Hi Dave!
Thanks for the explanation!
On 10/26/18 5:29 AM, David Miller wrote:
> (...)
> And that's how we loop forever.
>
> It should not crash the machine and here with an upstream kernel it does not for me.
Interestingly, we couldn't reproduce the issue on the SPARC-T5 anymore either. It
definitely crashes the Sun Fire 2000 used for development of the Free Pascal
compiler though, just re-tested:
root@stadler:~/kernel-crash-test# strace ./tweaklib2
execve("./tweaklib2", ["./tweaklib2"], 0x7feffaafb90 /* 22 vars */) = 0
brk(NULL) = 0x264000
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
mmap(NULL, 16384, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xffff800100024000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "./tls/v9v/libtweaklib1.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "./tls/libtweaklib1.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "./v9v/libtweaklib1.so", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "./libtweaklib1.so", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\2\1\0\0\0\0\0\0\0\0\0\0\3\0+\0\0\0\1\0\0\0\0\0\0\310\360"..., 832) = 832
fstat64(3, {st_mode=S_IFREG|0755, st_size=1165312, ...}) = 0
getcwd("/root/kernel-crash-test", 128) = 24
mmap(NULL, 1503776, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xffff800100128000
mprotect(0xffff800100188000, 1040384, PROT_NONE) = 0
mmap(0xffff800100286000, 57344, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x5e000) = 0xffff800100286000
mmap(0xffff800100294000, 12832, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xffff800100294000
close(3) = 0
mprotect(0xffff800100286000, 8192, PROT_READ) = 0
mprotect(0x252000, 8192, PROT_READ) = 0
mprotect(0xffff800100122000, 8192, PROT_READ) = 0
getrlimit(RLIMIT_STACK, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
rt_sigaction(SIGFPE, {sa_handler=0xffff800100180e10, sa_mask=[], sa_flags=SA_SIGINFO}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 0xffff800100134ca8, 8) = 0
rt_sigaction(SIGSEGV, {sa_handler=0xffff800100180e10, sa_mask=[], sa_flags=SA_SIGINFO}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 0xffff800100134ca8, 8) = 0
rt_sigaction(SIGBUS, {sa_handler=0xffff800100180e10, sa_mask=[], sa_flags=SA_SIGINFO}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 0xffff800100134ca8, 8) = 0
rt_sigaction(SIGILL, {sa_handler=0xffff800100180e10, sa_mask=[], sa_flags=SA_SIGINFO}, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 0xffff800100134ca8, 8) = 0
ioctl(1, TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(2, TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(1, TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(2, TCGETS, {B38400 opost isig icanon echo ...}) = 0
readlink("/proc/self/exe", "/root/kernel-crash-test/tweaklib"..., 255) = 33
rt_sigaction(SIGFPE, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, NULL, 0xffff800100134ca8, 8) = 0
rt_sigaction(SIGSEGV, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, NULL, 0xffff800100134ca8, 8) = 0
rt_sigaction(SIGBUS, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, NULL, 0xffff800100134ca8, 8) = 0
rt_sigaction(SIGILL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, NULL, 0xffff800100134ca8, 8) = 0
And on the console:
sc> console -f
Warning: User < > currently has write permission to this console and forcibly removing them will terminate any current write actions and all work will be lost. Would you like to continue? [y/n]y
Enter #. to return to ALOM.
[942798.597985] Unable to handle kernel paging request at virtual address 000000000153a000
[942798.598156] tsk->{mm,active_mm}->context = 0000000000000228
[942798.598253] tsk->{mm,active_mm}->pgd = ffff8007f5da8000
[942806.209845] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[942806.210036] rcu: 6-...0: (1 GPs behind) idle=84a/1/0x4000000000000002 softirq=8377262/8377263 fqs=2466
[942806.210137] rcu: (detected by 3, t=5337 jiffies, g=57015461, q=2750)
I will let you know whether your patch helps to address the problem.
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - glaubitz@xxxxxxxxxx
`. `' Freie Universitaet Berlin - glaubitz@xxxxxxxxxxxxxxxxxxx
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
