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client-ip=165.204.84.17; helo=satlexmb08.amd.com; pr=C Received: from satlexmb08.amd.com (165.204.84.17) by SJ5PEPF000001E8.mail.protection.outlook.com (10.167.242.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.382.8 via Frontend Transport; Wed, 2 Sep 2026 18:51:09 +0000 Received: from satlexmb08.amd.com (10.181.42.217) by satlexmb08.amd.com (10.181.42.217) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.46; Wed, 2 Sep 2026 13:51:09 -0500 Received: from [172.19.68.62] (10.180.168.240) by satlexmb08.amd.com (10.181.42.217) with Microsoft SMTP Server id 15.2.2562.46 via Frontend Transport; Wed, 2 Sep 2026 13:51:08 -0500 Message-ID: <83104024-65dc-4289-afe5-6892844dc344@amd.com> Date: Wed, 2 Sep 2026 11:51:03 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V1 2/2] accel/amdxdna: Fix potential deadlock in BO open and close callbacks To: Lizhi Hou , , , , , CC: , References: <20260902180955.3999242-1-lizhi.hou@amd.com> <20260902180955.3999242-2-lizhi.hou@amd.com> Content-Language: en-US From: Max Zhen In-Reply-To: <20260902180955.3999242-2-lizhi.hou@amd.com> Content-Type: text/plain; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: CupTSh4ltwLVIU9B+owz3gY3nL1+OVsldg3pA5NMfJlxRHgGqs4+mzbprzwI/shOI692I8KTBWIX9GP8fmCctGcejU+1K8jqJswN6bQM7WcY0TUzhDJ8WiBkR/UEpNcEg2Q3X7+sCW4lJwsEsi31JoFd7LyJvwuK3AMYm4Ecao0uE2/5UTgH0ebaghmBk0+sk+pq7tmmtadUZuVPSaTN4BanCU6G7aza+vDk5bgwjlmRr+4/LuXYmTmTPZulwzDSMDrwj+uQfiVG0HMccF2Hf4R/ZkEw9857kRpphOaj3PWO+R1FlTl/UKd/0PupCw7QNAIDLhaiDzEUzw97gXx+9s6rTrDjxikDXsdFwogOE1gT09WGo2p/XKUr4Y9NUcwxOwYK1b8HKZvUlTlfcWK8/HuEmc74tWBxwfkIT2yXmF6Lf4ptrnGzIBYk/xPqsqUK X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Sep 2026 18:51:09.6078 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: c4c011d6-e8e2-4bf3-c3b6-08df09232746 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb08.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SJ5PEPF000001E8.namprd05.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PPF04DCE520E On 9/2/2026 Wed 11:09, Lizhi Hou wrote: > In amdxdna_gem_obj_open(), abo->lock is held when calling > amdxdna_gem_add_bo_usage(), which then acquires client->mm_lock. > > However, the heap update path may acquire these locks in the reverse > order, creating a potential deadlock. > > Fix this by saving the client pointer locally before acquiring abo->lock, > and releasing abo->lock before calling amdxdna_gem_add_bo_usage(). > > Apply the same change to amdxdna_gem_obj_close(). > > Fixes: 1f513a3ec3a9 ("accel/amdxdna: Add per-process BO memory usage query support") > Signed-off-by: Lizhi Hou Reviewed-by: Max Zhen > --- > drivers/accel/amdxdna/amdxdna_gem.c | 34 +++++++++++++++++++---------- > 1 file changed, 22 insertions(+), 12 deletions(-) > > diff --git a/drivers/accel/amdxdna/amdxdna_gem.c b/drivers/accel/amdxdna/amdxdna_gem.c > index 1353393194e2..0d165b66c1fc 100644 > --- a/drivers/accel/amdxdna/amdxdna_gem.c > +++ b/drivers/accel/amdxdna/amdxdna_gem.c > @@ -641,10 +641,8 @@ amdxdna_gem_skip_bo_usage(struct amdxdna_gem_obj *abo) > } > > static void > -amdxdna_gem_add_bo_usage(struct amdxdna_gem_obj *abo) > +amdxdna_gem_add_bo_usage(struct amdxdna_client *client, struct amdxdna_gem_obj *abo) > { > - struct amdxdna_client *client = abo->client; > - > if (amdxdna_gem_skip_bo_usage(abo)) > return; > > @@ -656,10 +654,8 @@ amdxdna_gem_add_bo_usage(struct amdxdna_gem_obj *abo) > } > > static void > -amdxdna_gem_del_bo_usage(struct amdxdna_gem_obj *abo) > +amdxdna_gem_del_bo_usage(struct amdxdna_client *client, struct amdxdna_gem_obj *abo) > { > - struct amdxdna_client *client = abo->client; > - > if (amdxdna_gem_skip_bo_usage(abo)) > return; > > @@ -694,14 +690,20 @@ static int amdxdna_gem_obj_open(struct drm_gem_object *gobj, struct drm_file *fi > { > struct amdxdna_dev *xdna = to_xdna_dev(gobj->dev); > struct amdxdna_gem_obj *abo = to_xdna_obj(gobj); > + struct amdxdna_client *client; > int ret; > > - guard(mutex)(&abo->lock); > - if (abo->open_ref > 0 && filp->driver_priv != abo->client) > + mutex_lock(&abo->lock); > + if (abo->open_ref > 0 && filp->driver_priv != abo->client) { > + mutex_unlock(&abo->lock); > return -EPERM; > + } > + > abo->open_ref++; > - if (abo->open_ref > 1) > + if (abo->open_ref > 1) { > + mutex_unlock(&abo->lock); > return 0; > + } > > /* Attached to the client when first opened by it. */ > abo->client = filp->driver_priv; > @@ -712,26 +714,34 @@ static int amdxdna_gem_obj_open(struct drm_gem_object *gobj, struct drm_file *fi > if (ret) { > abo->open_ref--; > abo->client = NULL; > + mutex_unlock(&abo->lock); > return ret; > } > } > + client = abo->client; > + mutex_unlock(&abo->lock); > > - amdxdna_gem_add_bo_usage(abo); > + amdxdna_gem_add_bo_usage(client, abo); > return 0; > } > > static void amdxdna_gem_obj_close(struct drm_gem_object *gobj, struct drm_file *filp) > { > struct amdxdna_gem_obj *abo = to_xdna_obj(gobj); > + struct amdxdna_client *client = NULL; > > - guard(mutex)(&abo->lock); > + mutex_lock(&abo->lock); > abo->open_ref--; > > if (abo->open_ref == 0) { > - amdxdna_gem_del_bo_usage(abo); > /* Detach from the client when last closed by it. */ > + client = abo->client; > abo->client = NULL; > } > + mutex_unlock(&abo->lock); > + > + if (client) > + amdxdna_gem_del_bo_usage(client, abo); > } > > static int amdxdna_gem_obj_vmap(struct drm_gem_object *obj, struct iosys_map *map)