On Fri, Oct 27, 2017 at 07:42:45PM +0800, zhouchengming wrote:
> This is a real bug happened on one of our machines, below is the calltrace.
> We can see the trigger is at alternatives_text_reserved+0x20/0x80, and
> encounter a deleted (poisoned) list_head.
Looks like some out-of-tree, old kernel thing. We don't have
mlx4_stats_sysfs_create() upstream and looking at the boot timestamps,
it could be that register_jprobe() is not ready yet.
Looking at the Code, though:
20: 74 59 je 0x7b
22: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
29: 00 00
2b:* 48 3b 71 20 cmp 0x20(%rcx),%rsi <-- trapping
instruction
2f: 72 3a jb 0x6b
31: 48 3b 79 28 cmp 0x28(%rcx),%rdi
35: 77 34 ja 0x6b
%rcx is 0xdead0000000000d0 and that is POISON_POINTER_DELTA + 0xd0 so
that looks more like smp_alt_modules is not initialized yet but I could
could very well be wrong because this is an old kernel. So trigger that
with the upstream kernel without out of tree modules.
Thx.
--
Regards/Gruss,
Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284
(AG Nürnberg)
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