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From: Andrew Morton <akpm@linux-foundation.org>
To: Drif Abdelmalek Mohamed Said <drifabdelmalekmohamedsaid@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
	Shuah Khan <shuah@kernel.org>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] selftests/proc: proc-empty-vm: wait for child's SIGSEGV instead of sleep(1)
Date: Sun, 1 Nov 2026 20:31:13 -0800	[thread overview]
Message-ID: <20261101203113.74d0204f6d57deb81cdd0dc5@linux-foundation.org> (raw)
In-Reply-To: <20261023183434.9109-1-drifabdelmalekmohamedsaid@gmail.com>

On Fri, 23 Oct 2026 19:34:33 +0100 Drif Abdelmalek Mohamed Said <drifabdelmalekmohamedsaid@gmail.com> wrote:

> The test had a TODO asking for a reliable way to know when the child's
> munmap() has finished, and used sleep(1) in the meantime.
> 
> Unmapping the whole address space leaves the child with no code to run,
> so it segfaults. Since it is traced, the SIGSEGV stop is reported to
> the parent through waitpid(), which is exactly the signal the TODO
> wanted. Wait for it there and drop the sleep and the TODO.
> 
> The stop is now consumed up front, so SIGKILL the child before the
> final reap.

Thanks, checks out.

My review toy claims

: Separately, tools/testing/selftests/ptrace/vmaccess.c has similar
: sleep-based synchronization. A delayed child can make its attach test
: fail spuriously, or let its vmaccess test run before the intended
: blocked-exec state. That deserves a separate fix.

  parent reply	other threads:[~2026-11-02  4:31 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-23 18:34 Drif Abdelmalek Mohamed Said
2026-11-01 12:57 ` Alexey Dobriyan
2026-11-02  4:31 ` Andrew Morton [this message]
2026-11-02 19:14   ` DRIF ABDELMALEK MOHAMED SAID

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