netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH] Remove unused function parameter in __smc_diag_dump
@ 2024-11-09  6:28 Manas via B4 Relay
  2024-11-11 13:04 ` Jeongjun Park
  2024-11-11 14:11 ` Wenjia Zhang
  0 siblings, 2 replies; 7+ messages in thread
From: Manas via B4 Relay @ 2024-11-09  6:28 UTC (permalink / raw)
  To: Wenjia Zhang, Jan Karcher, D. Wythe, Tony Lu, Wen Gu,
	David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
	Simon Horman
  Cc: Shuah Khan, Anup Sharma, linux-s390, netdev, linux-kernel, Manas

From: Manas <manas18244@iiitd.ac.in>

The last parameter in __smc_diag_dump (struct nlattr *bc) is unused.
There is only one instance of this function being called and its passed
with a NULL value in place of bc.

Signed-off-by: Manas <manas18244@iiitd.ac.in>
---
The last parameter in __smc_diag_dump (struct nlattr *bc) is unused.
There is only one instance of this function being called and its passed
with a NULL value in place of bc.

Though, the compiler (gcc) optimizes it. Looking at the object dump of
vmlinux (via `objdump -D vmlinux`), a new function clone
(__smc_diag_dump.constprop.0) is added which removes this parameter from
calling convention altogether.

ffffffff8a701770 <__smc_diag_dump.constprop.0>:
ffffffff8a701770:       41 57                   push   %r15
ffffffff8a701772:       41 56                   push   %r14
ffffffff8a701774:       41 55                   push   %r13
ffffffff8a701776:       41 54                   push   %r12

There are 5 parameters in original function, but in the cloned function
only 4.

I believe this patch also fixes this oops bug[1], which arises in the
same function __smc_diag_dump. But I couldn't verify it further. Can
someone please test this?

[1] https://syzkaller.appspot.com/bug?extid=271fed3ed6f24600c364
---
 net/smc/smc_diag.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c
index 6fdb2d96777ad704c394709ec845f9ddef5e599a..8f7bd40f475945171a0afa5a2cce12d9aa2b1eb4 100644
--- a/net/smc/smc_diag.c
+++ b/net/smc/smc_diag.c
@@ -71,8 +71,7 @@ static int smc_diag_msg_attrs_fill(struct sock *sk, struct sk_buff *skb,
 
 static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb,
 			   struct netlink_callback *cb,
-			   const struct smc_diag_req *req,
-			   struct nlattr *bc)
+			   const struct smc_diag_req *req)
 {
 	struct smc_sock *smc = smc_sk(sk);
 	struct smc_diag_fallback fallback;
@@ -199,7 +198,6 @@ static int smc_diag_dump_proto(struct proto *prot, struct sk_buff *skb,
 	struct smc_diag_dump_ctx *cb_ctx = smc_dump_context(cb);
 	struct net *net = sock_net(skb->sk);
 	int snum = cb_ctx->pos[p_type];
-	struct nlattr *bc = NULL;
 	struct hlist_head *head;
 	int rc = 0, num = 0;
 	struct sock *sk;
@@ -214,7 +212,7 @@ static int smc_diag_dump_proto(struct proto *prot, struct sk_buff *skb,
 			continue;
 		if (num < snum)
 			goto next;
-		rc = __smc_diag_dump(sk, skb, cb, nlmsg_data(cb->nlh), bc);
+		rc = __smc_diag_dump(sk, skb, cb, nlmsg_data(cb->nlh));
 		if (rc < 0)
 			goto out;
 next:

---
base-commit: 59b723cd2adbac2a34fc8e12c74ae26ae45bf230
change-id: 20241109-fix-oops-__smc_diag_dump-06ab3e9d39f4

Best regards,
-- 
Manas <manas18244@iiitd.ac.in>



^ permalink raw reply related	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2024-11-12 18:22 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-11-09  6:28 [PATCH] Remove unused function parameter in __smc_diag_dump Manas via B4 Relay
2024-11-11 13:04 ` Jeongjun Park
2024-11-11 15:06   ` Manas
2024-11-11 14:11 ` Wenjia Zhang
2024-11-11 15:10   ` Manas
2024-11-12  7:36     ` Wenjia Zhang
2024-11-12 18:22       ` Simon Horman

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).