* [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path
@ 2018-10-30 16:49 Manjunath Patil
2018-10-30 16:52 ` Juergen Gross
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Manjunath Patil @ 2018-10-30 16:49 UTC (permalink / raw)
To: boris.ostrovsky, jgross, konrad.wilk, roger.pau
Cc: axboe, xen-devel, linux-block, linux-kernel, stable
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>
---
drivers/block/xen-blkfront.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 429d201..5d84da2 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;
}
--
1.7.1
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path
2018-10-30 16:49 [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path Manjunath Patil
@ 2018-10-30 16:52 ` Juergen Gross
2018-10-31 8:22 ` Roger Pau Monné
2018-11-06 9:37 ` Juergen Gross
2 siblings, 0 replies; 4+ messages in thread
From: Juergen Gross @ 2018-10-30 16:52 UTC (permalink / raw)
To: Manjunath Patil, boris.ostrovsky, konrad.wilk, roger.pau
Cc: axboe, xen-devel, linux-block, linux-kernel, stable
On 30/10/2018 17:49, Manjunath Patil wrote:
> 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>
Reviewed-by: Juergen Gross <jgross@suse.com>
Juergen
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path
2018-10-30 16:49 [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path Manjunath Patil
2018-10-30 16:52 ` Juergen Gross
@ 2018-10-31 8:22 ` Roger Pau Monné
2018-11-06 9:37 ` Juergen Gross
2 siblings, 0 replies; 4+ messages in thread
From: Roger Pau Monné @ 2018-10-31 8:22 UTC (permalink / raw)
To: Manjunath Patil
Cc: boris.ostrovsky, jgross, konrad.wilk, axboe, xen-devel,
linux-block, linux-kernel, stable
On Tue, Oct 30, 2018 at 09:49:21AM -0700, Manjunath Patil wrote:
> 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>
Thanks, Roger.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path
2018-10-30 16:49 [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path Manjunath Patil
2018-10-30 16:52 ` Juergen Gross
2018-10-31 8:22 ` Roger Pau Monné
@ 2018-11-06 9:37 ` Juergen Gross
2 siblings, 0 replies; 4+ messages in thread
From: Juergen Gross @ 2018-11-06 9:37 UTC (permalink / raw)
To: Manjunath Patil, boris.ostrovsky, konrad.wilk, roger.pau
Cc: axboe, xen-devel, linux-block, linux-kernel, stable
On 30/10/2018 17:49, Manjunath Patil wrote:
> 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>
Pushed to xen.git for-linus-4.20a
Juergen
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-10-30 16:49 [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path Manjunath Patil
2018-10-30 16:52 ` Juergen Gross
2018-10-31 8:22 ` Roger Pau Monné
2018-11-06 9:37 ` Juergen Gross
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