Messages in this thread | | | From | Linus Torvalds <> | Date | Fri, 16 Nov 2018 10:56:56 -0600 | Subject | Re: Oops: 0003 [#1] PREEMPT SMP NOPTI |
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On Thu, Nov 15, 2018 at 8:29 PM Kyle Sanderson <kyle.leet@gmail.com> wrote: > > 2008(!) dual-core Atom box. > [1027541.963573] BUG: unable to handle kernel paging request at ffffffffb0428a44 > [1027541.963647] IP: format_decode+0x20/0x3d0
The code decodes to:
0: 55 push %rbp 1: 48 8d 2e lea (%rsi),%rbp 4: 53 push %rbx 5: 48 8d 1f lea (%rdi),%rbx 8: 48 8d 64 24 f8 lea -0x8(%rsp),%rsp d: 0f b6 06 movzbl (%rsi),%eax 10: 48 89 3c 24 mov %rdi,(%rsp) 14: 3c 01 cmp $0x1,%al 16: 74 4c je 0x64 18: 3c 02 cmp $0x2,%al 1a: 0f 84 a2 01 00 00 je 0x1c2 20:* c6 06 00 movb $0x0,(%rsi) <-- trapping instruction 23: 0f b6 07 movzbl (%rdi),%eax 26: 84 c0 test %al,%al 28: 0f 84 db 02 00 00 je 0x309
and that trapping instruction is, as far as I can tell, this one:
/* By default */ spec->type = FORMAT_TYPE_NONE;
and the fault seems to be a protection fault due to a write to a read-only area (and yes, we *have* read from that 'spec' pointer before that write.
> [1027541.965114] RIP: 0010:format_decode+0x20/0x3d0 > [1027541.965463] Call Trace: > [1027541.965501] vsnprintf+0x56/0x4d0
This is all very odd, because that "spec" pointer points to an automatic variable on the stack of the vsnprintf() function, but we have:
RSP: ffff9e8c02267ba0 RSI: ffffffffb0428a44
so it looks like some completely crazy register state corruption.
Is this repeatable at all? Do you see other random faults?
Linus
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