From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 11F9D3E558D; Mon, 11 May 2026 12:47:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778503662; cv=none; b=M8h0DK9KOFwT9m75QzPBNkuBDFU2ycSdJtMnhvEHBagjO23PpRs4ChmdG0KQ+gsDgdIyHx1XMxBxtjdleaRUlDV/yjqt5NphLyJ/QuMhxF7vUeAP7WdAG5t8jqxJIUHek6+FgWRcEupQQofBURuBa2vZfq/4UKl1wXjrBwmiQQo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778503662; c=relaxed/simple; bh=qByFLGVe72rTgzx4RNADis8ATo7lw2Q1IJlWwe202SM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Y5CTDb1zGp4CayVJ2cs28MyWpAVVJVSGZ9KNoTdcsspdL/2sO+2Ej0NpxpZnnyCActZ+9ErziVV9kZOBkXncWKXHdnmIxLKnKtV+jY7sc250WqVcAo615SSK/phsFBh73ajXWDSbv1N4rXj2XnhCn4XGmoqSdtVaDd4JEJNJxaA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=vMm+tJlf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="vMm+tJlf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5ABA0C2BCC9; Mon, 11 May 2026 12:47:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778503661; bh=qByFLGVe72rTgzx4RNADis8ATo7lw2Q1IJlWwe202SM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=vMm+tJlf0KqF5tq3PABUCWaZAb074MhjWjqY+BZbZVFwfwG/ev+CCws2dBMA/GOAe B9RMCwdrMehqc6WVfjccnog//+xXgEjpz7VJ0q3v50X3bic8VPLCwF3TUMzw1tUr05 7TObAuuiIZR930Xt++jqz66SHq6BrhGMdkrevJjSYTKzdOxyb6zR1njxLLneD616Z5 x73PpLJW/OOsrH22EKVsy+FJjBmUeRW2FkKcf6HJMOFicq0fYc23Aw1M5FiEXusXFs +0Ulb617Zgt7/XLKTcQj0mKjRLy9yk4ACpIP0cQqf0OCdoDNUUNlVbIGrbNcm371wT iAFRAaWwR5YLQ== Message-ID: Date: Mon, 11 May 2026 14:47:38 +0200 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] selftests/mm: handle fork() failure in migration tests To: Hu Song , akpm@linux-foundation.org, shuah@kernel.org, linux-kselftest@vger.kernel.org Cc: ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260511093433.2372985-1-husong@kylinos.cn> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/11/26 11:34, Hu Song wrote: > From: Song Hu > > When fork() fails and returns -1, the code falls into the else branch > and stores -1 into self->pids[i]. Later, kill(-1, SIGTERM) is called > which sends SIGTERM to every process the user has permission to signal, > potentially killing the entire user session. > > Add an explicit check for fork() returning -1 (pid < 0). On failure, > clean up any already-forked children before failing the test via > ASSERT_GE(pid, 0). This fix is applied to all three fork() call sites > in shared_anon, shared_anon_thp, and shared_anon_htlb tests. > > Signed-off-by: Hu Song > --- > tools/testing/selftests/mm/migration.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/tools/testing/selftests/mm/migration.c b/tools/testing/selftests/mm/migration.c > index 60e78bbfc0e3..f433e4f195ad 100644 > --- a/tools/testing/selftests/mm/migration.c > +++ b/tools/testing/selftests/mm/migration.c > @@ -163,6 +163,11 @@ TEST_F_TIMEOUT(migration, shared_anon, 2*RUNTIME) > memset(ptr, 0xde, TWOMEG); > for (i = 0; i < self->nthreads - 1; i++) { > pid = fork(); > + if (pid < 0) { > + while (--i >= 0) > + kill(self->pids[i], SIGTERM); > + ASSERT_GE(pid, 0); > + } > if (!pid) { I think "else if" reads nicer here. But why do we care about cleaning up the other processes? IIUC, we don't do that explicitly if e.g., ASSERT_EQ(migrate(ptr, self->n1, self->n2), 0); fails? -- Cheers, David