At 22:20 +0000 on 14 Dec (1292365230), Olaf Hering
wrote:>
> Should an interrupted live migration of a HVM guest crash Xen?
> I''m debugging live migration and made a mistake, so xc_save
crashed in the
> middle of the operation. During guest shutdown I got the backtrace below.
The
> same ASSERT is still in paging_free_log_dirty_bitmap() in xen-unstable.
> Is the ASSERT correct, or should it be removed?
The ASSERT is morally correct but clearly not actually correct. :)
The bug, I think, is that this function doesn''t hold the log-dirty
lock, so it can race with another CPU calling mark_dirty.
I''ll send a patch in a few minutes to fix that.
Tim.
> [ 863.693653] br0: port 2(vif1.0) entering disabled state
> [ 863.725132] br0: port 2(vif1.0) entering disabled state
> (XEN) Assertion ''d->arch.paging.log_dirty.allocs == 0''
failed at paging.c:201
> (XEN) Debugging connection not set up.
> (XEN) ----[ Xen-4.0.1_01-20101214.214555 x86_64 debug=y Tainted: C
]----
> (XEN) CPU: 3
> (XEN) RIP: e008:[<ffff82c4801d078b>]
paging_free_log_dirty_bitmap+0x237/0x260
> (XEN) RFLAGS: 0000000000010206 CONTEXT: hypervisor
> (XEN) rax: 0000000000000000 rbx: ffff83000f11c000 rcx: ffff82c4804a8fe0
> (XEN) rdx: ffff82f6001e1380 rsi: 0000000000000000 rdi: ffff82c4802520b8
> (XEN) rbp: ffff83013fed7d28 rsp: ffff83013fed7cb8 r8: ffffffffffffffff
> (XEN) r9: 0000000000000020 r10: 0000000000000001 r11: 0000000000000001
> (XEN) r12: ffff8301385e0000 r13: ffff83000f11c000 r14: ffff8301385e0000
> (XEN) r15: ffff83000f11d000 cr0: 0000000080050033 cr4: 00000000000026f0
> (XEN) cr3: 0000000132b29000 cr2: 0000000000c2e030
> (XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: e010 cs: e008
> (XEN) Xen stack trace from rsp=ffff83013fed7cb8:
> (XEN) ffff83000f11e000 ffff830000001000 ffff830000000000
000004ffffffffff
> (XEN) ffff830000001000 ffff83000f11d000 ffff83000f11dff8
ffff83000f11cff8
> (XEN) ffff83000f11e000 ffff83013fed7f28 ffff8301385e0000
ffff8301385e0f30
> (XEN) 0000000000000000 00007f7c0f715830 ffff83013fed7d58
ffff82c4801d0897
> (XEN) 0000000000000000 ffff8301385e0000 00000000ffffffea
ffff8301385e0000
> (XEN) ffff83013fed7d98 ffff82c48015719c ffff83013fed7d98
ffff8301385e0000
> (XEN) 00000000ffffffea ffff8800ec795e58 0000000000000000
00007f7c0f715830
> (XEN) ffff83013fed7db8 ffff82c4801070cf fffffffffffffff3
0000000001268000
> (XEN) ffff83013fed7f08 ffff82c4801058ed ffff83013fed7de8
ffff82c48015233c
> (XEN) ffff83013fe60000 0000000000000004 ffff83013fed7df8
ffff82c480152375
> (XEN) ffff83013fed7e28 ffff82c4801083ea 0000000000000292
ffff83013fe60000
> (XEN) 0000000000000004 ffff83013fe60190 ffff83013fed7e58
ffff82c4801088b1
> (XEN) ffff83013fed7e68 ffff82c48012421f 0000000700000002
00000000011f0001
> (XEN) 0000000000cdaff9 0000000000d853a0 00007f7c1a6a4608
00007f7c1a405457
> (XEN) 0000003000000018 00007f7c0f7158b0 00007f7c0f7157f0
000000000120ab40
> (XEN) 00007f7c1a6a4608 0000000000000000 00007f7c0f7158c4
0000000000000000
> (XEN) 0000000000f2a468 00007f7c1a690380 0000000000000000
0000000000e55a10
> (XEN) 0000000000000000 ffff8300bf4ea000 ffff8800f1531c00
ffff8800ec795e58
> (XEN) 0000000000000000 00007f7c0f715830 00007cfec01280b7
ffff82c4802091bf
> (XEN) ffffffff8000348a 0000000000000024 00007f7c0f715830
0000000000000000
> (XEN) Xen call trace:
> (XEN) [<ffff82c4801d078b>]
paging_free_log_dirty_bitmap+0x237/0x260
> (XEN) [<ffff82c4801d0897>] paging_teardown+0xe3/0x13f
> (XEN) [<ffff82c48015719c>] domain_relinquish_resources+0x6b/0x23f
> (XEN) [<ffff82c4801070cf>] domain_kill+0x93/0xe7
> (XEN) [<ffff82c4801058ed>] do_domctl+0xa97/0x12aa
> (XEN) [<ffff82c4802091bf>] syscall_enter+0xef/0x149
> (XEN)
> (XEN)
> (XEN) ****************************************
> (XEN) Panic on CPU 3:
> (XEN) Assertion ''d->arch.paging.log_dirty.allocs == 0''
failed at paging.c:201
> (XEN) ****************************************
> (XEN)
> (XEN) Reboot in five seconds...
>
>
>
> _______________________________________________
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> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
--
Tim Deegan <Tim.Deegan@citrix.com>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd. (Company #02937203, SL9 0BG)
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