Messages in this thread Patch in this message | | | Date | Fri, 6 Jan 2017 10:50:32 -0600 | From | Josh Poimboeuf <> | Subject | Re: stack unwinder warning. |
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On Fri, Jan 06, 2017 at 12:09:47AM -0500, Dave Jones wrote: > On Thu, Jan 05, 2017 at 11:02:14AM -0600, Josh Poimboeuf wrote: > > On Thu, Jan 05, 2017 at 08:52:49AM -0600, Josh Poimboeuf wrote: > > > On Tue, Dec 27, 2016 at 02:00:30PM -0500, Dave Jones wrote: > > > > I'm not sure what to make of this. Josh ? (4.10-rc1) > > > > > > > > WARNING: kernel stack frame pointer at ffffc900003e7858 in trinity-c6:29122 has bad value ffffffff82103a80 > > > > unwind stack type:0 next_sp: (null) mask:2 graph_idx:0 > > > > ffffc900003e7808: ffffffff811a02e5 (ring_buffer_lock_reserve+0x1d5/0x580) > > > > ffffc900003e7810: ffffffff8119adc3 (rb_commit+0x93/0x350) > > > > ffffc900003e7818: ffffffff811b31d4 (function_trace_call+0x104/0x1f0) > > > > ffffc900003e7820: ffff8804f10ec000 (0xffff8804f10ec000) > > > > ffffc900003e7828: 0000000000000000 ... > > > > ffffc900003e7830: ffffffff8119b3ae (ring_buffer_unlock_commit+0x8e/0x120) > > > > ffffc900003e7838: 0000000000000001 (0x1) > > > > ffffc900003e7840: ffffea0002854e00 (0xffffea0002854e00) > > > > ffffc900003e7848: 000000000000000a (0xa) > > > > ffffc900003e7850: ffffea0002854ec0 (0xffffea0002854ec0) > > > > ffffc900003e7858: ffffea000287c480 (0xffffea000287c480) > > > > > > The value reported by the warning contradicts the value reported by the > > > dump. So this seems to have been caused by dumping the stack of a task > > > which is running on another CPU. There are still some places in the > > > code where that's possible. So I'm going to need to remove these > > > unwinder warnings for now. > > > > I'll be submitting the following patch soon, which I think should > > silence the warning. If the warning is recreatable, would you mind > > testing it? > > I didn't wait long enough.. > > WARNING: kernel stack frame pointer at ffffc90001443f30 in kworker/u8:8:30468 has bad value (null) > unwind stack type:0 next_sp: (null) mask:6 graph_idx:0
This is actually a separate issue. The below patch should fix it.
Would you mind running it for a bit along with the other patch?
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 5b21970..044d18e 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -36,6 +36,7 @@ #include <asm/smap.h> #include <asm/pgtable_types.h> #include <asm/export.h> +#include <asm/frame.h> #include <linux/err.h> .code64 @@ -408,17 +409,19 @@ END(__switch_to_asm) * r12: kernel thread arg */ ENTRY(ret_from_fork) + FRAME_BEGIN /* help unwinder find end of stack */ movq %rax, %rdi - call schedule_tail /* rdi: 'prev' task parameter */ + call schedule_tail /* rdi: 'prev' task parameter */ - testq %rbx, %rbx /* from kernel_thread? */ - jnz 1f /* kernel threads are uncommon */ + testq %rbx, %rbx /* from kernel_thread? */ + jnz 1f /* kernel threads are uncommon */ 2: - movq %rsp, %rdi + leaq FRAME_OFFSET(%rsp),%rdi /* pt_regs pointer */ call syscall_return_slowpath /* returns with IRQs disabled */ TRACE_IRQS_ON /* user mode is traced as IRQS on */ SWAPGS + FRAME_END jmp restore_regs_and_iret 1:
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