[Xen-devel] Re: Crash on blktap shutdown

[Daniel Stodden <daniel.stodden@xxxxxxxxxx>]

On Wed, 2010-02-24 at 17:55 -0500, Jeremy Fitzhardinge wrote:
> When rebooting the machine,  I got this crash from blktap.  The rip maps to 
> line 262 in
> 0xffffffff812548a1 is in blktap_request_pool_free 
> (/home/jeremy/git/linux/drivers/xen/blktap/request.c:262).

Uhm, where did that RIP come from?

pool_free is on the module exit path. The stack trace below looks like a
crash from the broadcasted SIGTERM before reboot.

Daniel

> 257           spin_lock_irqsave(&pool.lock, flags);
> 258   
> 259           pool.status = BLKTAP_POOL_CLOSING;
> 260           while (atomic_read(&pool.reqs_in_use)) {
> 261                   spin_unlock_irqrestore(&pool.lock, flags);
> 262                   wait_event(pool.wait_queue, 
> !atomic_read(&pool.reqs_in_use));
> 263                   spin_lock_irqsave(&pool.lock, flags);
> 264           }
> 265   
> 266           for (i = 0; i<  MAX_BUCKETS; i++) {
> 
> 
> blktap_ring_vm_close: unmapping ring 6
> blktap_ring_release: freeing device 6
> general protection fault: 0000 [#2] SMP DEBUG_PAGEALLOC
> last sysfs file: /sys/devices/virtual/net/eth0/address
> CPU 1
> Modules linked in: e1000 evdev ahci dm_mod sd_mod mptspi mptscsih mptbase 
> scsi_]
> Pid: 993, comm: tapdisk2 Tainted: G      D    2.6.32.8 #355 PowerEdge 1850
> RIP: e030:[<ffffffff8125413b>]  [<ffffffff8125413b>] 
> blktap_device_restart+0x7a8
> RSP: e02b:ffff88002d767be8  EFLAGS: 00010092
> RAX: ffff88002ea06b08 RBX: ffff88002f319090 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 6b6b6b6b6b6b6b6b
> RBP: ffff88002d767bf8 R08: 0000000000000002 R09: 0000000000000001
> R10: ffffffff8125412d R11: ffffffff811eaa4a R12: ffff88002f319330
> R13: ffff88002f3191b8 R14: ffff8800242a3a50 R15: 0000000000000001
> FS:  00007f7e3234a740(0000) GS:ffff8800028fb000(0000) knlGS:0000000000000000
> CS:  e033 DS: 0000 ES: 0000 CR0: 000000008005003b
> CR2: 00000036a05a8d84 CR3: 000000002d364000 CR4: 0000000000000660
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Process tapdisk2 (pid: 993, threadinfo ffff88002d766000, task 
> ffff8800242c3d00)
> Stack:
>   ffff88002f319090 ffff88002f319238 ffff88002d767c28 ffffffff81251b3b
> <0>  ffff8800242a3a50 ffff88002f2c2870 ffff880002909820 ffff88002400ad60
> <0>  ffff88002d767c48 ffffffff8109aead ffff8800242a3a50 ffff88002400ad00
> Call Trace:
>   [<ffffffff81251b3b>] blktap_ring_vm_close+0x39/0x12d
>   [<ffffffff8109aead>] remove_vma+0x3b/0x71
>   [<ffffffff8109b036>] exit_mmap+0x153/0x175
>   [<ffffffff8103eef6>] mmput+0x3e/0xd9
>   [<ffffffff81042b83>] exit_mm+0x100/0x10b
>   [<ffffffff81044416>] do_exit+0x1b9/0x638
>   [<ffffffff8104d797>] ? get_signal_to_deliver+0x2dd/0x36e
>   [<ffffffff8100efef>] ? xen_restore_fl_direct_end+0x0/0x1
>   [<ffffffff81044908>] do_group_exit+0x73/0x9c
>   [<ffffffff8104d809>] get_signal_to_deliver+0x34f/0x36e
>   [<ffffffff810111c4>] do_signal+0x6d/0x6b0
>   [<ffffffff8104ef1f>] ? sys_getsid+0x88/0xaf
>   [<ffffffff810bd680>] ? poll_select_copy_remaining+0xc9/0xee
>   [<ffffffff8101182e>] do_notify_resume+0x27/0x47
>   [<ffffffff81390f80>] ? trace_hardirqs_on_thunk+0x3a/0x3f
>   [<ffffffff810549ef>] ? remove_wait_queue+0x12/0x45
>   [<ffffffff81011f56>] int_signal+0x12/0x17
> Code: a8 01 74 0a 48 89 df e8 24 e6 ff ff eb 46 4c 8d a3 a0 02 00 00 4c 89 e7 
> e
> RIP  [<ffffffff8125413b>] blktap_device_restart+0x7a/0xa8
>   RSP<ffff88002d767be8>
> ---[ end trace 1b88501e9b8effb5 ]---
> 
>       J
> 



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