From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Subject: dma-debug: avoid spinlock recursion when disabling dma-debug
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@xxxxxxxxxxxxxxx
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/dma-debug.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN lib/dma-debug.c~dma-debug-avoid-spinlock-recursion-when-disabling-dma-debug lib/dma-debug.c
--- a/lib/dma-debug.c~dma-debug-avoid-spinlock-recursion-when-disabling-dma-debug
+++ a/lib/dma-debug.c
@@ -657,9 +657,9 @@ 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;
}
_
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