Roland McGrath [[email protected]] wrote:
| > Yes. Perhaps it would be nice to add a helper,
|
| I agree.
|
| > > sys_kill, do_tkill all look wrong to me.
| >
| > They should be fine, note the
| >
| > if (from_ancestor_ns)
| > q->info.si_pid = 0;
| >
| > in __send_signal(). If we send the signal "down" to the sub-namespace,
| > si_pid == 0 is correct. And, unlike do_notify_parent/ptrace_notify/etc
| > kill/tkill can't send the signal "up".
|
| Ah, right. I knew there was something around this I was forgetting.
Setting si_pid to task_tgid_vnr(current); in places like do_tkill() is
slightly misleading bc, it can get modified later in send_signal(). We
can't set si_pid correctly in do_tkill() since we must first establish
pid-namespace relationship and that can mess up control flow.
Maybe a comment will help.
Hi,
I want to inform 2.6.29 signal issues,
As per my understanding I have noticed that if there is a delay
(sleep/nanosleep/usleep) in the child process. Child could not
reporting exit status to parent at this situation parent is waiting
for ever by combinations of SIGSTOP and SIGCONT. So test cases are
reporting as HUNG.
Here I have attached open posix test cases which are reported as HUNG
with 2.6.29 kernels.
1.ltp/testcases/open_posix_testsuite/conformance/interfaces/clock_nanosleep/1-5.c
2.ltp/testcases/open_posix_testsuite/conformance/interfaces/nanosleep/3-2.c
ARCH: ARM
KERNEL: 2.6.29.1
Glibc: 2.9
Gcc: 4.3.3
/*****************************************************************/
open_posix_testsuite/conformance/interfaces/clock_nanosleep/1-5.c
/*****************************************************************/
/*
* Copyright (c) 2002-3, Intel Corporation. All rights reserved.
* Created by: julie.n.fleischer REMOVE-THIS AT intel DOT com
* This file is licensed under the GPL license. For the full content
* of this license, see the COPYING file at the top level of this
* source tree.
* Test that clock_nanosleep() does not stop if a signal is received
* that has no signal handler. clock_nanosleep() should still respond
* to the signal, but should resume after a SIGCONT signal is received.
*
* SIGSTOP will be used to stop the sleep.
*/
#include <stdio.h>
#include <time.h>
#include <signal.h>
#include <unistd.h>
#include <sys/wait.h>
#include <stdlib.h>
#define PTS_PASS 0
#define PTS_FAIL 1
#define PTS_UNRESOLVED 2
#define PTS_UNSUPPORTED 4
#define PTS_UNTESTED 5
#define SLEEPSEC 5
#define CHILDPASS 1
#define CHILDFAIL 0
int main(int argc, char *argv[])
{
int pid, slepts;
struct timespec tsbefore, tsafter;
if (clock_gettime(CLOCK_REALTIME, &tsbefore) != 0) {
perror("clock_gettime() did not return success\n");
return PTS_UNRESOLVED;
}
if ((pid = fork()) == 0) {
/* child here */
struct timespec tssleep;
tssleep.tv_sec=SLEEPSEC;
tssleep.tv_nsec=0;
if (clock_nanosleep(CLOCK_REALTIME, 0, &tssleep, NULL) == 0) {
printf("clock_nanosleep() returned success\n");
return CHILDPASS;
} else {
printf("clock_nanosleep() did not return success\n");
return CHILDFAIL;
}
return CHILDFAIL;
} else {
/* parent here */
int i;
sleep(1);
if (kill(pid, SIGSTOP) != 0) {
printf("Could not raise SIGSTOP\n");
return PTS_UNRESOLVED;
}
if (kill(pid, SIGCONT) != 0) {
printf("Could not raise SIGCONT\n");
return PTS_UNRESOLVED;
}
if (wait(&i) == -1) {
perror("Error waiting for child to exit\n");
return PTS_UNRESOLVED;
}
if (!WIFEXITED(i) || !WEXITSTATUS(i)) {
printf("Test FAILED\n");
return PTS_FAIL;
}
if (clock_gettime(CLOCK_REALTIME, &tsafter) == -1) {
perror("Error in clock_gettime()\n");
return PTS_UNRESOLVED;
}
slepts=tsafter.tv_sec-tsbefore.tv_sec;
#ifdef DEBUG
printf("Start %d sec; End %d sec\n", (int) tsbefore.tv_sec,
(int) tsafter.tv_sec);
#endif
if (slepts >= SLEEPSEC) {
printf("Test PASSED\n");
return PTS_PASS;
} else {
printf("clock_nanosleep() did not sleep long enough\n");
return PTS_FAIL;
}
} //end fork
return PTS_UNRESOLVED;
}
/*****************************************************************/
open_posix_testsuite/conformance/interfaces/nanosleep/3-2.c
/*****************************************************************/
/*
* Copyright (c) 2002, Intel Corporation. All rights reserved.
