On 2017/10/23 下午7:42, Stefan Priebe - Profihost AG wrote:

Hello,

i picked all bcache patches from for-next to my 4.4 kernel to test the
new controller.

After doing so i see random kernel panics with the following trace:

Hi Stefan,

Thanks for the report. This is the 3rd report I see recently for NULL
pointer dereference, maybe they are related (or maybe not). Is it a
panic when bcache starts to run, or during heavy workload ?

If I may have chance to trigger similar oops on my server, that will be
much easier. So far I cannot reproduce any oops, neither by rebooting
and assemble bcache device by udev rules, nor compose bcache device and
run it by bash scripts...

Thank you in advance.

Coly Li

BUG: unable to handle kernel NULL pointer dereference at 0000000000000019
IP: [<ffffffffc04ef62e>] closure_sub+0xe/0xc0 [bcache]
PGD 0
Oops: 0002 [#1] SMP
Modules linked in: netconsole xt_multiport ipt_REJECT nf_reject_ipv4
xt_set iptable_filter ip_tables x_tables ip_set_hash_net ip_set
nfnetlink bonding ipmi_devintf sb_edac edac_core x86_pkg_temp_thermal
mgag200 kvm_intel ttm drm_kms_helper kvm irqbypass drm fb_sys_fops
syscopyarea crc32_pclmul sysfillrect sysimgblt ghash_clmulni_intel wmi
ipmi_si ipmi_msghandler shpchp button coretemp 8021q garp fuse btrfs xor
raid6_pq dm_mod usb_storage ohci_hcd usbhid bcache sg sd_mod ahci
ehci_pci i2c_i801 libahci ehci_hcd isci igb i2c_algo_bit ixgbe usbcore
libsas i2c_core mdio usb_common scsi_transport_sas ptp pps_core
CPU: 6 PID: 50 Comm: ksoftirqd/6 Not tainted 4.4.92+534-ph #1
Hardware name: Supermicro
X9SRE/X9SRE-3F/X9SRi/X9SRi-3F/X9SRE/X9SRE-3F/X9SRi/X9SRi-3F, BIOS 3.0
07/05/2013
task: ffff8802196ccb00 ti: ffff8802196d4000 task.ti: ffff8802196d4000
RIP: 0010:[<ffffffffc04ef62e>] [<ffffffffc04ef62e>] closure_sub+0xe/0xc0
[bcache]
RSP: 0018:ffff8802196d7c20 EFLAGS: 00010297
RAX: 00000000fdffffff RBX: fffffffffffffff1 RCX: 00000000000f4240
RDX: 0000000000070651 RSI: 0000000002000001 RDI: fffffffffffffff1
RBP: ffff8802196d7c28 R08: 0000000000000007 R09: ffff880219568000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000e00
R13: 0000000000000000 R14: 0000000000000e00 R15: ffff8805eb2dbd60
FS: 0000000000000000(0000) GS:ffff880c7f580000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000019 CR3: 0000000c7ee0b000 CR4: 00000000001406e0Stack:
fffffffffffffff1 ffff8802196d7c40 ffffffffc04ef70d ffff880c459ecbc0
ffff8802196d7c58 ffffffffc04f20df ffff880c459eccf0 ffff8802196d7c70
ffffffffc04ef616 ffff880c459eccf0 ffff8802196d7c88 ffffffffc04f16a7
Call Trace:
[<ffffffffc04ef70d>] __closure_wake_up+0x2d/0x40 [bcache]
[<ffffffffc04f20df>] journal_write_done+0x2f/0xa0 [bcache]
[<ffffffffc04ef616>] closure_put+0xb6/0xc0 [bcache]
[<ffffffffc04f16a7>] journal_write_endio+0x37/0x40 [bcache]
[<ffffffff81397b16>] bio_endio+0x56/0x60
[<ffffffff813a00cb>] blk_update_request+0x8b/0x370
[<ffffffff8150b663>] scsi_end_request+0x33/0x1c0
[<ffffffff8150dddd>] scsi_io_completion+0x18d/0x660
[<ffffffff815046df>] scsi_finish_command+0xcf/0x120
[<ffffffff8150d566>] scsi_softirq_done+0x126/0x150
[<ffffffff813a7f88>] blk_done_softirq+0x78/0x90
[<ffffffff8108a48c>] __do_softirq+0x11c/0x2e0
[<ffffffff8108a678>] run_ksoftirqd+0x28/0x50
[<ffffffff810a6fb9>] smpboot_thread_fn+0x139/0x1a0
[<ffffffff810a3aeb>] kthread+0xeb/0x110
[<ffffffff816dbd0f>] ret_from_fork+0x3f/0x70
DWARF2 unwinder stuck at ret_from_fork+0x3f/0x70
Leftover inexact backtrace:
2017-10-23 13:35:09
[<ffffffff810a3a00>] ? kthread_park+0x60/0x60
Code: e8 a8 d6 ba c0 84 c0 75 83 0f 0b 48 8b 5f 20 eb af ff d1 e9 74 ff
ff ff 0f 0b 0f 1f 00 0f 1f 44 00 00 55 89 f0 f7 d8 48 89 e5 53 <f0> 0f
c1 47 28 29 f0 89 c1 81 e1 ff ff 7f 00 a9 00 00 00 55 75
RIP [<ffffffffc04ef62e>] closure_sub+0xe/0xc0 [bcache]
RSP <ffff8802196d7c20>
CR2: 0000000000000019
---[ end trace a4cc6c37159f8e49 ]---
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range:
0xffffffff80000000-0xffffffffbfffffff)