Messages in this thread | | | Subject | Re: Linus GIT - INFO: possible circular locking dependency detected | From | Peter Zijlstra <> | Date | Wed, 09 Nov 2011 20:52:12 +0100 |
| |
On Wed, 2011-11-09 at 19:11 +0000, Luis Henriques wrote: > [ 12.948038] -> #0 (&sig->cred_guard_mutex){+.+.+.}: > [ 12.948038] [<ffffffff8108ff9f>] __lock_acquire+0x17bf/0x2020 > [ 12.948038] [<ffffffff81092e4f>] lock_acquire+0xaf/0x1f0 > [ 12.948038] [<ffffffff8135b2a5>] __mutex_lock_common+0x65/0x4d0 > [ 12.948038] [<ffffffff8135b76b>] mutex_lock_killable_nested+0x1b/0x20 > [ 12.948038] [<ffffffff811b301e>] lock_trace+0x2e/0x80 > [ 12.948038] [<ffffffff811b73ab>] proc_readfd_common+0x5b/0x4b0 > [ 12.948038] [<ffffffff811b7835>] proc_readfd+0x15/0x20 > [ 12.948038] [<ffffffff8115f8f0>] vfs_readdir+0xb0/0xd0 > [ 12.948038] [<ffffffff8115fa09>] sys_getdents+0x89/0x100 > [ 12.948038] [<ffffffff8135e8c2>] system_call_fastpath+0x16/0x1b > > sb->s_type->i_mutex_key is shown as being acquired in the execve path, > which seems to be wrong -- it was acquired in the vfs_readdir (on the 2nd > trace). > > This means that the initial analysis from Vasiliy is incorrect, as he > assumed the execve path. Or Am I interpreting this log incorrectly? > (Probably I am...).
->#0 shows where sig->cred_guard_mutex was taken, as it was the first lock there is no nesting yet and therefore the ->i_mutex_key#6 thing should not be associated with this stacktrace.
->#1 shows where ->i_mutex_key#6 was taken while holding ->cred_guard_mutex (but doesn't explicitly show where that was taken).
Mostly ->#0 information is useless in lockdep reports and can be safely ignored.
| |