Re: WARNING: at drivers/scsi/scsi_lib.c:1704
From: Steffen Maier
Date: Thu Nov 10 2011 - 10:51:38 EST
On 11/07/2011 03:51 PM, James Bottomley wrote:
On Mon, 2011-11-07 at 17:24 +1100, Stephen Rothwell wrote:
WARNING: at drivers/scsi/scsi_lib.c:1704
I get lots more of these. The obvious commit to point the finger at
is 3308511c93e6 ("[SCSI] Make scsi_free_queue() kill pending SCSI
commands") but the root cause may be something different.
Actually, I don't think it's anything to do with this: it's Anton's
fault
commit f7c9c6bb14f3104608a3a83cadea10a6943d2804
Author: Anton Blanchard<anton@xxxxxxxxx>
Date: Thu Nov 3 08:56:22 2011 +1100
[SCSI] Fix block queue and elevator memory leak in scsi_alloc_sdev
Doesn't completely do the teardown. The true fix is to do a proper
teardown instead of hand rolling it. Does this fix it for you?
James
---
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 72273a0..b3c6d95 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -319,11 +319,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
return sdev;
out_device_destroy:
- scsi_device_set_state(sdev, SDEV_DEL);
- transport_destroy_device(&sdev->sdev_gendev);
- put_device(&sdev->sdev_dev);
- scsi_free_queue(sdev->request_queue);
- put_device(&sdev->sdev_gendev);
+ __scsi_remove_device(sdev);
out:
if (display_failure_msg)
printk(ALLOC_FAILURE_MSG, __func__);
James, is it OK that __scsi_remove_device() now also calls
sdev->host->hostt->slave_destroy(sdev) which wasn't there before?
I cannot prove it yet, but with this patch and some asorted others on
top of 3.1 our zfcp LLD gets called with an sdev argument that was freed
before or at least before dereferencing (found with DEBUG_PAGEALLOC).
Steffen
Linux on System z Development
IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martin Jetter
GeschÃftsfÃhrung: Dirk Wittkopp
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