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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 DD5CCC433DB for ; Tue, 16 Mar 2021 16:14:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7399650F8 for ; Tue, 16 Mar 2021 16:14:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238510AbhCPQN5 (ORCPT ); Tue, 16 Mar 2021 12:13:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238502AbhCPQNt (ORCPT ); Tue, 16 Mar 2021 12:13:49 -0400 Received: from mail-qt1-x835.google.com (mail-qt1-x835.google.com [IPv6:2607:f8b0:4864:20::835]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2638C06174A for ; Tue, 16 Mar 2021 09:13:48 -0700 (PDT) Received: by mail-qt1-x835.google.com with SMTP id r14so12033777qtt.7 for ; Tue, 16 Mar 2021 09:13:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=rbhnLt5Po3f4G5kXjVguaqd4p3iDZvyNukbT4E52Qls=; b=BOyj8/P7Nwc+5cPDa7gAcH6HI5QbkFpZoeri7JOM4JTZf9Q7VBjhaMn/YjIVCFAvc7 oWD4HH+Px5/hFPs/TvTIwMmYwhUo8PdnEQ7zfQcyK5zoQWADKrNpkD1GLt1Jeih2SYdt Wcig87PXy13Po8QOW9RHObYCkIel2GznrGPFLKVVXCGG5lRmZ3blFR0kfkSwD7ZHb+uU 1HEVDIM1qoHbs3Fyrme9khgO/D4NU3P/7AW36wAUY+QueIcuwtgxHMAbSr6XOjIKvMtG O21ufWxOk4AAsv4rNUNW4b7n/16QNkWzyiJ1odPBG1vBJMIr3otTOjkj1gdiYdNQSYlV pIjg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=rbhnLt5Po3f4G5kXjVguaqd4p3iDZvyNukbT4E52Qls=; b=tIh0WmoN4V92yGF10uYXb1k7hFhtyE2W1Ez2KhqnyP4MO70t8zjWPO5p3VVb2b64tr dpMZKB1m5+UMWJ/3YD5kUnyOPIoa3ANDrUMoiKGBEncckAqPrVDrI3EuPT4hNaSv8amy hlfMAdt5DUQehoVISJ7MkzoW+h9Gr9T76GSkZc5pp0O1MKvKwNLwJ+jXP+YTSa8I/17n TJy+b1QjqZwRWiOpm5aNt8MXD0DIEF7301oyKBsIf6RNLZx6mG8d/Ek2GKyPt7zkF9F9 N7rUvRh+LITm9diKgLg0cqHUvXU5DELapn4OqsHrOmgrLFG7XkGgoEmhdcRm/MZgJuvd zOEA== X-Gm-Message-State: AOAM532o4yQGWQFRm/V8AkXHKAS20bqrxgJ+vJ0rEgR49nyWOsERR1L6 lDVIuYAZ1112xi7+K59VGH78CqcSqQFYOR/T/6CVpQ== X-Google-Smtp-Source: ABdhPJyAxwxQDmSMM15n0z9V4H5wXTd3E4ty8mFcjXa3K2UqMp8/sXOv3+YW23BrgCK4XlTQg8Ayb1tzb7ZNtgCaKsg= X-Received: by 2002:ac8:4558:: with SMTP id z24mr444357qtn.66.1615911227679; Tue, 16 Mar 2021 09:13:47 -0700 (PDT) MIME-Version: 1.0 References: <00000000000069802205bda22b7f@google.com> <20210316155102.GP1463@shell.armlinux.org.uk> In-Reply-To: From: Dmitry Vyukov Date: Tue, 16 Mar 2021 17:13:36 +0100 Message-ID: Subject: Re: [syzbot] kernel panic: corrupted stack end in openat To: Arnd Bergmann Cc: Russell King - ARM Linux admin , syzbot , Linus Walleij , Linux ARM , Andrew Morton , LKML , Linux-MM , syzkaller-bugs , =?UTF-8?Q?Uwe_Kleine=2DK=C3=B6nig?= Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 16, 2021 at 5:03 PM Arnd Bergmann wrote: > > On Tue, Mar 16, 2021 at 4:51 PM Russell King - ARM Linux admin > wrote: > > On Tue, Mar 16, 2021 at 04:44:45PM +0100, Arnd Bergmann wrote: > > > On Tue, Mar 16, 2021 at 11:17 AM Dmitry Vyukov wrote: > > > > The compiler is gcc version 10.2.1 20210110 (Debian 10.2.1-6) > > > > > > Ok, building with Ubuntu 10.2.1-1ubuntu1 20201207 locally, that's > > > the closest I have installed, and I think the Debian and Ubuntu versions > > > are generally quite close in case of gcc since they are maintained by > > > the same packagers. > > > > ... which