From 0f74964627e0ece4ac8da0e2cd01906ec322b4fe Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Wed, 12 Jul 2006 09:03:10 -0700
Subject: [PATCH] lockdep: HPET/RTC fix
Joseph Fannin reported that hpet_rtc_interrupt() enables hardirqs
in irq context:
[ 25.628000] [<c014af4e>] trace_hardirqs_on+0xce/0x200
[ 25.628000] [<c036cf21>] _spin_unlock_irq+0x31/0x70
[ 25.628000] [<c0296584>] rtc_get_rtc_time+0x44/0x1a0
[ 25.628000] [<c01198bb>] hpet_rtc_interrupt+0x21b/0x280
[ 25.628000] [<c0161141>] handle_IRQ_event+0x31/0x70
[ 25.628000] [<c0162d37>] handle_edge_irq+0xe7/0x210
[ 25.628000] [<c0106192>] do_IRQ+0x92/0x120
[ 25.628000] [<c0104121>] common_interrupt+0x25/0x2c
the call of rtc_get_rtc_time() is highly suspect. At a minimum we
need the patch below to save/restore hardirq state.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Joseph Fannin <jfannin@gmail.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
drivers/char/rtc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
(limited to 'drivers/char/rtc.c')
diff --git a/drivers/char/rtc.c b/drivers/char/rtc.c
index 6ccc364..6e6a7c7 100644
--- a/drivers/char/rtc.c
+++ b/drivers/char/rtc.c
@@ -1245,7 +1245,7 @@ static int rtc_proc_open(struct inode *inode, struct file *file)
void rtc_get_rtc_time(struct rtc_time *rtc_tm)
{
- unsigned long uip_watchdog = jiffies;
+ unsigned long uip_watchdog = jiffies, flags;
unsigned char ctrl;
#ifdef CONFIG_MACH_DECSTATION
unsigned int real_year;
@@ -1272,7 +1272,7 @@ void rtc_get_rtc_time(struct rtc_time *rtc_tm)
* RTC has RTC_DAY_OF_WEEK, we should usually ignore it, as it is
* only updated by the RTC when initially set to a non-zero value.
*/
- spin_lock_irq(&rtc_lock);
+ spin_lock_irqsave(&rtc_lock, flags);
rtc_tm->tm_sec = CMOS_READ(RTC_SECONDS);
rtc_tm->tm_min = CMOS_READ(RTC_MINUTES);
rtc_tm->tm_hour = CMOS_READ(RTC_HOURS);
@@ -1286,7 +1286,7 @@ void rtc_get_rtc_time(struct rtc_time *rtc_tm)
real_year = CMOS_READ(RTC_DEC_YEAR);
#endif
ctrl = CMOS_READ(RTC_CONTROL);
- spin_unlock_irq(&rtc_lock);
+ spin_unlock_irqrestore(&rtc_lock, flags);
if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
{
--
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