From 2ef435a872abc347dc0a92f1c213bb0af3cbf195 Mon Sep 17 00:00:00 2001 From: Max Kellermann Date: Wed, 17 Sep 2025 17:36:31 +0200 Subject: [PATCH] fs: add might_sleep() annotation to iput() and more When iput() drops the reference counter to zero, it may sleep via inode_wait_for_writeback(). This happens rarely because it's usually the dcache which evicts inodes, but really iput() should only ever be called in contexts where sleeping is allowed. This annotation allows finding buggy callers. Additionally, this patch annotates a few low-level functions that can call iput() conditionally. Cc: Mateusz Guzik Signed-off-by: Max Kellermann Link: https://lore.kernel.org/20250917153632.2228828-1-max.kellermann@ionos.com Reviewed-by: Jan Kara Signed-off-by: Christian Brauner --- fs/inode.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/fs/inode.c b/fs/inode.c index bf75037602066..1a9d4fa5e0cb1 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1279,6 +1279,8 @@ struct inode *inode_insert5(struct inode *inode, unsigned long hashval, struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval); struct inode *old; + might_sleep(); + again: spin_lock(&inode_hash_lock); old = find_inode(inode->i_sb, head, test, data, true); @@ -1382,6 +1384,8 @@ struct inode *iget5_locked_rcu(struct super_block *sb, unsigned long hashval, struct hlist_head *head = inode_hashtable + hash(sb, hashval); struct inode *inode, *new; + might_sleep(); + again: inode = find_inode(sb, head, test, data, false); if (inode) { @@ -1422,6 +1426,9 @@ struct inode *iget_locked(struct super_block *sb, unsigned long ino) { struct hlist_head *head = inode_hashtable + hash(sb, ino); struct inode *inode; + + might_sleep(); + again: inode = find_inode_fast(sb, head, ino, false); if (inode) { @@ -1605,6 +1612,9 @@ struct inode *ilookup5(struct super_block *sb, unsigned long hashval, int (*test)(struct inode *, void *), void *data) { struct inode *inode; + + might_sleep(); + again: inode = ilookup5_nowait(sb, hashval, test, data); if (inode) { @@ -1630,6 +1640,9 @@ struct inode *ilookup(struct super_block *sb, unsigned long ino) { struct hlist_head *head = inode_hashtable + hash(sb, ino); struct inode *inode; + + might_sleep(); + again: inode = find_inode_fast(sb, head, ino, false); @@ -1780,6 +1793,8 @@ int insert_inode_locked(struct inode *inode) ino_t ino = inode->i_ino; struct hlist_head *head = inode_hashtable + hash(sb, ino); + might_sleep(); + while (1) { struct inode *old = NULL; spin_lock(&inode_hash_lock); @@ -1826,6 +1841,8 @@ int insert_inode_locked4(struct inode *inode, unsigned long hashval, { struct inode *old; + might_sleep(); + inode->i_state |= I_CREATING; old = inode_insert5(inode, hashval, test, NULL, data); @@ -1908,6 +1925,7 @@ static void iput_final(struct inode *inode) */ void iput(struct inode *inode) { + might_sleep(); if (unlikely(!inode)) return; -- 2.47.3