diff mbox series

[RT,2/2,v3] list_bl: avoid BUG when the list is not locked

Message ID alpine.LRH.2.02.1911130616570.20335@file01.intranet.prod.int.rdu2.redhat.com (mailing list archive)
State Not Applicable, archived
Delegated to: Mike Snitzer
Headers show
Series None | expand

Commit Message

Mikulas Patocka Nov. 13, 2019, 11:18 a.m. UTC
list_bl would crash with BUG() if we used it without locking. dm-snapshot 
uses its own locking on realtime kernels (it can't use list_bl because 
list_bl uses raw spinlock and dm-snapshot takes other non-raw spinlocks 
while holding bl_lock).

To avoid this BUG, we must set LIST_BL_LOCKMASK = 0.

This patch is intended only for the realtime kernel patchset, not for the 
upstream kernel.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
 include/linux/list_bl.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


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diff mbox series

Patch

Index: linux-rt-devel/include/linux/list_bl.h
===================================================================
--- linux-rt-devel.orig/include/linux/list_bl.h	2019-11-13 12:15:50.000000000 +0100
+++ linux-rt-devel/include/linux/list_bl.h	2019-11-13 12:15:50.000000000 +0100
@@ -19,7 +19,7 @@ 
  * some fast and compact auxiliary data.
  */
 
-#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+#if (defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)) && !defined(CONFIG_PREEMPT_RT_BASE)
 #define LIST_BL_LOCKMASK	1UL
 #else
 #define LIST_BL_LOCKMASK	0UL