Re: [Xen-devel] [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path

2018-11-06 Thread Juergen Gross 
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 8175936f
> [exception RIP: blkif_free_ring+33]
> RIP: a0149491  RSP: 8804f7673c08  RFLAGS: 00010292
>  ...
>  #9 blkif_free at a0149aaa [xen_blkfront]
>  #10 talk_to_blkback at a014c8cd [xen_blkfront]
>  #11 blkback_changed at a014ea8b [xen_blkfront]
>  #12 xenbus_otherend_changed at 81424670
>  #13 backend_changed at 81426dc3
>  #14 xenwatch_thread at 81422f29
>  #15 kthread at 810abe6a
>  #16 ret_from_fork at 81754078
> 
> Cc: sta...@vger.kernel.org
> Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of 
> new VBDs")
> Signed-off-by: Manjunath Patil 

Pushed to xen.git for-linus-4.20a


Juergen

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Re: [Xen-devel] [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path

2018-10-31 Thread Roger Pau Monné 
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 8175936f
> [exception RIP: blkif_free_ring+33]
> RIP: a0149491  RSP: 8804f7673c08  RFLAGS: 00010292
>  ...
>  #9 blkif_free at a0149aaa [xen_blkfront]
>  #10 talk_to_blkback at a014c8cd [xen_blkfront]
>  #11 blkback_changed at a014ea8b [xen_blkfront]
>  #12 xenbus_otherend_changed at 81424670
>  #13 backend_changed at 81426dc3
>  #14 xenwatch_thread at 81422f29
>  #15 kthread at 810abe6a
>  #16 ret_from_fork at 81754078
> 
> Cc: sta...@vger.kernel.org
> Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of 
> new VBDs")
> Signed-off-by: Manjunath Patil 

Acked-by: Roger Pau Monné 

Thanks, Roger.

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Re: [Xen-devel] [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path

2018-10-30 Thread Juergen Gross 
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 8175936f
> [exception RIP: blkif_free_ring+33]
> RIP: a0149491  RSP: 8804f7673c08  RFLAGS: 00010292
>  ...
>  #9 blkif_free at a0149aaa [xen_blkfront]
>  #10 talk_to_blkback at a014c8cd [xen_blkfront]
>  #11 blkback_changed at a014ea8b [xen_blkfront]
>  #12 xenbus_otherend_changed at 81424670
>  #13 backend_changed at 81426dc3
>  #14 xenwatch_thread at 81422f29
>  #15 kthread at 810abe6a
>  #16 ret_from_fork at 81754078
> 
> Cc: sta...@vger.kernel.org
> Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of 
> new VBDs")
> Signed-off-by: Manjunath Patil 

Reviewed-by: Juergen Gross 


Juergen


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[Xen-devel] [PATCH v2] xen-blkfront: fix kernel panic with negotiate_mq error path

2018-10-30 Thread Manjunath Patil 
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 8175936f
[exception RIP: blkif_free_ring+33]
RIP: a0149491  RSP: 8804f7673c08  RFLAGS: 00010292
 ...
 #9 blkif_free at a0149aaa [xen_blkfront]
 #10 talk_to_blkback at a014c8cd [xen_blkfront]
 #11 blkback_changed at a014ea8b [xen_blkfront]
 #12 xenbus_otherend_changed at 81424670
 #13 backend_changed at 81426dc3
 #14 xenwatch_thread at 81422f29
 #15 kthread at 810abe6a
 #16 ret_from_fork at 81754078

Cc: sta...@vger.kernel.org
Fixes: 7ed8ce1c5fc7 ("xen-blkfront: move negotiate_mq to cover all cases of new 
VBDs")
Signed-off-by: Manjunath Patil 
---
 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


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