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* [PATCH v2] migration/rdma: Fix cm_event used before being initialized
@ 2021-05-19  6:47 Li Zhijian
  2021-05-19  8:11 ` Dr. David Alan Gilbert
  2021-05-26 11:26 ` Dr. David Alan Gilbert
  0 siblings, 2 replies; 3+ messages in thread
From: Li Zhijian @ 2021-05-19  6:47 UTC (permalink / raw)
  To: quintela, dgilbert; +Cc: qemu-devel, Li Zhijian

A segmentation fault was triggered when i try to abort a postcopy + rdma
migration.

since rdma_ack_cm_event releases a uninitialized cm_event in these case.

like below:
2496     ret = rdma_get_cm_event(rdma->channel, &cm_event);
2497     if (ret) {
2498         perror("rdma_get_cm_event after rdma_connect");
2499         ERROR(errp, "connecting to destination!");
2500         rdma_ack_cm_event(cm_event); <<<< cause segmentation fault
2501         goto err_rdma_source_connect;
2502     }

Refer to the rdma_get_cm_event() code, cm_event will be
updated/changed only if rdma_get_cm_event() returns 0. So it's okey to
remove the ack in error patch.

Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>

---
V2: remove ack from the error patch (Dave)
---
 migration/rdma.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/migration/rdma.c b/migration/rdma.c
index 00eac34232..41726cc74a 100644
--- a/migration/rdma.c
+++ b/migration/rdma.c
@@ -2497,7 +2497,6 @@ static int qemu_rdma_connect(RDMAContext *rdma, Error **errp)
     if (ret) {
         perror("rdma_get_cm_event after rdma_connect");
         ERROR(errp, "connecting to destination!");
-        rdma_ack_cm_event(cm_event);
         goto err_rdma_source_connect;
     }
 
-- 
2.30.2





^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] migration/rdma: Fix cm_event used before being initialized
  2021-05-19  6:47 [PATCH v2] migration/rdma: Fix cm_event used before being initialized Li Zhijian
@ 2021-05-19  8:11 ` Dr. David Alan Gilbert
  2021-05-26 11:26 ` Dr. David Alan Gilbert
  1 sibling, 0 replies; 3+ messages in thread
From: Dr. David Alan Gilbert @ 2021-05-19  8:11 UTC (permalink / raw)
  To: Li Zhijian; +Cc: qemu-devel, quintela

* Li Zhijian (lizhijian@cn.fujitsu.com) wrote:
> A segmentation fault was triggered when i try to abort a postcopy + rdma
> migration.
> 
> since rdma_ack_cm_event releases a uninitialized cm_event in these case.
> 
> like below:
> 2496     ret = rdma_get_cm_event(rdma->channel, &cm_event);
> 2497     if (ret) {
> 2498         perror("rdma_get_cm_event after rdma_connect");
> 2499         ERROR(errp, "connecting to destination!");
> 2500         rdma_ack_cm_event(cm_event); <<<< cause segmentation fault
> 2501         goto err_rdma_source_connect;
> 2502     }
> 
> Refer to the rdma_get_cm_event() code, cm_event will be
> updated/changed only if rdma_get_cm_event() returns 0. So it's okey to
> remove the ack in error patch.
> 
> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>

Thanks!


Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
> V2: remove ack from the error patch (Dave)
> ---
>  migration/rdma.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 00eac34232..41726cc74a 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -2497,7 +2497,6 @@ static int qemu_rdma_connect(RDMAContext *rdma, Error **errp)
>      if (ret) {
>          perror("rdma_get_cm_event after rdma_connect");
>          ERROR(errp, "connecting to destination!");
> -        rdma_ack_cm_event(cm_event);
>          goto err_rdma_source_connect;
>      }
>  
> -- 
> 2.30.2
> 
> 
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK



^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] migration/rdma: Fix cm_event used before being initialized
  2021-05-19  6:47 [PATCH v2] migration/rdma: Fix cm_event used before being initialized Li Zhijian
  2021-05-19  8:11 ` Dr. David Alan Gilbert
@ 2021-05-26 11:26 ` Dr. David Alan Gilbert
  1 sibling, 0 replies; 3+ messages in thread
From: Dr. David Alan Gilbert @ 2021-05-26 11:26 UTC (permalink / raw)
  To: Li Zhijian; +Cc: qemu-devel, quintela

* Li Zhijian (lizhijian@cn.fujitsu.com) wrote:
> A segmentation fault was triggered when i try to abort a postcopy + rdma
> migration.
> 
> since rdma_ack_cm_event releases a uninitialized cm_event in these case.
> 
> like below:
> 2496     ret = rdma_get_cm_event(rdma->channel, &cm_event);
> 2497     if (ret) {
> 2498         perror("rdma_get_cm_event after rdma_connect");
> 2499         ERROR(errp, "connecting to destination!");
> 2500         rdma_ack_cm_event(cm_event); <<<< cause segmentation fault
> 2501         goto err_rdma_source_connect;
> 2502     }
> 
> Refer to the rdma_get_cm_event() code, cm_event will be
> updated/changed only if rdma_get_cm_event() returns 0. So it's okey to
> remove the ack in error patch.
> 
> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>

Queued

> ---
> V2: remove ack from the error patch (Dave)
> ---
>  migration/rdma.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 00eac34232..41726cc74a 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -2497,7 +2497,6 @@ static int qemu_rdma_connect(RDMAContext *rdma, Error **errp)
>      if (ret) {
>          perror("rdma_get_cm_event after rdma_connect");
>          ERROR(errp, "connecting to destination!");
> -        rdma_ack_cm_event(cm_event);
>          goto err_rdma_source_connect;
>      }
>  
> -- 
> 2.30.2
> 
> 
> 
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK



^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-05-26 11:29 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-05-19  6:47 [PATCH v2] migration/rdma: Fix cm_event used before being initialized Li Zhijian
2021-05-19  8:11 ` Dr. David Alan Gilbert
2021-05-26 11:26 ` Dr. David Alan Gilbert

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