Re: [2.6.20] BUG: workqueue leaked lock

Peter Zijlstra
2007-03-16T08:41:25Z

On Thu, 2007-03-15 at 11:06 -0800, Andrew Morton wrote:
> > On Tue, 13 Mar 2007 17:50:14 +0100 Folkert van Heusden <folkert@vanheusden.com> wrote:
> > ...
> > [ 1756.728209] BUG: workqueue leaked lock or atomic: nfsd4/0x00000000/3577
> > [ 1756.728271] last function: laundromat_main+0x0/0x69 [nfsd]
> > [ 1756.728392] 2 locks held by nfsd4/3577:
> > [ 1756.728435] #0: (client_mutex){--..}, at: [<c1205b88>] mutex_lock+0x8/0xa
> > [ 1756.728679] #1: (&inode->i_mutex){--..}, at: [<c1205b88>] mutex_lock+0x8/0xa
> > [ 1756.728923] [<c1003d57>] show_trace_log_lvl+0x1a/0x30
> > [ 1756.729015] [<c1003d7f>] show_trace+0x12/0x14
> > [ 1756.729103] [<c1003e79>] dump_stack+0x16/0x18
> > [ 1756.729187] [<c102c2e8>] run_workqueue+0x167/0x170
> > [ 1756.729276] [<c102c437>] worker_thread+0x146/0x165
> > [ 1756.729368] [<c102f797>] kthread+0x97/0xc4
> > [ 1756.729456] [<c1003bdb>] kernel_thread_helper+0x7/0x10
> > [ 1756.729547] =======================
> > [ 1792.436492] svc: unknown version (0 for prog 100003, nfsd)
> > [ 1846.683648] BUG: workqueue leaked lock or atomic: nfsd4/0x00000000/3577
> > [ 1846.683701] last function: laundromat_main+0x0/0x69 [nfsd]
> > [ 1846.683832] 2 locks held by nfsd4/3577:
> > [ 1846.683885] #0: (client_mutex){--..}, at: [<c1205b88>] mutex_lock+0x8/0xa
> > [ 1846.683980] #1: (&inode->i_mutex){--..}, at: [<c1205b88>] mutex_lock+0x8/0xa
> > [ 1846.683988] [<c1003d57>] show_trace_log_lvl+0x1a/0x30
> > [ 1846.683994] [<c1003d7f>] show_trace+0x12/0x14
> > [ 1846.683997] [<c1003e79>] dump_stack+0x16/0x18
> > [ 1846.684001] [<c102c2e8>] run_workqueue+0x167/0x170
> > [ 1846.684006] [<c102c437>] worker_thread+0x146/0x165
> > [ 1846.684012] [<c102f797>] kthread+0x97/0xc4
> > [ 1846.684023] [<c1003bdb>] kernel_thread_helper+0x7/0x10
>
> Oleg, that's a fairly incomprehensible message we have in there. Can you
> please explain what it means?

I think I'm responsible for this message (commit
d5abe669172f20a4129a711de0f250a4e07db298); what is says is that the
function executed by the workqueue (here laundromat_main) leaked an
atomic context or is still holding locks (2 locks in this case).