Le 17/06/2021 à 08:36, Athira Rajeev a écrit :
On 16-Jun-2021, at 11:56 AM, Christophe Leroy <christophe.le...@csgroup.eu>
wrote:
Le 16/06/2021 à 05:40, Athira Rajeev a écrit :
On 16-Jun-2021, at 8:53 AM, Madhavan Srinivasan <ma...@linux.ibm.com> wrote:
On 6/15/21 8:35 PM, Christophe Leroy wrote:
For your information, I'm getting the following Oops. Detected with 5.13-rc6, it also oopses on
5.12 and 5.11.
Runs ok on 5.10. I'm starting bisecting now.
Thanks for reporting, got the issue. What has happened in this case is that, pmu device is not
registered
and trying to access the instruction point which will land in perf_instruction_pointer(). And
recently I have added
a workaround patch for power10 DD1 which has caused this breakage. My bad. We are working on a
fix patch
for the same and will post it out. Sorry again.
Hi Christophe,
Can you please try with below patch in your environment and test if it works
for you.
From 55d3afc9369dfbe28a7152c8e9f856c11c7fe43d Mon Sep 17 00:00:00 2001
From: Athira Rajeev <atraj...@linux.vnet.ibm.com>
Date: Tue, 15 Jun 2021 22:28:11 -0400
Subject: [PATCH] powerpc/perf: Fix crash with 'perf_instruction_pointer' when
pmu is not set
On systems without any specific PMU driver support registered, running
perf record causes oops:
[ 38.841073] NIP [c00000000013af54] perf_instruction_pointer+0x24/0x100
[ 38.841079] LR [c0000000003c7358] perf_prepare_sample+0x4e8/0x820
[ 38.841085] --- interrupt: 300
[ 38.841088] [c00000001cf03440] [c0000000003c6ef8]
perf_prepare_sample+0x88/0x820 (unreliable)
[ 38.841096] [c00000001cf034a0] [c0000000003c76d0]
perf_event_output_forward+0x40/0xc0
[ 38.841104] [c00000001cf03520] [c0000000003b45e8]
__perf_event_overflow+0x88/0x1b0
[ 38.841112] [c00000001cf03570] [c0000000003b480c]
perf_swevent_hrtimer+0xfc/0x1a0
[ 38.841119] [c00000001cf03740] [c0000000002399cc]
__hrtimer_run_queues+0x17c/0x380
[ 38.841127] [c00000001cf037c0] [c00000000023a5f8]
hrtimer_interrupt+0x128/0x2f0
[ 38.841135] [c00000001cf03870] [c00000000002962c] timer_interrupt+0x13c/0x370
[ 38.841143i] [c00000001cf038d0] [c000000000009ba4]
decrementer_common_virt+0x1a4/0x1b0
[ 38.841151] --- interrupt: 900 at copypage_power7+0xd4/0x1c0
During perf record session, perf_instruction_pointer() is called to
capture the sample ip. This function in core-book3s accesses ppmu->flags.
If a platform specific PMU driver is not registered, ppmu is set to NULL
and accessing its members results in a crash. Fix this crash by checking
if ppmu is set.
Signed-off-by: Athira Rajeev <atraj...@linux.vnet.ibm.com>
Reported-by: Christophe Leroy <christophe.le...@csgroup.eu>
Fixes: 2ca13a4cc56c ("powerpc/perf: Use regs->nip when SIAR is zero")
Cc: sta...@vger.kernel.org
Tested-by: Christophe Leroy <christophe.le...@csgroup.eu>
Hi Christophe,
Thanks for testing with the change. I have a newer version where I have added
braces around the check.
Can you please check once and can I add your tested-by for the below patch.
Yes it works, you can add my Tested-by:
Please also add Cc: sta...@vger.kernel.org, this needs to be backported as soon
as possible.
Thanks
Christophe
