From b13761ecd1d9977d2083da243e051e9f29097aef Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 28 Jul 2006 14:44:51 +0200 Subject: [PATCH] [PATCH] x86_64: Dump leftover backtrace entries when dwarf2 unwinder got stuck The dwarf2 unwinder currently often gets stuck because a lot of assembly code doesn't have proper dwarf2 annotiation yet. This currently often happens with __down. Should fix this by adding proper dwarf2 annotation to all inline assembly. However until that's done we need a quick fix for 2.6.18 to avoid incomplete backtraces. So when this happens dump the rest of the stack with the old unwinder instead of silently not dumping it. There was already a optional "both" mode that dumped both, but that was too ugly. I also clarified the headers for the different backtraces a bit. Also add a clear error message for missing dwarf2 annotation that people can work on. And I removed a dead variable left over from Ingo's changes. Cc: mingo@elte.hu Cc: jbeulich@novell.com Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/traps.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c index eb39a2775236..f7a9d1421078 100644 --- a/arch/x86_64/kernel/traps.c +++ b/arch/x86_64/kernel/traps.c @@ -254,7 +254,6 @@ void show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s { const unsigned cpu = safe_smp_processor_id(); unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr; - int i = 11; unsigned used = 0; printk("\nCall Trace:\n"); @@ -275,11 +274,20 @@ void show_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s if (unwind_init_blocked(&info, tsk) == 0) unw_ret = show_trace_unwind(&info, NULL); } - if (unw_ret > 0) { - if (call_trace > 0) + if (unw_ret > 0 && !arch_unw_user_mode(&info)) { +#ifdef CONFIG_STACK_UNWIND + unsigned long rip = info.regs.rip; + print_symbol("DWARF2 unwinder stuck at %s\n", rip); + if (call_trace == 1) { + printk("Leftover inexact backtrace:\n"); + stack = (unsigned long *)info.regs.rsp; + } else if (call_trace > 1) return; - printk("Legacy call trace:"); - i = 18; + else + printk("Full inexact backtrace again:\n"); +#else + printk("Inexact backtrace:\n"); +#endif } } @@ -1118,8 +1126,10 @@ static int __init call_trace_setup(char *s) call_trace = -1; else if (strcmp(s, "both") == 0) call_trace = 0; - else if (strcmp(s, "new") == 0) + else if (strcmp(s, "newfallback") == 0) call_trace = 1; + else if (strcmp(s, "new") == 0) + call_trace = 2; return 1; } __setup("call_trace=", call_trace_setup); -- 2.39.5