From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Vince Weaver <vincent.weaver@maine.edu>,
Jiri Olsa <jolsa@redhat.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Corey Ashford <cjashfor@linux.vnet.ibm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@elte.hu>, Namhyung Kim <namhyung@kernel.org>,
Paul Mackerras <paulus@samba.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>
Subject: [ 13/59] perf: Remove WARN_ON_ONCE() check in __perf_event_enable() for valid scenario
Date: Fri, 26 Jul 2013 13:52:37 -0700 [thread overview]
Message-ID: <20130726205015.229288074@linuxfoundation.org> (raw)
In-Reply-To: <20130726205013.795696531@linuxfoundation.org>
3.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jiri Olsa <jolsa@redhat.com>
commit 06f417968beac6e6b614e17b37d347aa6a6b1d30 upstream.
The '!ctx->is_active' check has a valid scenario, so
there's no need for the warning.
The reason is that there's a time window between the
'ctx->is_active' check in the perf_event_enable() function
and the __perf_event_enable() function having:
- IRQs on
- ctx->lock unlocked
where the task could be killed and 'ctx' deactivated by
perf_event_exit_task(), ending up with the warning below.
So remove the WARN_ON_ONCE() check and add comments to
explain it all.
This addresses the following warning reported by Vince Weaver:
[ 324.983534] ------------[ cut here ]------------
[ 324.984420] WARNING: at kernel/events/core.c:1953 __perf_event_enable+0x187/0x190()
[ 324.984420] Modules linked in:
[ 324.984420] CPU: 19 PID: 2715 Comm: nmi_bug_snb Not tainted 3.10.0+ #246
[ 324.984420] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010
[ 324.984420] 0000000000000009 ffff88043fce3ec8 ffffffff8160ea0b ffff88043fce3f00
[ 324.984420] ffffffff81080ff0 ffff8802314fdc00 ffff880231a8f800 ffff88043fcf7860
[ 324.984420] 0000000000000286 ffff880231a8f800 ffff88043fce3f10 ffffffff8108103a
[ 324.984420] Call Trace:
[ 324.984420] <IRQ> [<ffffffff8160ea0b>] dump_stack+0x19/0x1b
[ 324.984420] [<ffffffff81080ff0>] warn_slowpath_common+0x70/0xa0
[ 324.984420] [<ffffffff8108103a>] warn_slowpath_null+0x1a/0x20
[ 324.984420] [<ffffffff81134437>] __perf_event_enable+0x187/0x190
[ 324.984420] [<ffffffff81130030>] remote_function+0x40/0x50
[ 324.984420] [<ffffffff810e51de>] generic_smp_call_function_single_interrupt+0xbe/0x130
[ 324.984420] [<ffffffff81066a47>] smp_call_function_single_interrupt+0x27/0x40
[ 324.984420] [<ffffffff8161fd2f>] call_function_single_interrupt+0x6f/0x80
[ 324.984420] <EOI> [<ffffffff816161a1>] ? _raw_spin_unlock_irqrestore+0x41/0x70
[ 324.984420] [<ffffffff8113799d>] perf_event_exit_task+0x14d/0x210
[ 324.984420] [<ffffffff810acd04>] ? switch_task_namespaces+0x24/0x60
[ 324.984420] [<ffffffff81086946>] do_exit+0x2b6/0xa40
[ 324.984420] [<ffffffff8161615c>] ? _raw_spin_unlock_irq+0x2c/0x30
[ 324.984420] [<ffffffff81087279>] do_group_exit+0x49/0xc0
[ 324.984420] [<ffffffff81096854>] get_signal_to_deliver+0x254/0x620
[ 324.984420] [<ffffffff81043057>] do_signal+0x57/0x5a0
[ 324.984420] [<ffffffff8161a164>] ? __do_page_fault+0x2a4/0x4e0
[ 324.984420] [<ffffffff8161665c>] ? retint_restore_args+0xe/0xe
[ 324.984420] [<ffffffff816166cd>] ? retint_signal+0x11/0x84
[ 324.984420] [<ffffffff81043605>] do_notify_resume+0x65/0x80
[ 324.984420] [<ffffffff81616702>] retint_signal+0x46/0x84
[ 324.984420] ---[ end trace 442ec2f04db3771a ]---
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1373384651-6109-2-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/events/core.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1702,7 +1702,16 @@ static int __perf_event_enable(void *inf
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
int err;
- if (WARN_ON_ONCE(!ctx->is_active))
+ /*
+ * There's a time window between 'ctx->is_active' check
+ * in perf_event_enable function and this place having:
+ * - IRQs on
+ * - ctx->lock unlocked
+ *
+ * where the task could be killed and 'ctx' deactivated
+ * by perf_event_exit_task.
