[Crash-utility] Re: [PATCH] RISCV64: add panic signature to panic_msg to properly display the PANIC message

Date: Fri, 8 Nov 2024 21:13:19 +1300 From: Tao Liu <ltao(a)redhat.com&gt; Subject: [Crash-utility] Re: [PATCH] RISCV64: add panic signature to panic_msg to properly display the PANIC message To: Austin Kim <austindh.kim(a)gmail.com&gt; Cc: lijiang <lijiang(a)redhat.com&gt;, devel(a)lists.crash-utility.osci.io, Austin Kim <austindhkim(a)gmail.com&gt;, 김동현 <austin.kim(a)lge.com&gt; Message-ID: < CAO7dBbWgemin4FPcSkgQ21dbbqW-S8KeFtNuaH8otOZvNWQVSA(a)mail.gmail.com&gt; Content-Type: text/plain; charset="UTF-8" Hi Austin & Lianbo, On Fri, Nov 8, 2024 at 1:35 AM Austin Kim <austindh.kim(a)gmail.com&gt; wrote: > > Hello Lianbo, > > 2024년 11월 6일 (수) 오후 12:53, lijiang <lijiang(a)redhat.xn--com&gt;-4f21ay07k 작성: > > > > Hi, Austin > > Thank you for the patch. > > > > On Fri, Nov 1, 2024 at 5:19 PM < devel-request(a)lists.crash-utility.osci.io&gt; wrote: > >> > >> Date: Tue, 29 Oct 2024 17:32:07 +0900 > >> From: Austin Kim <austindh.kim(a)gmail.com&gt; > >> Subject: [Crash-utility] [PATCH] RISCV64: add panic signature to > >> panic_msg to properly display the PANIC message > >> To: devel(a)lists.crash-utility.osci.io > >> Cc: austindh.kim(a)gmail.com, austin.kim(a)lge.com > >> Message-ID: <20241029083207.GA30130@adminpc-PowerEdge-R7525> > >> Content-Type: text/plain; charset=us-ascii > >> > >> Using 'sys' command, we can view the panic message with general system > >> information. If we run RISCV64-based vmcore, PANIC message is not properly > >> displayed. > >> > >> The reason is that "Unable to handle kernel" is first printed in the kernel log > >> when exception occurs in the RISC-V based Linux kernel. The corresponding > >> kernel commit is 21733cb518471. > >> > >> Without the patch: > >> crash> sys > >> KERNEL: vmlinux [TAINTED] > >> DUMPFILE: vmcore > >> CPUS: 4 > >> DATE: Thu Aug 22 16:13:08 KST 2024 > >> UPTIME: 00:33:25 > >> LOAD AVERAGE: 0.07, 0.07, 0.02 > >> TASKS: 385 > >> NODENAME: starfive > >> RELEASE: 6.6.20+ > >> VERSION: #13 SMP Mon Aug 19 12:58:52 KST 2024 > >> MACHINE: riscv64 (unknown Mhz) > >> MEMORY: 4 GB > >> PANIC: "" > >> > >> With the patch: > >> crash> sys > >> KERNEL: vmlinux [TAINTED] > >> DUMPFILE: vmcore > >> CPUS: 4 > >> DATE: Thu Aug 22 16:13:08 KST 2024 > >> UPTIME: 00:33:25 > >> LOAD AVERAGE: 0.07, 0.07, 0.02 > >> TASKS: 385 > >> NODENAME: starfive > >> RELEASE: 6.6.20+ > >> VERSION: #13 SMP Mon Aug 19 12:58:52 KST 2024 > >> MACHINE: riscv64 (unknown Mhz) > >> MEMORY: 4 GB > >> PANIC: "Unable to handle kernel access to user memory without uaccess routines at virtual address 0000000000000000" > >> > >> Signed-off-by: Austin Kim <austindh.kim(a)gmail.com&gt; > >> --- > >> task.c | 1 + > >> 1 file changed, 1 insertion(+) > >> > >> diff --git a/task.c b/task.c > >> index d52ce0b..443f488 100644 > >> --- a/task.c > >> +++ b/task.c > >> @@ -6330,6 +6330,7 @@ static const char* panic_msg[] = { > >> "[Hardware Error]: ", > >> "Bad mode in ", > >> "Oops: ", > >> + "Unable to handle kernel access ", > > > > > > I would tend to search the panic keywords again as below, which can cover both riscv64 and aarch64 cases. > > > > diff --git a/task.c b/task.c > > index c131cc32067d..9613adebab57 100644 > > --- a/task.c > > +++ b/task.c > > @@ -6392,6 +6392,9 @@ get_panicmsg(char *buf) > > get_symbol_data("sysrq_pressed", sizeof(int), &msg_found); > > break; > > } > > + > > + /* try to search panic string with panic keywords*/ > > + search_panic_task_by_keywords(buf, &msg_found); > > } With this patch applied, no regression found, I think this one can work.

Thanks, Tao Liu > > > > found: > > > > > > What do you think? I haven't tested this one, not sure if it can work for you, could you please try it? > > Thank you for the positive feedback on the patch and for sharing > another great idea. > I tested the patch you suggested, and it worked well on my side. > Here’s the crash message: > > crash> sys | grep PANIC > PANIC: "Unable to handle kernel access to user memory without > uaccess routines at virtual address 0000000000000000" > > This new patch is useful not only for RISC-V but also for a wider > range of architectures, > and it seems like a better approach than modifying panic_msg[]. > > Best regards, > Austin Kim > > > Tao, can we also do a regression test to double check if there are any risks? > > > > Thanks > > Lianbo > > > > > >> > >> }; > >> > >> #define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0])) > >> -- > >> 2.17.1 >