Hello kernel experts,
I was wondering if someone has any ideas on this Oops. My analysis must
be incorrect. From what I can tell, this shouldn't have caused a bad
page fault, but it did :).
Here is what I see in the crash dump:
dmesg log shows this:
[ 1053.156266] BUG: unable to handle kernel paging request at
0000000000040fc0
[ 1053.216620] IP: [<ffffffffa02b202e>] c4iw_ev_handler+0x2e/0x84 [iw_cxgb4]
[ 1053.216638] PGD 8b9877067 PUD 86cd37067 PMD 0
[ 1053.216642] Oops: 0002 [#1] SMP
c4iw_ev_handler+0x2e is:
crash> dis -r c4iw_ev_handler+0x2e
0xffffffffa02b2000 <c4iw_ev_handler>: push %rbp
0xffffffffa02b2001 <c4iw_ev_handler+1>: push %rbx
0xffffffffa02b2002 <c4iw_ev_handler+2>: sub $0x8,%rsp
0xffffffffa02b2006 <c4iw_ev_handler+6>: mov %rdi,%rbp
0xffffffffa02b2009 <c4iw_ev_handler+9>: mov %esi,%ebx
0xffffffffa02b200b <c4iw_ev_handler+11>: lea 0x8a0(%rdi),%rdi
0xffffffffa02b2012 <c4iw_ev_handler+18>: callq 0xffffffff811e1020
<idr_find>
0xffffffffa02b2017 <c4iw_ev_handler+23>: mov %rax,%rcx
0xffffffffa02b201a <c4iw_ev_handler+26>: test %rax,%rax
0xffffffffa02b201d <c4iw_ev_handler+29>: je 0xffffffffa02b203d
<c4iw_ev_handler+61>
0xffffffffa02b201f <c4iw_ev_handler+31>: movzwl 0x88(%rax),%eax
0xffffffffa02b2026 <c4iw_ev_handler+38>: mov 0x38(%rcx),%rdx
0xffffffffa02b202a <c4iw_ev_handler+42>: shl $0x6,%rax
0xffffffffa02b202e <c4iw_ev_handler+46>: movb $0x0,0xe(%rax,%rdx,1)
Crash shows these regs:
crash> bt
PID: 12915 TASK: ffff8808d50da200 CPU: 4 COMMAND: "DSI_SvrReceiveR"
#0 [ffff880751c039b0] machine_kexec at ffffffff81020a62
#1 [ffff880751c03a00] crash_kexec at ffffffff81088780
#2 [ffff880751c03ad0] oops_end at ffffffff8139efe0
#3 [ffff880751c03af0] __bad_area_nosemaphore at ffffffff8102ed15
#4 [ffff880751c03bb0] page_fault at ffffffff8139e25f
[exception RIP: c4iw_ev_handler+46]
RIP: ffffffffa02b202e RSP: ffff880751c03c60 RFLAGS: 00010206
RAX: 0000000000040fc0 RBX: 0000000000000404 RCX: ffff880c35da9080
RDX: ffff8808b5500000 RSI: 0000000000000404 RDI: ffff8808d5fabd50
RBP: ffff880c2e5a4000 R8: 0000000000000000 R9: ffff8808d5fabb30
R10: 0000000000000110 R11: ffffffff8101f9b0 R12: 0000000000000000
R13: ffff880c20598230 R14: ffff880c2e5a4000 R15: ffff880c3dbf1480
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
<snip>
So 'movb $0x0,0xe(%rax,%rdx,1)' should be storing 0 into the byte
location:
%rax + 0xe + (%rdx * 1) ==
0x40fc+ 0xe + 0xffff8808b5500000 ==
0xffff8808b5540fce.
That address is readable in the crash dump:
crash> x/8b 0x0000000000040fc0+0xe+0xffff8808b5500000
0xffff8808b5540fce: 0x00 0x00 0x00 0x00 0x00 0x00
0x00 0x00
And why does the page fault show 0x40fc0 as the faulting address? It
should be 0xffff8808b5540fce and it shouldn't have caused a page fault.
What am I missing?
Thanks in advance,
Steve.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
