2.6.35.3 + BFS + BFQ patch + zram module = random segfault some programs

[GoogleCodeExporter]

What steps will reproduce the problem?
1.compile 2.6.35 vanilla kernel with BFS & BFQ patch
2.compile zram from git as module 
3.insmod /usr/share/compcache/zram.ko num_devices=4
4.echo $((200*1024*1024)) > /sys/block/zram0/disksize
5.mkswap /dev/zram0
6.swapon /dev/zram0

What version of the product are you using? On what operating system?
compcache version 0.7 
2.6.35.3 vanilla kernel with BFS & BFQ patch
Debian Squeeze
Please provide any additional information below.

Original issue reported on code.google.com by 0x800cc...@gmail.com on 26 Aug 2010 at 11:15

[GoogleCodeExporter]

Please provide:
 - /proc/cpuinfo
 - kernel .config file

I'm wondering if this is same as issue 69 which seems to happen only on highmem 
systems.

Original comment by nitingupta910@gmail.com on 30 Aug 2010 at 12:01

[GoogleCodeExporter]

system-root@asus:~$ cat /proc/cpuinfo 
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 14
model name  : Intel(R) Celeron(R) M CPU        420  @ 1.60GHz
stepping    : 8
cpu MHz     : 1599.996
cache size  : 1024 KB
fdiv_bug    : no
hlt_bug     : no
f00f_bug    : no
coma_bug    : no
fpu     : yes
fpu_exception   : yes
cpuid level : 10
wp      : yes
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov clflush 
dts acpi mmx fxsr sse sse2 ss tm pbe nx constant_tsc arch_perfmon bts 
aperfmperf pni monitor tm2 xtpr pdcm
bogomips    : 3200.19
clflush size    : 64
cache_alignment : 64
address sizes   : 32 bits physical, 32 bits virtual
power management:

system-root@asus:~$ 

and kernel .config file in attach
I changed kernel to a  2.6.35.4 but still have that problem 

Original comment by 0x800cc...@gmail.com on 31 Aug 2010 at 7:33

Attachments:

• .config

[GoogleCodeExporter]

This happens here too.

processor   : 0
vendor_id   : AuthenticAMD
cpu family  : 15
model       : 107
model name  : AMD Athlon(tm) 64 X2 Dual Core Processor 5400+
stepping    : 2
cpu MHz     : 3121.469
cache size  : 512 KB
physical id : 0
siblings    : 2
core id     : 0
cpu cores   : 2
apicid      : 0
initial apicid  : 0
fdiv_bug    : no
hlt_bug     : no
f00f_bug    : no
coma_bug    : no
fpu     : yes
fpu_exception   : yes
cpuid level : 1
wp      : yes
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat 
pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt rdtscp lm 
3dnowext 3dnow extd_apicid pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy 
3dnowprefetch lbrv
bogomips    : 6242.93
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management: ts fid vid ttp tm stc 100mhzsteps

Original comment by term...@gmail.com on 10 Sep 2010 at 12:15

Attachments:

• config.gz

[GoogleCodeExporter]

Difficult to debug this since too many variables here: BFS + BFQ

Try removing BFQ and then try zram. Pull the compcache code again before you 
try since a bug was fixed today only.

Original comment by nitingupta910@gmail.com on 10 Sep 2010 at 9:47

[GoogleCodeExporter]

+1, I have no BFS or BFQ, I use CFQ as default IO sched. kernel 2.6.34 with 
grsecurity, Funtoo Linux.

Original comment by jabberu...@gmail.com on 11 Sep 2010 at 2:56

[GoogleCodeExporter]

I have tried zram on 2 2.6.35 computers, one with 512MB of RAM and another with 
4GB of RAM. Both experienced frequent crashes/segfaults in programs that tried 
to utilize zram with moderate frequency. It can handle things OK for a short 
while, but things that swap to it seem to crash within a minute or less.

No BFS/BFQ/ck/zen on the kernels I'm running, just a stock build.

About the only thing the two machines have in common is that they are both 
using stock 2.6.35.x from ArchLinux and both have Intel-family microprocessors 
(one is a P4, the other C2D E6600).

Someone in #archlinux says he thinks that zram now requires 2.6.36+ to function 
correctly. If so, this should be clearly marked somewhere.

I've struggled somewhat to find reliable info on zram/compcache. If you could 
update this site sometime, that would be helpful.

Here is my /proc/cpuinfo on the C2D:
processor   : 0
vendor_id   : GenuineIntel
cpu family  : 6
model       : 15
model name  : Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz
stepping    : 6
cpu MHz     : 2399.964
cache size  : 4096 KB
physical id : 0
siblings    : 2
core id     : 0
cpu cores   : 2
apicid      : 0
initial apicid  : 0
fpu     : yes
fpu_exception   : yes
cpuid level : 10
wp      : yes
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat 
pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm 
constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor 
ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm tpr_shadow
bogomips    : 4801.92
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor   : 1
vendor_id   : GenuineIntel
cpu family  : 6
model       : 15
model name  : Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz
stepping    : 6
cpu MHz     : 2399.964
cache size  : 4096 KB
physical id : 0
siblings    : 2
core id     : 1
cpu cores   : 2
apicid      : 1
initial apicid  : 1
fpu     : yes
fpu_exception   : yes
cpuid level : 10
wp      : yes
flags       : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat 
pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm 
constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor 
ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm lahf_lm tpr_shadow
bogomips    : 4833.00
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:

config.gz from /proc attached. This should be a fairly standard stock install.

Original comment by cookieca...@gmail.com on 28 Sep 2010 at 3:14

Attachments:

• config.gz

[GoogleCodeExporter]

The code in the repository in now sync'ed with the mainline which has quite 
stable zram implementation.  So, Can you please pull and try again? or try 
2.6.37 kernel directly.

Original comment by nitingupta910@gmail.com on 23 Jan 2011 at 12:00

[GoogleCodeExporter]

Please repoen if you are still facing this issue.

Original comment by nitingupta910@gmail.com on 27 Jan 2011 at 3:36

• Changed state: Done