On Sun, Jul 24, 2011 at 02:06:04PM +0300, Török Edwin wrote:
> On 07/24/2011 10:14 AM, Maciej Rutecki wrote:
> > On czwartek, 21 lipca 2011 o 22:55:04 Török Edwin wrote:
> >> Hi,
> >>
> >> Just got this BUG in my dmesg:
> >> [47504.938446] BUG: unable to handle kernel paging request at
> >> ffff884058ec3270 [47504.938488] IP: [<ffffffff8127baf1>]
> > [...]
> >
> > 2.6.39 works OK?. It is regression?
>
> I don't know, I was not able to reproduce the bug on 3.0 either.
> Either the bug was fixed between 3.0-rc7 and 3.0, or it is very hard to reproduce.
There were some regressions in 3.0-rc1 through 3.0-rc7 that are fixed
in 3.0. If you cannot reproduce in 3.0, then I would guess that you
are hitting one of those bugs.
Thanx, Paul
> I tried with the attached test program (which creates a mess^H some files in the current directory, performs I/O and dumps core
> from 2 processes in parallel.).
>
> All I got was 2 hung kernel threads for 2m+ in xfs_evict_inode + xfs_file_sync, trigerring the hung_check timer and NMI backtraces,
> and the process was unkillable (by kill -9) for a while. It eventually recovered though, and its not surprising that this happened
> : the test program generated 100Mb/s - 500Mb/s I/O.
>
> I'll have to see if I can reproduce the BUG with 3.0-rc7. Although I don't see any XFS changes between 3.0-rc7 and 3.0
> there were some RCU fixes to core VFS code.
>
> Best regards,
> --Edwin
> #include <stdlib.h>
> #include <stdint.h>
> #include <unistd.h>
> #include <string.h>
> #include <pthread.h>
> #include <stdio.h>
> #include <errno.h>
>
> void alloc_and_die(void)
> {
> uint64_t i;
> uint64_t n = 4*1024*1024*1024ll;
> char *x = malloc(n);
> printf("touching pages\n");
> /* touch each page once */
> for (i=0;i<n;i += 4096) {
> x[i] = 42;
> }
> /* wait a bit */
> printf("sleeping\n");
> /* parallel coredump */
> fork();
> sleep(10);
> printf("Dumping core...\n");
> /* now die */
> abort();
> }
>
> void *iothread(void *dummy)
> {
> uint16_t data[4000];
> char fname[128] = "iothreadXXXXXX";
> unsigned int seed = 0x42;
> unsigned i;
> uint64_t pos = 0;
> unsigned counter = 0;
>
> int fd = mkstemp(fname);
>
> if (fd == -1) {
> perror("mkstemp");
> abort();
> }
>
> for (i=0;i<sizeof(data)/sizeof(data[0]);i++) {
> data[i] = rand_r(&seed);
> }
> /* continously write to a 1MB sized file */
> while (1) {
> if (write(fd, data, sizeof(data)) != sizeof(data)) {
> perror("write failed");
> abort();
> }
> pos += sizeof(data);
> if (pos > 10*1024*1024ll) {
> counter++;
> if (counter%2) {
> fsync(fd);
> lseek(fd, 0, SEEK_SET);
> } else {
> unlink(fname);
> close(fd);
> strncpy(fname, "iothreadXXXXXX", sizeof(fname));
> fd = mkstemp(fname);
> if (fd == -1) {
> perror("mkstemp");
> abort();
> }
> }
> for (i=0;i<sizeof(data)/sizeof(data[0]);i++) {
> data[i] = rand_r(&seed);
> }
> }
> }
>
> return NULL;
> }
>
> void run_iothread(void)
> {
> pthread_t thr;
> int rc;
> rc = pthread_create(&thr, NULL,
> iothread, NULL);
> if (rc) {
> errno = rc;
> perror("pthread_create");
> abort();
> }
> }
>
> int main()
> {
> switch (fork()) {
> case 0:
> run_iothread();
> run_iothread();
> alloc_and_die();
> break;
> case -1:
> perror("fork failed\n");
> abort();
> break;
> default:
> run_iothread();
> run_iothread();
> run_iothread();
> run_iothread();
> iothread(NULL);
> break;
> }
> return 0;
> }
>
_______________________________________________
xfs mailing list
xfs@xxxxxxxxxxx
http://oss.sgi.com/mailman/listinfo/xfs
