From: Ville Syrjälä Date: Thu, 26 May 2016 22:16:25 +0000 (-0700) Subject: dma-debug: avoid spinlock recursion when disabling dma-debug X-Git-Tag: firefly_0821_release~176^2~4^2~42^2~10 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=7d0b494532b703da654f96389804f491a6594bbb;p=firefly-linux-kernel-4.4.55.git dma-debug: avoid spinlock recursion when disabling dma-debug 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/lib/dma-debug.c b/lib/dma-debug.c index 4a1515f4b452..51a76af25c66 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -657,9 +657,9 @@ 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; }