PR/59618 CVS commit: src/sys/dev/pci

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

The following reply was made to PR kern/59618; it has been noted by GNATS.

From: "Taylor R Campbell" <riastradh%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/59618 CVS commit: src/sys/dev/pci
Date: Sat, 6 Sep 2025 02:56:52 +0000

 Module Name:	src
 Committed By:	riastradh
 Date:		Sat Sep  6 02:56:52 UTC 2025
 
 Modified Files:
 	src/sys/dev/pci: pvscsi.c
 
 Log Message:
 pvscsi(4): Zero rings before using them.
 
 bus_dmamem_alloc(9) doesn't guarantee zeroing, as far as I can tell,
 and who knows what might happen if the ring header and contents have
 anything nonzero initially.
 
 Insert an initial preread/prewrite sync between zeroing and first
 use, and, out of paranoia, a final postread/postwrite sync between
 last use and unload/free.
 
 Prompted by (but not really related to):
 
 PR kern/59618: occasional virtio block device lock ups/hangs
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.4 -r1.5 src/sys/dev/pci/pvscsi.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.