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 587C2352FD3; Tue, 26 Aug 2025 13:51:32 +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=1756216292; cv=none; b=MoxVAXiRmFx23A5crOCyQs/0AvroZaCvnbAS1i2oaxpFwV8Oht+ZTIhLr1xyYuq7ejF+hFeoEqCZ5s0J0fR+iMZypGjUcd9BPOysGUABGQPLEaoU26MM8V0I2TL9voJlCEouSAg7a7RjR4um8+4JYpBTG4VPPvllvDpI1PSUeXE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756216292; c=relaxed/simple; bh=IWhVfqyKmsiJ4AUAfagZ2OMv6pIkpb19NbgfZlp8JcI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OwFZy7KeJjXq2DQwL5ooVecZxEvG2xscUcsh6GRgjY2+areD2RmhcN51Zcn5sdD49YT77pQaEkAIMREntS4b8ZlibRz6vQR/W2N6ijdx+8Dh0T5BGnHS1SG8eAWRpbV86nN++rlmv6PNTGGjDI/P46MbaizOsDXmF1O+IiQtp5s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xspsMZZP; 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="xspsMZZP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8E0CC113CF; Tue, 26 Aug 2025 13:51:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756216292; bh=IWhVfqyKmsiJ4AUAfagZ2OMv6pIkpb19NbgfZlp8JcI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xspsMZZP750C3A/KPc+i2D/X7J9m8+fcLQqQTAlLu+2PS+TtKMhhVJMBhJqeihhdi Pzk+LQgWEwMHOdRLIcgbCoOb1AgT3dnPQhhPZl5EwOLrYJ+bW4u+1vVCHlaxTdAq9j PWt5pI1kg8eVwAK+GqIuOpqr1VK4qV1WeXpCHrFc= 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 5.15 357/644] drm/msm: use trylock for debugfs Date: Tue, 26 Aug 2025 13:07:28 +0200 Message-ID: <20250826110955.249870863@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110946.507083938@linuxfoundation.org> References: <20250826110946.507083938@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 5.15-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 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c index d280dd64744d..36ced8f83434 100644 --- a/drivers/gpu/drm/msm/msm_gem.c +++ b/drivers/gpu/drm/msm/msm_gem.c @@ -886,7 +886,8 @@ 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; -- 2.39.5