Re: [Crash-utility] arm64: Support overflow stack panic

+ if (symbol_exists("overflow_stack") && + (sp = per_cpu_symbol_search("overflow_stack")) && + get_symbol_type("overflow_stack", NULL, req)) { + if (CRASHDEBUG(1)) { + fprintf(fp, "overflow_stack: \n"); + fprintf(fp, " type: %x, %s\n", + (int)req->typecode, + (req->typecode == TYPE_CODE_PTR) ? + "TYPE_CODE_PTR" : "other");

@@ -2673,6 +2724,12 @@ arm64_back_trace_cmd(struct bt_info *bt) bt->hp->eip : GET_STACK_ULONG(bt->hp->esp); stackframe.sp = bt->hp->esp + 8; bt->flags &= ~BT_REGS_NOT_FOUND; + } else if (arm64_on_overflow_stack(bt->tc->processor, bt->frameptr)) { + arm64_set_overflow_stack(bt); + bt->flags |= BT_OVERFLOW_STACK;

+ stackframe.sp = bt->stkptr; + stackframe.pc = bt->instptr; + stackframe.fp = bt->frameptr;

} else { if (arm64_on_irq_stack(bt->tc->processor, bt->frameptr)) { arm64_set_irq_stack(bt);

+static int +arm64_in_alternate_stack(int cpu, ulong stkptr) +{ + struct machine_specific *ms = machdep->machspec; + + return arm64_in_alternate_stackv(cpu, stkptr, + ms->irq_stacks, ms->irq_stack_size); +}

Hi Kazu Here are the latest patches for supporting to run bt command against a core dump with kernel stack overflow exception for arm64. Please help to review and advise if any further change needed. Tested bt command with options: bt bt -a bt -c 3 By the way, 'mach' command also updated to show overflow stacks info as same as IRQ stacks. Thanks Hong ________________________________ From: HAGIO KAZUHITO(萩尾　一仁) <k-hagio-ab(a)nec.com&gt; Sent: Wednesday, November 17, 2021 15:23 To: Hong Yang3 杨红 <hong.yang3(a)nio.com&gt; Cc: Discussion list for crash utility usage, maintenance and development <crash-utility(a)redhat.com&gt; Subject: RE: arm64: Support overflow stack panic 注意：此封邮件来自于公司外部，请注意信息安全！ Attention: This email comes from outside of the company, please pay attention to the information security! Hi Hong, Thank you for the patch and sending it to this list. -----Original Message----- > Hi Crash > > I'll keep refining the patch before it get approved: OK, so we will wait for the refined patch. Thanks, Kazu > > > 1. Fix the error in arm64_overflow_stack_init() which saved the overflow stack address into > ms->irqstacks[], which would cause bt command crash on other cpus. The normal IRQ stacks should be used > for bt command for other cpus. > 2. In addition to unwind on the overflow stack, try to go through the IRQ stack to find more useful > information > > Kernel stack overflow case would be rarely but I'd like to sharp the crash to cover this kind of issue. > > Best regards > Hong > ________________________________ > > From: Hong Yang3 杨红 > Sent: Tuesday, November 16, 2021 9:55 > To: crash-utility(a)redhat.com <crash-utility(a)redhat.com&gt; > Subject: arm64: Support overflow stack panic > > Hi All > > When I was trying to open a core of an overflow stack panic result, the bt command caused a segment fault, > after a while I figured out the overflow stack is not supported by crash utility. > > This patch is trying to initialize the overflow stack information on startup stage, and the bt command works > as expected to dump the correct call trace in the overflow stack, currently it only apply to arm64 target. > > I'm not sure if any other sub command also need to be fixed for full support for the overflow stack, please > advise and I'll try to improve the patch. > > Thanks > Hong YANG