Messages in this thread Patch in this message | | | From | Jiri Slaby <> | Subject | [PATCH 3.12 48/56] dma-debug: avoid spinlock recursion when disabling dma-debug | Date | Wed, 15 Jun 2016 09:31:12 +0200 |
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From: Ville Syrjälä <ville.syrjala@linux.intel.com>
3.12-stable review patch. If anyone has any objections, please let me know.
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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: Jiri Slaby <jslaby@suse.cz> --- 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 eb43517bf261..c32437f6be61 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; } -- 2.9.0
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