From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932764AbcHUPys (ORCPT ); Sun, 21 Aug 2016 11:54:48 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:55701 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754092AbcHUPeQ (ORCPT ); Sun, 21 Aug 2016 11:34:16 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?latin1?q?Ville=20Syrj=E4l=E4?= , Andrew Morton , Linus Torvalds , Willy Tarreau Subject: [PATCH 3.10 089/180] dma-debug: avoid spinlock recursion when disabling dma-debug Date: Sun, 21 Aug 2016 17:30:19 +0200 Message-Id: <1471793510-13022-90-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1471793510-13022-1-git-send-email-w@1wt.eu> References: <1471793510-13022-1-git-send-email-w@1wt.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=latin1 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ville Syrjälä commit 3017cd63f26fc655d56875aaf497153ba60e9edf upstream. With netconsole (at least) the pr_err("... disablingn") call can recurse back into the dma-debug code, where it'll try to grab free_entries_lock again. Avoid the problem by doing the printk after dropping the lock. Link: http://lkml.kernel.org/r/1463678421-18683-1-git-send-email-ville.syrjala@linux.intel.com Signed-off-by: Ville Syrjälä Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Willy Tarreau --- lib/dma-debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/dma-debug.c b/lib/dma-debug.c index eb43517b..c32437f 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -445,9 +445,9 @@ static struct dma_debug_entry *dma_entry_alloc(void) spin_lock_irqsave(&free_entries_lock, flags); if (list_empty(&free_entries)) { - pr_err("DMA-API: debugging out of memory - disabling\n"); global_disable = true; spin_unlock_irqrestore(&free_entries_lock, flags); + pr_err("DMA-API: debugging out of memory - disabling\n"); return NULL; } -- 2.8.0.rc2.1.gbe9624a