From 3b3fa11bc7000bb86c9fd30703da3689a9a9758d Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 20 Oct 2016 11:34:43 -0500 Subject: [PATCH] x86/dumpstack: Print any pt_regs found on the stack Now that we can find pt_regs registers on the stack, print them. Here's an example of what it looks like: Call Trace: [] dump_stack+0x86/0xc3 [] hrtimer_interrupt+0xb3/0x1c0 [] local_apic_timer_interrupt+0x36/0x60 [] smp_apic_timer_interrupt+0x3d/0x50 [] apic_timer_interrupt+0x9e/0xb0 RIP: 0010:[] [] _raw_spin_unlock_irq+0x33/0x60 RSP: 0018:ffff880079c4f760 EFLAGS: 00000202 RAX: ffff880078738000 RBX: ffff88007d3da0c0 RCX: 0000000000000007 RDX: 0000000000006d78 RSI: ffff8800787388f0 RDI: ffff880078738000 RBP: ffff880079c4f768 R08: 0000002199088f38 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff81e0d540 R13: ffff8800369fb700 R14: 0000000000000000 R15: ffff880078738000 [] finish_task_switch+0xb4/0x250 [] ? finish_task_switch+0x76/0x250 [] __schedule+0x3e1/0xb20 ... [] trace_do_page_fault+0x58/0x2c0 [] do_async_page_fault+0x2c/0xa0 [] async_page_fault+0x28/0x30 RIP: 0010:[] [] __clear_user+0x42/0x70 RSP: 0018:ffff880079c4fd38 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000000000138 RCX: 0000000000000138 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000000061b640 RBP: ffff880079c4fd48 R08: 0000002198feefd7 R09: ffffffff82a40928 R10: 0000000000000001 R11: 0000000000000000 R12: 000000000061b640 R13: 0000000000000000 R14: ffff880079c50000 R15: ffff8800791d7400 [] ? __clear_user+0x23/0x70 [] clear_user+0x2b/0x40 [] load_elf_binary+0x1472/0x1750 [] search_binary_handler+0xa1/0x200 [] do_execveat_common.isra.36+0x6cb/0x9f0 [] ? do_execveat_common.isra.36+0x623/0x9f0 [] SyS_execve+0x3a/0x50 [] do_syscall_64+0x6c/0x1e0 [] entry_SYSCALL64_slow_path+0x25/0x25 RIP: 0033:[<00007fd2e2f2e537>] [<00007fd2e2f2e537>] 0x7fd2e2f2e537 RSP: 002b:00007ffc449c5fc8 EFLAGS: 00000246 RAX: ffffffffffffffda RBX: 00007ffc449c8860 RCX: 00007fd2e2f2e537 RDX: 000000000127cc40 RSI: 00007ffc449c8860 RDI: 00007ffc449c6029 RBP: 00007ffc449c60b0 R08: 65726f632d667265 R09: 00007ffc449c5e20 R10: 00000000000005a7 R11: 0000000000000246 R12: 000000000127cc40 R13: 000000000127ce05 R14: 00007ffc449c6029 R15: 000000000127ce01 Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/5cc2c512ec82cfba00dd22467644d4ed751a48c0.1476973742.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/dumpstack.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 32511772b424..64281a1d4e48 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -82,7 +82,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, * - softirq stack * - hardirq stack */ - for (; stack; stack = stack_info.next_sp) { + for (regs = NULL; stack; stack = stack_info.next_sp) { const char *str_begin, *str_end; /* @@ -119,6 +119,15 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, if (!__kernel_text_address(addr)) continue; + /* + * Don't print regs->ip again if it was already printed + * by __show_regs() below. + */ + if (regs && stack == ®s->ip) { + unwind_next_frame(&state); + continue; + } + if (stack == ret_addr_p) reliable = 1; @@ -146,6 +155,11 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, * of the addresses will just be printed as unreliable. */ unwind_next_frame(&state); + + /* if the frame has entry regs, print them */ + regs = unwind_get_entry_regs(&state); + if (regs) + __show_regs(regs, 0); } if (str_end) -- 2.20.1