+ */
+ if (!ctx->is_active)
return -EINVAL;
raw_spin_lock(&ctx->lock);
next prev parent reply other threads:[~2013-07-26 21:23 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-26 20:52 [ 00/59] 3.4.55-stable review Greg Kroah-Hartman
2013-07-26 20:52 ` [ 01/59] ext3: fix data=journal fast mount/umount hang Greg Kroah-Hartman
2013-07-26 20:52 ` [ 02/59] libata: skip SRST for all SIMG [34]7x port-multipliers Greg Kroah-Hartman
2013-07-26 20:52 ` [ 03/59] ata_piix: IDE-mode SATA patch for Intel Coleto Creek DeviceIDs Greg Kroah-Hartman
2013-07-26 20:52 ` [ 04/59] ASoC: sglt5000: Fix SGTL5000_PLL_FRAC_DIV_MASK Greg Kroah-Hartman
2013-07-26 20:52 ` [ 05/59] tick: Prevent uncontrolled switch to oneshot mode Greg Kroah-Hartman
2013-07-26 20:52 ` [ 06/59] rt2x00: read 5GHz TX power values from the correct offset Greg Kroah-Hartman
2013-07-26 20:52 ` [ 07/59] ath9k: Do not assign noise for NULL caldata Greg Kroah-Hartman
2013-07-26 20:52 ` [ 08/59] SCSI: zfcp: fix adapter (re)open recovery while link to SAN is down Greg Kroah-Hartman
2013-07-26 20:52 ` [ 09/59] SCSI: mpt2sas: fix firmware failure with wrong task attribute Greg Kroah-Hartman
2013-07-26 20:52 ` [ 10/59] tracing: Use current_uid() for critical time tracing Greg Kroah-Hartman
2013-07-26 20:52 ` [ 11/59] iommu/amd: Only unmap large pages from the first pte Greg Kroah-Hartman
2013-07-26 20:52 ` [ 12/59] perf: Clone child context from parent context pmu Greg Kroah-Hartman
2013-07-26 20:52 ` Greg Kroah-Hartman [this message]
2013-07-26 20:52 ` [ 14/59] perf: Fix perf_lock_task_context() vs RCU Greg Kroah-Hartman
2013-07-26 20:52 ` [ 15/59] sparc32: vm_area_struct access for old Sun SPARCs Greg Kroah-Hartman
2013-07-27 21:45 ` Ben Hutchings
2013-07-28 2:27 ` David Miller
2013-07-28 18:37 ` Greg KH
2013-07-26 20:52 ` [ 16/59] sparc64 address-congruence property Greg Kroah-Hartman
2013-07-26 20:52 ` [ 17/59] sparc: tsb must be flushed before tlb Greg Kroah-Hartman
2013-07-26 20:52 ` [ 18/59] bridge: fix switched interval for MLD Query types Greg Kroah-Hartman
2013-07-26 20:52 ` [ 19/59] ipv4: Fixed MD5 key lookups when adding/ removing MD5 to/ from TCP sockets Greg Kroah-Hartman
2013-07-26 20:52 ` [ 20/59] ipv6: dont call addrconf_dst_alloc again when enable lo Greg Kroah-Hartman
2013-07-26 20:52 ` [ 21/59] macvtap: fix recovery from gup errors Greg Kroah-Hartman
2013-07-26 20:52 ` [ 22/59] ipv6: ip6_sk_dst_check() must not assume ipv6 dst Greg Kroah-Hartman
2013-07-26 20:52 ` [ 23/59] af_key: fix info leaks in notify messages Greg Kroah-Hartman
2013-07-26 20:52 ` [ 24/59] sh_eth: fix unhandled RFE interrupt Greg Kroah-Hartman
2013-07-26 20:52 ` [ 25/59] neighbour: fix a race in neigh_destroy() Greg Kroah-Hartman
2013-07-26 20:52 ` [ 26/59] x25: Fix broken locking in ioctl error paths Greg Kroah-Hartman
2013-07-26 20:52 ` [ 27/59] net: Swap ver and type in pppoe_hdr Greg Kroah-Hartman
2013-07-26 20:52 ` [ 28/59] ipv6,mcast: always hold idev->lock before mca_lock Greg Kroah-Hartman
2013-07-26 20:52 ` [ 29/59] l2tp: add missing .owner to struct pppox_proto Greg Kroah-Hartman
