From d3fc373ac5061cab7a654502b942e7d00e77f733 Mon Sep 17 00:00:00 2001 From: Frederik Deweerdt Date: Fri, 5 Jan 2007 12:04:33 -0800 Subject: [PATCH] sysfs: suppress lockdep warnings Lockdep issues the following warning: [ 9.064000] ============================================= [ 9.064000] [ INFO: possible recursive locking detected ] [ 9.064000] 2.6.20-rc3-mm1 #3 [ 9.064000] --------------------------------------------- [ 9.064000] init/1 is trying to acquire lock: [ 9.064000] (&sysfs_inode_imutex_key){--..}, at: [] mutex_lock+0x1c/0x1f [ 9.064000] [ 9.064000] but task is already holding lock: [ 9.064000] (&sysfs_inode_imutex_key){--..}, at: [] mutex_lock+0x1c/0x1f [ 9.065000] [ 9.065000] other info that might help us debug this: [ 9.065000] 2 locks held by init/1: [ 9.065000] #0: (tty_mutex){--..}, at: [] mutex_lock+0x1c/0x1f [ 9.065000] #1: (&sysfs_inode_imutex_key){--..}, at: [] mutex_lock+0x1c/0x1f [ 9.065000] [ 9.065000] stack backtrace: [ 9.065000] [] show_trace_log_lvl+0x1a/0x30 [ 9.066000] [] show_trace+0x12/0x14 [ 9.066000] [] dump_stack+0x16/0x18 [ 9.066000] [] print_deadlock_bug+0xb9/0xc3 [ 9.066000] [] check_deadlock+0x55/0x5a [ 9.066000] [] __lock_acquire+0x371/0xbf0 [ 9.066000] [] lock_acquire+0x69/0x83 [ 9.066000] [] __mutex_lock_slowpath+0x75/0x2d1 [ 9.066000] [] mutex_lock+0x1c/0x1f [ 9.066000] [] sysfs_drop_dentry+0xb1/0x133 [ 9.066000] [] sysfs_hash_and_remove+0xb3/0x142 [ 9.066000] [] sysfs_remove_file+0xd/0x10 [ 9.067000] [] device_remove_file+0x23/0x2e [ 9.067000] [] device_del+0x188/0x1e6 [ 9.067000] [] device_unregister+0xb/0x15 [ 9.067000] [] device_destroy+0x9c/0xa9 [ 9.067000] [] vcs_remove_sysfs+0x1c/0x3b [ 9.067000] [] con_close+0x5e/0x6b [ 9.067000] [] release_dev+0x4c4/0x6e5 [ 9.067000] [] tty_release+0x12/0x1c [ 9.067000] [] __fput+0x177/0x1a0 [ 9.067000] [] fput+0x3b/0x41 [ 9.068000] [] filp_close+0x36/0x65 [ 9.068000] [] sys_close+0x63/0xa4 [ 9.068000] [] sysenter_past_esp+0x5f/0x99 [ 9.068000] ======================= This is due to sysfs_hash_and_remove() holding dir->d_inode->i_mutex before calling sysfs_drop_dentry() which calls orphan_all_buffers() which in turn takes node->i_mutex. Signed-off-by: Frederik Deweerdt Cc: Oliver Neukum Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/sysfs/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index 1a81ebce20..dbd820f9ae 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -215,7 +215,7 @@ static inline void orphan_all_buffers(struct inode *node) struct sysfs_buffer_collection *set = node->i_private; struct sysfs_buffer *buf; - mutex_lock(&node->i_mutex); + mutex_lock_nested(&node->i_mutex, I_MUTEX_CHILD); if (node->i_private) { list_for_each_entry(buf, &set->associates, associates) { down(&buf->sem); @@ -272,7 +272,7 @@ int sysfs_hash_and_remove(struct dentry * dir, const char * name) return -ENOENT; parent_sd = dir->d_fsdata; - mutex_lock(&dir->d_inode->i_mutex); + mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT); list_for_each_entry(sd, &parent_sd->s_children, s_sibling) { if (!sd->s_element) continue; -- 2.39.5