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 X-Spam-Level: X-Spam-Status: No, score=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 760F5C433B4 for ; Tue, 11 May 2021 06:09:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FB5E6191D for ; Tue, 11 May 2021 06:09:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230355AbhEKGK7 (ORCPT ); Tue, 11 May 2021 02:10:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:35997 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229840AbhEKGK5 (ORCPT ); Tue, 11 May 2021 02:10:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1620713391; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=iCqlWXsYzQ4M50g/8LZgXjNs7GwMMEWU8lAHhEw1x0I=; b=fxnrSE85q1DFrLiM0VIz9XemJEf2rHHk1I1Jckwf2zJ9BcnHMBg4l0QOCLyJ5NN4SlwoD+ k65lcYr9EcFABfvLNpAQBcpsshjCuCcebPcr6x5YLJj+QES/kRQZW+rGVGxyI60F/STRKP RLuoMJ4zCuy7e0Wdjdi+5CuRdL0JeJQ= Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-383-eAfJlhXFMBO7BWksRNcTVg-1; Tue, 11 May 2021 02:09:47 -0400 X-MC-Unique: eAfJlhXFMBO7BWksRNcTVg-1 Received: by mail-ed1-f71.google.com with SMTP id q18-20020a0564025192b02903888712212fso10316980edd.19 for ; Mon, 10 May 2021 23:09:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition; bh=iCqlWXsYzQ4M50g/8LZgXjNs7GwMMEWU8lAHhEw1x0I=; b=oVbEvJwzUU8zVC4vlC3qkomRGu1b4731kzOAy3GmmCP2OQxxAge6piMU9GhI3k04Gd ukPdMatzjDxbneGvCk3Nels8L8vQGMibayItxcSNJcVlgwsA3XTxu8Lpfj0Wt3+iNRNw cS4upfp+tIvHyV1Se5d402F8819GV2I6mpyEUEPyL5GC9pjbMQ46MadocP1kYfORvzd6 aN76hbK3jfCE+2vWbYQUvdXuyCERcbxfn/4aiQ6foEPofjxvECmuUnbhPzAUWVWtlQML zsF6KEeXbqs8U9V6C+IGdF4SYwJvkHToCYZ3h/0I7EaH2JOdvQieQq8xik0jz38ObJCA Hcow== X-Gm-Message-State: AOAM53085sUjP0N1wWLW7SKdrT4CqCJJl2Vtio7eus1IyupD2L/jeUSu 0eMikyBr6mRsUeD7mIu17mKUKNCU1ToMH1AbxNlxKWtfVQ4INkd+OTSnhKi3kQpNMEu1mH4R15m T70qTUge6XUp+qX144bi4iZIP X-Received: by 2002:a05:6402:177c:: with SMTP id da28mr33312011edb.135.1620713385499; Mon, 10 May 2021 23:09:45 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyRZlDgHMwqPw6Hh/70Be2C5J22YJG9jLtexJBcsEd/38SWL5S6OQfC3T7Je+jRAjd8TxM+MQ== X-Received: by 2002:a05:6402:177c:: with SMTP id da28mr33311991edb.135.1620713385294; Mon, 10 May 2021 23:09:45 -0700 (PDT) Received: from localhost.localdomain ([151.29.103.229]) by smtp.gmail.com with ESMTPSA id h23sm10808283ejx.90.2021.05.10.23.09.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 May 2021 23:09:44 -0700 (PDT) Date: Tue, 11 May 2021 08:09:42 +0200 From: Juri Lelli To: Thomas Gleixner , Sebastian Andrzej Siewior Cc: linux-rt-users , LKML , sassmann@redhat.com Subject: [RT] Question about i40e threaded irq Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, The following has been reported on RT. [ 2007.106483] list_add corruption. next->prev should be prev (ffff8d86a0aadd00), but was ffff8d86a0aadec8. (next=ffff8d86a0aadd00). [ 2007.118155] ------------[ cut here ]------------ [ 2007.118156] kernel BUG at lib/list_debug.c:25! [ 2007.118160] invalid opcode: 0000 [#1] PREEMPT_RT SMP NOPTI [ 2007.118162] CPU: 36 PID: 4651 Comm: irq/429-i40e-en Kdump: loaded Tainted: G I #1 [ 2007.118163] Hardware name: Dell Inc. PowerEdge R740xd/04FC42, BIOS 2.6.4 04/09/2020 [ 2007.118168] RIP: 0010:__list_add_valid.cold.0+0x12/0x28 [ 