Patch "dma-debug: avoid spinlock recursion when disabling dma-debug" has been added to the 3.14-stable tree

Patch "dma-debug: avoid spinlock recursion when disabling dma-debug" has been added to the 3.14-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    dma-debug: avoid spinlock recursion when disabling dma-debug

to the 3.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     dma-debug-avoid-spinlock-recursion-when-disabling-dma-debug.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 3017cd63f26fc655d56875aaf497153ba60e9edf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Thu, 26 May 2016 15:16:25 -0700
Subject: dma-debug: avoid spinlock recursion when disabling dma-debug
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

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 <ville.syrjala@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 lib/dma-debug.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -646,9 +646,9 @@ static struct dma_debug_entry *dma_entry
 	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;
 	}
 


Patches currently in stable-queue which might be from ville.syrjala@linux.intel.com are

queue-3.14/dma-debug-avoid-spinlock-recursion-when-disabling-dma-debug.patch