From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69F11C61D85 for ; Thu, 23 Nov 2023 08:51:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344994AbjKWIvG (ORCPT ); Thu, 23 Nov 2023 03:51:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229543AbjKWIvE (ORCPT ); Thu, 23 Nov 2023 03:51:04 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F2A792 for ; Thu, 23 Nov 2023 00:51:09 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id D3FA221902; Thu, 23 Nov 2023 08:51:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1700729467; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=udBEUjYcPicLpK46H3BbzFQivSojujoRMSapQr3MUVo=; b=dHfHv2fZn1fRdP0GHiHbDgFUEmZ5n5tImiYp1lahaLPUzW4Fjt7OKxcmO6cuPGzIf0sfnB BoImydeJY0XJhQqW6+ZWcZDLJKOAivvoGi0spri9lCnUwFcoupJCIm5oMqrsQfgy3JvJhP 1gT4EUVoSF1vPR/TP2xMs3/SK+Pu3ac= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id A82AC133B6; Thu, 23 Nov 2023 08:51:07 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id Cmn3JXsSX2XbCgAAMHmgww (envelope-from ); Thu, 23 Nov 2023 08:51:07 +0000 Date: Thu, 23 Nov 2023 09:51:06 +0100 From: Michal Hocko To: gaoxu Cc: Andrew Morton , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Suren Baghdasaryan , yipengxiang Subject: Re: [PATCH] mm,oom_reaper: avoid run queue_oom_reaper if task is not oom Message-ID: References: <400d13bddb524ef6af37cb2220808c75@hihonor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <400d13bddb524ef6af37cb2220808c75@hihonor.com> Authentication-Results: smtp-out1.suse.de; none X-Spamd-Result: default: False [-0.07 / 50.00]; ARC_NA(0.00)[]; TO_DN_EQ_ADDR_SOME(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; NEURAL_SPAM_SHORT(3.00)[1.000]; MIME_GOOD(-0.10)[text/plain]; REPLY(-4.00)[]; RCPT_COUNT_FIVE(0.00)[6]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; NEURAL_SPAM_LONG(3.50)[1.000]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; MID_RHS_NOT_FQDN(0.50)[]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-2.97)[99.85%] Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 22-11-23 12:46:44, gaoxu wrote: > The function queue_oom_reaper tests and sets tsk->signal->oom_mm->flags. > However, it is necessary to check if 'tsk' is an OOM victim before > executing 'queue_oom_reaper' because the variable may be NULL. > > We encountered such an issue, and the log is as follows: > [3701:11_see]Out of memory: Killed process 3154 (system_server) > total-vm:23662044kB, anon-rss:0kB, file-rss:0kB, shmem-rss:0kB, > UID:1000 pgtables:4056kB oom_score_adj:-900 > [3701:11_see][RB/E]rb_sreason_str_set: sreason_str set null_pointer > [3701:11_see][RB/E]rb_sreason_str_set: sreason_str set unknown_addr What are these? > [3701:11_see]Unable to handle kernel NULL pointer dereference at virtual > address 0000000000000328 > [3701:11_see]user pgtable: 4k pages, 39-bit VAs, pgdp=00000000821de000 > [3701:11_see][0000000000000328] pgd=0000000000000000, > p4d=0000000000000000,pud=0000000000000000 > [3701:11_see]tracing off > [3701:11_see]Internal error: Oops: 96000005 [#1] PREEMPT SMP > [3701:11_see]Call trace: > [3701:11_see] queue_oom_reaper+0x30/0x170 Could you resolve this offset into the code line please? > [3701:11_see] __oom_kill_process+0x590/0x860 > [3701:11_see] oom_kill_process+0x140/0x274 > [3701:11_see] out_of_memory+0x2f4/0x54c > [3701:11_see] __alloc_pages_slowpath+0x5d8/0xaac > [3701:11_see] __alloc_pages+0x774/0x800 > [3701:11_see] wp_page_copy+0xc4/0x116c > [3701:11_see] do_wp_page+0x4bc/0x6fc > [3701:11_see] handle_pte_fault+0x98/0x2a8 > [3701:11_see] __handle_mm_fault+0x368/0x700 > [3701:11_see] do_handle_mm_fault+0x160/0x2cc > [3701:11_see] do_page_fault+0x3e0/0x818 > [3701:11_see] do_mem_abort+0x68/0x17c > [3701:11_see] el0_da+0x3c/0xa0 > [3701:11_see] el0t_64_sync_handler+0xc4/0xec > [3701:11_see] el0t_64_sync+0x1b4/0x1b8 > [3701:11_see]tracing off > > Signed-off-by: Gao Xu > --- > mm/oom_kill.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 9e6071fde..3754ab4b6 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -984,7 +984,7 @@ static void __oom_kill_process(struct task_struct *victim, const char *message) > } > rcu_read_unlock(); > > - if (can_oom_reap) > + if (can_oom_reap && tsk_is_oom_victim(victim)) > queue_oom_reaper(victim); I do not understand. We always do send SIGKILL and call mark_oom_victim(victim); on victim task when reaching out here. How can tsk_is_oom_victim can ever be false? > > mmdrop(mm); > -- > 2.17.1 > > -- Michal Hocko SUSE Labs