* [BUG] lib/kernel_lock.c:126 with cgroups regression ltp tests
@ 2009-06-17 10:51 Sachin Sant
2009-06-17 11:20 ` Michael Ellerman
0 siblings, 1 reply; 3+ messages in thread
From: Sachin Sant @ 2009-06-17 10:51 UTC (permalink / raw)
To: linux-kernel; +Cc: linuxppc-dev, menage, Balbir Singh
[-- Attachment #1: Type: text/plain, Size: 2356 bytes --]
While executing cgroups regression tests from LTP May 2009
release on a Power6 box came across the following bug.
This is with 2.6.30-git10 (300df7dc89cc276377fc020704e34875d5c473b6)
------------[ cut here ]------------
kernel BUG at lib/kernel_lock.c:126!
Oops: Exception in kernel mode, sig: 5 [#1]
SMP NR_CPUS=1024 NUMA pSeries
Modules linked in: ipv6 fuse loop dm_mod sr_mod ehea cdrom sg ibmveth sd_mod crc_t10dif ibmvscsic scsi_transport_srp scsi_tgt scsi_mod
NIP: c0000000005c6dac LR: c0000000001965ac CTR: 0000000000000006
REGS: c00000002a5d3910 TRAP: 0700 Not tainted (2.6.30-git10)
MSR: 8000000000029032 <EE,ME,CE,IR,DR> CR: 82042442 XER: 00000000
TASK = c0000000407cbc20[9581] 'mount' THREAD: c00000002a5d0000 CPU: 3
<6>GPR00: 0000000000000001 c00000002a5d3b90 c000000000ef31f0 fffffffffffffff0
<6>GPR04: c0000000000f0098 c000000000799813 0000000000000000 0000000000000001
<6>GPR08: c000000000e36aa0 c0000000407cbc20 0000000000000002 c0000000407cbc20
<6>GPR12: 0000000024042424 c000000000ff2a00 00000fffed50f6fd 00000fffed506e08
<6>GPR16: 00000fffed506db8 000000001002b638 0000000000000000 0000000000000000
<6>GPR20: 00000000100329a0 00000fffed506e0c c00000003e14b870 0000000000000000
<6>GPR24: 0000000000000000 c00000002a030000 0000000000000000 0000000000000000
<6>GPR28: c00000003e14b800 fffffffffffffff0 c000000000e7aa40 c00000002a5d3b90
NIP [c0000000005c6dac] .unlock_kernel+0x20/0x78
LR [c0000000001965ac] .do_remount_sb+0x190/0x204
Call Trace:
[c00000002a5d3bd0] [c00000000019659c] .do_remount_sb+0x180/0x204
[c00000002a5d3c70] [c0000000001b8210] .do_mount+0x38c/0x9fc
[c00000002a5d3d60] [c0000000001b8940] .SyS_mount+0xc0/0x12c
[c00000002a5d3e30] [c000000000008534] syscall_exit+0x0/0x40
Instruction dump:
383f0040 ebc1fff0 ebe1fff8 4e800020 fbc1fff0 fbe1fff8 f821ffc1 7c3f0b78
ebc2c0b8 e92d01b0 e809001e 78000fe0 <0b000000> e96d01b0 812b001c 3929ffff
---[ end trace 3bf0012ad33d52b2 ]---
Corresponding c code is :
void __lockfunc unlock_kernel(void)
{
BUG_ON(current->lock_depth < 0); <<======
if (likely(--current->lock_depth < 0))
__unlock_kernel();
Have attached the cgroups regression test run log.
