Received-SPF: pass (google.com: domain of linux-kernel+bounces-171345-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
Message-ID: <8980975d-87db-4d57-9e23-4fb7fbb62e7d@gmail.com>
Date: Tue, 7 May 2024 15:09:56 +0200
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [Linaro-mm-sig] [PATCH] dma-buf/sw-sync: don't enable IRQ from
 sync_print_obj()
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
 syzbot <syzbot+a225ee3df7e7f9372dbe@syzkaller.appspotmail.com>,
 syzkaller-bugs@googlegroups.com, Sumit Semwal <sumit.semwal@linaro.org>,
 Gustavo Padovan <gustavo@padovan.org>,
 Christian Konig <christian.koenig@amd.com>, Sean Paul
 <seanpaul@chromium.org>, Chris Wilson <chris@chris-wilson.co.uk>
Cc: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
 linaro-mm-sig@lists.linaro.org, dri-devel@lists.freedesktop.org
References: <0000000000000946190610bf7bd5@google.com>
 <c2e46020-aaa6-4e06-bf73-f05823f913f0@I-love.SAKURA.ne.jp>
Content-Language: en-US
From: =?UTF-8?Q?Christian_K=C3=B6nig?= <ckoenig.leichtzumerken@gmail.com>
In-Reply-To: <c2e46020-aaa6-4e06-bf73-f05823f913f0@I-love.SAKURA.ne.jp>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit

Am 05.05.24 um 16:08 schrieb Tetsuo Handa:
> Since commit a6aa8fca4d79 ("dma-buf/sw-sync: Reduce irqsave/irqrestore from
> known context") by error replaced spin_unlock_irqrestore() with
> spin_unlock_irq() for both sync_debugfs_show() and sync_print_obj() despite
> sync_print_obj() is called from sync_debugfs_show(), lockdep complains
> inconsistent lock state warning.
>
> Use plain spin_{lock,unlock}() for sync_print_obj(), for
> sync_debugfs_show() is already using spin_{lock,unlock}_irq().
>
> Reported-by: syzbot <syzbot+a225ee3df7e7f9372dbe@syzkaller.appspotmail.com>
> Closes: https://syzkaller.appspot.com/bug?extid=a225ee3df7e7f9372dbe
> Fixes: a6aa8fca4d79 ("dma-buf/sw-sync: Reduce irqsave/irqrestore from known context")
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>   drivers/dma-buf/sync_debug.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma-buf/sync_debug.c b/drivers/dma-buf/sync_debug.c
> index 101394f16930..237bce21d1e7 100644
> --- a/drivers/dma-buf/sync_debug.c
> +++ b/drivers/dma-buf/sync_debug.c
> @@ -110,12 +110,12 @@ static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
>   
>   	seq_printf(s, "%s: %d\n", obj->name, obj->value);
>   
> -	spin_lock_irq(&obj->lock);
> +	spin_lock(&obj->lock); /* Caller already disabled IRQ. */
>   	list_for_each(pos, &obj->pt_list) {
>   		struct sync_pt *pt = container_of(pos, struct sync_pt, link);
>   		sync_print_fence(s, &pt->base, false);
>   	}
> -	spin_unlock_irq(&obj->lock);
> +	spin_unlock(&obj->lock);
>   }
>   
>   static void sync_print_sync_file(struct seq_file *s,