linux-kernel - Re: [PATCH] drm/syncobj: Fix syncobj leak in drm_syncobj_eventfd

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Message-ID: <7aef07b2-9859-40a8-ba5b-22aba68c2d9c@amd.com>
Date: Tue, 10 Sep 2024 09:30:45 +0200
From: Christian König <christian.koenig@....com>
To: Tvrtko Ursulin <tursulin@...ulin.net>, "T.J. Mercier"
 <tjmercier@...gle.com>, Maarten Lankhorst
 <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>,
 Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>,
 Daniel Vetter <daniel@...ll.ch>, Simon Ser <contact@...rsion.fr>,
 Pekka Paalanen <pekka.paalanen@...labora.com>
Cc: Xingyu Jin <xingyuj@...gle.com>, dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH] drm/syncobj: Fix syncobj leak in
 drm_syncobj_eventfd_ioctl

Am 10.09.24 um 09:26 schrieb Tvrtko Ursulin:
>
> On 09/09/2024 21:53, T.J. Mercier wrote:
>> A syncobj reference is taken in drm_syncobj_find, but not released if
>> eventfd_ctx_fdget or kzalloc fails. Put the reference in these error
>> paths.
>>
>> Reported-by: Xingyu Jin <xingyuj@...gle.com>
>> Fixes: c7a472297169 ("drm/syncobj: add IOCTL to register an eventfd")
>> Signed-off-by: T.J. Mercier <tjmercier@...gle.com>
>> ---
>>   drivers/gpu/drm/drm_syncobj.c | 17 +++++++++++++----
>>   1 file changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_syncobj.c 
>> b/drivers/gpu/drm/drm_syncobj.c
>> index a0e94217b511..4fcfc0b9b386 100644
>> --- a/drivers/gpu/drm/drm_syncobj.c
>> +++ b/drivers/gpu/drm/drm_syncobj.c
>> @@ -1464,6 +1464,7 @@ drm_syncobj_eventfd_ioctl(struct drm_device 
>> *dev, void *data,
>>       struct drm_syncobj *syncobj;
>>       struct eventfd_ctx *ev_fd_ctx;
>>       struct syncobj_eventfd_entry *entry;
>> +    int ret;
>>         if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
>>           return -EOPNOTSUPP;
>> @@ -1479,13 +1480,15 @@ drm_syncobj_eventfd_ioctl(struct drm_device 
>> *dev, void *data,
>>           return -ENOENT;
>>         ev_fd_ctx = eventfd_ctx_fdget(args->fd);
>> -    if (IS_ERR(ev_fd_ctx))
>> -        return PTR_ERR(ev_fd_ctx);
>> +    if (IS_ERR(ev_fd_ctx)) {
>> +        ret = PTR_ERR(ev_fd_ctx);
>> +        goto err_fdget;
>> +    }
>>         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
>>       if (!entry) {
>> -        eventfd_ctx_put(ev_fd_ctx);
>> -        return -ENOMEM;
>> +        ret = -ENOMEM;
>> +        goto err_kzalloc;
>>       }
>>       entry->syncobj = syncobj;
>>       entry->ev_fd_ctx = ev_fd_ctx;
>> @@ -1496,6 +1499,12 @@ drm_syncobj_eventfd_ioctl(struct drm_device 
>> *dev, void *data,
>>       drm_syncobj_put(syncobj);
>>         return 0;
>> +
>> +err_kzalloc:
>> +    eventfd_ctx_put(ev_fd_ctx);
>> +err_fdget:
>> +    drm_syncobj_put(syncobj);
>> +    return ret;
>>   }
>>     int
>
> Easy enough to review while browsing the list:
>
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@...lia.com>

Looks reasonable to me as well.

Reviewed-by. Christian König <christian.koenig@....com>
CC: stable?

Let me know when you need someone to push it to drm-misc-fixes.

Regards,
Christian.

>
> Regards,
>
> Tvrtko