Thanks
-Sachin
--
---------------------------------
Sachin Sant
IBM Linux Technology Center
India Systems and Technology Labs
Bangalore, India
---------------------------------
[-- Attachment #2: controller-run.log --]
[-- Type: text/x-log, Size: 2832 bytes --]
cgroup_regression_test 1 PASS : no kernel bug was found
/ltp-full-20090531/testcases/bin/cgroup_regression_test.sh: line 102: 7036 Terminated ./fork_processes
cgroup_regression_test 2 PASS : notify_on_release is inherited
cgroup_regression_test 3 PASS : no kernel bug was found
cgroup_regression_test 4 CONF : CONFIG_LOCKDEP is not enabled
cgroup_regression_test 5 PASS : no kernel bug was found
/ltp-full-20090531/testcases/bin/cgroup_regression_test.sh: line 253: 8781 Terminated sleep 100
/ltp-full-20090531/testcases/bin/cgroup_regression_test.sh: line 325: 8800 Terminated ./test_6_2
cgroup_regression_test 6 PASS : no kernel bug was found
------------[ cut here ]------------
Oops: Exception in kernel mode, sig: 5 [#1]
SMP NR_CPUS=1024 NUMA pSeries
Modules linked in: ipv6 fuse loop dm_mod sr_mod ehea cdrom sg ibmveth sd_mod crc_t10dif ibmvscsic scsi_transport_srp scsi_tgt scsi_mod
NIP: c0000000005c6dac LR: c0000000001965ac CTR: 0000000000000006
REGS: c00000002a5d3910 TRAP: 0700 Not tainted (2.6.30-git10)
MSR: 8000000000029032 <EE,ME,CE,IR,DR> CR: 82042442 XER: 00000000
TASK = c0000000407cbc20[9581] 'mount' THREAD: c00000002a5d0000 CPU: 3
<6>GPR00: 0000000000000001 c00000002a5d3b90 c000000000ef31f0 fffffffffffffff0
<6>GPR04: c0000000000f0098 c000000000799813 0000000000000000 0000000000000001
<6>GPR08: c000000000e36aa0 c0000000407cbc20 0000000000000002 c0000000407cbc20
<6>GPR12: 0000000024042424 c000000000ff2a00 00000fffed50f6fd 00000fffed506e08
<6>GPR16: 00000fffed506db8 000000001002b638 0000000000000000 0000000000000000
<6>GPR20: 00000000100329a0 00000fffed506e0c c00000003e14b870 0000000000000000
<6>GPR24: 0000000000000000 c00000002a030000 0000000000000000 0000000000000000
<6>GPR28: c00000003e14b800 fffffffffffffff0 c000000000e7aa40 c00000002a5d3b90
NIP [c0000000005c6dac] .unlock_kernel+0x20/0x78
LR [c0000000001965ac] .do_remount_sb+0x190/0x204
Call Trace:
[c00000002a5d3bd0] [c00000000019659c] .do_remount_sb+0x180/0x204
[c00000002a5d3c70] [c0000000001b8210] .do_mount+0x38c/0x9fc
[c00000002a5d3d60] [c0000000001b8940] .SyS_mount+0xc0/0x12c
[c00000002a5d3e30] [c000000000008534] syscall_exit+0x0/0x40
Instruction dump:
383f0040 ebc1fff0 ebe1fff8 4e800020 fbc1fff0 fbe1fff8 f821ffc1 7c3f0b78
ebc2c0b8 e92d01b0 e809001e 78000fe0 <0b000000> e96d01b0 812b001c 3929ffff
---[ end trace 3bf0012ad33d52b2 ]---
/ltp-full-20090531/testcases/bin/cgroup_regression_test.sh: line 347: 9581 Trace/breakpoint trap mount -t cgroup -o remount xxx cgroup/ 2> /dev/null
/ltp-full-20090531/testcases/bin/cgroup_regression_test.sh: line 363: 9579 Terminated sleep 100 < cgroup/0
Cannot create link /etc/mtab~
Perhaps there is a stale lock file?
Cannot create link /etc/mtab~
Perhaps there is a stale lock file?
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [BUG] lib/kernel_lock.c:126 with cgroups regression ltp tests
2009-06-17 10:51 [BUG] lib/kernel_lock.c:126 with cgroups regression ltp tests Sachin Sant
@ 2009-06-17 11:20 ` Michael Ellerman
2009-06-17 12:16 ` Sachin Sant
0 siblings, 1 reply; 3+ messages in thread
From: Michael Ellerman @ 2009-06-17 11:20 UTC (permalink / raw)
To: Sachin Sant
Cc: linux-kernel, linuxppc-dev, Al Viro, menage, abogani,
Balbir Singh
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On Wed, 2009-06-17 at 16:21 +0530, Sachin Sant wrote:
> While executing cgroups regression tests from LTP May 2009
> release on a Power6 box came across the following bug.
> This is with 2.6.30-git10 (300df7dc89cc276377fc020704e34875d5c473b6)
Looks like 337eb00a2 missed some return paths in do_remount_sb()?
$ git log -p -U13 337eb00a2c3a421999c39c94ce7e33545ee8baa7 fs/super.c
commit 337eb00a2c3a421999c39c94ce7e33545ee8baa7
Author: Alessio Igor Bogani <abogani@texware.it>
Date: Tue May 12 15:10:54 2009 +0200
Push BKL down into ->remount_fs()
[xfs, btrfs, capifs, shmem don't need BKL, exempt]
Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/super.c b/fs/super.c
index 1905f4a..83b4741 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -530,53 +530,51 @@ int do_remount_sb(struct super_block *sb, int flags, void
{
int retval;
int remount_rw;
#ifdef CONFIG_BLOCK
if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
return -EACCES;
#endif
if (flags & MS_RDONLY)
acct_auto_close(sb);
shrink_dcache_sb(sb);
sync_filesystem(sb);
- lock_kernel();
/* If we are remounting RDONLY and current sb is read/write,
make sure there are no rw files opened */
if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
if (force)
mark_files_ro(sb);
else if (!fs_may_remount_ro(sb)) {
unlock_kernel();
return -EBUSY;
}
retval = vfs_dq_off(sb, 1);
if (retval < 0 && retval != -ENOSYS) {
unlock_kernel();
return -EBUSY;
}
}
remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);
if (sb->s_op->remount_fs) {
retval = sb->s_op->remount_fs(sb, &flags, data);
if (retval) {
unlock_kernel();
return retval;
}
}
sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
- unlock_kernel();
cheers
> ------------[ cut here ]------------
> kernel BUG at lib/kernel_lock.c:126!
