From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx115.postini.com [74.125.245.115]) by kanga.kvack.org (Postfix) with SMTP id 9E5176B0092 for ; Fri, 2 Mar 2012 19:09:34 -0500 (EST) Received: by mail-bk0-f41.google.com with SMTP id q16so2705588bkw.14 for ; Fri, 02 Mar 2012 16:09:34 -0800 (PST) Date: Sat, 3 Mar 2012 04:09:32 +0400 From: Anton Vorontsov Subject: [PATCH 3/3] vmevent: Should not grab mutex in the atomic context Message-ID: <20120303000932.GC30207@oksana.dev.rtsoft.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: John Stultz , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org There is not need to grab mutex in the atomic context, moreover this is wrong and causes the following bug: BUG: sleeping function called from invalid context at kernel/mutex.c:271 in_atomic(): 1, irqs_disabled(): 1, pid: 1056, name: m no locks held by m/1056. irq event stamp: 58768 hardirqs last enabled at (58767): [] do_page_fault+0x275/0x450 hardirqs last disabled at (58768): [] apic_timer_interrupt+0x6b/0x80 softirqs last enabled at (58676): [] __do_softirq+0x10f/0x160 softirqs last disabled at (58671): [] call_softirq+0x1c/0x26 Pid: 1056, comm: m Not tainted 3.2.0+ #3 Call Trace: [] ? print_irqtrace_events+0xd0/0xe0 [] __might_sleep+0x12a/0x1e0 [] mutex_lock_nested+0x3c/0x340 [] ? __run_hrtimer+0x4c/0x100 [] ? vmevent_read+0x100/0x100 [] vmevent_sample+0x6e/0xf0 [] vmevent_timer_fn+0x26/0x60 [] __run_hrtimer+0x52/0x100 [] hrtimer_interrupt+0xf3/0x220 [] smp_apic_timer_interrupt+0x64/0xa0 [] apic_timer_interrupt+0x70/0x80 [] ? do_page_fault+0x27a/0x450 [] ? do_page_fault+0x275/0x450 [] ? do_softirq+0x6f/0xc0 [] ? retint_restore_args+0xe/0xe [] ? retint_swapgs+0xe/0x13 [] ? trace_hardirqs_off_thunk+0x3a/0x3c [] page_fault+0x1f/0x30 Signed-off-by: Anton Vorontsov --- The patch is for git://github.com/penberg/linux.git vmevent/core. mm/vmevent.c | 4 ---- 1 files changed, 0 insertions(+), 4 deletions(-) diff --git a/mm/vmevent.c b/mm/vmevent.c index 1375f9d..1dbefb5 100644 --- a/mm/vmevent.c +++ b/mm/vmevent.c @@ -71,8 +71,6 @@ static void vmevent_sample(struct vmevent_watch *watch) if (!vmevent_match(watch, &event)) return; - mutex_lock(&watch->mutex); - watch->pending = true; if (watch->config.event_attrs & VMEVENT_EATTR_NR_AVAIL_PAGES) @@ -85,8 +83,6 @@ static void vmevent_sample(struct vmevent_watch *watch) watch->attr_values[n++] = event.nr_swap_pages; watch->nr_attrs = n; - - mutex_unlock(&watch->mutex); } static enum hrtimer_restart vmevent_timer_fn(struct hrtimer *hrtimer) -- 1.7.7.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org