From: Mikulas Patocka <mpatocka@redhat.com>
To: tglx@linutronix.de, linux-rt-users@vger.kernel.org
Cc: Mike Snitzer <msnitzer@redhat.com>,
Nikos Tsironis <ntsironis@arrikto.com>,
Scott Wood <swood@redhat.com>,
Ilias Tsitsimpis <iliastsi@arrikto.com>,
dm-devel@redhat.com, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, Daniel Wagner <dwagner@suse.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH RT 2/2 v3] list_bl: avoid BUG when the list is not locked
Date: Wed, 13 Nov 2019 06:18:08 -0500 (EST) [thread overview]
Message-ID: <alpine.LRH.2.02.1911130616570.20335@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <alpine.LRH.2.02.1911121110430.12815@file01.intranet.prod.int.rdu2.redhat.com>
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(-)
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
next prev parent reply other threads:[~2019-11-13 11:18 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 16:16 [PATCH RT 2/2 v2] list_bl: avoid BUG when the list is not locked Mikulas Patocka
2019-11-13 10:29 ` Nikos Tsironis
2019-11-13 11:16 ` Mikulas Patocka
2019-11-13 11:50 ` Nikos Tsironis
2019-11-13 12:05 ` Mikulas Patocka
2019-11-13 11:18 ` Mikulas Patocka [this message]
2019-11-13 13:10 ` [PATCH RT 2/2 v4] " Nikos Tsironis
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