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Tue, 16 Mar 2021 09:03:45 -0700 (PDT) X-Gm-Message-State: AOAM533qHbF5zdGaRicRkf7nyv8kpk5nkyXMkQBShQDEEJ0c6QjfvOoG xspTYuaJDI8aj+JMtPniYQKmmqtxSzt5/7UbuqQ= X-Google-Smtp-Source: ABdhPJzvg7khTfsWw0+lYh5ooXKFpK4N7dQmAEpOTsDsESTAmD+qkzykYqJhHr+bPCnXpTkiKegc41OpcF0yH5B0hAg= X-Received: by 2002:a5d:4fcb:: with SMTP id h11mr6005224wrw.66.1615910625200; Tue, 16 Mar 2021 09:03:45 -0700 (PDT) MIME-Version: 1.0 References: <00000000000069802205bda22b7f@google.com> <20210316155102.GP1463@shell.armlinux.org.uk> In-Reply-To: <20210316155102.GP1463@shell.armlinux.org.uk> From: Arnd Bergmann Date: Tue, 16 Mar 2021 17:03:28 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [syzbot] kernel panic: corrupted stack end in openat To: Russell King - ARM Linux admin Cc: Dmitry Vyukov , 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" X-Provags-ID: V03:K1:z5IkA795qJB28uGs9g5dLwPyj15zymV74A34sDy7kyQ7/79+rns AOeyyHH87Y0DfrVI9EWbn0jhqVkLzp5M4oSGxLEYm1z5kepO70YY9x6GOTEjEmrH0JBrjGL JLauu/iscb3q7WtfNhTvY1v2NM0IcRXIYwsLalO+qlkBe2mUzQX7L23NZCZLdef7BVW6aKk x3+DWcwfVd4jmIu4/POUw== X-UI-Out-Filterresults: notjunk:1;V03:K0:58FPZqcO9AI=:gJlDPxS72MwUvdMHvztKYm KPQ7xJOwGsVnX2Twqccj69RSd++vnFHSZfEuGn1lJpC7hiXchUlu4h6EO5muDRKWzVFYfCWcT VsXIEf0aPJcdJqh2iKeaMVSnafUk5Z9D/3sMzZx0qtDYzsrOU7Lih9W1Rm088RvL0iw32vbWD FFr+dM3hsLi9MYDAC8C+5W7HmxE4cFX/fdgA0dsZ4/iR0xdXUfh+wJkEAEm9pv7v6HlVFxm1M j+7O/yn6cfLOrVmWJgajn4meWeRdiXP/YAiLloW8shOO7dwtGH89DWVgWXfDzvzbDBgiyRrXf mJ20tAVB42AfuMLSASbDKrOnMwU59iSEtTU3JROUwvBqOjWGRLcW9yAwyNUdi4+aRbo/NI18l yOfUQIf9Yll7TMN5u0VK/B/XkPt/o7bH45MFf7Txa8+wBGs8wlww3fkxPVXkMtPvyBQ0cQ1XU sZjBY1kwly7me90vWJYcmo4CCqV+ykiDdv6kB4Slbnn7lq6ksDfipK6FA/2CcOng9CPv7toEm cj87a0DmjQLx++emJ/TPrX0DM/4E1McVTIiWPHjmLu8X7YIP3lldkpOdJTZu9eOrg== X-Stat-Signature: twoi3auwsea9ss4efw6dmjnddae5qzfc X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 672D32000DAF Received-SPF: none (arndb.de>: No applicable sender policy available) receiver=imf18; identity=mailfrom; envelope-from=""; helo=mout.kundenserver.de; client-ip=212.227.126.135 X-HE-DKIM-Result: none/none X-HE-Tag: 1615910627-933369 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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. Arnd