From: Kirill Tkhai <ktkhai@virtuozzo.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
tj@kernel.org, cl@linux.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
Jonathan Corbet <corbet@lwn.net>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>
Subject: Re: [PATCH] Improve mutex documentation
Date: Thu, 15 Mar 2018 16:23:09 +0300 [thread overview]
Message-ID: <053b66a4-ce68-fe00-ef06-e09a3b14d524@virtuozzo.com> (raw)
In-Reply-To: <20180315131832.GC9949@bombadil.infradead.org>
On 15.03.2018 16:18, Matthew Wilcox wrote:
> On Thu, Mar 15, 2018 at 03:12:30PM +0300, Kirill Tkhai wrote:
>>> +/**
>>> + * mutex_lock_killable() - Acquire the mutex, interruptible by fatal signals.
>>
>> Shouldn't we clarify that fatal signals are SIGKILL only?
>
> It's more complicated than it might seem (... welcome to signal handling!)
> If you send SIGINT to a task that's waiting on a mutex_killable(), it will
> still die. I *think* that's due to the code in complete_signal():
>
> if (sig_fatal(p, sig) &&
> !(signal->flags & SIGNAL_GROUP_EXIT) &&
> !sigismember(&t->real_blocked, sig) &&
> (sig == SIGKILL || !p->ptrace)) {
> ...
> sigaddset(&t->pending.signal, SIGKILL);
>
> You're correct that this code only checks for SIGKILL, but any fatal
> signal will result in the signal group receiving SIGKILL.
>
> Unless I've misunderstood, and it wouldn't be the first time I've
> misunderstood signal handling.
Sure, thanks for the explanation.
Kirill
next prev parent reply other threads:[~2018-03-15 13:23 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-14 11:51 [PATCH] percpu: Allow to kill tasks doing pcpu_alloc() and waiting for pcpu_balance_workfn() Kirill Tkhai
2018-03-14 13:55 ` Tejun Heo
2018-03-14 20:56 ` Andrew Morton
2018-03-14 22:09 ` Tejun Heo
2018-03-14 22:22 ` Andrew Morton
2018-03-15 8:58 ` Kirill Tkhai
2018-03-15 10:48 ` Tetsuo Handa
2018-03-15 12:09 ` Kirill Tkhai
2018-03-15 14:09 ` Tetsuo Handa
2018-03-15 14:42 ` Kirill Tkhai
2018-03-19 15:13 ` Tejun Heo
2018-03-15 11:58 ` [PATCH] Improve mutex documentation Matthew Wilcox
2018-03-15 12:12 ` Kirill Tkhai
2018-03-15 13:18 ` Matthew Wilcox
2018-03-15 13:23 ` Kirill Tkhai [this message]
2018-03-16 13:57 ` Peter Zijlstra
2018-03-19 15:14 ` [PATCH] percpu: Allow to kill tasks doing pcpu_alloc() and waiting for pcpu_balance_workfn() Tejun Heo
2018-03-19 15:32 ` [PATCH v2] mm: " Kirill Tkhai
2018-03-19 16:39 ` Tejun Heo
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