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Mon, 11 May 2026 12:47:44 +0000 (UTC) X-FDA: 84755115648.06.ADA6829 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf12.hostedemail.com (Postfix) with ESMTP id A739C40002 for ; Mon, 11 May 2026 12:47:42 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=vMm+tJlf; spf=pass (imf12.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1778503662; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=piSl0NeQrbjlS0csXN4uGW/cPXY9oks0JFPMT8zO/Dw=; b=edb+sFaP0DG6lJdASEcuI3GZUuMiXz5y9z4sWcnX+yGiZrTkiTghnK3Z+c4dXrm9qIN+12 J66wX0i3T/YPdQiZGidgPiQlNZERwEa6eygSJYkx8zNlIn2GD31L5PRFJqnKN8Zdznclpk CKCDNe8EngQMtBrCkOYpxcPUqFd0mPI= ARC-Seal: i=1; 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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 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; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260511093433.2372985-1-husong@kylinos.cn> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: A739C40002 X-Rspam-User: X-Stat-Signature: ama9ec9x46r5c5hskmdao8ukz53noupg X-HE-Tag: 1778503662-323572 X-HE-Meta: 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 rAJ9Dyb7 hjK3+Gwoh0MQeAKz5OGGDo4EXD1/2xSxmQxfMMunvhkhy+PogJ8mcMuuX3VR4o7o5iLpHIbjH0V5VDzRZ+gfO1GrSdFhXBEvD3O6zcC5r4UxWCLPLvu4pZL+ncGlbAuQO00WP6BvHRDQufrOL09YeuOCur4N8fAAfMXbbjy61AmVrNbawcq/cmhdQidpd6Gl6mg54uyeImjQoJPNIO2qKHfMWof3HO8SxBDbNFJgJvHkKrmRIr/5hmqH1P98NUTJngyEi Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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