[patch 41/67] rtc: lockdep fix/workaround

Greg KH
2006-10-11T21:21:55Z

[-- Attachment #1: rtc-lockdep-fix-workaround.patch --]
[-- Type: text/plain, Size: 1429 bytes --]

-stable review patch. If anyone has any objections, please let us know.

------------------
From: Peter Zijlstra <a.p.zijlstra@chello.nl>

BUG: warning at kernel/lockdep.c:1816/trace_hardirqs_on() (Not tainted)
[<c04051ee>] show_trace_log_lvl+0x58/0x171
[<c0405802>] show_trace+0xd/0x10
[<c040591b>] dump_stack+0x19/0x1b
[<c043abee>] trace_hardirqs_on+0xa2/0x11e
[<c06143c3>] _spin_unlock_irq+0x22/0x26
[<c0541540>] rtc_get_rtc_time+0x32/0x176
[<c0419ba4>] hpet_rtc_interrupt+0x92/0x14d
[<c0450f94>] handle_IRQ_event+0x20/0x4d
[<c0451055>] __do_IRQ+0x94/0xef
[<c040678d>] do_IRQ+0x9e/0xbd
[<c0404a49>] common_interrupt+0x25/0x2c
DWARF2 unwinder stuck at common_interrupt+0x25/0x2c

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/char/rtc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- linux-2.6.18.orig/drivers/char/rtc.c
+++ linux-2.6.18/drivers/char/rtc.c
@@ -209,11 +209,12 @@ static const unsigned char days_in_mo[]
*/
static inline unsigned char rtc_is_updating(void)
{
+ unsigned long flags;
unsigned char uip;

- spin_lock_irq(&rtc_lock);
+ spin_lock_irqsave(&rtc_lock, flags);
uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
- spin_unlock_irq(&rtc_lock);
+ spin_unlock_irqrestore(&rtc_lock, flags);
return uip;
}

--