On 04/04/2013 10:55 PM, Tejun Heo wrote: >>From 5c529597e922c26910fe49b8d5f93aeaca9a2415 Mon Sep 17 00:00:00 2001 > From: Lai Jiangshan <la...@cn.fujitsu.com> > Date: Thu, 4 Apr 2013 10:05:38 +0800 > > destroy_workqueue() performs several sanity checks before proceeding > with destruction of a workqueue. One of the checks verifies that > refcnt of each pwq (pool_workqueue) is over 1 as at that point there > should be no in-flight work items and the only holder of pwq refs is > the workqueue itself. > > This worked fine as a workqueue used to hold only one reference to its > pwqs; however, since 4c16bd327c ("workqueue: implement NUMA affinity > for unbound workqueues"), a workqueue may hold multiple references to > its default pwq triggering this sanity check spuriously. > > Fix it by not triggering the pwq->refcnt assertion on default pwqs. > > An example spurious WARN trigger follows. > > WARNING: at kernel/workqueue.c:4201 destroy_workqueue+0x6a/0x13e() > Hardware name: 4286C12 > Modules linked in: sdhci_pci sdhci mmc_core usb_storage i915 drm_kms_helper > drm i2c_algo_bit i2c_core video > Pid: 361, comm: umount Not tainted 3.9.0-rc5+ #29 > Call Trace: > [<c04314a7>] warn_slowpath_common+0x7c/0x93 > [<c04314e0>] warn_slowpath_null+0x22/0x24 > [<c044796a>] destroy_workqueue+0x6a/0x13e > [<c056dc01>] ext4_put_super+0x43/0x2c4 > [<c04fb7b8>] generic_shutdown_super+0x4b/0xb9 > [<c04fb848>] kill_block_super+0x22/0x60 > [<c04fb960>] deactivate_locked_super+0x2f/0x56 > [<c04fc41b>] deactivate_super+0x2e/0x31 > [<c050f1e6>] mntput_no_expire+0x103/0x108 > [<c050fdce>] sys_umount+0x2a2/0x2c4 > [<c050fe0e>] sys_oldumount+0x1e/0x20 > [<c085ba4d>] sysenter_do_call+0x12/0x38 > > tj: Rewrote description. > > Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com> > Signed-off-by: Tejun Heo <t...@kernel.org> > Reported-by: Fengguang Wu <fengguang...@intel.com>
Hi, Wu Could you also send regression-report of workqueue to me? Thanks, Lai > --- > Applied to wq/for-3.10. > > Thanks. > > kernel/workqueue.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index dd2a4c4..c273376 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -4201,7 +4201,7 @@ void destroy_workqueue(struct workqueue_struct *wq) > } > } > > - if (WARN_ON(pwq->refcnt > 1) || > + if (WARN_ON((pwq != wq->dfl_pwq) && (pwq->refcnt > 1)) || > WARN_ON(pwq->nr_active) || > WARN_ON(!list_empty(&pwq->delayed_works))) { > mutex_unlock(&wq->mutex); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/