* Created by: julie.n.fleischer REMOVE-THIS AT intel DOT com
* This file is licensed under the GPL license. For the full content
* of this license, see the COPYING file at the top level of this
* source tree.
*
* Regression test motivated by an LKML discussion. Test that nanosleep()
* can be interrupted and then continue.
*/
#include <stdio.h>
#include <time.h>
#include <signal.h>
#include <unistd.h>
#include <sys/wait.h>
#include <stdlib.h>
#define PTS_PASS 0
#define PTS_FAIL 1
#define PTS_UNRESOLVED 2
#define PTS_UNSUPPORTED 4
#define PTS_UNTESTED 5
#define SLEEPSEC 5
#define CHILDPASS 0 //if interrupted, child will return 0
#define CHILDFAIL 1
int main(int argc, char *argv[])
{
int pid, slepts;
struct timespec tsbefore, tsafter;
if (clock_gettime(CLOCK_REALTIME, &tsbefore) != 0) {
perror("clock_gettime() did not return success\n");
return PTS_UNRESOLVED;
}
if ((pid = fork()) == 0) {
/* child here */
struct timespec tssleep;
tssleep.tv_sec=SLEEPSEC;
tssleep.tv_nsec=0;
if (nanosleep(&tssleep, NULL) == 0) {
printf("nanosleep() returned success\n");
return CHILDPASS;
} else {
printf("nanosleep() did not return success\n");
return CHILDFAIL;
}
return CHILDFAIL;
} else {
/* parent here */
int i;
sleep(1);
if (kill(pid, SIGSTOP) != 0) {
printf("Could not raise SIGSTOP\n");
return PTS_UNRESOLVED;
}
if (kill(pid, SIGCONT) != 0) {
printf("Could not raise SIGCONT\n");
return PTS_UNRESOLVED;
}
if (wait(&i) == -1) {
perror("Error waiting for child to exit\n");
return PTS_UNRESOLVED;
}
if (!WIFEXITED(i)) {
printf("nanosleep() did not return 0\n");
return PTS_FAIL;
}
if (clock_gettime(CLOCK_REALTIME, &tsafter) == -1) {
perror("Error in clock_gettime()\n");
return PTS_UNRESOLVED;
}
slepts=tsafter.tv_sec-tsbefore.tv_sec;
printf("Start %d sec; End %d sec\n", (int) tsbefore.tv_sec,
(int) tsafter.tv_sec);
if (slepts >= SLEEPSEC) {
printf("Test PASSED\n");
return PTS_PASS;
} else {
printf("nanosleep() did not sleep long enough\n");
return PTS_FAIL;
}
} //end fork
return PTS_UNRESOLVED;
}
/*****************************************************************/
thanks for your time.
Best regards,
Naresh Kamboju
On Tue, Jun 2, 2009 at 10:24 AM, Sukadev
Bhattiprolu<[email protected]> wrote:
> Roland McGrath [[email protected]] wrote:
> | > Yes. Perhaps it would be nice to add a helper,
> |
> | I agree.
> |
> | > > sys_kill, do_tkill all look wrong to me.
> | >
> | > They should be fine, note the
> | >
> | > ? ? if (from_ancestor_ns)
> | > ? ? ? ? ? ? q->info.si_pid = 0;
> | >
> | > in __send_signal(). If we send the signal "down" to the sub-namespace,
> | > si_pid == 0 is correct. And, unlike do_notify_parent/ptrace_notify/etc
> | > kill/tkill can't send the signal "up".
> |
> | Ah, right. ?I knew there was something around this I was forgetting.
>
> Setting si_pid to task_tgid_vnr(current); in places like do_tkill() is
> slightly misleading bc, it can get modified later in send_signal(). ?We
> can't set si_pid correctly in do_tkill() since we must first establish
> pid-namespace relationship and that can mess up control flow.
>
> Maybe a comment will help.
> --
> 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/
>
This has absolutely nothing to do with the patch/thread you replied to.
Post about your signals issues separately.
