nvt_write_wakeup_codes acquires the same lock as the ISR but doesn't
disable interrupts on the local CPU. This caused the following
deadlock. Fix this by using spin_lock_irqsave.
[ 432.362008] ================================
[ 432.362074] WARNING: inconsistent lock state
[ 432.362144] 4.10.0-rc7-next-20170210 #1 Not tainted
[ 432.362219] --------------------------------
[ 432.362286] inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage.
[ 432.362379] swapper/0/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
[ 432.362457] (&(&nvt->lock)->rlock){?.+...}, at: [<ffffffffa016b17d>] nvt_cir_isr+0x2d/0x520 [nuvoton_cir]
[ 432.362611] {HARDIRQ-ON-W} state was registered at:
[ 432.362686]
[ 432.362698] [<ffffffff810adb7c>] __lock_acquire+0x5dc/0x1260
[ 432.362812]
[ 432.362817] [<ffffffff810aec29>] lock_acquire+0xe9/0x1d0
[ 432.362927]
[ 432.362934] [<ffffffff81609f63>] _raw_spin_lock+0x33/0x50
[ 432.363045]
[ 432.363051] [<ffffffffa016b822>] nvt_write_wakeup_codes.isra.12+0x22/0xe0 [nuvoton_cir]
[ 432.363193]
[ 432.363199] [<ffffffffa016b9bf>] wakeup_data_store+0xdf/0xf0 [nuvoton_cir]
[ 432.363327]
[ 432.363333] [<ffffffff81484223>] dev_attr_store+0x13/0x20
[ 432.363441]
[ 432.363449] [<ffffffff81232450>] sysfs_kf_write+0x40/0x50
[ 432.363558]
[ 432.363564] [<ffffffff81231640>] kernfs_fop_write+0x150/0x1e0
[ 432.363676]
[ 432.363685] [<ffffffff811b36a3>] __vfs_write+0x23/0x120
[ 432.363791]
[ 432.363798] [<ffffffff811b4d53>] vfs_write+0xc3/0x1e0
[ 432.363902]
[ 432.363909] [<ffffffff811b6124>] SyS_write+0x44/0xa0
[ 432.364012]
[ 432.364021] [<ffffffff81002c47>] do_syscall_64+0x57/0x140
[ 432.364129]
[ 432.364135] [<ffffffff8160a9e4>] return_from_SYSCALL_64+0x0/0x7a
[ 432.364252] irq event stamp: 415118
[ 432.364313] hardirqs last enabled at (415115): [<ffffffff814fd2eb>] cpuidle_enter_state+0x11b/0x370
[ 432.364445] hardirqs last disabled at (415116): [<ffffffff8160b2cb>] common_interrupt+0x8b/0x90
[ 432.364573] softirqs last enabled at (415118): [<ffffffff8106157c>] _local_bh_enable+0x1c/0x50
[ 432.364699] softirqs last disabled at (415117): [<ffffffff810629a3>] irq_enter+0x43/0x60
[ 432.364814]
other info that might help us debug this:
[ 432.364909] Possible unsafe locking scenario:
[ 432.367821] CPU0
[ 432.370645] ----
[ 432.373432] lock(&(&nvt->lock)->rlock);
[ 432.376228] <Interrupt>
[ 432.378982] lock(&(&nvt->lock)->rlock);
[ 432.381757]
*** DEADLOCK ***
[ 432.389888] no locks held by swapper/0/0.
