Aneesh Kumar K.V 65ed76010d hugetlbfs: lockdep annotate root inode properly ... This fixes the below reported false lockdep warning. e096d0c7e2 ("lockdep: Add helper function for dir vs file i_mutex annotation") added a similar annotation for every other inode in hugetlbfs but missed the root inode because it was allocated by a separate function. For HugeTLB fs we allow taking i_mutex in mmap. HugeTLB fs doesn't support file write and its file read callback is modified in a05b0855fd ("hugetlbfs: avoid taking i_mutex from hugetlbfs_read()") to not take i_mutex. Hence for HugeTLB fs with regular files we really don't take i_mutex with mmap_sem held. ====================================================== [ INFO: possible circular locking dependency detected ] 3.4.0-rc1+ #322 Not tainted ------------------------------------------------------- bash/1572 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [<ffffffff810f1618>] might_fault+0x40/0x90 but task is already holding lock: (&sb->s_type->i_mutex_key#12){+.+.+.}, at: [<ffffffff81125f88>] vfs_readdir+0x56/0xa8 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&sb->s_type->i_mutex_key#12){+.+.+.}: [<ffffffff810a09e5>] lock_acquire+0xd5/0xfa [<ffffffff816a2f5e>] __mutex_lock_common+0x48/0x350 [<ffffffff816a3325>] mutex_lock_nested+0x2a/0x31 [<ffffffff811fb8e1>] hugetlbfs_file_mmap+0x7d/0x104 [<ffffffff810f859a>] mmap_region+0x272/0x47d [<ffffffff810f8a39>] do_mmap_pgoff+0x294/0x2ee [<ffffffff810f8b65>] sys_mmap_pgoff+0xd2/0x10e [<ffffffff8103d19e>] sys_mmap+0x1d/0x1f [<ffffffff816a5922>] system_call_fastpath+0x16/0x1b -> #0 (&mm->mmap_sem){++++++}: [<ffffffff810a0256>] __lock_acquire+0xa81/0xd75 [<ffffffff810a09e5>] lock_acquire+0xd5/0xfa [<ffffffff810f1645>] might_fault+0x6d/0x90 [<ffffffff81125d62>] filldir+0x6a/0xc2 [<ffffffff81133a83>] dcache_readdir+0x5c/0x222 [<ffffffff81125fa8>] vfs_readdir+0x76/0xa8 [<ffffffff811260b6>] sys_getdents+0x79/0xc9 [<ffffffff816a5922>] system_call_fastpath+0x16/0x1b other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sb->s_type->i_mutex_key#12); lock(&mm->mmap_sem); lock(&sb->s_type->i_mutex_key#12); lock(&mm->mmap_sem); *** DEADLOCK *** 1 lock held by bash/1572: #0: (&sb->s_type->i_mutex_key#12){+.+.+.}, at: [<ffffffff81125f88>] vfs_readdir+0x56/0xa8 stack backtrace: Pid: 1572, comm: bash Not tainted 3.4.0-rc1+ #322 Call Trace: [<ffffffff81699a3c>] print_circular_bug+0x1f8/0x209 [<ffffffff810a0256>] __lock_acquire+0xa81/0xd75 [<ffffffff810f38aa>] ? handle_pte_fault+0x5ff/0x614 [<ffffffff8109e622>] ? mark_lock+0x2d/0x258 [<ffffffff810f1618>] ? might_fault+0x40/0x90 [<ffffffff810a09e5>] lock_acquire+0xd5/0xfa [<ffffffff810f1618>] ? might_fault+0x40/0x90 [<ffffffff816a3249>] ? __mutex_lock_common+0x333/0x350 [<ffffffff810f1645>] might_fault+0x6d/0x90 [<ffffffff810f1618>] ? might_fault+0x40/0x90 [<ffffffff81125d62>] filldir+0x6a/0xc2 [<ffffffff81133a83>] dcache_readdir+0x5c/0x222 [<ffffffff81125cf8>] ? sys_ioctl+0x74/0x74 [<ffffffff81125cf8>] ? sys_ioctl+0x74/0x74 [<ffffffff81125cf8>] ? sys_ioctl+0x74/0x74 [<ffffffff81125fa8>] vfs_readdir+0x76/0xa8 [<ffffffff811260b6>] sys_getdents+0x79/0xc9 [<ffffffff816a5922>] system_call_fastpath+0x16/0x1b Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Dave Jones <davej@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2012-04-25 21:26:34 -07:00
..
inode.c	hugetlbfs: lockdep annotate root inode properly	2012-04-25 21:26:34 -07:00
Makefile