2007.118169] Code: 85 5d 00 00 00 48 8b 50 08 48 39 f2 0f 85 42 00 00 00 b8 01 00 00 00 c3 48 89 d1 48 c7 c7 20 1e 6e ad 48 89 c2 e8 e0 11 cd ff <0f> 0b 48 89 c1 4c 89 c6 48 c7 c7 78 1e 6e ad e8 cc 11 cd ff 0f 0b [ 2007.118170] RSP: 0018:ffffa598d9b0be68 EFLAGS: 00010246 [ 2007.118171] RAX: 0000000000000075 RBX: ffff8d86a0aadd00 RCX: 0000000000000001 [ 2007.118171] RDX: 0000000000000000 RSI: ffffffffad6cf723 RDI: 00000000ffffffff [ 2007.118172] RBP: ffff8d8694112010 R08: 0000000000000000 R09: 0000000000000a36 [ 2007.118173] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8d86a0aadd00 [ 2007.118173] R13: ffffffffac71f240 R14: ffff8d869d3758a0 R15: ffff8d993af88000 [ 2007.118174] FS: 0000000000000000(0000) GS:ffff8d86a0a80000(0000) knlGS:0000000000000000 [ 2007.118174] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2007.118175] CR2: 00007fa2d29211a0 CR3: 00000011d8c0e002 CR4: 00000000007606e0 [ 2007.118175] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2007.118176] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 2007.118176] PKRU: 55555554 [ 2007.118176] Call Trace: [ 2007.118180] __napi_schedule_irqoff+0x34/0x60 [ 2007.118191] i40e_msix_clean_rings+0x3f/0x50 [i40e] [ 2007.118195] irq_forced_thread_fn+0x30/0x80 [ 2007.118196] irq_thread+0xdd/0x180 [ 2007.118198] ? wake_threads_waitq+0x30/0x30 [ 2007.118198] ? irq_thread_check_affinity+0x20/0x20 [ 2007.118202] kthread+0x112/0x130 [ 2007.118203] ? kthread_flush_work_fn+0x10/0x10 [ 2007.118207] ret_from_fork+0x1f/0x40 The following tracing bits have been then collected, which seem relevant. irq/532--4667 36....2 13343.788389: softirq_raise: vec=3 [action=NET_RX] irq/532--4667 36....2 13343.788391: kernel_stack: => trace_event_raw_event_softirq (ffffffff83eb6f77) => __raise_softirq_irqoff (ffffffff83eb7acd) => i40e_msix_clean_rings (ffffffffc03fe6ef) => irq_forced_thread_fn (ffffffff83f1f2a0) => irq_thread (ffffffff83f1f58d) => kthread (ffffffff83ed5f42) => ret_from_fork (ffffffff8480023f) irq/529--4664 36d.h.2 13343.788402: softirq_raise: vec=3 [action=NET_RX] irq/529--4664 36d.h.2 13343.788404: kernel_stack: => trace_event_raw_event_softirq (ffffffff83eb6f77) => __raise_softirq_irqoff (ffffffff83eb7acd) => rps_trigger_softirq (ffffffff8452fa49) => flush_smp_call_function_queue (ffffffff83f591c3) => smp_call_function_single_interrupt (ffffffff8480294b) => call_function_single_interrupt (ffffffff84801c3f) => __list_add_valid (ffffffff8424b050) => __napi_schedule_irqoff (ffffffff8452fa94) => i40e_msix_clean_rings (ffffffffc03fe6ef) => irq_forced_thread_fn (ffffffff83f1f2a0) => irq_thread (ffffffff83f1f58d) => kthread (ffffffff83ed5f42) => ret_from_fork (ffffffff8480023f) My understanding is that rps_trigger_softirq() sneaked in while i40e_msix_clean_rings() threaded irq was running and, since the latter is using napi_schedule_irqoff(), the softnet_data poll_list got eventually corrupted. Now, doing s/napi_schedule_irqoff/napi_schedule/ in the i40e driver seem to cure the problem. I'm not sure that there isn't a more general solution, though. Is it expected that napi_schedule_irqoff users in RT know what they are doing or do we want/need to fix this in a more general way? Thanks! Juri