[3.13.y.z extended stable] Patch "sparc64: Fix lockdep warnings on reboot on Ultra-5" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Fri Oct 31 20:53:28 UTC 2014

This is a note to let you know that I have just added a patch titled

    sparc64: Fix lockdep warnings on reboot on Ultra-5

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:


This patch is scheduled to be released in version

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see



>From d7e3038597411e2c39d8160340f7e86ead90a140 Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem at davemloft.net>
Date: Fri, 10 Oct 2014 15:49:16 -0400
Subject: sparc64: Fix lockdep warnings on reboot on Ultra-5

[ Upstream commit bdcf81b658ebc4c2640c3c2c55c8b31c601b6996 ]

Inconsistently, the raw_* IRQ routines do not interact with and update
the irqflags tracing and lockdep state, whereas the raw_* spinlock
interfaces do.

This causes problems in p1275_cmd_direct() because we disable hardirqs
by hand using raw_local_irq_restore() and then do a raw_spin_lock()
which triggers a lockdep trace because the CPU's hw IRQ state doesn't
match IRQ tracing's internal software copy of that state.

The CPU's irqs are disabled, yet current->hardirqs_enabled is true.

reboot: Restarting system
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3536 check_flags+0x7c/0x240()
Modules linked in: openpromfs
CPU: 0 PID: 1 Comm: systemd-shutdow Tainted: G        W      3.17.0-dirty #145
Call Trace:
 [000000000045919c] warn_slowpath_common+0x5c/0xa0
 [0000000000459210] warn_slowpath_fmt+0x30/0x40
 [000000000048f41c] check_flags+0x7c/0x240
 [0000000000493280] lock_acquire+0x20/0x1c0
 [0000000000832b70] _raw_spin_lock+0x30/0x60
 [000000000068f2fc] p1275_cmd_direct+0x1c/0x60
 [000000000068ed28] prom_reboot+0x28/0x40
 [000000000043610c] machine_restart+0x4c/0x80
 [000000000047d2d4] kernel_restart+0x54/0x80
 [000000000047d618] SyS_reboot+0x138/0x200
 [00000000004060b4] linux_sparc_syscall32+0x34/0x60
---[ end trace 5c439fe81c05a100 ]---
possible reason: unannotated irqs-off.
irq event stamp: 2010267
hardirqs last  enabled at (2010267): [<000000000049a358>] vprintk_emit+0x4b8/0x580
hardirqs last disabled at (2010266): [<0000000000499f08>] vprintk_emit+0x68/0x580
softirqs last  enabled at (2010046): [<000000000045d278>] __do_softirq+0x378/0x4a0
softirqs last disabled at (2010039): [<000000000042bf08>] do_softirq_own_stack+0x28/0x40
Resetting ...

Use local_* variables of the hw IRQ interfaces so that IRQ tracing sees
all of our changes.

Reported-by: Meelis Roos <mroos at linux.ee>
Tested-by: Meelis Roos <mroos at linux.ee>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
 arch/sparc/prom/p1275.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/sparc/prom/p1275.c b/arch/sparc/prom/p1275.c
index 04a4540..ea5b427 100644
--- a/arch/sparc/prom/p1275.c
+++ b/arch/sparc/prom/p1275.c
@@ -10,6 +10,7 @@
 #include <linux/smp.h>
 #include <linux/string.h>
 #include <linux/spinlock.h>
+#include <linux/irqflags.h>

 #include <asm/openprom.h>
 #include <asm/oplib.h>
@@ -37,8 +38,8 @@ void p1275_cmd_direct(unsigned long *args)
 	unsigned long flags;

-	raw_local_save_flags(flags);
-	raw_local_irq_restore((unsigned long)PIL_NMI);
+	local_save_flags(flags);
+	local_irq_restore((unsigned long)PIL_NMI);

@@ -46,7 +47,7 @@ void p1275_cmd_direct(unsigned long *args)

-	raw_local_irq_restore(flags);
+	local_irq_restore(flags);

 void prom_cif_init(void *cif_handler, void *cif_stack)

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