[BUG] WARNING in ext4_journalled_invalidate_folio

[BUG] WARNING in ext4_journalled_invalidate_folio

[Farhad Alemi]

Hello,

As part of the kernel research at ASU's SEFCOM
lab, we hit the crash below. Crash reports can be found here:

  https://github.com/farhad-alemi/public_bug_reports/tree/main/172-warning-in-ext4-journalled-invalidate-folio/

  __ext4_journalled_invalidate_folio(folio, offset, length) < 0
  WARNING: fs/ext4/inode.c:3432 at
ext4_journalled_invalidate_folio+0x4a/0x50 fs/ext4/inode.c:3432,
CPU#0: syz.3.369/14887
  RIP: 0010:ext4_journalled_invalidate_folio+0x4a/0x50 fs/ext4/inode.c:3432
  Call Trace:
   ext4_journalled_invalidate_folio+0x4a/0x50 fs/ext4/inode.c:3432
   folio_invalidate mm/truncate.c:140 [inline]
   truncate_inode_partial_folio+0x33e/0x8d0 mm/truncate.c:249
   truncate_inode_pages_range+0x5de/0xdf0 mm/truncate.c:416
   ext4_truncate_failed_write fs/ext4/truncate.h:21 [inline]
   ext4_journalled_write_end+0x8f2/0xc70 fs/ext4/inode.c:1608
   generic_perform_write+0x611/0x8d0 mm/filemap.c:4346
   ext4_buffered_write_iter+0xce/0x3a0 fs/ext4/file.c:316
   ext4_file_write_iter+0x298/0x1bf0
   vfs_write+0x6f3/0xda0 fs/read_write.c:688

Our reproducer.c is available upon request.

Happy to test a patch if that would help.

Regards,

Re: [BUG] WARNING in ext4_journalled_invalidate_folio

[Theodore Tso]

On Thu, Aug 27, 2026 at 10:45:30PM -0500, Farhad Alemi wrote:
> Hello,
> 
> As part of the kernel research at ASU's SEFCOM
> lab, we hit the crash below. Crash reports can be found here:
> 
>   https://github.com/farhad-alemi/public_bug_reports/tree/main/172-warning-in-ext4-journalled-invalidate-folio/

Please send the reproducer.  Note that if it requries a maliciously
fuzzed file system, we consider this to be a minor bug (especially if
the maliciously file system would be fixed when the system
administrator runs fsck on the file system first), and not "security"
issue, so feel free to just send it to the list.

Cheers,

					- Ted