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Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:45044) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kRvfG-0003sM-JE; Mon, 12 Oct 2020 12:06:50 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1kRvfA-0005YE-9H; Mon, 12 Oct 2020 12:06:44 +0100 Date: Mon, 12 Oct 2020 12:06:44 +0100 From: Russell King - ARM Linux admin To: Sebastian Andrzej Siewior Subject: Re: [PATCH] arm:traps: Don't print stack or raw PC/LR values in backtraces Message-ID: <20201012110643.GO1551@shell.armlinux.org.uk> References: <20201009075957.110017-1-nixiaoming@huawei.com> <20201009080849.GM1551@shell.armlinux.org.uk> <20201009081820.jargnmck6zfkzegx@linutronix.de> <20201011213238.GN1551@shell.armlinux.org.uk> <20201012100318.4ikyffo3mcnq6bnl@linutronix.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201012100318.4ikyffo3mcnq6bnl@linutronix.de> 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-20201012_070702_041527_19A753D5 X-CRM114-Status: GOOD ( 24.42 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wangle6@huawei.com, walken@google.com, amanieu@gmail.com, dima@arista.com, Xiaoming Ni , vincent.whitchurch@axis.com, linux-kernel@vger.kernel.org, mingo@kernel.org, ben.dooks@codethink.co.uk, tglx@linutronix.de, viro@zeniv.linux.org.uk, jpoimboe@redhat.com, luohaizheng@huawei.com, akpm@linux-foundation.org, ldufour@linux.ibm.com, will@kernel.org, christian.brauner@ubuntu.com, linux-arm-kernel@lists.infradead.org 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 Mon, Oct 12, 2020 at 12:03:18PM +0200, Sebastian Andrzej Siewior wrote: > On 2020-10-11 22:32:38 [+0100], Russell King - ARM Linux admin wrote: > > I don't have a problem getting rid of the hex numbers in [< >] > > although then I will need to convert the symbol back to an address > > using the vmlinux to then calculate its address to then find the > > appropriate place in the objdump output - because objdump does > > _not_ use the symbol+offset annotation. Yes, I really do look up > > the numeric addresses in the objdump output to then read the > > disassembly. > > > > $ objdump -d vmlinux | less > > > > and then search for the address is the fastest and most convenient > > way for me rather than having to deal with some random script. > > > > Maybe I'm just antequated about how I do my debugging, but this > > seems to me to be the most efficient and fastest way. > > besides what Josh mentioned, there is also > scripts/decode_stacktrace.sh path-vmlinux > > where you can copy/paste your complete stack trace / dmesg and it will > decode it line by line. So if you invoke > scripts/decode_stacktrace.sh vmlinux.o > > and paste this: > > |[ 7.568155] 001: PC is at do_work_pending+0x190/0x5c4 > |[ 7.568641] 001: LR is at slow_work_pending+0xc/0x20 > |[ 7.569232] 001: Backtrace: > |[ 7.569367] 001: [] (do_work_pending) from [] (slow_work_pending+0xc/0x20) > > you get this in return: > |[ 7.568155] 001: PC is at do_work_pending (arch/arm/kernel/signal.c:616 arch/arm/kernel/signal.c:670) > |[ 7.568641] 001: LR is at slow_work_pending (arch/arm/kernel/entry-common.S:112) > |[ 7.569232] 001: Backtrace: > |[ 7.569367] 001: (do_work_pending) from slow_work_pending (arch/arm/kernel/entry-common.S:112) That's assuming: 1) you have built the kernel with debug information enabled (I never do, it uses way too much disk space) 2) you want to look at the C code rather than the assembly. I think you've assumed that I debug oopses by looking primerily at C code. I don't. I understand the assembly and then look at the C code. I've stated in the past in detail how I debug the kernel when someone has posted a hard-to-debug oops, going through the validation of the dumped state, sometimes to find the bug in a function several parents up from the one where the oops actually occurred. However, as I've said, I have little problem removing the hex values inside [< >] as I can work around that. Removing the other information is what I'm objecting to. -- 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