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 C1C29320CCC; Mon, 18 Aug 2025 13:31:05 +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=1755523865; cv=none; b=PvdHsalu61A7f2lLxTpyoF6zKn6ZXMBRjUAoF61NwMY6u/jM07Nq7aCfa5yLobCfQe2DR0k8VVoDr5OqbGmZSlwswje9PwdhD+5i0Wo8LAfyxSayY40ik/xkUkovg7UuemudT+Q497J96DeIqFgSjCC2aieqUI9p6dzKPLtW3Yg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755523865; c=relaxed/simple; bh=0dtosSHOvFio/gI+5KwDJMrOdjux8PckKVU0WRAe2Do=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=trDo95Z+ypUlGI/A737RsOHXXevkjcIj8IwXcq1z6ALEfEofrLq7U/qg1nZYO2cbmcryOik4cMq2UpIo6Fd9X/67KebwP93J/JAPGxjLaD0fK8bELaYiIgI2WBqUn9dD6guBSuXoSRET8Bhob4Mg5OCpzxbljR1y9OQ5wJIOrhk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=E7Fheh9D; 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="E7Fheh9D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 463CDC4CEEB; Mon, 18 Aug 2025 13:31:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755523865; bh=0dtosSHOvFio/gI+5KwDJMrOdjux8PckKVU0WRAe2Do=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E7Fheh9DpRiJUeDTiaSX4DPUJ1WL0ujXahrZTHD6RqsZ+3ZOQpbWWyA2WceRD0ftY vtJ75DCEvRoiiond50VeHnDeMpURccVAokyy4rKCMaRDvWr+vXBnd0fBz5s7mtSDPc bzzKDN7cblXB7DO2IgiPdLr8fAk2knbkwk+ycUHU= 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 6.15 254/515] drm/msm: use trylock for debugfs Date: Mon, 18 Aug 2025 14:44:00 +0200 Message-ID: <20250818124508.187062507@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250818124458.334548733@linuxfoundation.org> References: <20250818124458.334548733@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 6.15-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 ++- 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 ebc9ba66efb8..eeb3b65dd4d1 100644 --- a/drivers/gpu/drm/msm/msm_gem.c +++ b/drivers/gpu/drm/msm/msm_gem.c @@ -963,7 +963,8 @@ 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 85f0257e83da..748053f70ca7 100644 --- a/drivers/gpu/drm/msm/msm_gem.h +++ b/drivers/gpu/drm/msm/msm_gem.h @@ -188,6 +188,12 @@ 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