Commits
Konstantin Khorenko authored 8f2bfcd1dd0
kernfs: keep kernfs node alive for __kernfs_remove() __kernfs_remove() which is called under kernfs_mutex, assumes nobody kills kernfs node whie it's working on it and "get"s current kernfs node for that. But we hit a warning in kernfs_get(): kn->counter == 0 already: ------------[ cut here ]------------ WARNING: CPU: 2 PID: 63923 at fs/kernfs/dir.c:377 kernfs_get+0x2f/0x40 ... Call Trace: [<ffffffffa7f92e67>] dump_stack+0x19/0x1b [<ffffffffa78987b8>] __warn+0xd8/0x100 [<ffffffffa78988fd>] warn_slowpath_null+0x1d/0x20 [<ffffffffa7aecaff>] kernfs_get+0x2f/0x40 [<ffffffffa7aed233>] __kernfs_remove+0x113/0x260 [<ffffffffa7aee201>] kernfs_remove+0x21/0x30 [<ffffffffa7af1010>] sysfs_remove_dir+0x50/0x80 [<ffffffffa7b9fb38>] kobject_del+0x18/0x50 [<ffffffffa7a38a4d>] sysfs_slab_remove+0x3d/0x50 [<ffffffffa79f1e6b>] do_kmem_cache_release+0x3b/0x70 [<ffffffffa79f2aa1>] memcg_destroy_kmem_caches+0xb1/0xf0 [<ffffffffa7a4ed5c>] mem_cgroup_css_free+0x4c/0x280 [<ffffffffa79377fc>] cgroup_free_fn+0x4c/0x120 [<ffffffffa78bc222>] process_one_work+0x182/0x440 [<ffffffffa78bd3d6>] worker_thread+0x126/0x3c0 [<ffffffffa78c4441>] kthread+0xd1/0xe0 This could be for example because of kernfs_notify_workfn() which does kernfs_put(kn) out of kernfs_mutex held section, so move kernfs_put(kn) under the mutex. https://jira.sw.ru/browse/PSBM-93611 Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>