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Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:50760) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lKLZx-0005bT-AU; Thu, 11 Mar 2021 13:42:17 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1lKLZt-0001gO-FC; Thu, 11 Mar 2021 13:42:13 +0000 Date: Thu, 11 Mar 2021 13:42:13 +0000 From: Russell King - ARM Linux admin To: Dmitry Vyukov Cc: Linus Walleij , Arnd Bergmann , Krzysztof Kozlowski , syzkaller , kasan-dev , Hailong Liu , Linux ARM Subject: Re: Arm + KASAN + syzbot Message-ID: <20210311134213.GI1463@shell.armlinux.org.uk> References: <20210119123659.GJ1551@shell.armlinux.org.uk> <20210119194827.GL1551@shell.armlinux.org.uk> <20210127101911.GL1551@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210311_134529_259639_245D5941 X-CRM114-Status: GOOD ( 17.52 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; 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 Thu, Mar 11, 2021 at 11:54:22AM +0100, Dmitry Vyukov wrote: > The instance has KASAN disabled because Go binaries don't run on KASAN kernel: > https://lore.kernel.org/linux-arm-kernel/CACT4Y+YdJoNTqnBSELcEbcbVsKBtJfYUc7_GSXbUQfAJN3JyRg@mail.gmail.com/ I suspect this is unlikely to change as it hasn't attracted any interest. Someone using Go and KASAN needs to debug this... I suspect it may be due to something being KASAN instrumented that shouldn't be. > It also has KCOV disabled (so no coverage guidance and coverage > reports for now) because KCOV does not fully work on arm: > https://lore.kernel.org/linux-arm-kernel/20210119130010.GA2338@C02TD0UTHF1T.local/T/#m78fdfcc41ae831f91c93ad5dabe63f7ccfb482f0 Looking at those, they look a bit weird. First: PC is at check_kcov_mode kernel/kcov.c:163 [inline] PC is at __sanitizer_cov_trace_pc+0x40/0x78 kernel/kcov.c:197 Why is this duplicated? Second: sp : 8b4e6078 ip : 8b4e6088 fp : 8b4e6084 ... Process (pid: 0, stack limit = 0x147f9c36) The stack limit is definitely wrong, and it looks like the thread_info is likely wrong too. Given the value of "sp" I wonder if the kernel stack has overflowed and overwritten the thread_info structure at the bottom of the kernel stack. I've no idea what effect KCOV would have on the kernel - it's something I've never looked at, so I don't know what changes it would impose. At this point, as there's very little commercial interest in arm32, there's probably little hope in getting this sorted. It may make sense to force KCOV to be disabled for arm32. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel