs/nilfs2/segment.c:2115
  nilfs_segctor_construct+0x181/0x6b0 fs/nilfs2/segment.c:2479
  nilfs_segctor_thread_construct fs/nilfs2/segment.c:2587 [inline]
  nilfs_segctor_thread+0x69e/0xe80 fs/nilfs2/segment.c:2701
  kthread+0x2f0/0x390 kernel/kthread.c:389
  ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
  </TASK>

Both of these issues are caused by the callbacks that handle the
page/folio write requests, forcibly clear various states, including the
working state of the buffers they hold, at unexpected times when they
detect read-only fallback.

Fix these issues by checking if the buffer is referenced before clearing
the page/folio state, and skipping the clear if it is.

[konishi.ryusuke@gmail.com: adjusted for page/folio conversion]
Link: https://lkml.kernel.org/r/20250107200202.6432-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20250107200202.6432-2-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+b2b14916b77acf8626d7@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b2b14916b77acf8626d7
Reported-by: syzbot+d98fd19acd08b36ff422@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=d98fd19acd08b36ff422
Fixes: 8c26c4e269 ("nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption")
Tested-by: syzbot+b2b14916b77acf8626d7@syzkaller.appspotmail.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13 12:43:18 +01:00
arch alpha: replace hardcoded stack offsets with autogenerated ones 2025-03-13 12:43:18 +01:00
block partitions: mac: fix handling of bogus partition table 2025-03-13 12:43:16 +01:00
certs
crypto crypto: pcrypt - Call crypto layer directly when padata_do_parallel() return -EBUSY 2024-12-14 19:44:23 +01:00
Documentation dt-bindings: mmc: controller: clarify the address-cells description 2025-03-13 12:42:53 +01:00
drivers regmap-irq: Add missing kfree() 2025-03-13 12:43:16 +01:00
fs nilfs2: do not force clear folio if buffer is referenced 2025-03-13 12:43:18 +01:00
include net: add dev_net_rcu() helper 2025-03-13 12:43:17 +01:00
init initramfs: avoid filename buffer overrun 2024-12-14 19:44:21 +01:00
ipc
kernel tasklet: Introduce new initialization API 2025-03-13 12:43:04 +01:00
lib lib: string_helpers: silence snprintf() output truncation warning 2024-12-14 19:44:39 +01:00
LICENSES
mm mm: vmscan: account for free pages to prevent infinite Loop in throttle_direct_reclaim() 2025-01-09 13:23:37 +01:00
net ndisc: extend RCU protection in ndisc_send_skb() 2025-03-13 12:43:18 +01:00
samples samples/bpf: Fix a resource leak 2024-12-14 19:44:50 +01:00
scripts kbuild: Move -Wenum-enum-conversion to W=2 2025-03-13 12:43:09 +01:00
security tomoyo: don't emit warning in tomoyo_write_control() 2025-03-13 12:43:03 +01:00
sound ASoC: Intel: bytcr_rt5640: Add DMI quirk for Vexia Edu Atla 10 tablet 5V 2025-03-13 12:43:13 +01:00
tools perf bench: Fix undefined behavior in cmpworker() 2025-03-13 12:43:08 +01:00
usr
virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-11-08 16:20:33 +01:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile kbuild: userprogs: use correct lld when linking through clang 2025-03-13 12:43:04 +01:00
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