Re: [PATCH] mm: fix possible cause of a page_mapped BUG

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



>>> So, if this case is not caught later on in the code, I guess it solves
>>> the problem. During the fuzzing I didn't experience any panic's, but
>>> some other problems arose, i.e. cannot read /proc/<pid>/maps for some
>>> processes (sys_read hangs, and such process cannot be killed or
>>> stopped with any signal, still it's running (R state) and using CPU -
>>> I'll submit another report for that).
>>
>> Hmm. Sounds like an endless loop in kernel mode.
>>
>> Use "perf record -ag" as root, it should show up very clearly in the report.
>>
>> Â Â Â Â Â Â Â Â Â Â Â Â ÂLinus
>
> I've put some data here -
> http://groups.google.com/group/fa.linux.kernel/browse_thread/thread/4345dcc4f7750ce2
> - I think it's somewhat connected (sys_mlock appears on both cases).
>
> Attaching perf data (for 2.6.38) + kdb dumpall + procdump for process 14158
>
> Those 3 processes cannot be stopped/killed
>
> 14158 66.2 Â0.0 Â 8380 Â3012 ? ÂRL Â/tmp/iknowthis
> 17100 63.6 Â0.1 Â18248 Â4004 ? ÂRL Â/tmp/iknowthis
> 19772 63.8 Â0.0 Â 4000 Â1888 ? Â RL Â/tmp/iknowthis

Also, the system doesn't look usable after such fuzzing (executing a
few times some pretty deterministic program)

root@ise-test:~# gcc -m32 mlock.c  -o mlock

root@ise-test:~# ./mlock
./mlock: relocation error: ./mlock: symbol perror, version GLIBC_2.0
not defined in file libc.so.6 with link time reference

root@ise-test:~# ./mlock
mmap: Success
RET: 0xf751f000
mremap: Invalid argument
RET: 0xffffffff

root@ise-test:~# ./mlock
Segmentation fault

root@ise-test:~# dmesg | tail -n 1
[ 5164.961568] mlock[7097]: segfault at 0 ip           (null) sp
00000000ff8a00d4 error 14 in mlock[8048000+1000]

-- 
Robert ÅwiÄcki

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href


[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]