cc'ing x32 people On Fri, 21 Feb 2014, Vince Weaver wrote:
> So I'm not sure who exactly to report this to. Some perf people CC'd as > I trigger it while using the perf_fuzzer. > > This is with 3.14-rc3 on a core2 machine, although I've had the reboots > happen throughout at least 3.14-rc* > > I'm having a hard time coming up with a reproducible test case. Using the > random seed that caused the below will cause the perf_fuzzer to segfault > but not reboot. > > The log isn't very helpful, it reboots so fast that the oops doesn't > finish printing and the serial log just moves to the bootloader... > > [ 4466.804123] BUG: unable to handle kernel NULL pointer dereference at > 0000000000000050 > [ 4466.808014] IP: [<ffffffff81111783>] cache_reap+0x5e/0x1c5 > [ 4466.808014] PGD 0 > [ 4466.808014] Oops: 0000 [#1] GNU GRUB version 2.00-17 Maybe related, this is on an x32-compiled binary. When trying to reproduce the perf_fuzzer myseriously segfaults on what appears to be perfectly valid mmap'd perf ring-buffers. (running under gdb) Program received signal SIGSEGV, Segmentation fault. 0x0041efbb in __memset_sse2 () => 0x0041efbb <+2203>: movdqa %xmm0,(%rdi) rdi 0xf7f61000 4160098304 f7f61000-f7f72000 rw-s 00000000 00:08 4475 anon_inode:[perf_event] So I'm not sure if somehow something is wrong with the page mapping, that makes a valid write fail and sometimes (possibly due to address space randomization) reboot the system? Vince -- 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/
