Hi All,
Because I could not find a solution for the cpu stall problem on kernel
3.2.18-rt29. I thought I might try an older kernel. So I download
linux-2.6.33.9 and patch-2.6.33.9-rt31. But 2.6.33 doesn't have
vhost_net, so I ported vhost_net from 2.6.34 back to 2.6.33.9.
The kernel was patched and built successfully. But when I boot, I got
kernel NULL pointer dereference error. After the error, my system seems
stable, I can start KVM client without CPU stalls. But very frequently,
processes will locked up for long time, the wchan displayed by ps is
either sync_page or synchronize_rcu. It looks that rcu still causes
problem in the rt-kernel.
The dmesg out of NULL pointer is attached.
Thanks!
Dong
BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
IP: [<ffffffff810645f1>] release_resource+0x21/0x90
PGD 123efa067 PUD 120639067 PMD 0
Oops: 0000 [#1] PREEMPT SMP
last sysfs file: /sys/kernel/kexec_crash_size
CPU 2
Pid: 1826, comm: sh Not tainted 2.6.33.9-1.el6.preempt_rt.x86_64 #1 2A9Ch/HP Elite 7100 Microtower PC
RIP: 0010:[<ffffffff810645f1>] [<ffffffff810645f1>] release_resource+0x21/0x90
RSP: 0018:ffff880124fffde8 EFLAGS: 00010296
RAX: 0000000000000000 RBX: ffffffff81ac6e40 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000284 RDI: ffffffff8176a620
RBP: ffff880124fffdf8 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff81aee8a0 R15: 0000000000000000
FS: 00007f877dd96700(0000) GS:ffff880028280000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000030 CR3: 000000011f4da000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process sh (pid: 1826, threadinfo ffff880124ffe000, task ffff88011f426240)
Stack:
ffff880124fffdf8 0000000000000000 ffff880124fffe48 ffffffff810a366b
<0> ffff880124fffe48 0000000000000000 0000000000000000 0000000000000001
<0> ffff880124ffff48 ffff8801271cf870 ffffffff81aee8a0 ffff880121c348c0
Call Trace:
[<ffffffff810a366b>] crash_shrink_memory+0x14b/0x170
[<ffffffff810845b1>] kexec_crash_size_store+0x41/0x60
[<ffffffff81221e27>] kobj_attr_store+0x17/0x20
[<ffffffff811b1a8c>] sysfs_write_file+0xfc/0x180
[<ffffffff81147a78>] vfs_write+0xb8/0x1a0
[<ffffffff810b96ea>] ? audit_syscall_entry+0x29a/0x2c0
[<ffffffff81148451>] sys_write+0x51/0x90
[<ffffffff8100b172>] system_call_fastpath+0x16/0x1b
Code: 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 53 48 83 ec 08 0f 1f 44 00 00 48 89 fb 48 c7 c7 c0 34 a8 81 e8 23 1b 43 00 48 8b 53 20 <48\
> 8b 42 30 48 85 c0 74 20 48 39 c3 75 0e eb 33 0f 1f 80 00 00
RIP [<ffffffff810645f1>] release_resource+0x21/0x90
RSP <ffff880124fffde8>
CR2: 0000000000000030
