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From: sashiko-bot@kernel.org
To: "Thomas Richter" <tmricht@linux.ibm.com>
Cc: "Heiko Carstens" <hca@linux.ibm.com>,
	"Vasily Gorbik" <gor@linux.ibm.com>,
	linux-s390@vger.kernel.org,
	"Alexander Gordeev" <agordeev@linux.ibm.com>
Subject: Re: [PATCH] s390/pai: Handle CPU hotplug add for PAI PMU
Date: Fri, 31 Jul 2026 08:47:56 +0000	[thread overview]
Message-ID: <20260731084757.188E21F000E9@smtp.kernel.org> (raw)
In-Reply-To: <20260731084011.2568310-1-tmricht@linux.ibm.com>

> The command 'perf stat -e pai_crypto/CRYPTO_ALL/ -- <command>
> crashes the kernel when CPUs are hotplug added during that run.
> 
> Root cause is the allocation of struct pai_mapptr at first
> event initialization. The allocation is dynamic and the first
> event that has task context creates such a structure for
> each online CPU. This is not sufficient. CPUs may be offline
> during event creation and can be set online during the
> perf run time. For example commands
> 
>  # echo 0 > /sys/devices/system/cpu/cpu1/online
>  # perf stat -e pai_crypto/CRYPTO_ALL/ -i -- stress-ng -t10s --matrix X
>  # sleep 1
>  # echo 1 > /sys/devices/system/cpu/cpu1/online
> 
> [ ... ]
> possible CPUs, not just the ones currently online.
> 
> Fixes: 92ea686840ac ("s390/pai_crypto: Enable per-task counting event")
> Cc: <Stable@vger.kernel.org> # v6.11+
> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260731084011.2568310-1-tmricht@linux.ibm.com?part=1


      reply	other threads:[~2026-07-31  8:47 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-31  8:40 [PATCH] s390/pai: Handle CPU hotplug add for PAI PMU Thomas Richter
2026-07-31  8:47 ` sashiko-bot [this message]

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