shouldn't be a problem - that's just over 1/4 of the stack > > space. Could it be the syzbot's gcc is doing something weird and > > inflating the stack frames? > > It's possible, I think that's really unlikely given that it's just Debian's > gcc, which is as close to mainline as the version I was using. > > Uwe's DEBUG_STACKOVERFLOW patch from a while ago might > help if this was the problem though: > https://lore.kernel.org/linux-arm-kernel/20200108082913.29710-1-u.kleine-koenig@pengutronix.de/ > > My best guess is something going wrong in the interrupt > that triggered the preempt_schedule() which ended up calling > task_stack_end_corrupted() in schedule_debug(), as you suggested > earlier. FWIW I see slightly larger frames with the config: 073ab64 : 8073ab64: e1a0c00d mov ip, sp 8073ab68: e92ddff0 push {r4, r5, r6, r7, r8, r9, sl, fp, ip, lr, pc} 8073ab6c: e24cb004 sub fp, ip, #4 8073ab70: e24ddfa7 sub sp, sp, #668 ; 0x29c page_alloc can also do reclaim, I had the impression that reclaim can be quite heavy-weight in all respects. 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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 854C7C433E0 for ; Tue, 16 Mar 2021 16:15:43 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0098A650FB for ; Tue, 16 Mar 2021 16:15:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0098A650FB Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Mar 16, 2021 at 5:03 PM Arnd Bergmann wrote: > > On Tue, Mar 16, 2021 at 4:51 PM Russell King - ARM Linux admin > wrote: > > On Tue, Mar 16, 2021 at 04:44:45PM +0100, Arnd Bergmann wrote: > > > On Tue, Mar 16, 2021 at 11:17 AM Dmitry Vyukov wrote: > > > > The compiler is gcc version 10.2.1 20210110 (Debian 10.2.1-6) > > > > > > Ok, building with Ubuntu 10.2.1-1ubuntu1 20201207 locally, that's > > > the closest I have installed, and I think the Debian and Ubuntu versions > > > are generally quite close in case of gcc since they are maintained by > > > the same packagers. > > > > ... which shouldn't be a problem - that's just over 1/4 of the stack > > space. Could it be the syzbot's gcc is doing something weird and > > inflating the stack frames? > > It's possible, I think that's really unlikely given that it's just Debian's > gcc, which is as close to mainline as the version I was using. > > Uwe's DEBUG_STACKOVERFLOW patch from a while ago might > help if this was the problem though: > https://lore.kernel.org/linux-arm-kernel/20200108082913.29710-1-u.kleine-koenig@pengutronix.de/ > > My best guess is something going wrong in the interrupt > that triggered the preempt_schedule() which ended up calling > task_stack_end_corrupted() in schedule_debug(), as you suggested > earlier. FWIW I see slightly larger frames with the config: 073ab64 : 8073ab64: e1a0c00d mov ip, sp 8073ab68: e92ddff0 push {r4, r5, r6, r7, r8, r9, sl, fp, ip, lr, pc} 8073ab6c: e24cb004 sub fp, ip, #4 8073ab70: e24ddfa7 sub sp, sp, #668 ; 0x29c page_alloc can also do reclaim, I had the impression that reclaim can be quite heavy-weight in all respects. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel