On 08/03, Trond Myklebust wrote: > > On Fri, 2007-08-03 at 09:38 -0700, Andrew Morton wrote: > > > stack backtrace: > > > [<c0104fda>] show_trace_log_lvl+0x1a/0x30 > > > [<c0105c02>] show_trace+0x12/0x20 > > > [<c0105d15>] dump_stack+0x15/0x20 > > > [<c013ee42>] __lock_acquire+0xc22/0x1030 > > > [<c013f2b1>] lock_acquire+0x61/0x80 > > > [<c012edd9>] flush_workqueue+0x49/0x70 > > > [<c012ee0d>] flush_scheduled_work+0xd/0x10 > > > [<dcf55c0c>] nfs_release_automount_timer+0x2c/0x30 [nfs] > > > [<dcf45d8e>] nfs_free_server+0x9e/0xd0 [nfs] > > > [<dcf4e626>] nfs_kill_super+0x16/0x20 [nfs] > > > [<c017b38d>] deactivate_super+0x7d/0xa0 > > > [<c018f94b>] mntput_no_expire+0x4b/0x80 > > > [<c018fd94>] expire_mount_list+0xe4/0x140 > > > [<c0191219>] mark_mounts_for_expiry+0x99/0xb0 > > > [<dcf55d1d>] nfs_expire_automounts+0xd/0x40 [nfs] > > > [<c012e61b>] run_workqueue+0x12b/0x1e0 > > > [<c012f05b>] worker_thread+0x9b/0x100 > > > [<c0131c72>] kthread+0x42/0x70 > > > [<c0104c0f>] kernel_thread_helper+0x7/0x18 > > > ======================= > > > > > > > There is new debugging stuff in -mm: deadlockable usage of workqueue > > primitives will now trigger lockdep warnings. See > > > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.23-rc1/2.6.23-rc1-mm2/broken-out/workqueue-debug-flushing-deadlocks-with-lockdep.patch > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.23-rc1/2.6.23-rc1-mm2/broken-out/workqueue-debug-work-related-deadlocks-with-lockdep.patch > > > > I am suspecting that running flush_scheduled_work() from within > > run_workqueue() > > isn't good. > > I'll have a look at this. I suspect that most if not all of our calls to > run_workqueue()/flush_scheduled_work() can now be replaced by more > targeted calls to cancel_work_sync() and cancel_delayed_work_sync().
Yes, please, if possible. To avoid a possible confusion: it is still OK if work->func() flushes its own workqueue, so strictly speaking this trace is false positive, but it would be very nice if we can get rid of this practice. Oleg. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
