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| author | Ryusuke Konishi <konishi.ryusuke@gmail.com> | 2023-08-05 22:20:38 +0900 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-08-21 13:07:21 -0700 |
| commit | f83913f8c5b882a312e72b7669762f8a5c9385e4 (patch) | |
| tree | 6076dbd4064da7d78d992a687b7ca58712c5d483 /fs/nilfs2/segment.c | |
| parent | 5805192c7b7257d290474cb1a3897d0567281bbc (diff) | |
| download | linux-f83913f8c5b882a312e72b7669762f8a5c9385e4.tar.gz linux-f83913f8c5b882a312e72b7669762f8a5c9385e4.tar.bz2 linux-f83913f8c5b882a312e72b7669762f8a5c9385e4.zip | |
nilfs2: fix general protection fault in nilfs_lookup_dirty_data_buffers()
A syzbot stress test reported that create_empty_buffers() called from
nilfs_lookup_dirty_data_buffers() can cause a general protection fault.
Analysis using its reproducer revealed that the back reference "mapping"
from a page/folio has been changed to NULL after dirty page/folio gang
lookup in nilfs_lookup_dirty_data_buffers().
Fix this issue by excluding pages/folios from being collected if, after
acquiring a lock on each page/folio, its back reference "mapping" differs
from the pointer to the address space struct that held the page/folio.
Link: https://lkml.kernel.org/r/20230805132038.6435-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+0ad741797f4565e7e2d2@syzkaller.appspotmail.com
Closes: https://lkml.kernel.org/r/0000000000002930a705fc32b231@google.com
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/nilfs2/segment.c')
| -rw-r--r-- | fs/nilfs2/segment.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c index 581691e4be49..7ec16879756e 100644 --- a/fs/nilfs2/segment.c +++ b/fs/nilfs2/segment.c @@ -725,6 +725,11 @@ static size_t nilfs_lookup_dirty_data_buffers(struct inode *inode, struct folio *folio = fbatch.folios[i]; folio_lock(folio); + if (unlikely(folio->mapping != mapping)) { + /* Exclude folios removed from the address space */ + folio_unlock(folio); + continue; + } head = folio_buffers(folio); if (!head) { create_empty_buffers(&folio->page, i_blocksize(inode), 0); |