dm multipath: fix oops when request based io fails when no paths
The patch posted at http://marc.info/?l=dm-devel&m=124539787228784&w=2
which was merged into cec47e3d4a861e1d942b3a580d0bbef2700d2bb2 ("dm:
prepare for request based option") introduced a regression in
request-based dm.
If map_request() calls dm_kill_unmapped_request() to complete a cloned
bio without dispatching it, clone->bio is still set when
dm_end_request() is called and the BUG_ON(clone->bio) is incorrect.
The patch fixes this bug by freeing bio in dm_end_request() if the clone
has bio. I've redone my tests to cover all I/O paths and confirmed
there's no other regression.
Here is the oops I hit in request-based dm when I do I/O to a multipath
device which doesn't have any active path nor queue_if_no_path setting:
------------[ cut here ]------------
kernel BUG at /root/2.6.31-rc4.rqdm/drivers/md/dm.c:828!
invalid opcode: 0000 [#1] SMP
last sysfs file: /sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map
CPU 1
Modules linked in: autofs4 sunrpc cpufreq_ondemand acpi_cpufreq dm_mirror dm_region_hash dm_log dm_service_time dm_multipath scsi_dh dm_mod video output sbs sbshc battery ac sg sr_mod e1000e button cdrom serio_raw rtc_cmos rtc_core rtc_lib piix lpfc scsi_transport_fc ata_piix libata megaraid_sas sd_mod scsi_mod crc_t10dif ext3 jbd uhci_hcd ohci_hcd ehci_hcd [last unloaded: microcode]
Pid: 7, comm: ksoftirqd/1 Not tainted 2.6.31-rc4.rqdm #1 Express5800/120Lj [N8100-1417]
RIP: 0010:[<ffffffffa023629d>] [<ffffffffa023629d>] dm_softirq_done+0xbd/0x100 [dm_mod]
RSP: 0018:ffff8800280a1f08 EFLAGS: 00010282
RAX: ffffffffa02544e0 RBX: ffff8802aa1111d0 RCX: ffff8802aa1111e0
RDX: ffff8802ab913e70 RSI: 0000000000000000 RDI: ffff8802ab913e70
RBP: ffff8800280a1f28 R08: ffffc90005457040 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 00000000fffffffb
R13: ffff8802ab913e88 R14: ffff8802ab9c1438 R15: 0000000000000100
FS: 0000000000000000(0000) GS:ffff88002809e000(0000) knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000003d54a98640 CR3: 000000029f0a1000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process ksoftirqd/1 (pid: 7, threadinfo ffff8802ae50e000, task ffff8802ae4f8040)
Stack:
ffff8800280a1f38 0000000000000020 ffffffff814f30a0 0000000000000004
<0> ffff8800280a1f58 ffffffff8116b245 ffff8800280a1f38 ffff8800280a1f38
<0> ffff8800280a1f58 0000000000000001 ffff8800280a1fa8 ffffffff810477bc
Call Trace:
<IRQ>
[<ffffffff8116b245>] blk_done_softirq+0x75/0x90
[<ffffffff810477bc>] __do_softirq+0xcc/0x210
[<ffffffff81047170>] ? ksoftirqd+0x0/0x110
[<ffffffff8100ce7c>] call_softirq+0x1c/0x50
<EOI>
[<ffffffff8100e785>] do_softirq+0x65/0xa0
[<ffffffff81047170>] ? ksoftirqd+0x0/0x110
[<ffffffff810471e0>] ksoftirqd+0x70/0x110
[<ffffffff81059559>] kthread+0x99/0xb0
[<ffffffff8100cd7a>] child_rip+0xa/0x20
[<ffffffff8100c73c>] ? restore_args+0x0/0x30
[<ffffffff810594c0>] ? kthread+0x0/0xb0
[<ffffffff8100cd70>] ? child_rip+0x0/0x20
Code: 44 89 e6 48 89 df e8 23 fb f2 e0 be 01 00 00 00 4c 89 f7 e8 f6 fd ff ff 5b 41 5c 41 5d 41 5e c9 c3 4c 89 ef e8 85 fe ff ff eb ed <0f> 0b eb fe 41 8b 85 dc 00 00 00 48 83 bb 10 01 00 00 00 89 83
RIP [<ffffffffa023629d>] dm_softirq_done+0xbd/0x100 [dm_mod]
RSP <ffff8800280a1f08>
---[ end trace 16af0a1d8542da55 ]---
Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1 file changed