Jack,
Follwing is the stack. We located the code line that causes unaligned data access
according to the PC address in mvs_slot_complete(). After applying the
patch, the disk io stress testing run well. Actually reading the source code,
I found that it seems that slot->response is not really surely 8-byte aligned.
Considering the affected code line is rarely called, we can just simply use
get_unaligned_*().
Thanks,
Paul
Pid: 0, comm: swapper, CPU: 1
r0 : 0xfffffe43f67e2c94 r1 : 0xfffffe43f86b2450 r2 : 0xfffffe43f86b2450
r3 : 0xfffffe43f86b2440 r4 : 0x0000000000000000 r5 : 0x0000000000000000
r6 : 0x0000000000000000 r7 : 0x0000000000000000 r8 : 0x0000000000000000
r9 : 0x0000000000000000 r10: 0xfffffe43f86b2450 r11: 0xfffffe43f86b2448
r12: 0xe000003780f29b84 r13: 0x1fffffc87f0d647c r14: 0x0000000000000001
r15: 0x0000000000000080 r16: 0x0000000000000040 r17: 0x0000000000000002
r18: 0x0000000000000001 r19: 0xfffffe43f86b2448 r20: 0x0000000000000001
r21: 0x0000000000020000 r22: 0xfffffe43ffedfaa8 r23: 0x0000000000020000
r24: 0xfffffe43ffedfab0 r25: 0xfffffe43ffedfaf0 r26: 0xfffffe43ffedfab8
r27: 0xfffffe03f8a64648 r28: 0x00000000000245f0 r29: 0x000000000000245f
r30: 0xfffffe43f86b2300 r31: 0xfffffe03f8a40000 r32: 0x0000000000000001
r33: 0xfffffe03f8a42590 r34: 0x0000000000000001 r35: 0x0000000000030001
r36: 0xfffffe43f86b2318 r37: 0xfffffe03f8a40058 r38: 0xfffffe03f8a64610
r39: 0x0000000000000001 r40: 0x0000000000000000 r41: 0x0000000000000000
r42: 0xfffffe0000a856f8 r43: 0xfffffe00009a78d8 r44: 0xfffffe00008e1298
r45: 0xfffffe0000a70080 r46: 0x0000000000000001 r47: 0x0000000000000000
r48: 0x0000000000000000 r49: 0x0000000000000000 r50: 0x0000000000000000
r51: 0x0000000000000000 r52: 0xfffffe43ffedfc40 tp : 0x000001f4ff730000
sp : 0xfffffe43ffedfa90 lr : 0xfffffff7002abec0 pc : 0xfffffff7002ac370
ex1: 1 faultnum: 17
Starting stack dump of tid 0, pid 0 (swapper) on cpu 1 at cycle 341465978177
frame 0: 0xfffffff7002ac370 mvs_slot_complete+0x5f0/0x12a0 (sp 0xfffffe43ffedfa90)
frame 1: 0xfffffff7002abec0 mvs_slot_complete+0x140/0x12a0 (sp 0xfffffe43ffedfa90)
frame 2: 0xfffffff7005cc840 mvs_int_rx+0x140/0x2a0 (sp 0xfffffe43ffedfb00)
frame 3: 0xfffffff7005bbaf0 mvs_94xx_isr+0xd8/0x2b8 (sp 0xfffffe43ffedfb68)
frame 4: 0xfffffff700658ba0 mvs_tasklet+0x128/0x1f8 (sp 0xfffffe43ffedfba8)
frame 5: 0xfffffff7003e8230 tasklet_action+0x178/0x2c8 (sp 0xfffffe43ffedfbe0)
frame 6: 0xfffffff700103850 __do_softirq+0x210/0x398 (sp 0xfffffe43ffedfc40)
frame 7: 0xfffffff700180308 do_softirq+0xc8/0x140 (sp 0xfffffe43ffedfcd8)
frame 8: 0xfffffff7000bd7f0 irq_exit+0xb0/0x158 (sp 0xfffffe43ffedfcf0)
frame 9: 0xfffffff70013fa58 tile_dev_intr+0x1d8/0x2f0 (sp 0xfffffe43ffedfd00)
frame 10: 0xfffffff70044ca78 handle_interrupt+0x270/0x278 (sp 0xfffffe43ffedfd40)
<interrupt 30 while in kernel mode>
frame 11: 0xfffffff700143e68 _cpu_idle_nap+0x0/0x18 (sp 0xfffffe43ffedffb0)
frame 12: 0xfffffff700482480 cpu_idle+0x310/0x428 (sp 0xfffffe43ffedffb0)
Stack dump complete Kernel panic - not syncing:
Kernel unalign fault running the idle task!
