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* [BUG] scsi/qla2xxx: a possible sleep-in-atomic bug in qlt_get_tag
@ 2017-12-13  3:18 Jia-Ju Bai
  2017-12-13  4:42 ` James Bottomley
  0 siblings, 1 reply; 3+ messages in thread
From: Jia-Ju Bai @ 2017-12-13  3:18 UTC (permalink / raw)
  To: qla2xxx-upstream, jejb, martin.petersen
  Cc: linux-scsi, Linux Kernel Mailing List

The driver may sleep under a spinlock.
The function call paths are:
qlt_handle_abts_recv_work (acquire the spinlock)
   qlt_response_pkt_all_vps
     qlt_response_pkt
       qlt_handle_cmd_for_atio
         qlt_get_tag
           percpu_ida_alloc --> may sleep

qla82xx_msix_rsp_q (acquire the spinlock)
   qla24xx_process_response_queue
     qlt_handle_abts_recv
       qlt_response_pkt_all_vps
         qlt_response_pkt
           qlt_handle_cmd_for_atio
             qlt_get_tag
               percpu_ida_alloc --> may sleep-in-atomic

qla24xx_intr_handler (acquire the spinlock)
   qla24xx_process_response_queue
     qlt_handle_abts_recv
       qlt_response_pkt
         qlt_handle_cmd_for_atio
           qlt_get_tag
             percpu_ida_alloc --> may sleep

I do not find a good way to fix it, so I only report.
This possible bug is found by my static analysis tool (DSAC) and checked 
by my code review.


Thanks,
Jia-Ju Bai

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [BUG] scsi/qla2xxx: a possible sleep-in-atomic bug in qlt_get_tag
  2017-12-13  3:18 [BUG] scsi/qla2xxx: a possible sleep-in-atomic bug in qlt_get_tag Jia-Ju Bai
@ 2017-12-13  4:42 ` James Bottomley
  2017-12-13  7:38   ` Jia-Ju Bai
  0 siblings, 1 reply; 3+ messages in thread
From: James Bottomley @ 2017-12-13  4:42 UTC (permalink / raw)
  To: Jia-Ju Bai, qla2xxx-upstream, martin.petersen
  Cc: linux-scsi, Linux Kernel Mailing List

On Wed, 2017-12-13 at 11:18 +0800, Jia-Ju Bai wrote:
> The driver may sleep under a spinlock.
> The function call paths are:
> qlt_handle_abts_recv_work (acquire the spinlock)
>    qlt_response_pkt_all_vps
>      qlt_response_pkt
>        qlt_handle_cmd_for_atio
>          qlt_get_tag
>            percpu_ida_alloc --> may sleep
> 
> qla82xx_msix_rsp_q (acquire the spinlock)
>    qla24xx_process_response_queue
>      qlt_handle_abts_recv
>        qlt_response_pkt_all_vps
>          qlt_response_pkt
>            qlt_handle_cmd_for_atio
>              qlt_get_tag
>                percpu_ida_alloc --> may sleep-in-atomic
> 
> qla24xx_intr_handler (acquire the spinlock)
>    qla24xx_process_response_queue
>      qlt_handle_abts_recv
>        qlt_response_pkt
>          qlt_handle_cmd_for_atio
>            qlt_get_tag
>              percpu_ida_alloc --> may sleep
> 
> I do not find a good way to fix it, so I only report.
> This possible bug is found by my static analysis tool (DSAC) and
> checked by my code review.

The report is incorrect: percpu_ida_alloc with state==TASK_RUNNING is
atomic (and interrupt) safe which appears to be the case here.

James

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [BUG] scsi/qla2xxx: a possible sleep-in-atomic bug in qlt_get_tag
  2017-12-13  4:42 ` James Bottomley
@ 2017-12-13  7:38   ` Jia-Ju Bai
  0 siblings, 0 replies; 3+ messages in thread
From: Jia-Ju Bai @ 2017-12-13  7:38 UTC (permalink / raw)
  To: James Bottomley, qla2xxx-upstream, martin.petersen
  Cc: linux-scsi, Linux Kernel Mailing List


On 2017/12/13 12:42, James Bottomley wrote:
> On Wed, 2017-12-13 at 11:18 +0800, Jia-Ju Bai wrote:
>> The driver may sleep under a spinlock.
>> The function call paths are:
>> qlt_handle_abts_recv_work (acquire the spinlock)
>>     qlt_response_pkt_all_vps
>>       qlt_response_pkt
>>         qlt_handle_cmd_for_atio
>>           qlt_get_tag
>>             percpu_ida_alloc --> may sleep
>>
>> qla82xx_msix_rsp_q (acquire the spinlock)
>>     qla24xx_process_response_queue
>>       qlt_handle_abts_recv
>>         qlt_response_pkt_all_vps
>>           qlt_response_pkt
>>             qlt_handle_cmd_for_atio
>>               qlt_get_tag
>>                 percpu_ida_alloc --> may sleep-in-atomic
>>
>> qla24xx_intr_handler (acquire the spinlock)
>>     qla24xx_process_response_queue
>>       qlt_handle_abts_recv
>>         qlt_response_pkt
>>           qlt_handle_cmd_for_atio
>>             qlt_get_tag
>>               percpu_ida_alloc --> may sleep
>>
>> I do not find a good way to fix it, so I only report.
>> This possible bug is found by my static analysis tool (DSAC) and
>> checked by my code review.
> The report is incorrect: percpu_ida_alloc with state==TASK_RUNNING is
> atomic (and interrupt) safe which appears to be the case here.
>
> James
>

Thanks for your reply :)
I have checked the definition of percpu_ida_alloc, and I think you are 
right.
Sorry for my incorrect bug report.


Thanks,
Jia-Ju Bai

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2017-12-13  7:38 UTC | newest]

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2017-12-13  3:18 [BUG] scsi/qla2xxx: a possible sleep-in-atomic bug in qlt_get_tag Jia-Ju Bai
2017-12-13  4:42 ` James Bottomley
2017-12-13  7:38   ` Jia-Ju Bai

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