Ubuntu
drbd8 package

DRBD 8.4 kernel crash when using same resource for 2 minors

Bug #1317833 reported by Dick Tump
14
This bug affects 3 people
Affects Status Importance Assigned to Milestone
drbd8 (Ubuntu)
Confirmed
Undecided
Unassigned

Bug Description

When you use the same resource for 2 minors, it crashes the kernel. Of course you should not do that, though I think it should not crash the kernel. The expected output is just an error message. This makes DRBD resource/minor management more difficult and also kind of dangerous.

DRBD 8.3 does not have this problem, probably because it works a bit different with resources/minors.

Steps to reproduce:
* drbdsetup new-resource test1
* drbdsetup new-minor test1 1 0
* drbdsetup new-minor test1 3 0

It exits showing the message 'Killed'. The kernel log shows some errors and DRBD is not usable anymore. After a short while or when executing other drbdsetup commands, the whole system crashes.

I am not sure whether it's the utils package, or the kernel module.

System info:
Description: Ubuntu 14.04 LTS
Release: 14.04
drbd8-utils version: 2:8.4.4-1ubuntu1
Installed kernel: linux-image-3.13.0-24-generic 3.13.0-24.47

Revision history for this message
Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in drbd8 (Ubuntu):
status: New → Confirmed
Revision history for this message
Bram Klein Gunnewiek (i-bram) wrote :
Download full text (6.1 KiB)

I can confirm this bug and have some additional information. When using a device name as minor number (e.g. /dev/drbdX) drbdsetup gives a correct error:

root@xxxx:~# drbdsetup new-minor r0 /dev/drbd0 0
root@xxxx:~# drbdsetup new-minor r0 /dev/drbd0 1
r0: Failure: (162) Invalid configuration request
additional info from kernel:
minor exists as different volume

When using only the minor number (root@xxxx:~# drbdsetup new-minor r0 1 0) drbdsetup hangs/crashes. The kernel log shows the following:

May 15 11:04:06 testnode1 kernel: [265432.796294] request: minor=0, volume=1; but that minor is volume 0 in r0
May 15 11:04:32 testnode1 kernel: [265458.326351] BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
May 15 11:04:32 testnode1 kernel: [265458.328289] IP: [<ffffffff81351b38>] blk_throtl_drain+0x28/0x130
May 15 11:04:32 testnode1 kernel: [265458.329938] PGD d767b067 PUD d7411067 PMD 0
May 15 11:04:32 testnode1 kernel: [265458.331067] Oops: 0000 [#1] SMP
May 15 11:04:32 testnode1 kernel: [265458.331889] Modules linked in: drbd dm_snapshot lru_cache libcrc32c nfsd bridge auth_rpcgss stp nfs_acl llc nfs lockd sunrpc fscache gpio_ich coretemp kvm_intel kvm psmouse serio_raw joydev lpc_ich lp parport ioatdma dca i7core_edac edac_core mac_hid hid_generic usbhid hid e1000e floppy ptp pps_core [last unloaded: drbd]
May 15 11:04:32 testnode1 kernel: [265458.339787] CPU: 4 PID: 22159 Comm: drbdsetup Not tainted 3.13.0-24-generic #47-Ubuntu
May 15 11:04:32 testnode1 kernel: [265458.341696] Hardware name: Supermicro X8STi/X8STi, BIOS 2.0 09/17/10
May 15 11:04:32 testnode1 kernel: [265458.343456] task: ffff88019260dfc0 ti: ffff88009b8b2000 task.ti: ffff88009b8b2000
May 15 11:04:32 testnode1 kernel: [265458.345260] RIP: 0010:[<ffffffff81351b38>] [<ffffffff81351b38>] blk_throtl_drain+0x28/0x130
May 15 11:04:32 testnode1 kernel: [265458.347357] RSP: 0018:ffff88009b8b3b10 EFLAGS: 00010046
May 15 11:04:32 testnode1 kernel: [265458.348636] RAX: 0000000000000000 RBX: ffff88019258e148 RCX: 000000000000b562
May 15 11:04:32 testnode1 kernel: [265458.350641] RDX: 000000000000000e RSI: 0000000000000001 RDI: 0000000000000000
May 15 11:04:32 testnode1 kernel: [265458.352361] RBP: ffff88009b8b3b28 R08: 00000000000172a0 R09: ffff88019fc972a0
May 15 11:04:32 testnode1 kernel: [265458.354080] R10: ffffea0000d90000 R11: ffffffff81340f10 R12: ffff88019258e148
May 15 11:04:32 testnode1 kernel: [265458.355800] R13: ffff8800d7747300 R14: ffff88019258e798 R15: ffff880192180000
May 15 11:04:32 testnode1 kernel: [265458.357521] FS: 00007f18ff858740(0000) GS:ffff88019fc80000(0000) knlGS:0000000000000000
May 15 11:04:32 testnode1 kernel: [265458.359618] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
May 15 11:04:32 testnode1 kernel: [265458.361043] CR2: 0000000000000028 CR3: 00000000d5c44000 CR4: 00000000000007e0
May 15 11:04:32 testnode1 kernel: [265458.362797] Stack:
May 15 11:04:32 testnode1 kernel: [265458.363282] ffff88019258e148 0000000000000001 ffff88019258e7a8 ffff88009b8b3b38
May 15 11:04:32 testnode1 kernel: [265458.365152] ffffffff8134eb7e ffff88009b8b3b68 ffffffff81332c84 ffff88019258e148
May 15 11:04:32 testnode1 kernel: [265458...

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Revision history for this message
Dick Tump (dicktump) wrote :

I have done a bit more testing and this also happens with a manually compiled DRBD 8.4.5 and manually compiled drbdsetup, so this bug is probably more something for the DRBD developers to fix. I will address this issue on their mailinglist.

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