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Tue, 16 Mar 2021 02:51:26 -0700 (PDT) MIME-Version: 1.0 References: <00000000000069802205bda22b7f@google.com> <20210316092420.GN1463@shell.armlinux.org.uk> In-Reply-To: <20210316092420.GN1463@shell.armlinux.org.uk> From: Dmitry Vyukov Date: Tue, 16 Mar 2021 10:51:14 +0100 Message-ID: Subject: Re: [syzbot] kernel panic: corrupted stack end in openat To: Russell King - ARM Linux admin Cc: syzbot , Arnd Bergmann , Linus Walleij , Linux ARM , Andrew Morton , LKML , Linux-MM , syzkaller-bugs Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 472028019143 X-Stat-Signature: gohpuiy1pw9kt3qc1346ksugpq3wka3x Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf16; identity=mailfrom; envelope-from=""; helo=mail-qk1-f174.google.com; client-ip=209.85.222.174 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615888287-361467 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 10:24 AM Russell King - ARM Linux admin wrote: > > On Tue, Mar 16, 2021 at 08:59:17AM +0100, Dmitry Vyukov wrote: > > On Tue, Mar 16, 2021 at 8:18 AM syzbot > > wrote: > > > > > > Hello, > > > > > > syzbot found the following issue on: > > > > > > HEAD commit: 1e28eed1 Linux 5.12-rc3 > > > git tree: upstream > > > console output: https://syzkaller.appspot.com/x/log.txt?x=167535e6d00000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=e0cee1f53de33ca3 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=0b06ef9b44d00d600183 > > > userspace arch: arm > > > > > > Unfortunately, I don't have any reproducer for this issue yet. > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > > Reported-by: syzbot+0b06ef9b44d00d600183@syzkaller.appspotmail.com > > > > +arm32 maintainer > > I think this is a real stack overflow on arm32, the stack is indeed deep. > > There's no way to know for sure because there's no indication of the > stack pointer in this, so we don't know how much space remains. > Therefore we don't know whether this is something in the dumped > path, or an interrupt causing it. Agree, to know for sure we would need support for VMAP_STACK. But do we really need to know it? If it's an interrupt on top, it does not make any difference?