cmos_interrrupt() is called directly on resume paths, and by the irqhandler. It currently assumes that it can only be invoked directly from a hardirq, and so leads to the lockdep splat:
<4>[ 259.166718] WARNING: inconsistent lock state <4>[ 259.166725] 5.6.0-rc3-CI-CI_DRM_8038+ #1 Tainted: G U <4>[ 259.166727] -------------------------------- <4>[ 259.166731] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. <4>[ 259.166741] rtcwake/4221 [HC0[0]:SC0[0]:HE1:SE1] takes: <4>[ 259.166745] ffffffff82635198 (rtc_lock){?...}, at: cmos_interrupt+0x18/0x100 <4>[ 259.166768] {IN-HARDIRQ-W} state was registered at: <4>[ 259.166780] lock_acquire+0xa7/0x1c0 <4>[ 259.166790] _raw_spin_lock+0x2a/0x40 <4>[ 259.166799] cmos_interrupt+0x18/0x100 <4>[ 259.166808] rtc_handler+0x75/0xc0 <4>[ 259.166822] acpi_ev_fixed_event_detect+0xf9/0x132 <4>[ 259.166829] acpi_ev_sci_xrupt_handler+0xb/0x28 <4>[ 259.166838] acpi_irq+0x13/0x30 <4>[ 259.166849] __handle_irq_event_percpu+0x41/0x2c0 <4>[ 259.166859] handle_irq_event_percpu+0x2b/0x70 <4>[ 259.166868] handle_irq_event+0x2f/0x50 <4>[ 259.166875] handle_fasteoi_irq+0x8e/0x150 <4>[ 259.166883] do_IRQ+0x7e/0x160 <4>[ 259.166891] ret_from_intr+0x0/0x35 <4>[ 259.166898] mwait_idle+0x7e/0x200 <4>[ 259.166905] do_idle+0x1bb/0x260 <4>[ 259.166912] cpu_startup_entry+0x14/0x20 <4>[ 259.166921] start_secondary+0x15f/0x1b0 <4>[ 259.166929] secondary_startup_64+0xa4/0xb0 <4>[ 259.167264] irq event stamp: 41593 <4>[ 259.167275] hardirqs last enabled at (41593): [<ffffffff81a394e7>] _raw_spin_unlock_irqrestore+0x47/0x60 <4>[ 259.167285] hardirqs last disabled at (41592): [<ffffffff81a3926d>] _raw_spin_lock_irqsave+0xd/0x50 <4>[ 259.167296] softirqs last enabled at (41568): [<ffffffff81e00385>] __do_softirq+0x385/0x47f <4>[ 259.167306] softirqs last disabled at (41561): [<ffffffff810babaa>] irq_exit+0xba/0xc0 <4>[ 259.167309] other info that might help us debug this: <4>[ 259.167312] Possible unsafe locking scenario:
<4>[ 259.167314] CPU0 <4>[ 259.167316] ---- <4>[ 259.167319] lock(rtc_lock); <4>[ 259.167324] <Interrupt> <4>[ 259.167326] lock(rtc_lock); <4>[ 259.167332] *** DEADLOCK ***
<4>[ 259.167337] 6 locks held by rtcwake/4221: <4>[ 259.167665] #0: ffff888175e89408 (sb_writers#5){.+.+}, at: vfs_write+0x1a4/0x1d0 <4>[ 259.167687] #1: ffff88816e112080 (&of->mutex){+.+.}, at: kernfs_fop_write+0xdd/0x1b0 <4>[ 259.167706] #2: ffff888179be85e0 (kn->count#236){.+.+}, at: kernfs_fop_write+0xe6/0x1b0 <4>[ 259.167728] #3: ffffffff82641e00 (system_transition_mutex){+.+.}, at: pm_suspend+0xb3/0x3b0 <4>[ 259.167748] #4: ffffffff826b3ea0 (acpi_scan_lock){+.+.}, at: acpi_suspend_begin+0x47/0x80 <4>[ 259.167763] #5: ffff888178f6b960 (&dev->mutex){....