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| author | Svyatoslav Feldsherov <feldsherov@google.com> | 2022-11-15 20:20:01 +0000 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2022-11-22 17:00:00 -0500 |
| commit | 4e3c51f4e805291b057d12f5dda5aeb50a538dc4 (patch) | |
| tree | e9f12c22f0aebe3ad2bc4ad620b3fca71a8a64ec /fs/fs-writeback.c | |
| parent | f6b1a1cf1c3ee430d3f5e47847047ce789a690aa (diff) | |
| download | linux-4e3c51f4e805291b057d12f5dda5aeb50a538dc4.tar.gz linux-4e3c51f4e805291b057d12f5dda5aeb50a538dc4.tar.bz2 linux-4e3c51f4e805291b057d12f5dda5aeb50a538dc4.zip | |
fs: do not update freeing inode i_io_list
After commit cbfecb927f42 ("fs: record I_DIRTY_TIME even if inode
already has I_DIRTY_INODE") writeback_single_inode can push inode with
I_DIRTY_TIME set to b_dirty_time list. In case of freeing inode with
I_DIRTY_TIME set this can happen after deletion of inode from i_io_list
at evict. Stack trace is following.
evict
fat_evict_inode
fat_truncate_blocks
fat_flush_inodes
writeback_inode
sync_inode_metadata(inode, sync=0)
writeback_single_inode(inode, wbc) <- wbc->sync_mode == WB_SYNC_NONE
This will lead to use after free in flusher thread.
Similar issue can be triggered if writeback_single_inode in the
stack trace update inode->i_io_list. Add explicit check to avoid it.
Fixes: cbfecb927f42 ("fs: record I_DIRTY_TIME even if inode already has I_DIRTY_INODE")
Reported-by: syzbot+6ba92bd00d5093f7e371@syzkaller.appspotmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Svyatoslav Feldsherov <feldsherov@google.com>
Link: https://lore.kernel.org/r/20221115202001.324188-1-feldsherov@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/fs-writeback.c')
| -rw-r--r-- | fs/fs-writeback.c | 30 |
1 files changed, 19 insertions, 11 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 443f83382b9b..9958d4020771 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1712,18 +1712,26 @@ static int writeback_single_inode(struct inode *inode, wb = inode_to_wb_and_lock_list(inode); spin_lock(&inode->i_lock); /* - * If the inode is now fully clean, then it can be safely removed from - * its writeback list (if any). Otherwise the flusher threads are - * responsible for the writeback lists. + * If the inode is freeing, its i_io_list shoudn't be updated + * as it can be finally deleted at this moment. */ - if (!(inode->i_state & I_DIRTY_ALL)) - inode_cgwb_move_to_attached(inode, wb); - else if (!(inode->i_state & I_SYNC_QUEUED)) { - if ((inode->i_state & I_DIRTY)) - redirty_tail_locked(inode, wb); - else if (inode->i_state & I_DIRTY_TIME) { - inode->dirtied_when = jiffies; - inode_io_list_move_locked(inode, wb, &wb->b_dirty_time); + if (!(inode->i_state & I_FREEING)) { + /* + * If the inode is now fully clean, then it can be safely + * removed from its writeback list (if any). Otherwise the + * flusher threads are responsible for the writeback lists. + */ + if (!(inode->i_state & I_DIRTY_ALL)) + inode_cgwb_move_to_attached(inode, wb); + else if (!(inode->i_state & I_SYNC_QUEUED)) { + if ((inode->i_state & I_DIRTY)) + redirty_tail_locked(inode, wb); + else if (inode->i_state & I_DIRTY_TIME) { + inode->dirtied_when = jiffies; + inode_io_list_move_locked(inode, + wb, + &wb->b_dirty_time); + } } } |