On 1/24/23 07:49, mwilck@xxxxxxxx wrote:
From: Martin Wilck <mwilck@xxxxxxxx>
Since the might_sleep() annotation was added in scsi_device_put() and
alua_rtpg_queue(), we have seen repeated reports of "BUG: sleeping function
called from invalid context" [1], [2]. alua_rtpg_queue() is always called
from contexts where the caller must hold at least one reference to the scsi
device in question. This means that the reference taken by
alua_rtpg_queue() itself can't be the last one, and thus can be dropped
without entering the code path in which scsi_device_put() might actually
sleep.
Add a new helper function, scsi_device_put_nosleep() for cases like this,
where a device reference is put from atomic context, and at the same time
it is certain that this reference is not the last one, and use it from
alua_rtpg_queue().
Something I should have asked earlier, has this alternative been
considered? This alternative has the advantage that no new functions are
introduced.
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 1426b9b03612..9feb0323bc44 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -588,8 +588,6 @@ void scsi_device_put(struct scsi_device *sdev)
{
struct module *mod = sdev->host->hostt->module;
- might_sleep();
-
put_device(&sdev->sdev_gendev);
module_put(mod);
}
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 981d1bab2120..8ef9a5494340 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -452,5 +451,7 @@ static void scsi_device_dev_release(struct device
unsigned long flags;
+ might_sleep();
+
scsi_dh_release_device(sdev);
parent = sdev->sdev_gendev.parent;
Thanks,
Bart.
