On Tue, 15 Nov 2016, Peter Zijlstra wrote:
> On Tue, Nov 15, 2016 at 12:43:56PM -0500, Vince Weaver wrote:
> >
> > Running on my haswell machine with the imc/uncore patch applied, the
> > perf_fuzzer next tripped over this issue.
> >
> > [ 202.034495] BAD LUCK: lost 371 message(s) from NMI context!
> > [ 202.034496]
> > ==================================================================
> > [ 202.048327] BUG: KASAN: stack-out-of-bounds in
> > unwind_get_return_address+0x35/0x80 at addr ffff8800cff0bd90
> > [ 202.058826] Read of size 8 by task perf_fuzzer/16254
> > [ 202.064186] page:ffffea00033fc2c0 count:1 mapcount:0 mapping:
> > (null) index:0x0^Ac
> > [ 202.073068] flags: 0x1ffff8000000400(reserved)
> > [ 202.077885] page dumped because: kasan: bad access detected
> > [ 202.083880] CPU: 4 PID: 16254 Comm: perf_fuzzer Not tainted 4.9.0-rc5+ #5
> > [ 202.091204] Hardware name: LENOVO 10AM000AUS/SHARKBAY, BIOS FBKT72AUS
> > 01/26/2014
> > [ 202.099181] ffff8800cff0b1d8^Ac ffffffff816bb796^Ac ffff8800cff0b270^Ac
> > ffff8800cff0bd90^Ac
> > [ 202.107896] ffff8800cff0b260^Ac ffffffff812fbe95^Ac 00007ffc9d1ab480^Ac
> > 0000000000000000^Ac
> > [ 202.116638] ffffffff8125117d^Ac 0000000000000092^Ac 0000000000000000^Ac
> > ffff8800cff0b7c0^Ac
> > [ 202.125339] Call Trace:
> > [ 202.127994] <NMI> [<ffffffff816bb796>] dump_stack+0x63/0x8d
> > [ 202.134184] [<ffffffff812fbe95>] kasan_report_error+0x495/0x4c0
> > [ 202.140680] [<ffffffff8125117d>] ? perf_output_begin+0x28d/0x4c0
> > [ 202.147228] [<ffffffff812fc319>] kasan_report+0x39/0x40
> > [ 202.152987] [<ffffffff81095ce5>] ? unwind_get_return_address+0x35/0x80
> > [ 202.160094] [<ffffffff812fa8fe>] __asan_load8+0x5e/0x70
> > [ 202.165859] [<ffffffff81095ce5>] unwind_get_return_address+0x35/0x80
>
> Josh, any ideas?
>From what I can tell this maps to:
unsigned long unwind_get_return_address(struct unwind_state *state)
{
unsigned long addr;
unsigned long *addr_p = unwind_get_return_address_ptr(state);
if (unwind_done(state))
return 0;
>> addr = ftrace_graph_ret_addr(state->task, &state->graph_idx, *addr_p,
addr_p);
return __kernel_text_address(addr) ? addr : 0;
}
