From: Jan Kara jack@suse.cz
[ Upstream commit a9438b44bc7015b18931e312bbd249a25bb59a65 ]
In the past we had several use-after-free issues with inodes getting added to writeback lists after evict() removed them. These are painful to debug so add some asserts to catch the problem earlier. The only non-obvious change in the commit is that we need to tweak redirty_tail_locked() to avoid triggering assertion in inode_io_list_move_locked().
Signed-off-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20221212113633.29181-1-jack@suse.cz Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- fs/fs-writeback.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index f4a5a0c2858a..0f747eb7706a 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -121,6 +121,7 @@ static bool inode_io_list_move_locked(struct inode *inode, { assert_spin_locked(&wb->list_lock); assert_spin_locked(&inode->i_lock); + WARN_ON_ONCE(inode->i_state & I_FREEING);
list_move(&inode->i_io_list, head);
@@ -280,6 +281,7 @@ static void inode_cgwb_move_to_attached(struct inode *inode, { assert_spin_locked(&wb->list_lock); assert_spin_locked(&inode->i_lock); + WARN_ON_ONCE(inode->i_state & I_FREEING);
inode->i_state &= ~I_SYNC_QUEUED; if (wb != &wb->bdi->wb) @@ -1164,6 +1166,7 @@ static void inode_cgwb_move_to_attached(struct inode *inode, { assert_spin_locked(&wb->list_lock); assert_spin_locked(&inode->i_lock); + WARN_ON_ONCE(inode->i_state & I_FREEING);
inode->i_state &= ~I_SYNC_QUEUED; list_del_init(&inode->i_io_list); @@ -1329,6 +1332,17 @@ static void redirty_tail_locked(struct inode *inode, struct bdi_writeback *wb) { assert_spin_locked(&inode->i_lock);
+ inode->i_state &= ~I_SYNC_QUEUED; + /* + * When the inode is being freed just don't bother with dirty list + * tracking. Flush worker will ignore this inode anyway and it will + * trigger assertions in inode_io_list_move_locked(). + */ + if (inode->i_state & I_FREEING) { + list_del_init(&inode->i_io_list); + wb_io_lists_depopulated(wb); + return; + } if (!list_empty(&wb->b_dirty)) { struct inode *tail;
@@ -1337,7 +1351,6 @@ static void redirty_tail_locked(struct inode *inode, struct bdi_writeback *wb) inode->dirtied_when = jiffies; } inode_io_list_move_locked(inode, wb, &wb->b_dirty); - inode->i_state &= ~I_SYNC_QUEUED; }
static void redirty_tail(struct inode *inode, struct bdi_writeback *wb)