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Commit 563585ec4bf1319f193c2f51682985bcae400cb4

Authored by James Bottomley
1 parent 3c6c0d6ca3
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

[SCSI] qla2xxx: Fix race that could hang kthread_stop() 

There is a small race window in qla2x00_do_dpc() between
checking for kthread_should_stop() and going to sleep after
setting TASK_INTERRUPTIBLE. If qla2x00_free_device() is called
in this window, kthread_stop will wait forever because there
will be no one to wake up the process.

Fix by making sure we only set TASK_INTERRUPTIBLE before checking
kthread_stop().

Reported-by: Bandan Das <bandan.das@stratus.com>
Acked-by: Madhuranath Iyengar <Madhu.Iyengar@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

Showing 1 changed file with 3 additions and 1 deletions Side-by-side Diff

drivers/scsi/qla2xxx/qla_os.c
Diff comments   View file @ 563585e
... ... @@ -3282,10 +3282,10 @@
3282 3282  
3283 3283 set_user_nice(current, -20);
3284 3284  
  3285 + set_current_state(TASK_INTERRUPTIBLE);
3285 3286 while (!kthread_should_stop()) {
3286 3287 DEBUG3(printk("qla2x00: DPC handler sleeping\n"));
3287 3288  
3288   - set_current_state(TASK_INTERRUPTIBLE);
3289 3289 schedule();
3290 3290 __set_current_state(TASK_RUNNING);
3291 3291  
3292 3292  
... ... @@ -3454,7 +3454,9 @@
3454 3454 qla2x00_do_dpc_all_vps(base_vha);
3455 3455  
3456 3456 ha->dpc_active = 0;
  3457 + set_current_state(TASK_INTERRUPTIBLE);
3457 3458 } /* End of while(1) */
  3459 + __set_current_state(TASK_RUNNING);
3458 3460  
3459 3461 DEBUG(printk("scsi(%ld): DPC handler exiting\n", base_vha->host_no));
3460 3462