Re: [Xen-devel] Re: Out sw-iommu space problem

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

> 
> Sep 15 15:29:15 heliMN02WV kernel: [  641.006286] tapdisk2[6891]: segfault
> at 7fff58bb7fe8 ip 00000000004082ac sp 00007fff58bb7ff0 error 6 in
> tapdisk2[400000+39000]
> Sep 15 15:29:15 heliMN02WV kernel: [  641.026060] BUG: unable to handle
> kernel NULL pointer dereference at 0000000000000048
> Sep 15 15:29:15 heliMN02WV kernel: [  641.026200] IP: [<ffffffff810ce79e>]
> apply_to_page_range+0x47/0x2f3
> Sep 15 15:29:15 heliMN02WV kernel: [  641.026291] PGD 0 
> Sep 15 15:29:15 heliMN02WV kernel: [  641.026371] Oops: 0000 [#1] SMP 
> Sep 15 15:29:15 heliMN02WV kernel: [  641.026483] last sysfs file:
> /sys/devices/virtual/blktap2/blktap6/remove
> Sep 15 15:29:15 heliMN02WV kernel: [  641.026541] CPU 2 
> Sep 15 15:29:15 heliMN02WV kernel: [  641.026619] Modules linked in:
> xt_tcpudp tun xt_physdev iptable_filter ip_tables x_tables bridge stp
> ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp
> libiscsi_tcp libiscsi scsi_transport_iscsi ext2 sha256_generic aes_x86_64
> aes_generic cbc blktap xen_evtchn xenfs loop dm_crypt snd_pcm snd_timer snd
> soundcore snd_page_alloc evdev joydev dcdbas pcspkr power_meter button
> processor acpi_processor ext4 mbcache jbd2 crc16 dm_mod sd_mod crc_t10dif sg
> sr_mod cdrom usbhid hid ata_generic ehci_hcd ata_piix usbcore libata
> nls_base bnx2 mpt2sas scsi_transport_sas scsi_mod thermal thermal_sys [last
> unloaded: scsi_wait_scan]
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029000] Pid: 6891, comm: tapdisk2
> Not tainted 2.6.32-5-xen-amd64 #1 PowerEdge T310
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029082] RIP:
> e030:[<ffffffff810ce79e>]  [<ffffffff810ce79e>]
> apply_to_page_range+0x47/0x2f3
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029191] RSP: e02b:ffff88003dda3b58 
> EFLAGS: 00010202
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029246] RAX: 0000000000000880 RBX:
> ffff88003ebc1000 RCX: ffff88003ebc2000
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029313] RDX: 0000000000000000 RSI:
> ffff88003ebc1000 RDI: 0000000000000000
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029372] RBP: ffff88003e7383d0 R08:
> 0000000000000000 R09: ffff88003c4d4780
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029431] R10: 0000000000000002 R11:
> 0000000000000000 R12: 0000000000000000
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029491] R13: ffff88003e7383d0 R14:
> ffff88003deb7800 R15: 0000000000000000
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029555] FS: 
> 00007f185cd15740(0000) GS:ffff880003728000(0000) knlGS:0000000000000000
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029630] CS:  e033 DS: 0000 ES:
> 0000 CR0: 000000008005003b
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029686] CR2: 0000000000000048 CR3:
> 0000000001001000 CR4: 0000000000002660
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029744] DR0: 0000000000000000 DR1:
> 0000000000000000 DR2: 0000000000000000
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029802] DR3: 0000000000000000 DR6:
> 00000000ffff0ff0 DR7: 0000000000000400
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029861] Process tapdisk2 (pid:
> 6891, threadinfo ffff88003dda2000, task ffff8800027ae9f0)
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029936] Stack:
> Sep 15 15:29:15 heliMN02WV kernel: [  641.029984]  0000000000000000
