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authorSvyatoslav Feldsherov <feldsherov@google.com>2022-11-15 23:20:01 +0300
committerTheodore Ts'o <tytso@mit.edu>2022-11-23 01:00:00 +0300
commit4e3c51f4e805291b057d12f5dda5aeb50a538dc4 (patch)
treee9f12c22f0aebe3ad2bc4ad620b3fca71a8a64ec
parentf6b1a1cf1c3ee430d3f5e47847047ce789a690aa (diff)
downloadlinux-4e3c51f4e805291b057d12f5dda5aeb50a538dc4.tar.xz
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>
-rw-r--r--fs/fs-writeback.c30
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);
+ }
}
}