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From: Florian Weimer <fweimer@redhat.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH 3/3] Refactor atfork handlers
Date: Tue, 20 Feb 2018 14:42:35 +0100	[thread overview]
Message-ID: <fb02baf9-fcae-c224-4ae0-7a7857b7d8fc@redhat.com> (raw)
In-Reply-To: <780cefa6-543f-1a04-4b4e-9059a30d211b@linaro.org>

On 02/20/2018 02:27 PM, Adhemerval Zanella wrote:
> I think it might occur with proposed implementation only if a callback tries to call
> pthread_atfork or fork itself.  It these scenario you have in mind? And should we
> really support them if this is the case?

No.

__libc_fork starts like this:

   bool multiple_threads
     = THREAD_GETMEM (THREAD_SELF, header.multiple_threads);

   __run_fork_handlers (atfork_run_prepare);

And then acquires _IO_list_lock.

I don't see anything which prevents concurrent registration of 
additional fork handlers between the first and second call to 
__run_fork_handlers.

As I said, that shouldn't prevent inclusion of the current patch, but we 
need to fix this before 2.28, I think.

Thanks,
Florian


  reply	other threads:[~2018-02-20 13:40 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-07 13:09 [PATCH 1/3] Refactor Linux ARCH_FORK implementation Adhemerval Zanella
2018-02-07 13:09 ` [PATCH 2/3] dynarray: Implement remove function Adhemerval Zanella
2018-02-07 14:48   ` Alexander Monakov
2018-02-07 16:06     ` Adhemerval Zanella
2018-02-07 13:09 ` [PATCH 3/3] Refactor atfork handlers Adhemerval Zanella
2018-02-07 15:07   ` Florian Weimer
2018-02-07 17:16     ` Adhemerval Zanella
2018-02-08  8:32       ` Florian Weimer
2018-02-08 12:50         ` Adhemerval Zanella
2018-02-20 11:29           ` Florian Weimer
2018-02-20 13:00             ` Adhemerval Zanella
2018-02-20 13:05               ` Florian Weimer
2018-02-20 13:27                 ` Adhemerval Zanella
2018-02-20 13:42                   ` Florian Weimer [this message]
2018-02-20 13:48                     ` Adhemerval Zanella
2018-02-20 13:58                       ` Florian Weimer
2018-02-20 14:23                         ` Adhemerval Zanella
2018-02-23 10:41                           ` Florian Weimer
2018-02-23 12:10                             ` Adhemerval Zanella
2018-02-27  8:25                               ` Florian Weimer
2018-03-07 16:51 ` [PATCH 1/3] Refactor Linux ARCH_FORK implementation Adhemerval Zanella
2018-03-08 12:05 ` Florian Weimer
2018-03-08 12:58   ` Adhemerval Zanella

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