From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EE1BC1EB9F2; Tue, 26 Aug 2025 12:56:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756212962; cv=none; b=jdSWf8IOV4/h6d8sTFz+Y7kvbu3sSMYurcGxo2GrR5dt9lZLcIR6UFCFZdq4q1r6qtEPKHwTPTjeY7L+NQY+NS4ujoZFmNDUmuiPboZ4Hgy5Hb6JeCI8HERQaLyvgZk9rUIr9zCzNGKvQqfr7kZlGTnLiwamlVIIsNaaWL/44EU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756212962; c=relaxed/simple; bh=+EVIEPoVrZaeEgbCoXtp5AzCI8ZyLy4HDVqxEOlFePw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=R1YfXXVahyUpvF6ysyxuK9fpPBfB6+Py4qHG9sLnxAQVFHfjiD7kRdzAtTOJbBMRW65D8HJPvwLJgyPByBU9c2jSv+GotuZRVE5WjMtU3ERHt5grDoi2hAp44dRLsXTVx31OozHMvHzmB2XEccoCIRBd7mpX9dggbQfvob/YgBc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=JOzJxCY9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="JOzJxCY9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B35DC4CEF1; Tue, 26 Aug 2025 12:56:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756212961; bh=+EVIEPoVrZaeEgbCoXtp5AzCI8ZyLy4HDVqxEOlFePw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JOzJxCY9N+WD7QzUkVZyTE90u91LmN24GwrAKVO8o2Z+QfypkX40JDhujZO319N/8 xrz5kbvrsOjMdIexyMXqENB9C9+rFzO/Nz320vnfsjSGNyBgMakFwjowvb0sXG5ZWx b1+s8KSGNzZKguRiwrUSwUyqUr8tBmxoYu4U+aUY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Rob Clark , Rob Clark , Antonino Maniscalco , Sasha Levin Subject: [PATCH 6.6 169/587] drm/msm: use trylock for debugfs Date: Tue, 26 Aug 2025 13:05:18 +0200 Message-ID: <20250826110957.245400560@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110952.942403671@linuxfoundation.org> References: <20250826110952.942403671@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Rob Clark [ Upstream commit 0a1ff88ec5b60b41ba830c5bf08b6cd8f45ab411 ] This resolves a potential deadlock vs msm_gem_vm_close(). Otherwise for _NO_SHARE buffers msm_gem_describe() could be trying to acquire the shared vm resv, while already holding priv->obj_lock. But _vm_close() might drop the last reference to a GEM obj while already holding the vm resv, and msm_gem_free_object() needs to grab priv->obj_lock, a locking inversion. OTOH this is only for debugfs and it isn't critical if we undercount by skipping a locked obj. So just use trylock() and move along if we can't get the lock. Signed-off-by: Rob Clark Signed-off-by: Rob Clark Tested-by: Antonino Maniscalco Reviewed-by: Antonino Maniscalco Patchwork: https://patchwork.freedesktop.org/patch/661525/ Signed-off-by: Sasha Levin --- drivers/gpu/drm/msm/msm_gem.c | 3 ++- drivers/gpu/drm/msm/msm_gem.h | 6 ++++++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c index 1113e6b2ec8e..aaf7c338eb96 100644 --- a/drivers/gpu/drm/msm/msm_gem.c +++ b/drivers/gpu/drm/msm/msm_gem.c @@ -928,7 +928,8 @@ void msm_gem_describe(struct drm_gem_object *obj, struct seq_file *m, uint64_t off = drm_vma_node_start(&obj->vma_node); const char *madv; - msm_gem_lock(obj); + if (!msm_gem_trylock(obj)) + return; stats->all.count++; stats->all.size += obj->size; diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h index 8ddef5443140..631a9aa129bd 100644 --- a/drivers/gpu/drm/msm/msm_gem.h +++ b/drivers/gpu/drm/msm/msm_gem.h @@ -183,6 +183,12 @@ msm_gem_lock(struct drm_gem_object *obj) dma_resv_lock(obj->resv, NULL); } +static inline bool __must_check +msm_gem_trylock(struct drm_gem_object *obj) +{ + return dma_resv_trylock(obj->resv); +} + static inline int msm_gem_lock_interruptible(struct drm_gem_object *obj) { -- 2.39.5