diff options
| author | Amir Goldstein <amir73il@gmail.com> | 2022-04-22 15:03:26 +0300 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2022-04-25 14:43:07 +0200 |
| commit | e79719a2ca5c61912c0493bc1367db52759cf6fd (patch) | |
| tree | cd6dcbe7721275017a061ba736b212a6dedd82e7 /fs/notify | |
| parent | 7d5e005d982527e4029b0139823d179986e34cdc (diff) | |
fanotify: use fsnotify group lock helpers
Direct reclaim from fanotify mark allocation context may try to evict
inodes with evictable marks of the same group and hit this deadlock:
[<0>] fsnotify_destroy_mark+0x1f/0x3a
[<0>] fsnotify_destroy_marks+0x71/0xd9
[<0>] __destroy_inode+0x24/0x7e
[<0>] destroy_inode+0x2c/0x67
[<0>] dispose_list+0x49/0x68
[<0>] prune_icache_sb+0x5b/0x79
[<0>] super_cache_scan+0x11c/0x16f
[<0>] shrink_slab.constprop.0+0x23e/0x40f
[<0>] shrink_node+0x218/0x3e7
[<0>] do_try_to_free_pages+0x12a/0x2d2
[<0>] try_to_free_pages+0x166/0x242
[<0>] __alloc_pages_slowpath.constprop.0+0x30c/0x903
[<0>] __alloc_pages+0xeb/0x1c7
[<0>] cache_grow_begin+0x6f/0x31e
[<0>] fallback_alloc+0xe0/0x12d
[<0>] ____cache_alloc_node+0x15a/0x17e
[<0>] kmem_cache_alloc_trace+0xa1/0x143
[<0>] fanotify_add_mark+0xd5/0x2b2
[<0>] do_fanotify_mark+0x566/0x5eb
[<0>] __x64_sys_fanotify_mark+0x21/0x24
[<0>] do_syscall_64+0x6d/0x80
[<0>] entry_SYSCALL_64_after_hwframe+0x44/0xae
Set the FSNOTIFY_GROUP_NOFS flag to prevent going into direct reclaim
from allocations under fanotify group lock and use the safe group lock
helpers.
Link: https://lore.kernel.org/r/20220422120327.3459282-16-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220321112310.vpr7oxro2xkz5llh@quack3.lan/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify')
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index ae36138afead..228cf25e9230 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1035,10 +1035,10 @@ static int fanotify_remove_mark(struct fsnotify_group *group, __u32 removed; int destroy_mark; - mutex_lock(&group->mark_mutex); + fsnotify_group_lock(group); fsn_mark = fsnotify_find_mark(connp, group); if (!fsn_mark) { - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); return -ENOENT; } @@ -1048,7 +1048,7 @@ static int fanotify_remove_mark(struct fsnotify_group *group, fsnotify_recalc_mask(fsn_mark->connector); if (destroy_mark) fsnotify_detach_mark(fsn_mark); - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); if (destroy_mark) fsnotify_free_mark(fsn_mark); @@ -1196,13 +1196,13 @@ static int fanotify_add_mark(struct fsnotify_group *group, bool recalc; int ret = 0; - mutex_lock(&group->mark_mutex); + fsnotify_group_lock(group); fsn_mark = fsnotify_find_mark(connp, group); if (!fsn_mark) { fsn_mark = fanotify_add_new_mark(group, connp, obj_type, fan_flags, fsid); if (IS_ERR(fsn_mark)) { - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); return PTR_ERR(fsn_mark); } } @@ -1231,7 +1231,7 @@ static int fanotify_add_mark(struct fsnotify_group *group, fsnotify_recalc_mask(fsn_mark->connector); out: - mutex_unlock(&group->mark_mutex); + fsnotify_group_unlock(group); fsnotify_put_mark(fsn_mark); return ret; @@ -1385,7 +1385,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) /* fsnotify_alloc_group takes a ref. Dropped in fanotify_release */ group = fsnotify_alloc_group(&fanotify_fsnotify_ops, - FSNOTIFY_GROUP_USER); + FSNOTIFY_GROUP_USER | FSNOTIFY_GROUP_NOFS); if (IS_ERR(group)) { return PTR_ERR(group); } |