Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932631AbbHDIwP (ORCPT ); Tue, 4 Aug 2015 04:52:15 -0400 Received: from terminus.zytor.com ([198.137.202.10]:49944 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932188AbbHDIwM (ORCPT ); Tue, 4 Aug 2015 04:52:12 -0400 Date: Tue, 4 Aug 2015 01:51:27 -0700 From: tip-bot for Peter Zijlstra Message-ID: Cc: acme@kernel.org, tglx@linutronix.de, peterz@infradead.org, vincent.weaver@maine.edu, stable@vger.kernel.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, mingo@kernel.org, hpa@zytor.com Reply-To: tglx@linutronix.de, acme@kernel.org, peterz@infradead.org, torvalds@linux-foundation.org, vincent.weaver@maine.edu, stable@vger.kernel.org, mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org In-Reply-To: <1434011521.1495.71.camel@twins> References: <1434011521.1495.71.camel@twins> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf: Fix fasync handling on inherited events Git-Commit-ID: fed66e2cdd4f127a43fd11b8d92a99bdd429528c X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2745 Lines: 75 Commit-ID: fed66e2cdd4f127a43fd11b8d92a99bdd429528c Gitweb: http://git.kernel.org/tip/fed66e2cdd4f127a43fd11b8d92a99bdd429528c Author: Peter Zijlstra AuthorDate: Thu, 11 Jun 2015 10:32:01 +0200 Committer: Ingo Molnar CommitDate: Tue, 4 Aug 2015 09:57:52 +0200 perf: Fix fasync handling on inherited events Vince reported that the fasync signal stuff doesn't work proper for inherited events. So fix that. Installing fasync allocates memory and sets filp->f_flags |= FASYNC, which upon the demise of the file descriptor ensures the allocation is freed and state is updated. Now for perf, we can have the events stick around for a while after the original FD is dead because of references from child events. So we cannot copy the fasync pointer around. We can however consistently use the parent's fasync, as that will be updated. Reported-and-Tested-by: Vince Weaver Signed-off-by: Peter Zijlstra (Intel) Cc: Cc: Arnaldo Carvalho deMelo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: eranian@google.com Link: http://lkml.kernel.org/r/1434011521.1495.71.camel@twins Signed-off-by: Ingo Molnar --- kernel/events/core.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 10d076b..072b8a6 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4740,12 +4740,20 @@ static const struct file_operations perf_fops = { * to user-space before waking everybody up. */ +static inline struct fasync_struct **perf_event_fasync(struct perf_event *event) +{ + /* only the parent has fasync state */ + if (event->parent) + event = event->parent; + return &event->fasync; +} + void perf_event_wakeup(struct perf_event *event) { ring_buffer_wakeup(event); if (event->pending_kill) { - kill_fasync(&event->fasync, SIGIO, event->pending_kill); + kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill); event->pending_kill = 0; } } @@ -6124,7 +6132,7 @@ static int __perf_event_overflow(struct perf_event *event, else perf_event_output(event, data, regs); - if (event->fasync && event->pending_kill) { + if (*perf_event_fasync(event) && event->pending_kill) { event->pending_wakeup = 1; irq_work_queue(&event->pending); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/