| Message ID | 20200221144739.11746-1-ville.syrjala@linux.intel.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | rtc: cmos: Use spin_lock_irqsave() in cmos_interrupt() | expand |
On 21/02/2020 16:47:39+0200, Ville Syrjala wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > cmos_interrupt() isn't always called from hardirq context, so > we must use spin_lock_irqsave() & co. > > ================================ > WARNING: inconsistent lock state > 5.6.0-rc2-CI-CI_DRM_7981+ #1 Tainted: G U > -------------------------------- > inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. > rtcwake/4315 [HC0[0]:SC0[0]:HE1:SE1] takes: > ffffffff82635198 (rtc_lock){?...}, at: cmos_interrupt+0x18/0x100 > {IN-HARDIRQ-W} state was registered at: > lock_acquire+0xa7/0x1c0 > _raw_spin_lock+0x2a/0x40 > cmos_interrupt+0x18/0x100 > rtc_handler+0x75/0xc0 > acpi_ev_fixed_event_detect+0xf9/0x132 > acpi_ev_sci_xrupt_handler+0xb/0x28 > acpi_irq+0x13/0x30 > __handle_irq_event_percpu+0x41/0x2c0 > handle_irq_event_percpu+0x2b/0x70 > handle_irq_event+0x2f/0x50 > handle_fasteoi_irq+0x8e/0x150 > do_IRQ+0x7e/0x160 > ret_from_intr+0x0/0x35 > mwait_idle+0x7e/0x200 > do_idle+0x1bb/0x260 > cpu_startup_entry+0x14/0x20 > start_secondary+0x15f/0x1b0 > secondary_startup_64+0xa4/0xb0 > irq event stamp: 42003 > hardirqs last enabled at (42003): [<ffffffff81a36567>] _raw_spin_unlock_irqrestore+0x47/0x60 > hardirqs last disabled at (42002): [<ffffffff81a362ed>] _raw_spin_lock_irqsave+0xd/0x50 > softirqs last enabled at (41848): [<ffffffff81e00385>] __do_softirq+0x385/0x47f > softirqs last disabled at (41841): [<ffffffff810bab3a>] irq_exit+0xba/0xc0 > > other info that might help us debug this: > Possible unsafe locking scenario: > > CPU0 > ---- > lock(rtc_lock); > <Interrupt> > lock(rtc_lock); > > *** DEADLOCK *** > > 6 locks held by rtcwake/4315: > #0: ffff888175dc9408 (sb_writers#5){.+.+}, at: vfs_write+0x1a4/0x1d0 > #1: ffff88817406ca80 (&of->mutex){+.+.}, at: kernfs_fop_write+0xdd/0x1b0 > #2: ffff888179be85e0 (kn->count#236){.+.+}, at: kernfs_fop_write+0xe6/0x1b0 > #3: ffffffff82641e00 (system_transition_mutex){+.+.}, at: pm_suspend+0xb3/0x3b0 > #4: ffffffff826b3ee0 (acpi_scan_lock){+.+.}, at: acpi_suspend_begin+0x47/0x80 > #5: ffff888178fc3960 (&dev->mutex){....}, at: device_resume+0x92/0x1c0 > > stack backtrace: > CPU: 3 PID: 4315 Comm: rtcwake Tainted: G U 5.6.0-rc2-CI-CI_DRM_7981+ #1 > Hardware name: Google Soraka/Soraka, BIOS MrChromebox-4.10 08/25/2019 > Call Trace: > dump_stack+0x71/0x9b > mark_lock+0x49a/0x500 > ? print_shortest_lock_dependencies+0x200/0x200 > __lock_acquire+0x6d4/0x15d0 > ? __lock_acquire+0x460/0x15d0 > lock_acquire+0xa7/0x1c0 > ? cmos_interrupt+0x18/0x100 > _raw_spin_lock+0x2a/0x40 > ? cmos_interrupt+0x18/0x100 > cmos_interrupt+0x18/0x100 > cmos_resume+0x1fd/0x290 > ? __acpi_pm_set_device_wakeup+0x24/0x100 > pnp_bus_resume+0x5e/0x90 > ? pnp_bus_suspend+0x10/0x10 > dpm_run_callback+0x64/0x280 > device_resume+0xd4/0x1c0 > ? dpm_watchdog_set+0x60/0x60 > dpm_resume+0x106/0x410 > ? dpm_resume_early+0x38c/0x3e0 > dpm_resume_end+0x8/0x10 > suspend_devices_and_enter+0x16f/0xbe0 > ? rcu_read_lock_sched_held+0x4d/0x80 > pm_suspend+0x344/0x3b0 > state_store+0x78/0xe0 > kernfs_fop_write+0x112/0x1b0 > vfs_write+0xb9/0x1d0 > ksys_write+0x9f/0xe0 > do_syscall_64+0x4f/0x220 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x7ff934307154 > Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 b1 07 2e 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 41 54 55 49 89 d4 53 48 89 f5 > RSP: 002b:00007ffe2647c168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007ff934307154 > RDX: 0000000000000004 RSI: 000055de3ec4e5a0 RDI: 000000000000000a > RBP: 000055de3ec4e5a0 R08: 000055de3ec4c5e0 R09: 00007ff9349f3740 > R10: 000055de3ec4a010 R11: 0000000000000246 R12: 000055de3ec4c500 > R13: 0000000000000004 R14: 00007ff9345df2a0 R15: 00007ff9345de760 > > Cc: Alessandro Zummo <a.zummo@towertech.it> > Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> > Cc: linux-rtc@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/rtc/rtc-cmos.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > Applied, thanks.
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index b795fe4cbd2e..fb13993fad31 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -649,10 +649,11 @@ static struct cmos_rtc cmos_rtc; static irqreturn_t cmos_interrupt(int irq, void *p) { + unsigned long flags; u8 irqstat; u8 rtc_control; - spin_lock(&rtc_lock); + spin_lock_irqsave(&rtc_lock, flags); /* When the HPET interrupt handler calls us, the interrupt * status is passed as arg1 instead of the irq number. But @@ -686,7 +687,7 @@ static irqreturn_t cmos_interrupt(int irq, void *p) hpet_mask_rtc_irq_bit(RTC_AIE); CMOS_READ(RTC_INTR_FLAGS); } - spin_unlock(&rtc_lock); + spin_unlock_irqrestore(&rtc_lock, flags); if (is_intr(irqstat)) { rtc_update_irq(p, 1, irqstat);