Messages in this thread | | | Date | Wed, 11 Oct 2023 21:19:51 +0530 | Subject | Re: [PATCH] Remove extra unlock for the mutex | From | Abhinav Singh <> |
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On 10/11/23 12:00, Greg KH wrote: > On Wed, Oct 11, 2023 at 04:16:30AM +0530, Abhinav Singh wrote: >> There is a double unlock on mutex. This can cause undefined behaviour. >> >> Signed-off-by: Abhinav Singh <singhabhinav9051571833@gmail.com> >> --- >> net/ipv4/inet_connection_sock.c | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c >> index aeebe8816689..f11fe8c727a4 100644 >> --- a/net/ipv4/inet_connection_sock.c >> +++ b/net/ipv4/inet_connection_sock.c >> @@ -597,7 +597,6 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum) >> } >> if (head2_lock_acquired) >> spin_unlock(&head2->lock); >> - spin_unlock_bh(&head->lock); > > How was this tested? > > And where is the now-needed unlock of the head->lock? > > How was this change found? > > And your subject line needs a lot of work... > > thanks, > > greg k-h Hello, I used sparse tool and got it this warning message "warning: context imbalance in 'inet_csk_get_port' - unexpected unlock" Due to my over excitement of sending a good patch to kernel I didnt see correctly and misread `head` as `head2` and thought it was double unlocking the mutex. I m very sorry. But on a different note think we should do a check for `head->lock` as well before unlocking. Unlocking a non locked mutex can also trigger a undefined behaviour.
Thank you, Abhinav Singh
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