> ffff880001d03b40 0000000000000000 0000000000000000
> Sep 15 15:29:15 heliMN02WV kernel: [  641.030134] <0> ffffffffa02dcee8
> 0000000000000000 ffffffff8100ece2 ffff8800023c9cc0
> Sep 15 15:29:15 heliMN02WV kernel: [  641.030359] <0> ffff88003ebc2000
> 0000000000000000 0000000000000000 ffff8800023c9cc0
> Sep 15 15:29:15 heliMN02WV kernel: [  641.030635] Call Trace:
> Sep 15 15:29:15 heliMN02WV kernel: [  641.030699]  [<ffffffffa02dcee8>] ?
> blktap_umap_uaddr_fn+0x0/0x59 [blktap]
> Sep 15 15:29:15 heliMN02WV kernel: [  641.030764]  [<ffffffff8100ece2>] ?
> check_events+0x12/0x20
> Sep 15 15:29:15 heliMN02WV kernel: [  641.030831]  [<ffffffffa02de2a5>] ?
> blktap_device_end_request+0xbd/0x145 [blktap]
> Sep 15 15:29:15 heliMN02WV kernel: [  641.030917]  [<ffffffffa02dc743>] ?
> blktap_ring_vm_close+0x60/0xd1 [blktap]
> Sep 15 15:29:15 heliMN02WV kernel: [  641.030977]  [<ffffffff810d13f8>] ?
> remove_vma+0x2c/0x72
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031040]  [<ffffffff810d1567>] ?
> exit_mmap+0x129/0x148
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031097]  [<ffffffff8104cc5d>] ?
> mmput+0x3c/0xdf
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031153]  [<ffffffff81050862>] ?
> exit_mm+0x102/0x10d
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031212]  [<ffffffff8130d0d2>] ?
> _spin_lock_irq+0x7/0x22
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031274]  [<ffffffff81052287>] ?
> do_exit+0x1f8/0x6c6
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031340]  [<ffffffff8105d5a1>] ?
> __dequeue_signal+0xfb/0x124
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031399]  [<ffffffff8100eccf>] ?
> xen_restore_fl_direct_end+0x0/0x1
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031458]  [<ffffffff810e7f35>] ?
> kmem_cache_free+0x72/0xa3
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031514]  [<ffffffff810527cb>] ?
> do_group_exit+0x76/0x9d
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031570]  [<ffffffff8105f0b7>] ?
> get_signal_to_deliver+0x310/0x339
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031627]  [<ffffffff8101104f>] ?
> do_notify_resume+0x87/0x73f
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031684]  [<ffffffff810d15e1>] ?
> expand_downwards+0x5b/0x169
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031742]  [<ffffffff8130f589>] ?
> do_page_fault+0x1f3/0x2f2
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031798]  [<ffffffff810125dc>] ?
> retint_signal+0x48/0x8c
> Sep 15 15:29:15 heliMN02WV kernel: [  641.031853] Code: 48 89 4c 24 20 4c 89
> 44 24 18 48 89 54 24 40 72 04 0f 0b eb fe 48 8b 54 24 28 48 89 f0 48 8b 4c
> 24 40 48 c1 e8 24 25 f8 0f 00 00 <48> 8b 52 48 48 ff c9 48 89 0c 24 48 01 d0
> 48 89 44 24 30 48 b8 
> Sep 15 15:29:15 heliMN02WV kernel: [  641.033878] RIP  [<ffffffff810ce79e>]
> apply_to_page_range+0x47/0x2f3
> Sep 15 15:29:15 heliMN02WV kernel: [  641.033965]  RSP <ffff88003dda3b58>
> Sep 15 15:29:15 heliMN02WV kernel: [  641.034015] CR2: 0000000000000048
> Sep 15 15:29:15 heliMN02WV kernel: [  641.034067] ---[ end trace
> 162efc545a37e94b ]---
> Sep 15 15:29:15 heliMN02WV kernel: [  641.034120] Fixing recursive fault but
> reboot is needed!
> 
> 

Hm, there was another thread aobut it, and the analysis looks like it is:

xen: x86_32: do not enable iterrupts when returning from

which is getting backported in 2.6.32.

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