diff options
| author | Andrew Morton <akpm@linux-foundation.org> | 2008-02-04 16:48:10 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-02-04 16:48:10 +0100 |
| commit | 795d45b22c079946332bf3825afefe5a981a97b6 (patch) | |
| tree | 8952c202b021cb73f3a85988a91dd54724707a0b | |
| parent | 7b610eec7a06ede64f71459e7f412dfd96f4cc5e (diff) | |
| download | lwn-795d45b22c079946332bf3825afefe5a981a97b6.tar.gz lwn-795d45b22c079946332bf3825afefe5a981a97b6.zip | |
x86: fix RTC lockdep warning: potential hardirq recursion
After disabling both CONFIG_DEBUG_LOCKING_API_SELFTESTS and netconsole
(using current mainline) I get a login prompt, and also...
[ 5.181668] SELinux: policy loaded with handle_unknown=deny
[ 5.183315] type=1403 audit(1202100038.157:3): policy loaded auid=4294967295 ses=4294967295
[ 5.822073] SELinux: initialized (dev usbfs, type usbfs), uses genfs_contexts
[ 7.819146] ------------[ cut here ]------------
[ 7.819146] WARNING: at kernel/lockdep.c:2033 trace_hardirqs_on+0x9b/0x10d()
[ 7.819146] Modules linked in: generic ext3 jbd ide_disk ide_core
[ 7.819146] Pid: 399, comm: hwclock Not tainted 2.6.24 #4
[ 7.819146] [<c011d140>] warn_on_slowpath+0x41/0x51
[ 7.819146] [<c01364a9>] ? lock_release_holdtime+0x50/0x56
[ 7.819146] [<c013770c>] ? check_usage_forwards+0x19/0x3b
[ 7.819146] [<c01390c4>] ? __lock_acquire+0xac3/0xb0b
[ 7.819146] [<c0108c98>] ? native_sched_clock+0x8b/0x9f
[ 7.819146] [<c01364a9>] ? lock_release_holdtime+0x50/0x56
[ 7.819146] [<c030ca6c>] ? _spin_unlock_irq+0x22/0x42
[ 7.819146] [<c013848b>] trace_hardirqs_on+0x9b/0x10d
[ 7.819146] [<c030ca6c>] _spin_unlock_irq+0x22/0x42
[ 7.819146] [<c011481e>] hpet_rtc_interrupt+0xdf/0x290
[ 7.819146] [<c014ea90>] handle_IRQ_event+0x1a/0x46
[ 7.819146] [<c014f8ea>] handle_edge_irq+0xbe/0xff
[ 7.819146] [<c0106e08>] do_IRQ+0x6d/0x84
[ 7.819146] [<c0105596>] common_interrupt+0x2e/0x34
[ 7.819146] [<c013007b>] ? ktime_get_ts+0x8/0x3f
[ 7.819146] [<c0139420>] ? lock_release+0x167/0x16f
[ 7.819146] [<c017974a>] ? core_sys_select+0x2c/0x327
[ 7.819146] [<c0179792>] core_sys_select+0x74/0x327
[ 7.819146] [<c0108c98>] ? native_sched_clock+0x8b/0x9f
[ 7.819146] [<c01364a9>] ? lock_release_holdtime+0x50/0x56
[ 7.819146] [<c030ca6c>] ? _spin_unlock_irq+0x22/0x42
[ 7.819146] [<c01384d6>] ? trace_hardirqs_on+0xe6/0x10d
[ 7.819146] [<c030ca77>] ? _spin_unlock_irq+0x2d/0x42
[ 7.819146] [<c023b437>] ? rtc_do_ioctl+0x11b/0x677
[ 7.819146] [<c01c487e>] ? inode_has_perm+0x5e/0x68
[ 7.819146] [<c01364a9>] ? lock_release_holdtime+0x50/0x56
[ 7.819146] [<c0108c98>] ? native_sched_clock+0x8b/0x9f
[ 7.819146] [<c01c490b>] ? file_has_perm+0x83/0x8c
[ 7.819146] [<c023ba08>] ? rtc_ioctl+0xf/0x11
[ 7.819146] [<c017898d>] ? do_ioctl+0x55/0x67
[ 7.819146] [<c0179d15>] sys_select+0x93/0x163
[ 7.819146] [<c0104b39>] ? sysenter_past_esp+0x9a/0xa5
[ 7.819146] [<c0104afe>] sysenter_past_esp+0x5f/0xa5
[ 7.819146] =======================
[ 7.819146] ---[ end trace 96540ca301ffb84c ]---
[ 7.819210] rtc: lost 6 interrupts
[ 7.870668] type=1400 audit(1202128840.794:4): avc: denied { audit_write } for pid=399 comm="hwclock" capability=29 scontext=system_u:system_r:hwclock_t:s0 tcontext=system_u:system_r:hwclock_t:s0 tclass=capability
[ 9.538866] input: PC Speaker as /class/input/input5
Because hpet_rtc_interrupt()'s call to get_rtc_time() ends up
resolving to include/asm-generic/rtc.h's (hilariously inlined)
get_rtc_time(), which does spin_unlock_irq() from hard IRQ context.
The obvious patch fixes it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | include/asm-generic/rtc.h | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/include/asm-generic/rtc.h b/include/asm-generic/rtc.h index d3238f1f70a6..dd1bed860e64 100644 --- a/include/asm-generic/rtc.h +++ b/include/asm-generic/rtc.h @@ -35,10 +35,11 @@ static inline unsigned char rtc_is_updating(void) { unsigned char uip; + unsigned long flags; - 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; } @@ -46,6 +47,8 @@ static inline unsigned int get_rtc_time(struct rtc_time *time) { unsigned long uip_watchdog = jiffies; unsigned char ctrl; + unsigned long flags; + #ifdef CONFIG_MACH_DECSTATION unsigned int real_year; #endif @@ -72,7 +75,7 @@ static inline unsigned int get_rtc_time(struct rtc_time *time) * RTC has RTC_DAY_OF_WEEK, we 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); time->tm_sec = CMOS_READ(RTC_SECONDS); time->tm_min = CMOS_READ(RTC_MINUTES); time->tm_hour = CMOS_READ(RTC_HOURS); @@ -83,7 +86,7 @@ static inline unsigned int get_rtc_time(struct rtc_time *time) 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) { |