(change the subject)
On 06/05, naresh kamboju wrote:
>
> I want to inform 2.6.29 signal issues,
> As per my understanding I have noticed that if there is a delay
> (sleep/nanosleep/usleep) in the child process. Child could not
> reporting exit status to parent at this situation parent is waiting
> for ever by combinations of SIGSTOP and SIGCONT. So test cases are
> reporting as HUNG.
Thanks for report, but please provide more info.
> ARCH: ARM
is it ARM specific? I can't reproduce the problem on x86.
> KERNEL: 2.6.29.1
did you try other kernel versions?
> #define SLEEPSEC 5
...
> if ((pid = fork()) == 0) {
> /* child here */
> struct timespec tssleep;
>
> tssleep.tv_sec=SLEEPSEC;
> tssleep.tv_nsec=0;
> if (clock_nanosleep(CLOCK_REALTIME, 0, &tssleep, NULL) == 0) {
> printf("clock_nanosleep() returned success\n");
> return CHILDPASS;
> } else {
> printf("clock_nanosleep() did not return success\n");
> return CHILDFAIL;
> }
> return CHILDFAIL;
> } else {
> /* parent here */
> int i;
>
> sleep(1);
>
> if (kill(pid, SIGSTOP) != 0) {
> printf("Could not raise SIGSTOP\n");
> return PTS_UNRESOLVED;
> }
>
> if (kill(pid, SIGCONT) != 0) {
> printf("Could not raise SIGCONT\n");
> return PTS_UNRESOLVED;
> }
>
> if (wait(&i) == -1) {
And I guess it hangs here, right?
The child should sleep SLEEPSEC seconds then exit, so the whole
test-case should take SLEEPSEC seconds too.
Do you mean it really hangs and never completes?
Can you confirm it hangs in wait() ?
Does the child print "returned success" ?
If you can reproduce the problem, please send the content of
/proc/CHILD_PID/status and /proc/PARENT_PID/status.
Oleg.
Hi Oleg,
please find inline comments
On Sat, Jun 6, 2009 at 12:17 PM, Oleg Nesterov<[email protected]> wrote:
> (change the subject)
>
> On 06/05, naresh kamboju wrote:
>>
>> I want to inform 2.6.29 signal issues,
>> As per my understanding I have noticed that if there is a delay
>> (sleep/nanosleep/usleep) in the child process. Child could not
>> reporting exit status to parent at this situation parent is waiting
>> for ever by combinations of SIGSTOP and SIGCONT. So test cases are
>> reporting as HUNG.
>
> Thanks for report, but please provide more info.
>
>> ARCH: ARM
>
> is it ARM specific? I can't reproduce the problem on x86.
yes it is specific to ARM. test cases are PASSED on X86-2.6.29 Kernels.
>
>> KERNEL: 2.6.29.1
>
> did you try other kernel versions?
i have tried on 2.6.23 kernels it is PASSED on both ARM and X68.
>
>> #define SLEEPSEC 5
> ...
>> ? ? ? if ((pid = fork()) == 0) {
>> ? ? ? ? ? ? ? /* child here */
>> ? ? ? ? ? ? ? struct timespec tssleep;
>>
>> ? ? ? ? ? ? ? tssleep.tv_sec=SLEEPSEC;
>> ? ? ? ? ? ? ? tssleep.tv_nsec=0;
>> ? ? ? ? ? ? ? if (clock_nanosleep(CLOCK_REALTIME, 0, &tssleep, NULL) == 0) {
>> ? ? ? ? ? ? ? ? ? ? ? printf("clock_nanosleep() returned success\n");
>> ? ? ? ? ? ? ? ? ? ? ? return CHILDPASS;
>> ? ? ? ? ? ? ? } else {
>> ? ? ? ? ? ? ? ? ? ? ? printf("clock_nanosleep() did not return success\n");
>> ? ? ? ? ? ? ? ? ? ? ? return CHILDFAIL;
>> ? ? ? ? ? ? ? }
>> ? ? ? ? ? ? ? return CHILDFAIL;
>> ? ? ? } else {
>> ? ? ? ? ? ? ? /* parent here */
>> ? ? ? ? ? ? ? int i;
>>
>> ? ? ? ? ? ? ? sleep(1);
>>
>> ? ? ? ? ? ? ? if (kill(pid, SIGSTOP) != 0) {
>> ? ? ? ? ? ? ? ? ? ? ? printf("Could not raise SIGSTOP\n");
>> ? ? ? ? ? ? ? ? ? ? ? return PTS_UNRESOLVED;
>> ? ? ? ? ? ? ? }
>>
>> ? ? ? ? ? ? ? if (kill(pid, SIGCONT) != 0) {
>> ? ? ? ? ? ? ? ? ? ? ? printf("Could not raise SIGCONT\n");
>> ? ? ? ? ? ? ? ? ? ? ? return PTS_UNRESOLVED;
>> ? ? ? ? ? ? ? }
>>
>> ? ? ? ? ? ? ? if (wait(&i) == -1) {
>
> And I guess it hangs here, right?
