From 9d8117e72bf453dd9d85e0cd322ce4a0f8bccbc0 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 30 Sep 2010 15:15:38 -0700 Subject: [PATCH] reiserfs: fix unwanted reiserfs lock recursion Prevent from recursively locking the reiserfs lock in reiserfs_unpack() because we may call journal_begin() that requires the lock to be taken only once, otherwise it won't be able to release the lock while taking other mutexes, ending up in inverted dependencies between the journal mutex and the reiserfs lock for example. This fixes: ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.35.4.4a #3 ------------------------------------------------------- lilo/1620 is trying to acquire lock: (&journal->j_mutex){+.+...}, at: [] do_journal_begin_r+0x7f/0x340 [reiserfs] but task is already holding lock: (&REISERFS_SB(s)->lock){+.+.+.}, at: [] reiserfs_write_lock+0x28/0x40 [reiserfs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&REISERFS_SB(s)->lock){+.+.+.}: [] lock_acquire+0x67/0x80 [] __mutex_lock_common+0x4d/0x410 [] mutex_lock_nested+0x18/0x20 [] reiserfs_write_lock+0x28/0x40 [reiserfs] [] do_journal_begin_r+0x86/0x340 [reiserfs] [] journal_begin+0x77/0x140 [reiserfs] [] reiserfs_remount+0x224/0x530 [reiserfs] [] do_remount_sb+0x60/0x110 [] do_mount+0x625/0x790 [] sys_mount+0x84/0xb0 [] syscall_call+0x7/0xb -> #0 (&journal->j_mutex){+.+...}: [] __lock_acquire+0x1026/0x1180 [] lock_acquire+0x67/0x80 [] __mutex_lock_common+0x4d/0x410 [] mutex_lock_nested+0x18/0x20 [] do_journal_begin_r+0x7f/0x340 [reiserfs] [] journal_begin+0x77/0x140 [reiserfs] [] reiserfs_persistent_transaction+0x41/0x90 [reiserfs] [] reiserfs_get_block+0x22c/0x1530 [reiserfs] [] __block_prepare_write+0x1bb/0x3a0 [] block_prepare_write+0x26/0x40 [] reiserfs_prepare_write+0x88/0x170 [reiserfs] [] reiserfs_unpack+0xe6/0x120 [reiserfs] [] reiserfs_ioctl+0x272/0x320 [reiserfs] [] vfs_ioctl+0x28/0xa0 [] do_vfs_ioctl+0x32d/0x5c0 [] sys_ioctl+0x63/0x70 [] syscall_call+0x7/0xb other info that might help us debug this: 2 locks held by lilo/1620: #0: (&sb->s_type->i_mutex_key#8){+.+.+.}, at: [] reiserfs_unpack+0x6a/0x120 [reiserfs] #1: (&REISERFS_SB(s)->lock){+.+.+.}, at: [] reiserfs_write_lock+0x28/0x40 [reiserfs] stack backtrace: Pid: 1620, comm: lilo Not tainted 2.6.35.4.4a #3 Call Trace: [] __lock_acquire+0x1026/0x1180 [] lock_acquire+0x67/0x80 [] __mutex_lock_common+0x4d/0x410 [] mutex_lock_nested+0x18/0x20 [] do_journal_begin_r+0x7f/0x340 [reiserfs] [] journal_begin+0x77/0x140 [reiserfs] [] reiserfs_persistent_transaction+0x41/0x90 [reiserfs] [] reiserfs_get_block+0x22c/0x1530 [reiserfs] [] __block_prepare_write+0x1bb/0x3a0 [] block_prepare_write+0x26/0x40 [] reiserfs_prepare_write+0x88/0x170 [reiserfs] [] reiserfs_unpack+0xe6/0x120 [reiserfs] [] reiserfs_ioctl+0x272/0x320 [reiserfs] [] vfs_ioctl+0x28/0xa0 [] do_vfs_ioctl+0x32d/0x5c0 [] sys_ioctl+0x63/0x70 [] syscall_call+0x7/0xb Reported-by: Jarek Poplawski Tested-by: Jarek Poplawski Signed-off-by: Frederic Weisbecker Cc: Jeff Mahoney Cc: All since 2.6.32 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/reiserfs/ioctl.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/reiserfs/ioctl.c b/fs/reiserfs/ioctl.c index 679d5029f50f..5cbb81e134ac 100644 --- a/fs/reiserfs/ioctl.c +++ b/fs/reiserfs/ioctl.c @@ -170,6 +170,7 @@ int reiserfs_prepare_write(struct file *f, struct page *page, int reiserfs_unpack(struct inode *inode, struct file *filp) { int retval = 0; + int depth; int index; struct page *page; struct address_space *mapping; @@ -189,7 +190,7 @@ int reiserfs_unpack(struct inode *inode, struct file *filp) ** us */ reiserfs_mutex_lock_safe(&inode->i_mutex, inode->i_sb); - reiserfs_write_lock(inode->i_sb); + depth = reiserfs_write_lock_once(inode->i_sb); write_from = inode->i_size & (blocksize - 1); /* if we are on a block boundary, we are already unpacked. */ @@ -224,6 +225,6 @@ int reiserfs_unpack(struct inode *inode, struct file *filp) out: mutex_unlock(&inode->i_mutex); - reiserfs_write_unlock(inode->i_sb); + reiserfs_write_unlock_once(inode->i_sb, depth); return retval; }