From 89996df4b5b1a09c279f50b3fd03aa9df735f5cb Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Wed, 6 May 2009 16:32:54 -0400 Subject: [PATCH] lockd: fix list corruption on lockd restart If lockd is signalled soon enough after restart then locks_start_grace() will try to re-add an entry to a list and trigger a lock corruption warning. Thanks to Wang Chen for the problem report and diagnosis. WARNING: at lib/list_debug.c:26 __list_add+0x27/0x5c() ... list_add corruption. next->prev should be prev (ef8fe958), but was ef8ff128. (next=ef8ff128). ... Pid: 23062, comm: lockd Tainted: G W 2.6.30-rc2 #3 Call Trace: [] warn_slowpath+0x71/0xa0 [] ? update_curr+0x11d/0x125 [] ? trace_hardirqs_on_caller+0x18/0x150 [] ? trace_hardirqs_on+0xb/0xd [] ? _raw_spin_lock+0x53/0xfa [] __list_add+0x27/0x5c [] locks_start_grace+0x22/0x30 [lockd] [] set_grace_period+0x39/0x53 [lockd] [] ? lock_kernel+0x1c/0x28 [] lockd+0x64/0x164 [lockd] [] ? trace_hardirqs_on_caller+0x18/0x150 [] ? complete+0x34/0x3e [] ? lockd+0x0/0x164 [lockd] [] ? lockd+0x0/0x164 [lockd] [] kthread+0x45/0x6b [] ? kthread+0x0/0x6b [] kernel_thread_helper+0x7/0x10 Reported-by: Wang Chen Signed-off-by: J. Bruce Fields Cc: stable@kernel.org --- fs/lockd/svc.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c index abf8388..1a54ae1 100644 --- a/fs/lockd/svc.c +++ b/fs/lockd/svc.c @@ -104,6 +104,16 @@ static void set_grace_period(void) schedule_delayed_work(&grace_period_end, grace_period); } +static void restart_grace(void) +{ + if (nlmsvc_ops) { + cancel_delayed_work_sync(&grace_period_end); + locks_end_grace(&lockd_manager); + nlmsvc_invalidate_all(); + set_grace_period(); + } +} + /* * This is the lockd kernel thread */ @@ -149,10 +159,7 @@ lockd(void *vrqstp) if (signalled()) { flush_signals(current); - if (nlmsvc_ops) { - nlmsvc_invalidate_all(); - set_grace_period(); - } + restart_grace(); continue; } -- 1.8.2.3