Wifi bug

[Felix Fietkau]

On 2021-09-27 13:33, e9hack wrote:
> Am 27.09.2021 um 12:59 schrieb Felix Fietkau:
>> 
>> Hi,
>> 
>> 
>> On 2021-09-26 14:48, e9hack wrote:
>>> Do you see a page fault from netifd in the log? If it does crash, it is restarted by procd. This does restart the network stack. If I start netifd with strace, I got this lines immediately before the page fault:
>>>
>>> unlink("/tmp/resolv.conf.d/resolv.conf.auto.tmp") = -1 ENOENT (No such file or directory)
>>> open("/tmp/resolv.conf.d/resolv.conf.auto.tmp", O_RDWR|O_CREAT|O_TRUNC|O_LARGEFILE, 0666) = 14
>>> ioctl(14, TIOCGWINSZ, 0x7f717a74)       = -1 ENOTTY (Not a tty)
>>> _llseek(14, 0, [0], SEEK_SET)           = 0
>>> readv(14, [{iov_base="", iov_len=1023}, {iov_base="", iov_len=1024}], 2) = 0
>>> close(14)                               = 0
>>> open("/tmp/resolv.conf.d/resolv.conf.auto", O_RDONLY|O_LARGEFILE) = 14
>>> readv(14, [{iov_base="", iov_len=1023}, {iov_base="", iov_len=1024}], 2) = 0
>>> close(14)                               = 0
>>> unlink("/tmp/resolv.conf.d/resolv.conf.auto.tmp") = 0
>>> munmap(0x77d61000, 8192)                = 0
>>> --- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=0x77d61038} ---
>>> +++ killed by SIGSEGV +++
>>>
>>> The part 0x77d61... does change on several starts. The offset 0x.....038 is the same.
>> On a crash, it should drop a .core file to /tmp. Please copy that to
>> your build host and use ./scripts/remote-gdb to obtain a backtrace from
>> it. I'd like to know, which line of code in netifd it crashes on, so I
>> can fix it. So far the bug has not shown up in my own tests...
>> 
>> - Felix
> 
> It doesn't generate a core-dump. How can I activate core-dumps?
Normally it should be active by default. Is CONFIG_KERNEL_ELF_CORE set
in your .config?

- Felix