Messages in this thread | | | Date | Wed, 6 Jun 2012 21:19:15 -0400 | From | Dave Jones <> | Subject | Re: processes hung after sys_renameat, and 'missing' processes |
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On Wed, Jun 06, 2012 at 05:42:35PM -0700, Linus Torvalds wrote:
> So Al meant you to test mutex_is_locked(dentry->d_inode->i_mutex) of > the parents.
ok, I ended up with..
WARN_ON_ONCE(!mutex_is_locked(&target->d_parent->d_inode->i_mutex));
if (dentry->d_parent != NULL) WARN_ON_ONCE(!mutex_is_locked(&dentry->d_inode->i_mutex));
but.. > And I'd suggest making it just a WARN_ON_ONCE(), because if you make > it a BUG_ON() and it triggers, your system will likely be dead. And > ONCE is all that matters - it should never happen.
I hit the second WARN very early on, before I even get out of the initramfs.
[ 6.365556] WARNING: at fs/dcache.c:2350 d_move+0xaf/0xc0() [ 6.365793] Modules linked in: [ 6.365909] Pid: 134, comm: mount Not tainted 3.5.0-rc1+ #69 [ 6.366030] Call Trace: [ 6.366147] [<ffffffff8104910f>] warn_slowpath_common+0x7f/0xc0 [ 6.366271] [<ffffffff8104916a>] warn_slowpath_null+0x1a/0x20 [ 6.366396] [<ffffffff811c5c4f>] d_move+0xaf/0xc0 [ 6.366521] [<ffffffff811b9654>] vfs_rename+0x3c4/0x4e0 [ 6.366647] [<ffffffff811bd741>] sys_renameat+0x201/0x230 [ 6.366773] [<ffffffff8132e59c>] ? debug_check_no_obj_freed+0x16c/0x210 [ 6.366902] [<ffffffff81171cfc>] ? vm_munmap+0x5c/0x80 [ 6.367026] [<ffffffff81086f91>] ? get_parent_ip+0x11/0x50 [ 6.367148] [<ffffffff81086f91>] ? get_parent_ip+0x11/0x50 [ 6.367273] [<ffffffff81651919>] ? sub_preempt_count+0x79/0xd0 [ 6.367397] [<ffffffff81655937>] ? sysret_check+0x1b/0x56 [ 6.367521] [<ffffffff810b7dd5>] ? trace_hardirqs_on_caller+0x115/0x1a0 [ 6.367647] [<ffffffff81326f4e>] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 6.367772] [<ffffffff811bd78b>] sys_rename+0x1b/0x20 [ 6.367891] [<ffffffff81655912>] system_call_fastpath+0x16/0x1b
Did I screw up the test again ? I'm feeling a bit hard-of-thinking tonight.
> > To be clear, do you want me to try that with or without the reverts ? > > I think either would be interesting.
For now, I still have those two commits applied.
Dave
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