yes.
it is hangs here.
wait4(-1, Process 464 suspended
>
> The child should sleep SLEEPSEC seconds then exit, so the whole
> test-case should take SLEEPSEC seconds too.
yes. that is the expected.
>
>
> Do you mean it really hangs and never completes?
yes. it is hangs and never completes.
>
> Can you confirm it hangs in wait() ?
yes. wait4() syscall is waiting for child status.
>
> Does the child print "returned success" ?
it is not notifying parent about its exit status.
>
> If you can reproduce the problem, please send the content of
> /proc/CHILD_PID/status and /proc/PARENT_PID/status.
i have attached strace and proc_log
please review the same.
Best regards
Naresh Kamboju
>
> Oleg.
execve("./3-2.test", ["./3-2.test"], [/* 10 vars */]) = 0
brk(0) = 0x11000
uname({sys="Linux", node="43.88.101.211", ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x4001d000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/devel/etc/ld.so.cache", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=13962, ...}) = 0
mmap2(NULL, 13962, PROT_READ, MAP_PRIVATE, 3, 0) = 0x4001e000
close(3) = 0
open("/devel/lib/libpthread.so.0", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0008B\0\0004\0\0\0\200"...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=805190, ...}) = 0
mmap2(NULL, 127472, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
0) = 0x40026000
mprotect(0x4003a000, 32768, PROT_NONE) = 0
mmap2(0x40042000, 8192, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x14) = 0x40042000
mmap2(0x40044000, 4592, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x40044000
close(3) = 0
open("/devel/lib/librt.so.1", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\240\26\0\0004\0\0\0\4"...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=163621, ...}) = 0
mmap2(NULL, 57876, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
0) = 0x40046000
mprotect(0x4004c000, 28672, PROT_NONE) = 0
mmap2(0x40053000, 8192, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x5) = 0x40053000
close(3) = 0
open("/devel/lib/libm.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\2601\0\0004\0\0\0\324"...,
512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1349258, ...}) = 0
mmap2(NULL, 688288, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
0) = 0x40055000
mprotect(0x400f5000, 28672, PROT_NONE) = 0
mmap2(0x400fc000, 8192, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x9f) = 0x400fc000
close(3) = 0
open("/devel/lib/libc.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0
R\1\0004\0\0\0\204"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=7855285, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x40022000
mmap2(NULL, 1249800, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE,
3, 0) = 0x400fe000
mprotect(0x40223000, 28672, PROT_NONE) = 0
mmap2(0x4022a000, 12288, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x124) = 0x4022a000
mmap2(0x4022d000, 8712, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x4022d000
close(3) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x40023000
set_tls(0x40022c80, 0x40022c80, 0x67c, 0x40023358, 0x40025048) = 0
mprotect(0x4022a000, 8192, PROT_READ) = 0
mprotect(0x400fc000, 4096, PROT_READ) = 0
mprotect(0x40053000, 4096, PROT_READ) = 0
mprotect(0x40042000, 4096, PROT_READ) = 0
mprotect(0x40024000, 4096, PROT_READ) = 0
munmap(0x4001e000, 13962) = 0
set_tid_address(0x40022828) = 464
set_robust_list(0x40022830, 0xc) = 0
rt_sigaction(SIGRTMIN, {0x4002a128, [], SA_SIGINFO|0x4000000}, NULL, 8) = 0
rt_sigaction(SIGRT_1, {0x40029ce8, [],
SA_RESTART|SA_SIGINFO|0x4000000}, NULL, 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0
getrlimit(RLIMIT_STACK, {rlim_cur=8192*1024, rlim_max=RLIM_INFINITY}) = 0
clock_gettime(CLOCK_REALTIME, {1245240048, 291313608}) = 0
clone(Process 465 attached (waiting for parent)
Process 465 resumed (parent 464 ready)
