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authorManjunath Patil <manjunath.b.patil@oracle.com>2018-10-30 09:49:21 -0700
committerJuergen Gross <jgross@suse.com>2018-11-06 10:33:36 +0100
commit6cc4a0863c9709c512280c64e698d68443ac8053 (patch)
treedc10a971c18a294f2fed2dcbdfb5fd89d0977bc9 /drivers/block
parentd9cccfa7c4d1d9ef967ec9308df7304a18609b30 (diff)
downloadlinux-6cc4a0863c9709c512280c64e698d68443ac8053.tar.bz2
xen-blkfront: fix kernel panic with negotiate_mq error path
info->nr_rings isn't adjusted in case of ENOMEM error from negotiate_mq(). This leads to kernel panic in error path. Typical call stack involving panic - #8 page_fault at ffffffff8175936f [exception RIP: blkif_free_ring+33] RIP: ffffffffa0149491 RSP: ffff8804f7673c08 RFLAGS: 00010292 ... #9 blkif_free at ffffffffa0149aaa [xen_blkfront] #10 talk_to_blkback at ffffffffa014c8cd [xen_blkfront] #11 blkback_changed at ffffffffa014ea8b [xen_blkfront] #12 xenbus_otherend_changed at ffffffff81424670 #13 backend_changed at ffffffff81426dc3 #14 xenwatch_thread at ffffffff81422f29 #15 kthread at ffffffff810abe6a #16 ret_from_fork at ffffffff81754078 Cc: stable@vger.kernel.org Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of new VBDs") Signed-off-by: Manjunath Patil <manjunath.b.patil@oracle.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/xen-blkfront.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 9eea83ae01c6..9ac3999a55b7 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1919,6 +1919,7 @@ static int negotiate_mq(struct blkfront_info *info)
GFP_KERNEL);
if (!info->rinfo) {
xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure");
+ info->nr_rings = 0;
return -ENOMEM;
}