From: Thomas Gleixner <tglx@linutronix.de>
To: "Chang S. Bae" <chang.seok.bae@intel.com>, linux-kernel@vger.kernel.org
Cc: dave.hansen@linux.intel.com, ebiederm@xmission.com,
oleg@redhat.com, bp@alien8.de, x86@kernel.org,
chang.seok.bae@intel.com
Subject: Re: [PATCH v2] signal: Skip the altstack update when not needed
Date: Mon, 13 Dec 2021 22:25:37 +0100 [thread overview]
Message-ID: <87pmq0tcxa.ffs@tglx> (raw)
In-Reply-To: <20211210225503.12734-1-chang.seok.bae@intel.com>
On Fri, Dec 10 2021 at 14:55, Chang S. Bae wrote:
> do_sigaltstack() acquires sigaltstack_lock() and is used for both
> sys_sigaltstack() and restoring the sigaltstack in sys_sigreturn().
> Check for changes to the sigaltstack before taking the lock. If no
> changes were made, return before acquiring the lock.
>
> This removes lock contention from the common-case sigreturn path.
>
> Reported-by: kernel test robot <oliver.sang@intel.com>
> [1] https://lore.kernel.org/lkml/20211207012128.GA16074@xsang-OptiPlex-9020/
> Fixes: 3aac3ebea08f ("x86/signal: Implement sigaltstack size validation")
> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
next prev parent reply other threads:[~2021-12-13 21:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-10 22:55 [PATCH v2] signal: Skip the altstack update when not needed Chang S. Bae
2021-12-13 21:25 ` Thomas Gleixner [this message]
2021-12-14 1:01 ` Bae, Chang Seok
2021-12-14 21:12 ` [tip: sched/urgent] " tip-bot2 for Chang S. Bae
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