I tried these patches but still don't get correct bt output.

From 4ae6ab8d181deea53ece847007d27d228166370d Mon Sep 17 00:00:00 2001

Rabin, New it works fine! Thanks! Sagar

On Wed, Oct 19, 2016 at 3:36 PM, Rabin Vincent <rabin(a)rab.in&gt; wrote: > On Tue, Oct 18, 2016 at 04:10:51PM -0700, Sagar Borikar wrote: >> I tried these patches but still don't get correct bt output. > > I think I see the problem now. Your EPC is 0 so we hit the if > (!IS_KVADDR(current.pc)) condition on the first iteration of the > backtrace loop and exit without trying futher. > > Could you please try the following patch? Please include a log with > debugging enabled ("set debug 8") if it still doesn't work. Thanks. > > 8<------------------ > >From 4ae6ab8d181deea53ece847007d27d228166370d Mon Sep 17 00:00:00 2001 > From: Rabin Vincent <rabinv(a)axis.com&gt; > Date: Thu, 20 Oct 2016 00:19:33 +0200 > Subject: [PATCH] mips: allow one invalid PC at start or after exception > > Before: > > PID: 2810 TASK: 835e41a8 CPU: 1 COMMAND: "sh" > #0 [8315bb00] crash_kexec at 800b26a4 > #1 [8315bbe0] panic at 800dc0fc > #2 [8315bc20] die at 8001fa74 > #3 [8315bc50] __do_page_fault at 8002de74 > #4 [8315bd28] ret_from_irq at 80019624 > $ 0 : 00000000 00000001 80690000 00000000 > $ 4 : 00000063 812972dc 81297db8 000000c2 > $ 8 : 00004b38 00000001 80680000 80620000 > $12 : 00000104 00000002 00000000 00000000 > $16 : 80622530 80620000 00000063 80620000 > $20 : 80622470 00000001 00000000 00b9f322 > $24 : 00000003 00000000 00440000 800dca80 > $28 : 8315a000 8315bde0 00000000 80313b30 > Hi : 00000046 > Lo : 0f5c2a0e > epc : 00000000 > ra : 80313b30 __handle_sysrq+0x144 > Status: 1100fc03 > Cause : 10800008 > BadVA : 00000000 > > After: > > crash> bt > PID: 2810 TASK: 835e41a8 CPU: 1 COMMAND: "sh" > #0 [8315bb00] crash_kexec at 800b26a4 > #1 [8315bbe0] panic at 800dc0fc > #2 [8315bc20] die at 8001fa74 > #3 [8315bc50] __do_page_fault at 8002de74 > #4 [8315bd28] ret_from_irq at 80019624 > $ 0 : 00000000 00000001 80690000 00000000 > $ 4 : 00000063 812972dc 81297db8 000000c2 > $ 8 : 00004b38 00000001 80680000 80620000 > $12 : 00000104 00000002 00000000 00000000 > $16 : 80622530 80620000 00000063 80620000 > $20 : 80622470 00000001 00000000 00b9f322 > $24 : 00000003 00000000 00440000 800dca80 > $28 : 8315a000 8315bde0 00000000 80313b30 > Hi : 00000046 > Lo : 0f5c2a0e > epc : 00000000 > ra : 80313b30 __handle_sysrq+0x144 > Status: 1100fc03 > Cause : 10800008 > BadVA : 00000000 > #5 [8315bde0] (invalid) at 0 > #6 [8315bde0] __handle_sysrq at 80313b30 > #7 [8315be18] write_sysrq_trigger at 80313c24 > #8 [8315be38] proc_reg_write at 80178074 > #9 [8315be58] __vfs_write at 8011ea78 > #10 [8315bec0] vfs_write at 8011fe7c > #11 [8315bef0] sys_write at 801201e8 > #12 [8315bf28] syscall_common at 800275c8 > --- > mips.c | 35 +++++++++++++++++++++++++---------- > 1 file changed, 25 insertions(+), 10 deletions(-) > > diff --git a/mips.c b/mips.c > index 6cd8d1f..1bb4d27 100644 > --- a/mips.c > +++ b/mips.c > @@ -413,7 +413,7 @@ mips_dump_backtrace_entry(struct bt_info *bt, struct > syment *sym, > struct mips_unwind_frame *current, > struct mips_unwind_frame *previous, int level) > { > - const char *name = sym->name; > + const char *name = sym ? sym->name : "(invalid)"; > struct load_module *lm; > char *name_plus_offset; > char buf[BUFSIZE]; > @@ -447,7 +447,7 @@ mips_dump_backtrace_entry(struct bt_info *bt, struct > syment *sym, > fprintf(fp, " %s\n", buf); > } > > - if (mips_is_exception_entry(sym)) { > + if (sym && mips_is_exception_entry(sym)) { > char pt_regs[SIZE(pt_regs)]; > > GET_STACK_DATA(current->sp, &pt_regs, SIZE(pt_regs)); > @@ -533,6 +533,7 @@ mips_back_trace_cmd(struct bt_info *bt) > { > struct mips_unwind_frame current, previous; > int level = 0; > + int invalid_ok = 1; > > if (bt->flags & BT_REGS_NOT_FOUND) > return; > @@ -549,22 +550,24 @@ mips_back_trace_cmd(struct bt_info *bt) > } > > while (INSTACK(current.sp, bt)) { > - struct syment *symbol; > + struct syment *symbol = NULL; > ulong offset; > > if (CRASHDEBUG(8)) > fprintf(fp, "level %d pc %#lx ra %#lx sp %lx\n", > level, current.pc, current.ra, current.sp); > > - if (!IS_KVADDR(current.pc)) > + if (!IS_KVADDR(current.pc) && !invalid_ok) > return; > > symbol = value_search(current.pc, &offset); > - if (!symbol) { > + if (!symbol && !invalid_ok) { > error(FATAL, "PC is unknown symbol (%lx)", > current.pc); > return; > } > > + invalid_ok = 0; > + > /* > * If we get an address which points to the start of a > * function, then it could one of the following: > @@ -586,7 +589,7 @@ mips_back_trace_cmd(struct bt_info *bt) > * * ret_from_fork > * * ret_from_kernel_thread > */ > - if (!current.ra && !offset && !STRNEQ(symbol->name, > "ret_from")) { > + if (!current.ra && !offset && symbol && > !STRNEQ(symbol->name, "ret_from")) { > if (CRASHDEBUG(8)) > fprintf(fp, "zero offset at %s, try > previous symbol\n", > symbol->name); > @@ -598,7 +601,7 @@ mips_back_trace_cmd(struct bt_info *bt) > } > } > > - if (mips_is_exception_entry(symbol)) { > + if (symbol && mips_is_exception_entry(symbol)) { > struct mips_pt_regs_main *mains; > struct mips_pt_regs_cp0 *cp0; > char pt_regs[SIZE(pt_regs)]; > @@ -617,18 +620,30 @@ mips_back_trace_cmd(struct bt_info *bt) > if (CRASHDEBUG(8)) > fprintf(fp, "exception pc %#lx ra %#lx sp > %lx\n", > previous.pc, previous.ra, > previous.sp); > - } else { > + > + /* The PC causing the exception may have been > invalid */ > + invalid_ok = 1; > + } else if (symbol) { > mips_analyze_function(symbol->value, offset, > &current, &previous); > + } else { > + /* > + * The current PC is invalid. Assume that the code > + * jumped through a invalid pointer and that the SP > has > + * not been adjusted. > + */ > + previous.sp = current.sp; > } > > mips_dump_backtrace_entry(bt, symbol, &current, &previous, > level++); > - if (!current.ra) > - break; > > current.pc = current.ra; > current.sp = previous.sp; > current.ra = previous.ra; > > + if (CRASHDEBUG(8)) > + fprintf(fp, "next %d pc %#lx ra %#lx sp %lx\n", > + level, current.pc, current.ra, current.sp); > + > previous.sp = previous.pc = previous.ra = 0; > } > } > -- > 2.1.4 > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://www.redhat.com/mailman/listinfo/crash-utility -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility