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[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>
This commit is contained in:
Ingo Molnar 2006-07-12 09:03:10 -07:00 committed by Linus Torvalds
parent a29b0b74e7
commit 0f74964627
1 changed files with 3 additions and 3 deletions
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6
drivers/char/rtc.c
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@ -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)
{