Starting stack dump of tid 0, pid 0 (swapper) on cpu 1 at cycle 341586172541
frame 0: 0xfffffff700140ee0 dump_stack+0x0/0x20 (sp 0xfffffe43ffedf420)
frame 1: 0xfffffff700283270 panic+0x150/0x3a0 (sp 0xfffffe43ffedf420)
frame 2: 0xfffffff70012bff8 jit_bundle_gen+0xfd8/0x27e0 (sp 0xfffffe43ffedf4c8)
frame 3: 0xfffffff7003b5b68 do_unaligned+0xc0/0x5a0 (sp 0xfffffe43ffedf710)
frame 4: 0xfffffff70044ca78 handle_interrupt+0x270/0x278 (sp 0xfffffe43ffedf840)
<interrupt 17 while in kernel mode>
frame 5: 0xfffffff7002ac370 mvs_slot_complete+0x5f0/0x12a0 (sp 0xfffffe43ffedfa90)
frame 6: 0xfffffff7002abec0 mvs_slot_complete+0x140/0x12a0 (sp 0xfffffe43ffedfa90)
frame 7: 0xfffffff7005cc840 mvs_int_rx+0x140/0x2a0 (sp 0xfffffe43ffedfb00)
frame 8: 0xfffffff7005bbaf0 mvs_94xx_isr+0xd8/0x2b8 (sp 0xfffffe43ffedfb68)
frame 9: 0xfffffff700658ba0 mvs_tasklet+0x128/0x1f8 (sp 0xfffffe43ffedfba8)
frame 10: 0xfffffff7003e8230 tasklet_action+0x178/0x2c8 (sp 0xfffffe43ffedfbe0)
frame 11: 0xfffffff700103850 __do_softirq+0x210/0x398 (sp 0xfffffe43ffedfc40)
frame 12: 0xfffffff700180308 do_softirq+0xc8/0x140 (sp 0xfffffe43ffedfcd8)
frame 13: 0xfffffff7000bd7f0 irq_exit+0xb0/0x158 (sp 0xfffffe43ffedfcf0)
frame 14: 0xfffffff70013fa58 tile_dev_intr+0x1d8/0x2f0 (sp 0xfffffe43ffedfd00)
frame 15: 0xfffffff70044ca78 handle_interrupt+0x270/0x278 (sp 0xfffffe43ffedfd40)
<interrupt 30 while in kernel mode>
frame 16: 0xfffffff700143e68 _cpu_idle_nap+0x0/0x18 (sp 0xfffffe43ffedffb0)
frame 17: 0xfffffff700482480 cpu_idle+0x310/0x428 (sp 0xfffffe43ffedffb0)
Stack dump complete Client requested halt.
> Paul，
>
> Could you also share the panic info?
>
> Thanks.
>
> Jack
>> We encountered panic during stress tesing on our platform,
>> due to unaligned data access in the mvsas driver.
>>
>>
>> Signed-off-by: Paul Guo <ggang@xxxxxxxxxx>
>> ---
>> drivers/scsi/mvsas/mv_sas.c | 5 +++--
>> drivers/scsi/mvsas/mv_sas.h | 1 +
>> 2 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/scsi/mvsas/mv_sas.c b/drivers/scsi/mvsas/mv_sas.c
>> index fd3b283..be4989e 100644
>> --- a/drivers/scsi/mvsas/mv_sas.c
>> +++ b/drivers/scsi/mvsas/mv_sas.c
>> @@ -1852,10 +1852,11 @@ int mvs_slot_complete(struct mvs_info *mvi, u32
>> rx_desc, u32 flags)
>> }
>>
>> /* error info record present */
>> - if (unlikely((rx_desc & RXQ_ERR) && (*(u64 *) slot->response))) {
>> + if (unlikely((rx_desc & RXQ_ERR) &&
>> + get_unaligned_le64((u64 *) slot->response))) {
>> mv_dprintk("port %d slot %d rx_desc %X has error info"
>> "%016llX.\n", slot->port->sas_port.id, slot_idx,
>> - rx_desc, (u64)(*(u64 *)slot->response));
>> + rx_desc, get_unaligned_le64((u64
> *)slot->response));
>> tstat->stat = mvs_slot_err(mvi, task, slot_idx);
>> tstat->resp = SAS_TASK_COMPLETE;
>> goto out;
>> diff --git a/drivers/scsi/mvsas/mv_sas.h b/drivers/scsi/mvsas/mv_sas.h
>> index c04a4f5..1bc093a 100644
>> --- a/drivers/scsi/mvsas/mv_sas.h
>> +++ b/drivers/scsi/mvsas/mv_sas.h
>> @@ -39,6 +39,7 @@
>> #include <linux/irq.h>
>> #include <linux/slab.h>
>> #include <linux/vmalloc.h>
>> +#include <asm/unaligned.h>
>> #include <scsi/libsas.h>
>> #include <scsi/scsi.h>
>> #include <scsi/scsi_tcq.h>
>> --
>> 1.7.10.3
>>
>> --
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