> Oops: Exception in kernel mode, sig: 5 [#1]
> SMP NR_CPUS=1024 NUMA pSeries
> Modules linked in: ipv6 fuse loop dm_mod sr_mod ehea cdrom sg ibmveth sd_mod crc_t10dif ibmvscsic scsi_transport_srp scsi_tgt scsi_mod
> NIP: c0000000005c6dac LR: c0000000001965ac CTR: 0000000000000006
> REGS: c00000002a5d3910 TRAP: 0700 Not tainted (2.6.30-git10)
> MSR: 8000000000029032 <EE,ME,CE,IR,DR> CR: 82042442 XER: 00000000
> TASK = c0000000407cbc20[9581] 'mount' THREAD: c00000002a5d0000 CPU: 3
> <6>GPR00: 0000000000000001 c00000002a5d3b90 c000000000ef31f0 fffffffffffffff0
> <6>GPR04: c0000000000f0098 c000000000799813 0000000000000000 0000000000000001
> <6>GPR08: c000000000e36aa0 c0000000407cbc20 0000000000000002 c0000000407cbc20
> <6>GPR12: 0000000024042424 c000000000ff2a00 00000fffed50f6fd 00000fffed506e08
> <6>GPR16: 00000fffed506db8 000000001002b638 0000000000000000 0000000000000000
> <6>GPR20: 00000000100329a0 00000fffed506e0c c00000003e14b870 0000000000000000
> <6>GPR24: 0000000000000000 c00000002a030000 0000000000000000 0000000000000000
> <6>GPR28: c00000003e14b800 fffffffffffffff0 c000000000e7aa40 c00000002a5d3b90
> NIP [c0000000005c6dac] .unlock_kernel+0x20/0x78
> LR [c0000000001965ac] .do_remount_sb+0x190/0x204
> Call Trace:
> [c00000002a5d3bd0] [c00000000019659c] .do_remount_sb+0x180/0x204
> [c00000002a5d3c70] [c0000000001b8210] .do_mount+0x38c/0x9fc
> [c00000002a5d3d60] [c0000000001b8940] .SyS_mount+0xc0/0x12c
> [c00000002a5d3e30] [c000000000008534] syscall_exit+0x0/0x40
> Instruction dump:
> 383f0040 ebc1fff0 ebe1fff8 4e800020 fbc1fff0 fbe1fff8 f821ffc1 7c3f0b78
> ebc2c0b8 e92d01b0 e809001e 78000fe0 <0b000000> e96d01b0 812b001c 3929ffff
> ---[ end trace 3bf0012ad33d52b2 ]---
>
> Corresponding c code is :
>
> void __lockfunc unlock_kernel(void)
> {
> BUG_ON(current->lock_depth < 0); <<======
> if (likely(--current->lock_depth < 0))
> __unlock_kernel();
>
> Have attached the cgroups regression test run log.
>
> Thanks
> -Sachin
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [BUG] lib/kernel_lock.c:126 with cgroups regression ltp tests
2009-06-17 11:20 ` Michael Ellerman
@ 2009-06-17 12:16 ` Sachin Sant
0 siblings, 0 replies; 3+ messages in thread
From: Sachin Sant @ 2009-06-17 12:16 UTC (permalink / raw)
To: michael
Cc: linux-kernel, chrisw, linuxppc-dev, Al Viro, menage, abogani,
Balbir Singh
Michael Ellerman wrote:
> On Wed, 2009-06-17 at 16:21 +0530, Sachin Sant wrote:
>
>> While executing cgroups regression tests from LTP May 2009
>> release on a Power6 box came across the following bug.
>>
>
>
>> This is with 2.6.30-git10 (300df7dc89cc276377fc020704e34875d5c473b6)
>>
>
> Looks like 337eb00a2 missed some return paths in do_remount_sb()?
>
> $ git log -p -U13 337eb00a2c3a421999c39c94ce7e33545ee8baa7 fs/super.c
> commit 337eb00a2c3a421999c39c94ce7e33545ee8baa7
> Author: Alessio Igor Bogani <abogani@texware.it>
Thanks Michael.
The following submitted patch from Chris fixes this issue.
http://patchwork.kernel.org/patch/30675/
Thanks
-Sachin
--
---------------------------------
Sachin Sant
IBM Linux Technology Center
India Systems and Technology Labs
Bangalore, India
---------------------------------
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2009-06-17 10:51 [BUG] lib/kernel_lock.c:126 with cgroups regression ltp tests Sachin Sant
2009-06-17 11:20 ` Michael Ellerman
2009-06-17 12:16 ` Sachin Sant
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