lkml.org 
[lkml]   [2009]   [Sep]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] scsi_lib.c: sleeping function called from invalid context
Date
Driver scsi_lib.c might sleep in atomic context, because it calls 
scsi_device_put under spin_lock_irqsave.
drivers/scsi/scsi_lib.c:356:
spin_lock_irqsave(shost->host_lock, flags);
scsi_device_put(sdev);
Path to might_sleep macro from scsi_device_put:
1. scsi_device_put calls put_device at ./drivers/scsi/scsi.c:1111
2. put_device calls kobject_put at ./drivers/base/core.c:1038
3. kobject_put calls kref_put at ./lib/kobject.c
4. kref_put may call callback function kobject_release at ./lib/kref.c if
refcount becomes zero, which might_sleep because it calls user event. Details:
4.1 kobject_cleanup calls kobject_uevent at ./lib/kobject.c:555
4.2 kobject_uevent calls kobject_uevent_env at ./lib/kobject_uevent.c:282
4.3 kobject_uevent_env calls call_usermodehelper_exec at
./include/linux/kmod.h:83
4.4 call_usermodehelper_exec calls wait_for_completion at
./kernel/kmod.c:481
4.5 wait_for_completion calls wait_for_common at ./kernel/sched.c:5710
4.5 wait_for_common calls might_sleep at ./kernels/sched.c:5692

Found by Linux Driver Verification project.

Delete wrong sleeping function calls.

Signed-off-by: Alexander Strakh <strakh@ispras.ru>

---
diff --git a/./a/drivers/scsi/scsi_lib.c b/./b/drivers/scsi/scsi_lib.c
index f3c4089..a8f8e2f 100644
--- a/./a/drivers/scsi/scsi_lib.c
+++ b/./b/drivers/scsi/scsi_lib.c
@@ -353,9 +353,9 @@ static void scsi_single_lun_run(struct scsi_device
*current_sdev)

spin_unlock_irqrestore(shost->host_lock, flags);
blk_run_queue(sdev->request_queue);
- spin_lock_irqsave(shost->host_lock, flags);

- scsi_device_put(sdev);
+ scsi_device_put(sdev);
+ spin_lock_irqsave(shost->host_lock, flags);
}
out:
spin_unlock_irqrestore(shost->host_lock, flags);


\
 
 \ /
  Last update: 2009-09-23 15:59    [W:0.056 / U:0.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site