This patch fixes two sparse warnings (`make C=1`):
net/ipv6/icmp.c:103:20: warning: context imbalance in 'icmpv6_xmit_lock' - wrong count at exit
net/ipv6/icmp.c:119:13: warning: context imbalance in 'icmpv6_xmit_unlock' - unexpected unlock

Since `icmp6_xmit_lock()` and `icmp6_xmit_unlock()` are designed as they
are named, entering/returning the function without lock/unlock doesn't
matter.

Signed-off-by: Moon Yeounsu <yyyynoom@gmail.com>
---
 net/ipv6/icmp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 071b0bc1179d..d8cc3d63c942 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -101,6 +101,7 @@ static const struct inet6_protocol icmpv6_protocol = {
 
 /* Called with BH disabled */
 static struct sock *icmpv6_xmit_lock(struct net *net)
+	__acquires(&sk->sk_lock.slock)
 {
 	struct sock *sk;
 
@@ -117,6 +118,7 @@ static struct sock *icmpv6_xmit_lock(struct net *net)
 }
 
 static void icmpv6_xmit_unlock(struct sock *sk)
+	__releases(&sk->sk_lock.slock)
 {
 	sock_net_set(sk, &init_net);
 	spin_unlock(&sk->sk_lock.slock);
-- 
2.46.1

On Thu, Sep 19, 2024 at 11:21:49PM +0900, Moon Yeounsu wrote:
> This patch fixes two sparse warnings (`make C=1`):
> net/ipv6/icmp.c:103:20: warning: context imbalance in 'icmpv6_xmit_lock' - wrong count at exit
> net/ipv6/icmp.c:119:13: warning: context imbalance in 'icmpv6_xmit_unlock' - unexpected unlock
> 
> Since `icmp6_xmit_lock()` and `icmp6_xmit_unlock()` are designed as they
> are named, entering/returning the function without lock/unlock doesn't
> matter.
> 
> Signed-off-by: Moon Yeounsu <yyyynoom@gmail.com>

Hi Moon,

Without this patch applied I see the warnings cited above.

However, with this patch applied, I see the following.
So I think this needs more work.

net/ipv6/icmp.c: note: in included file (through include/linux/sched.h, include/linux/percpu.h, arch/x86/include/asm/msr.h, arch/x86/include/asm/tsc.h, arch/x86/include/asm/timex.h, include/linux/timex.h, ...):
./include/linux/spinlock.h:361:16: warning: context imbalance in 'icmpv6_xmit_lock' - different lock contexts for basic block
net/ipv6/icmp.c: note: in included file (through include/linux/spinlock.h, include/linux/sched.h, include/linux/percpu.h, arch/x86/include/asm/msr.h, arch/x86/include/asm/tsc.h, arch/x86/include/asm/timex.h, ...):
./include/linux/bottom_half.h:33:30: warning: context imbalance in 'icmp6_send' - different lock contexts for basic block
./include/linux/bottom_half.h:33:30: warning: context imbalance in 'icmpv6_echo_reply' - different lock contexts for basic block

Also, It is my feeling that addressing warnings of this nature
is not a fix for net, but rather but rather an enhancement for net-next.

net-next is currently closed for the v6.12 merge windows, so non-RFC,
patches should not be posted for net-next until it re-opens once v6.12-rc1
has been released, most likely during the week of 30th September.

-- 
pw-bot: changes-requested

On Thu, Sep 19, 2024 at 11:56 PM Simon Horman <horms@kernel.org> wrote:

> Hi Moon,
>
> Without this patch applied I see the warnings cited above.
>
> However, with this patch applied, I see the following.
> So I think this needs more work.
Okay, I'll fix and update. (Of course, patch after release `-rc1`)

> net-next is currently closed for the v6.12 merge windows, so non-RFC,
> patches should not be posted for net-next until it re-opens once v6.12-rc1
> has been released, most likely during the week of 30th September.
Thank you for letting me know : )
During this time, I'll read patches, docs, and code to increase my sense.

I appreciate you reviewing my patch!