On Tue, Nov 7, 2017 at 2:25 AM, Fengguang Wu <[email protected]> wrote:
>
> FYI this happens in v4.14-rc8 -- it's not necessarily a new bug.
Yeah, no it is not new.
It also likely doesn't matter (I suspect it happens if you try to
force-load crazy modules that don't exist, and ISA doesn't have proper
probing).
But the code disassembles to
0: 8b 50 7c mov 0x7c(%eax),%edx
3: 83 05 38 86 21 44 01 addl $0x1,X
a:* 8b 4a 0c mov 0xc(%edx),%ecx <-- trapping instruction
d: 83 15 3c 86 21 44 00 adcl $0x0,X+4
14: 85 c9 test %ecx,%ecx
and while I have no idea what that odd addl/adcl is (other than the
obvious "it's a 64-bit increment" - probably some random statistics
due to your config), it looks like the oops is due to
struct isa_driver *isa_driver = dev->platform_data;
if (isa_driver->shutdown)
with isa_driver being NULL (EDX: 00000000).
So dev->platform_data is NULL, but why that actually happens I don't
know. Some bad ISA device registration that _should_ have failed but
instead got into some half-alive state, I'm sure.
I'm not sure if anybody cares, but maybe adding a NULL check just to
make the 0day robot not report this is a good idea.
Linus