2013-07-26 20:52 ` [ 30/59] ipv6: call udp_push_pending_frames when uncorking a socket with AF_INET pending data Greg Kroah-Hartman
2013-07-26 20:52 ` [ 31/59] ipv6: ip6_append_data_mtu did not care about pmtudisc and frag_size Greg Kroah-Hartman
2013-07-26 20:52 ` [ 32/59] sunvnet: vnet_port_remove must call unregister_netdev Greg Kroah-Hartman
2013-07-26 20:52 ` [ 33/59] ifb: fix rcu_sched self-detected stalls Greg Kroah-Hartman
2013-07-26 20:52 ` [ 34/59] macvtap: correctly linearize skb when zerocopy is used Greg Kroah-Hartman
2013-07-26 20:52 ` [ 35/59] ipv6: in case of link failure remove route directly instead of letting it expire Greg Kroah-Hartman
2013-07-26 20:53 ` [ 36/59] 9p: fix off by one causing access violations and memory corruption Greg Kroah-Hartman
2013-07-26 20:53 ` [ 37/59] dummy: fix oops when loading the dummy failed Greg Kroah-Hartman
2013-07-26 20:53 ` [ 38/59] ifb: fix oops when loading the ifb failed Greg Kroah-Hartman
2013-07-26 20:53 ` [ 39/59] atl1e: fix dma mapping warnings Greg Kroah-Hartman
2013-07-26 20:53 ` [ 40/59] atl1e: unmap partially mapped skb on dma error and free skb Greg Kroah-Hartman
2013-07-26 20:53 ` [ 41/59] vlan: fix a race in egress prio management Greg Kroah-Hartman
2013-07-26 20:53 ` [ 42/59] writeback: Fix periodic writeback after fs mount Greg Kroah-Hartman
2013-07-26 20:53 ` [ 43/59] SCSI: megaraid_sas: fix memory leak if SGL has zero length entries Greg Kroah-Hartman
2013-07-26 20:53 ` [ 44/59] SCSI: Fix incorrect memset in bnx2fc_parse_fcp_rsp Greg Kroah-Hartman
2013-07-26 20:53 ` [ 45/59] [SCSI] zfcp: block queue limits with data router Greg Kroah-Hartman
2013-07-26 20:53 ` [ 46/59] usb: serial: option: blacklist ONDA MT689DC QMI interface Greg Kroah-Hartman
2013-07-26 20:53 ` [ 47/59] usb: option: add TP-LINK MA260 Greg Kroah-Hartman
2013-07-26 20:53 ` [ 48/59] usb: serial: option: add Olivetti Olicard 200 Greg Kroah-Hartman
2013-07-26 20:53 ` [ 49/59] usb: serial: option.c: remove ONDA MT825UP product ID fromdriver Greg Kroah-Hartman
2013-07-26 20:53 ` [ 50/59] USB: option: append Petatel NP10T device to GSM modems list Greg Kroah-Hartman
2013-07-26 20:53 ` [ 51/59] USB: option: add D-Link DWM-152/C1 and DWM-156/C1 Greg Kroah-Hartman
2013-07-26 20:53 ` [ 52/59] usb: serial: option: Add ONYX 3G device support Greg Kroah-Hartman
2013-07-26 20:53 ` [ 53/59] usb: serial: cp210x: Add USB ID for Netgear Switches embedded serial adapter Greg Kroah-Hartman
2013-07-26 20:53 ` [ 54/59] USB: cp210x: add MMB and PI ZigBee USB Device Support Greg Kroah-Hartman
2013-07-26 20:53 ` [ 55/59] usb: cp210x support SEL C662 Vendor/Device Greg Kroah-Hartman
2013-07-26 20:53 ` [ 56/59] lockd: protect nlm_blocked access in nlmsvc_retry_blocked Greg Kroah-Hartman
2013-07-26 20:53 ` [ 57/59] tracing: Fix irqs-off tag display in syscall tracing Greg Kroah-Hartman
2013-07-26 20:53 ` [ 58/59] hrtimers: Move SMP function call to thread context Greg Kroah-Hartman
2013-07-26 20:53 ` [ 59/59] ALSA: usb-audio: 6fire: return correct XRUN indication Greg Kroah-Hartman
2013-07-27 21:28 ` [ 00/59] 3.4.55-stable review linux
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