linux-kernel - Re: [PATCH v2] lockdep: Let lock_is_held_type() detect recursive read as read

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <6bfddae4-dd66-b105-480f-ad4fe5c03276@redhat.com>
Date:   Wed, 8 Sep 2021 10:35:46 -0400
From:   Waiman Long <llong@...hat.com>
To:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Waiman Long <llong@...hat.com>
Cc:     linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
        Boqun Feng <boqun.feng@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v2] lockdep: Let lock_is_held_type() detect recursive read
 as read

On 9/3/21 4:40 AM, Sebastian Andrzej Siewior wrote:
> lock_is_held_type(, 1) detects acquired read locks. It only recognized
> locks acquired with lock_acquire_shared(). Read locks acquired with
> lock_acquire_shared_recursive() are not recognized because a `2' is
> stored as the read value.
>
> Rework the check to additionally recognise lock's read value one and two
> as a read held lock.
>
> Fixes: e918188611f07 ("locking: More accurate annotations for read_lock()")
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> ---
> v1…v2:
>    - simplify the read check to !!read as suggested by Waiman Long.
>
>   kernel/locking/lockdep.c |    2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -5366,7 +5366,7 @@ int __lock_is_held(const struct lockdep_
>   		struct held_lock *hlock = curr->held_locks + i;
>   
>   		if (match_held_lock(hlock, lock)) {
> -			if (read == -1 || hlock->read == read)
> +			if (read == -1 || hlock->read == !!read)
>   				return LOCK_STATE_HELD;
>   
>   			return LOCK_STATE_NOT_HELD;
>
Thanks for accepting my suggestion.

Acked-by: Waiman Long <longman@...hat.com>