child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
child_tidptr=0x40022828) = 465
[pid 465] nanosleep({5, 0}, <unfinished ...>
[pid 464] rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
[pid 464] rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
[pid 464] rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
[pid 464] nanosleep({1, 0}, {1, 0}) = 0
[pid 464] kill(465, SIGSTOP <unfinished ...>
[pid 465] <... nanosleep resumed> 0) = ? ERESTART_RESTARTBLOCK (To
be restarted)
[pid 465] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 465] --- SIGSTOP (Stopped (signal)) @ 0 (0) ---
[pid 464] <... kill resumed> ) = 0
[pid 464] kill(465, SIGCONT) = 0
[pid 464] wait4(-1, Process 464 suspended
<unfinished ...>
[pid 465] --- SIGCONT (Continued) @ 0 (0) ---
/**************************************************************/
-bash-3.2# uname -a
Linux 2.6.29.2
-bash-3.2# cat proc/464/status
Name: 3-2.test
State: T (tracing stop)
Tgid: 464
Pid: 464
PPid: 462
TracerPid: 462
Uid: 0 0 0 0
Gid: 0 0 0 0
FDSize: 32
Groups: 0
VmPeak: 2332 kB
VmSize: 2316 kB
VmLck: 0 kB
VmHWM: 404 kB
VmRSS: 404 kB
VmData: 32 kB
VmStk: 84 kB
VmExe: 4 kB
VmLib: 2032 kB
VmPTE: 8 kB
Threads: 1
SigQ: 0/1024
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000000
SigCgt: 0000000180000000
CapInh: 0000000000000000
CapPrm: fffffffffffffeff
CapEff: fffffffffffffeff
CapBnd: fffffffffffffeff
voluntary_ctxt_switches: 126
nonvoluntary_ctxt_switches: 31
-bash-3.2#
-bash-3.2# cat proc/465/status
Name: 3-2.test
State: R (running)
Tgid: 465
Pid: 465
PPid: 464
TracerPid: 462
Uid: 0 0 0 0
Gid: 0 0 0 0
FDSize: 32
Groups: 0
VmPeak: 2316 kB
VmSize: 2316 kB
VmLck: 0 kB
VmHWM: 164 kB
VmRSS: 164 kB
VmData: 32 kB
VmStk: 84 kB
VmExe: 4 kB
VmLib: 2032 kB
VmPTE: 8 kB
Threads: 1
SigQ: 0/1024
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000000
SigCgt: 0000000180000000
CapInh: 0000000000000000
CapPrm: fffffffffffffeff
CapEff: fffffffffffffeff
CapBnd: fffffffffffffeff
voluntary_ctxt_switches: 7
nonvoluntary_ctxt_switches: 36623
-bash-3.2#
>
>
On 06/17, naresh kamboju wrote:
>
> please find inline comments
Thanks Naresh.
> >> ARCH: ARM
> >
> > is it ARM specific? I can't reproduce the problem on x86.
> yes it is specific to ARM. test cases are PASSED on X86-2.6.29 Kernels.
Not good, because I know nothing about arm and don't have the arm machine ;)
Will try to look...
> > If you can reproduce the problem, please send the content of
> > /proc/CHILD_PID/status and /proc/PARENT_PID/status.
>
> i have attached strace and proc_log
> please review the same.
Thanks.
Could you reproduce without strace, and send the output of /proc/xxx/status ?
I don't really expect we will see something interesting, but just in case.
Also, the output of sysrq-t may help. (the part which relates to these 2
processes).
Oleg.
Thank you very much.
just before i have reported the same issue to ARM Kernel mailing list.
Best regards,
Naresh Kamboju
On Wed, Jun 17, 2009 at 6:59 PM, Oleg Nesterov<[email protected]> wrote:
> On 06/17, naresh kamboju wrote:
>>
>> please find inline comments
>
> Thanks Naresh.
>
>> >> ARCH: ARM
>> >
>> > is it ARM specific? I can't reproduce the problem on x86.
>> yes it is specific to ARM. test cases are PASSED on X86-2.6.29 Kernels.
>
> Not good, because I know nothing about arm and don't have the arm machine ;)
> Will try to look...
>
>> > If you can reproduce the problem, please send the content of
>> > /proc/CHILD_PID/status and /proc/PARENT_PID/status.
>>
>> i have attached ?strace and proc_log
>> please review the same.
>
> Thanks.
>
> Could you reproduce without strace, and send the output of /proc/xxx/status ?
> I don't really expect we will see something interesting, but just in case.
>
> Also, the output of sysrq-t may help. (the part which relates to these 2
> processes).
>
> Oleg.
>
>