BUG: unable to handle kernel NULL pointer dereference at (null)

This document (7023106) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 11 Service Pack 4 (SLES 11 SP4)
SUSE Linux Enterprise Server 12 Service Pack 2 (SLES 12 SP2)

Situation

On a SLES server a system panic can be encountered followed by the issued backtrace:

<1>[1299303.841465] BUG: unable to handle kernel NULL pointer dereference at           (null)
<1>[1299303.842692] IP: [<          (null)>]           (null)
<4>[1299303.843404] PGD 0
<0>[1299303.843798] Oops: 0010 [#1] SMP
<4>[1299303.844048] CPU 2
<4>[1299303.844048] Modules linked in: autofs4 edd nfs lockd fscache auth_rpcgss nfs_acl sunrpc mperf fuse loop ipv6_lib pcspkr serio_raw sg virtio_balloon sr_mod cdrom virtio_net rtc_cmos floppy i2c_piix4 button container dm_mirror dm_region_hash dm_log linear raid456 async_raid6_recov async_pq raid6_pq async_xor xor async_memcpy async_tx raid10 raid1 raid0 ttm drm_kms_helper drm i2c_core sysimgblt sysfillrect syscopyarea sd_mod crc_t10dif uhci_hcd ehci_hcd virtio_scsi usbcore usb_common intel_agp intel_gtt dm_snapshot dm_mod ext3 mbcache jbd fan processor virtio_blk virtio_pci virtio_ring virtio ata_generic ata_piix libata scsi_mod thermal thermal_sys hwmon
<4>[1299303.844048] Supported: Yes
<4>[1299303.844048]
<4>[1299303.844048] Pid: 2249, comm: klogd Not tainted 3.0.101-108.10-default #1 QEMU Standard PC (i440FX + PIIX, 1996)
<4>[1299303.844048] RIP: 0010:[<0000000000000000>] [<          (null)>]           (null)
<4>[1299303.844048] RSP: 0018:ffff880bf1527d30 EFLAGS: 00010046
<4>[1299303.844048] RAX: ffffffff81605c60 RBX: ffff880bf6628440 RCX: 0000000000001e89
<4>[1299303.844048] RDX: 0000000000000011 RSI: ffff880bf6628440 RDI: ffff880c3fc90b00
<4>[1299303.844048] RBP: ffff880bf1527d58 R08: 0000000000000001 R09: 00000000ffffffff
<4>[1299303.844048] R10: ffff880c3fc90ba0 R11: 0000000000000000 R12: ffff880c3fc90b00
<4>[1299303.844048] R13: 0000000000000000 R14: 0000000000000063 R15: 0000000000000000
<4>[1299303.844048] FS: 00007fc1f1fd1700(0000) GS:ffff880c3fc80000(0000) knlGS:0000000000000000
<4>[1299303.844048] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[1299303.844048] CR2: 0000000000000000 CR3: 0000000bf254b000 CR4: 00000000000006e0
<4>[1299303.844048] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
<4>[1299303.844048] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
<4>[1299303.844048] Process klogd (pid: 2249, threadinfo ffff880bf1526000, task ffff880bf2e1a580)
<0>[1299303.844048] Stack:
<4>[1299303.844048] ffffffff8105869e ffff880bf1527fd8 ffff880bf6628440 0000000000000000
<4>[1299303.844048] ffff880c3fc90b00 ffff880bf1527d88 ffffffff81058724 ffff880bf2e1a580
<4>[1299303.844048] ffff880bf6628440 0000000000010b00 00007fc1f1f8f073 ffff880bf1527da8
<0>[1299303.844048] Call Trace:
<0>[1299303.844048] Inexact backtrace:
<0>[1299303.844048]
<4>[1299303.844048] [<ffffffff8105869e>] ? ttwu_do_activate+0x3e/0x80
<4>[1299303.844048] [<ffffffff81058724>] ? sched_ttwu_do_pending+0x44/0x60
<4>[1299303.844048] [<ffffffff81058777>] ? scheduler_ipi+0x37/0x140
<4>[1299303.844048] [<ffffffff814742f3>] ? reschedule_interrupt+0x13/0x20
<4>[1299303.844048] [<ffffffff8106463f>] ? do_syslog+0x3df/0x4d0
<4>[1299303.844048] [<ffffffff8106465b>] ? do_syslog+0x3fb/0x4d0
<4>[1299303.844048] [<ffffffff810856b0>] ? wake_up_bit+0x40/0x40
<4>[1299303.844048] [<ffffffff811c9ffe>] ? kmsg_read+0x2e/0x70
<4>[1299303.844048] [<ffffffff811be4a7>] ? proc_reg_read+0x77/0xc0
<4>[1299303.844048] [<ffffffff81160687>] ? vfs_read+0xc7/0x130
<4>[1299303.844048] [<ffffffff811607f3>] ? sys_read+0x53/0xa0
<4>[1299303.844048] [<ffffffff814733f2>] ? system_call_fastpath+0x16/0x1b
<0>[1299303.844048] Code: Bad RIP value.
<1>[1299303.844048] RIP [<          (null)>]           (null)
<4>[1299303.844048] RSP <ffff880bf1527d30>
<0>[1299303.844048] CR2: 0000000000000000

Resolution

Fix is available for SLES11 SP4 in kernel-default-3.0.101-108.35.1

Fix is available for SLE12 SP2 in kernel-default-4.4.103-92.53.1

Cause

The swapper process is sleeping while being in an interrupt context.

Additional Information

Disclaimer

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