From e3b5360919a2491a6ed34426a083f4afdcbc7973 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: [PATCH] dma-debug: avoid spinlock recursion when disabling dma-debug
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[ Upstream commit 3017cd63f26fc655d56875aaf497153ba60e9edf ]
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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
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 1ff0fd098504d..c83ac43418be4 100644
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -646,9 +646,9 @@ 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;
}