[Drbd-dev] [PATCH resent] drbd: Fix exception handling in nla_put_drbd_cfg_context()

[Markus Elfring]

Date: Fri, 17 Mar 2023 18:32:05 +0100

The label “nla_put_failure” was used to jump to another pointer check
despite of the detail in the implementation of the function
“nla_put_drbd_cfg_context” that it was determined already that
the corresponding variable contained a null pointer.

* Thus return directly after a call of the function
  “nla_nest_start_noflag” failed.

* Delete an extra pointer check which became unnecessary
  with this refactoring.


This issue was detected by using the Coccinelle software.

Fixes: 543cc10b4cc5c60aa9fcc62705ccfb9998bf4697 ("drbd: drbd_adm_get_status needs to show some more detail")
Signed-off-by: Markus Elfring <elfring at users.sourceforge.net>
---
 drivers/block/drbd/drbd_nl.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index f49f2a5282e1..9cb947127472 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -3187,7 +3187,7 @@ static int nla_put_drbd_cfg_context(struct sk_buff *skb,
 	struct nlattr *nla;
 	nla = nla_nest_start_noflag(skb, DRBD_NLA_CFG_CONTEXT);
 	if (!nla)
-		goto nla_put_failure;
+		return -EMSGSIZE;
 	if (device &&
 	    nla_put_u32(skb, T_ctx_volume, device->vnr))
 		goto nla_put_failure;
@@ -3205,8 +3205,7 @@ static int nla_put_drbd_cfg_context(struct sk_buff *skb,
 	return 0;

 nla_put_failure:
-	if (nla)
-		nla_nest_cancel(skb, nla);
+	nla_nest_cancel(skb, nla);
 	return -EMSGSIZE;
 }

--
2.40.0