}, at: device_resume+0x92/0x1c0 <4>[ 259.167778] stack backtrace: <4>[ 259.167788] CPU: 1 PID: 4221 Comm: rtcwake Tainted: G U 5.6.0-rc3-CI-CI_DRM_8038+ #1 <4>[ 259.168106] Hardware name: Google Soraka/Soraka, BIOS MrChromebox-4.10 08/25/2019 <4>[ 259.168110] Call Trace: <4>[ 259.168123] dump_stack+0x71/0x9b <4>[ 259.168133] mark_lock+0x49a/0x500 <4>[ 259.168457] ? print_shortest_lock_dependencies+0x200/0x200 <4>[ 259.168469] __lock_acquire+0x6d4/0x15d0 <4>[ 259.168479] ? __lock_acquire+0x460/0x15d0 <4>[ 259.168490] lock_acquire+0xa7/0x1c0 <4>[ 259.168500] ? cmos_interrupt+0x18/0x100 <4>[ 259.168824] _raw_spin_lock+0x2a/0x40 <4>[ 259.168834] ? cmos_interrupt+0x18/0x100 <4>[ 259.168843] cmos_interrupt+0x18/0x100 <4>[ 259.169159] cmos_resume+0x1fd/0x290 <4>[ 259.169174] ? __acpi_pm_set_device_wakeup+0x24/0x100 <4>[ 259.169498] pnp_bus_resume+0x5e/0x90 <4>[ 259.169509] ? pnp_bus_suspend+0x10/0x10 <4>[ 259.169518] dpm_run_callback+0x64/0x280 <4>[ 259.169530] device_resume+0xd4/0x1c0 <4>[ 259.169540] ? dpm_watchdog_set+0x60/0x60 <4>[ 259.169860] dpm_resume+0x106/0x410 <4>[ 259.169870] ? dpm_resume_early+0x38c/0x3e0 <4>[ 259.169881] dpm_resume_end+0x8/0x10 <4>[ 259.170195] suspend_devices_and_enter+0x16f/0xbe0 <4>[ 259.170211] ? rcu_read_lock_sched_held+0x4d/0x80 <4>[ 259.170528] pm_suspend+0x344/0x3b0 <4>[ 259.170542] state_store+0x78/0xe0 <4>[ 259.170559] kernfs_fop_write+0x112/0x1b0 <4>[ 259.170579] vfs_write+0xb9/0x1d0 <4>[ 259.170896] ksys_write+0x9f/0xe0 <4>[ 259.170907] do_syscall_64+0x4f/0x220 <4>[ 259.170918] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4>[ 259.171229] RIP: 0033:0x7f9b4f3cb154 <4>[ 259.171240] 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 <4>[ 259.171245] RSP: 002b:00007ffc057ce438 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 <4>[ 259.171253] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f9b4f3cb154 <4>[ 259.171257] RDX: 0000000000000004 RSI: 000055f4b3d185a0 RDI: 000000000000000a <4>[ 259.171572] RBP: 000055f4b3d185a0 R08: 000055f4b3d165e0 R09: 00007f9b4fab7740 <4>[ 259.171576] R10: 000055f4b3d14010 R11: 0000000000000246 R12: 000055f4b3d16500 <4>[ 259.171580] R13: 0000000000000004 R14: 00007f9b4f6a32a0 R15: 00007f9b4f6a2760
Fixes: c6d3a278cc12 ("rtc: cmos: acknowledge ACPI driven wake alarms upon resume") Fixes: 311ee9c151ad ("rtc: cmos: allow using ACPI for RTC alarm instead of HPET") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Zhang Rui rui.zhang@intel.com Cc: Alexandre Belloni alexandre.belloni@bootlin.com Cc: Alessandro Zummo a.zummo@towertech.it Cc: stable@vger.kernel.org # v4.18+ --- drivers/rtc/rtc-cmos.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index b795fe4cbd2e..7754225c6f9d 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -651,8 +651,9 @@ static irqreturn_t cmos_interrupt(int irq, void *p) { u8 irqstat; u8 rtc_control; + unsigned long flags;
- 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);