Oracle VM: VM Guest Crashed While Mapping/Unmapping Disk Showing Error: RIP "blkif_free+0x2e/0x1c0 [xen_blkfront]" (Doc ID 2586939.1)

Last updated on JULY 13, 2021

Applies to:

Symptoms

Oracle VM Guest crashed while mapping/unmapping disk showing below errors:

[] BUG: unable to handle kernel NULL pointer dereference at 0000000000000048
[] IP: [] blkif_free+0x2e/0x1c0 [xen_blkfront]
[] PGD 0
[] Oops: 0002 [#1] SMP
[] Modules linked in: dm_snapshot dm_bufio sd_mod sg iscsi_tcp libiscsi_tcp libiscsi arc4 des_generic ecb md4 nls_utf8 cifs nfsv3 xt_CHECKSUM iptable_mangle ipt_MASQUERADE nf_nat_masquerade_ipv4 iptable_nat nf_nat_ipv4 nf_na
[] xen_netfront ttm xen_blkfront drm ata_piix i2c_core libata serio_raw crc32c_intel floppy dm_mirror dm_region_hash dm_log dm_mod
[] CPU: 37 PID: 347 Comm: xenwatch Tainted: P O 4.1.12-124.20.7.el7uek.x86_64 #2
[] Hardware name: Xen HVM domU, BIOS 4.4.4OVM 11/16/2018
[] task: ffff88fba9bc4600 ti: ffff88fba963c000 task.ti: ffff88fba963c000
[] RIP: 0010:[] [] blkif_free+0x2e/0x1c0 [xen_blkfront]
[] RSP: 0018:ffff88fba963fc48 EFLAGS: 00010246
[] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffea00acfcd580
[] RDX: 000000000000003f RSI: 0000000000000000 RDI: 0000000000000000
[] RBP: ffff88fba963fc88 R08: ffff8801157259c0 R09: 000000018040003f
[] R10: ffffea000455c940 R11: ffffffff81424593 R12: ffff88822975ec00
[] R13: ffffffffa00b5080 R14: ffff88822975ec00 R15: 0000000000000000
[] FS: 0000000000000000(0000) GS:ffff88fc0df40000(0000) knlGS:0000000000000000
[] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[] CR2: 0000000000000048 CR3: 0000000001b46000 CR4: 0000000000160670
[] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[] Stack:
[] ffff88822975ec00 ffffffff81c35a30 ffff88fba963fcc8 000000001555a210
[] ffff8801157259c0 0000000000000000 ffff88822975ec00 ffffffffa00b5080
[] ffff88fba963fcc8 ffffffffa00aed87 ffff88fba963fcc8 ffff88822975ec48
[] Call Trace:
[] [] blkfront_remove+0x37/0x130 [xen_blkfront]
[] [] xenbus_dev_remove+0x5c/0xc0
[] [] __device_release_driver+0x8a/0x120
[] [] device_release_driver+0x23/0x30
[] [] bus_remove_device+0x10b/0x190
[] [] device_del+0x144/0x270
[] [] ? find_watch+0x50/0x50
[] [] device_unregister+0x22/0x70
[] [] xenbus_dev_changed+0xaf/0x1f0
[] [] ? find_watch+0x50/0x50
[] [] frontend_changed+0x29/0x60
[] [] xenwatch_thread+0x179/0x190
[] [] ? prepare_to_wait_event+0xf0/0xf0
[] [] kthread+0xda/0xf0
[] [] ? __schedule+0x23e/0x850
[] [] ? kthread_create_on_node+0x1b0/0x1b0
[] [] ret_from_fork+0x47/0x90
[] [] ? kthread_create_on_node+0x1b0/0x1b0
[] Code: 00 00 55 48 89 e5 41 55 41 54 53 48 89 fb 48 83 ec 28 65 48 8b 04 25 28 00 00 00 48 89 45 d8 31 c0 83 fe 01 19 c0 f7 d0 83 e0 02 47 48 48 8b 7f 50 48 85 ff 74 05 e8 91 79 27 e1 8b 93 f0 00
[] RIP [] blkif_free+0x2e/0x1c0 [xen_blkfront]
[] RSP <>
[] CR2: 0000000000000048

Changes

Cause

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