diff options
| author | Ryusuke Konishi <konishi.ryusuke@gmail.com> | 2024-11-07 01:07:32 +0900 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-11-11 17:20:23 -0800 |
| commit | cd45e963e44b0f10d90b9e6c0e8b4f47f3c92471 (patch) | |
| tree | 12c7c11fd3e772af724148e34b2f561df7c7377e /fs/nilfs2 | |
| parent | 66edc3a5894c74f8887c8af23b97593a0dd0df4d (diff) | |
nilfs2: fix null-ptr-deref in block_touch_buffer tracepoint
Patch series "nilfs2: fix null-ptr-deref bugs on block tracepoints".
This series fixes null pointer dereference bugs that occur when using
nilfs2 and two block-related tracepoints.
This patch (of 2):
It has been reported that when using "block:block_touch_buffer"
tracepoint, touch_buffer() called from __nilfs_get_folio_block() causes a
NULL pointer dereference, or a general protection fault when KASAN is
enabled.
This happens because since the tracepoint was added in touch_buffer(), it
references the dev_t member bh->b_bdev->bd_dev regardless of whether the
buffer head has a pointer to a block_device structure. In the current
implementation, the block_device structure is set after the function
returns to the caller.
Here, touch_buffer() is used to mark the folio/page that owns the buffer
head as accessed, but the common search helper for folio/page used by the
caller function was optimized to mark the folio/page as accessed when it
was reimplemented a long time ago, eliminating the need to call
touch_buffer() here in the first place.
So this solves the issue by eliminating the touch_buffer() call itself.
Link: https://lkml.kernel.org/r/20241106160811.3316-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20241106160811.3316-2-konishi.ryusuke@gmail.com
Fixes: 5305cb830834 ("block: add block_{touch|dirty}_buffer tracepoint")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: Ubisectech Sirius <bugreport@valiantsec.com>
Closes: https://lkml.kernel.org/r/86bd3013-887e-4e38-960f-ca45c657f032.bugreport@valiantsec.com
Reported-by: syzbot+9982fb8d18eba905abe2@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=9982fb8d18eba905abe2
Tested-by: syzbot+9982fb8d18eba905abe2@syzkaller.appspotmail.com
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/nilfs2')
| -rw-r--r-- | fs/nilfs2/page.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/fs/nilfs2/page.c b/fs/nilfs2/page.c index 10def4b55995..296dbf9cca22 100644 --- a/fs/nilfs2/page.c +++ b/fs/nilfs2/page.c @@ -39,7 +39,6 @@ static struct buffer_head *__nilfs_get_folio_block(struct folio *folio, first_block = (unsigned long)index << (PAGE_SHIFT - blkbits); bh = get_nth_bh(bh, block - first_block); - touch_buffer(bh); wait_on_buffer(bh); return bh; } |