From: Thomas Gleixner <tglx@linutronix.de>
To: Song liwei <liwei.song@windriver.com>
Cc: linux-kernel@vger.kernel.org,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
Will Deacon <will@kernel.org>, Borislav Petkov <bp@suse.de>,
Kulkarni <Ganapatrao.Kulkarni@cavium.com>,
Guo Ren <ren_guo@c-sky.com>, Joseph Lo <josephl@nvidia.com>,
Hoan Tran <Hoan@os.amperecomputing.com>,
Anju T Sudhakar <anju@linux.vnet.ibm.com>,
Rafael J <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH] x86/microcode, cpuhotplug: move microcode hotplug callback after cpu teardown
Date: Wed, 3 Jul 2019 11:17:04 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1907031114490.1802@nanos.tec.linutronix.de> (raw)
In-Reply-To: <1562143728-78052-1-git-send-email-liwei.song@windriver.com>
On Wed, 3 Jul 2019, Song liwei wrote:
> After CPUHP_TEARDOWN_CPU callback was invoked, the context will become
> atomic and IRQ disabled, while mc_cpu_down_prep will called
> kernfs_find_and_get_ns which will try to acquire mutext lock which may
> sleep.
>
> Adjust CPUHP_AP_MICROCODE_LOADER callback function run before
> CPUHP_TEARDOWN_CPU to fix this bug.
That's just wrong and reintroduces the bug which was fixed with that commit
as perf will access a non existing MSR which is brought in by the micro
code update.
Aside of that the mutex issue _is_ fixed in rc7 already:
5423f5ce5ca4 ("x86/microcode: Fix the microcode load on CPU hotplug for real")
Thanks,
tglx
prev parent reply other threads:[~2019-07-03 9:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-03 8:48 Song liwei
2019-07-03 9:17 ` Thomas Gleixner [this message]
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