From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 84F7FCCD18E for ; Thu, 9 Oct 2025 13:23:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=mkokWfseuhgXoMWLtIZInl/yn9ynP+UGFvH1sY5oshI=; b=pVyWzoR13qKfeXYswy2hjql6yJ w4etQFkV/F95lDsVzR3lcZmXLg2mNK+0nCSzH5f3BuAUzyELuA52Go8mXQKEW1XGx2Xu/DUmxjc2+ cKoEmYSqxvaF2U7RTiEQWoxRxmkNWHfLHUtv8/8mOe8LX7tHmkTKhGdy6pcQqDAZNx3dSQiqTgMCW s/NStvC++afTvH0NNJb7iSb6fxvB1+a2y55WBfg7sxTtYY9VbIWAObQlVWyAg1LEDFmO5C65+mC1t N98GeKZypylsi+mPFZE/k8Zi4zeVyVk6G3FHUHcsU3C9/4G9gJyw3WsYE+24jhsn/jXv4e0ZOdYx2 jL0262rA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v6qbu-00000006DTD-3Ex4; Thu, 09 Oct 2025 13:23:10 +0000 Received: from smtp-out2.suse.de ([195.135.223.131]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v6qbs-00000006DRF-20Eq for linux-arm-kernel@lists.infradead.org; Thu, 09 Oct 2025 13:23:09 +0000 Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 731CE1F7C5; Thu, 9 Oct 2025 13:22:55 +0000 (UTC) Authentication-Results: smtp-out2.suse.de; none Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 1E42C13A61; Thu, 9 Oct 2025 13:22:55 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id wMoyBi+352iECAAAD6G6ig (envelope-from ); Thu, 09 Oct 2025 13:22:55 +0000 From: Thomas Zimmermann To: jfalempe@redhat.com, javierm@redhat.com, mripard@kernel.org, maarten.lankhorst@linux.intel.com Cc: dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, linux-tegra@vger.kernel.org, Thomas Zimmermann Subject: [PATCH 2/4] drm/log: Do not hold lock across drm_client_release() Date: Thu, 9 Oct 2025 15:16:29 +0200 Message-ID: <20251009132006.45834-3-tzimmermann@suse.de> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251009132006.45834-1-tzimmermann@suse.de> References: <20251009132006.45834-1-tzimmermann@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spamd-Result: default: False [-4.00 / 50.00]; REPLY(-4.00)[] X-Rspamd-Queue-Id: 731CE1F7C5 X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Rspamd-Action: no action X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251009_062308_655146_0C392169 X-CRM114-Status: GOOD ( 11.49 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When calling drm_client_release(), the client is already quiescent. Internal locks should therefore be dropped before the caller releases the client. In the case of the DRM log, concurrency originates from the console or from client events. The console has been unregistered in the previous line. The caller of the unregister callback, drm_log_client_unregister(), holds clientlist_mutex from struct drm_device to protect against concurrent client events. It is therefore safe to release the client without holding locks. Signed-off-by: Thomas Zimmermann --- drivers/gpu/drm/clients/drm_log.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/clients/drm_log.c b/drivers/gpu/drm/clients/drm_log.c index d239f1e3c456..116e0ef9ae5d 100644 --- a/drivers/gpu/drm/clients/drm_log.c +++ b/drivers/gpu/drm/clients/drm_log.c @@ -302,8 +302,8 @@ static void drm_log_client_unregister(struct drm_client_dev *client) mutex_lock(&dlog->lock); drm_log_free_scanout(client); - drm_client_release(client); mutex_unlock(&dlog->lock); + drm_client_release(client); kfree(dlog); drm_dbg(dev, "Unregistered with drm log\n"); } -- 2.51.0