[ 432.392574]
stack backtrace:
[ 432.397774] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.0-rc7-next-20170210 #1
[ 432.400375] Hardware name: ZOTAC ZBOX-CI321NANO/ZBOX-CI321NANO, BIOS B246P105 06/01/2015
[ 432.403023] Call Trace:
[ 432.405636] <IRQ>
[ 432.408208] dump_stack+0x68/0x93
[ 432.410775] print_usage_bug+0x1dd/0x1f0
[ 432.413334] mark_lock+0x559/0x5c0
[ 432.415871] ? print_shortest_lock_dependencies+0x1a0/0x1a0
[ 432.418431] __lock_acquire+0x6b1/0x1260
[ 432.420941] lock_acquire+0xe9/0x1d0
[ 432.423396] ? nvt_cir_isr+0x2d/0x520 [nuvoton_cir]
[ 432.425844] _raw_spin_lock+0x33/0x50
[ 432.428252] ? nvt_cir_isr+0x2d/0x520 [nuvoton_cir]
[ 432.430670] nvt_cir_isr+0x2d/0x520 [nuvoton_cir]
[ 432.433085] __handle_irq_event_percpu+0x43/0x330
[ 432.435493] handle_irq_event_percpu+0x1e/0x50
[ 432.437884] handle_irq_event+0x34/0x60
[ 432.440236] handle_edge_irq+0x6a/0x150
[ 432.442561] handle_irq+0x15/0x20
[ 432.444854] do_IRQ+0x57/0x110
[ 432.447115] common_interrupt+0x90/0x90
[ 432.449380] RIP: 0010:cpuidle_enter_state+0x120/0x370
[ 432.451653] RSP: 0018:ffffffff81c03dd8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffffcc
[ 432.453994] RAX: ffffffff81c14500 RBX: 0000000000000008 RCX: 00000064aac6f2d2
[ 432.456349] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff81c14500
[ 432.458704] RBP: ffffffff81c03e18 R08: cccccccccccccccd R09: 0000000000000018
[ 432.461072] R10: 0000000000000000 R11: 0000000000000000 R12: ffff880100a21260
[ 432.463450] R13: ffffffff81c7e6f8 R14: 0000000000000008 R15: ffffffff81c7e6e0
[ 432.465819] </IRQ>
[ 432.468104] ? cpuidle_enter_state+0x11b/0x370
[ 432.470413] cpuidle_enter+0x12/0x20
[ 432.472698] call_cpuidle+0x1e/0x40
[ 432.474967] do_idle+0xe3/0x1c0
[ 432.477172] cpu_startup_entry+0x18/0x20
[ 432.479376] rest_init+0x130/0x140
[ 432.481565] start_kernel+0x3cc/0x3d9
[ 432.483750] x86_64_start_reservations+0x2a/0x2c
[ 432.485980] x86_64_start_kernel+0x178/0x18b
[ 432.488222] start_cpu+0x14/0x14
[ 432.490453] ? start_cpu+0x14/0x14
Fixes: 97c129747af5 "[media] rc: nuvoton-cir: Add support wakeup via sysfs filter callback"
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
drivers/media/rc/nuvoton-cir.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/media/rc/nuvoton-cir.c b/drivers/media/rc/nuvoton-cir.c
index b109f824..ec4b25bd 100644
--- a/drivers/media/rc/nuvoton-cir.c
+++ b/drivers/media/rc/nuvoton-cir.c
@@ -176,12 +176,13 @@ static void nvt_write_wakeup_codes(struct rc_dev *dev,
{
u8 tolerance, config;
struct nvt_dev *nvt = dev->priv;
+ unsigned long flags;
int i;
/* hardcode the tolerance to 10% */
tolerance = DIV_ROUND_UP(count, 10);
- spin_lock(&nvt->lock);
+ spin_lock_irqsave(&nvt->lock, flags);
nvt_clear_cir_wake_fifo(nvt);
nvt_cir_wake_reg_write(nvt, count, CIR_WAKE_FIFO_CMP_DEEP);
@@ -203,7 +204,7 @@ static void nvt_write_wakeup_codes(struct rc_dev *dev,
nvt_cir_wake_reg_write(nvt, config, CIR_WAKE_IRCON);
- spin_unlock(&nvt->lock);
+ spin_unlock_irqrestore(&nvt->lock, flags);
}
static ssize_t wakeup_data_show(struct device *dev,
--
2.11.1
