* dmaengine: rcar-dmac: Disable interrupts while stopping channels
@ 2018-07-09 16:51 Vinod Koul
0 siblings, 0 replies; 2+ messages in thread
From: Vinod Koul @ 2018-07-09 16:51 UTC (permalink / raw)
To: Geert Uytterhoeven
Cc: Dan Williams, Kuninori Morimoto, Yoshihiro Shimoda, dmaengine,
linux-renesas-soc
On 02-07-18, 17:02, Geert Uytterhoeven wrote:
> During system reboot or halt, with lockdep enabled:
>
> ================================
> WARNING: inconsistent lock state
> 4.18.0-rc1-salvator-x-00002-g9203dbec90a68103 #41 Tainted: G W
> --------------------------------
> inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
> reboot/2779 [HC0[0]:SC0[0]:HE1:SE1] takes:
> 0000000098ae4ad3 (&(&rchan->lock)->rlock){?.-.}, at: rcar_dmac_shutdown+0x58/0x6c
> {IN-HARDIRQ-W} state was registered at:
> lock_acquire+0x208/0x238
> _raw_spin_lock+0x40/0x54
> rcar_dmac_isr_channel+0x28/0x200
> __handle_irq_event_percpu+0x1c0/0x3c8
> handle_irq_event_percpu+0x34/0x88
> handle_irq_event+0x48/0x78
> handle_fasteoi_irq+0xc4/0x12c
> generic_handle_irq+0x18/0x2c
> __handle_domain_irq+0xa8/0xac
> gic_handle_irq+0x78/0xbc
> el1_irq+0xec/0x1c0
> arch_cpu_idle+0xe8/0x1bc
> default_idle_call+0x2c/0x30
> do_idle+0x144/0x234
> cpu_startup_entry+0x20/0x24
> rest_init+0x27c/0x290
> start_kernel+0x430/0x45c
> irq event stamp: 12177
> hardirqs last enabled at (12177): [<ffffff800881d804>] _raw_spin_unlock_irq+0x2c/0x4c
> hardirqs last disabled at (12176): [<ffffff800881d638>] _raw_spin_lock_irq+0x1c/0x60
> softirqs last enabled at (11948): [<ffffff8008081da8>] __do_softirq+0x160/0x4ec
> softirqs last disabled at (11935): [<ffffff80080ec948>] irq_exit+0xa0/0xfc
>
> other info that might help us debug this:
> Possible unsafe locking scenario:
>
> CPU0
> ----
> lock(&(&rchan->lock)->rlock);
> <Interrupt>
> lock(&(&rchan->lock)->rlock);
>
> *** DEADLOCK ***
>
> 3 locks held by reboot/2779:
> #0: 00000000bfabfa74 (reboot_mutex){+.+.}, at: sys_reboot+0xdc/0x208
> #1: 00000000c75d8c3a (&dev->mutex){....}, at: device_shutdown+0xc8/0x1c4
> #2: 00000000ebec58ec (&dev->mutex){....}, at: device_shutdown+0xd8/0x1c4
>
> stack backtrace:
> CPU: 6 PID: 2779 Comm: reboot Tainted: G W 4.18.0-rc1-salvator-x-00002-g9203dbec90a68103 #41
> Hardware name: Renesas Salvator-X 2nd version board based on r8a7795 ES2.0+ (DT)
> Call trace:
> dump_backtrace+0x0/0x148
> show_stack+0x14/0x1c
> dump_stack+0xb0/0xf0
> print_usage_bug.part.26+0x1c4/0x27c
> mark_lock+0x38c/0x610
> __lock_acquire+0x3fc/0x14d4
> lock_acquire+0x208/0x238
> _raw_spin_lock+0x40/0x54
> rcar_dmac_shutdown+0x58/0x6c
> platform_drv_shutdown+0x20/0x2c
> device_shutdown+0x160/0x1c4
> kernel_restart_prepare+0x34/0x3c
> kernel_restart+0x14/0x5c
> sys_reboot+0x160/0x208
> el0_svc_naked+0x30/0x34
>
> rcar_dmac_stop_all_chan() takes the channel lock while stopping a
> channel, but does not disable interrupts, leading to a deadlock when a
> DMAC interrupt comes in. Before, the same code block was called from an
> interrupt handler, hence taking the spinlock was sufficient.
>
> Fix this by disabling local interrupts while taking the spinlock.
Applied, thanks
^ permalink raw reply [flat|nested] 2+ messages in thread* dmaengine: rcar-dmac: Disable interrupts while stopping channels
@ 2018-07-02 15:02 Geert Uytterhoeven
0 siblings, 0 replies; 2+ messages in thread
From: Geert Uytterhoeven @ 2018-07-02 15:02 UTC (permalink / raw)
To: Vinod Koul, Dan Williams, Kuninori Morimoto, Yoshihiro Shimoda
Cc: dmaengine, linux-renesas-soc, Geert Uytterhoeven
During system reboot or halt, with lockdep enabled:
================================
WARNING: inconsistent lock state
4.18.0-rc1-salvator-x-00002-g9203dbec90a68103 #41 Tainted: G W
--------------------------------
inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
reboot/2779 [HC0[0]:SC0[0]:HE1:SE1] takes:
0000000098ae4ad3 (&(&rchan->lock)->rlock){?.-.}, at: rcar_dmac_shutdown+0x58/0x6c
{IN-HARDIRQ-W} state was registered at:
lock_acquire+0x208/0x238
_raw_spin_lock+0x40/0x54
rcar_dmac_isr_channel+0x28/0x200
__handle_irq_event_percpu+0x1c0/0x3c8
handle_irq_event_percpu+0x34/0x88
handle_irq_event+0x48/0x78
handle_fasteoi_irq+0xc4/0x12c
generic_handle_irq+0x18/0x2c
__handle_domain_irq+0xa8/0xac
gic_handle_irq+0x78/0xbc
el1_irq+0xec/0x1c0
arch_cpu_idle+0xe8/0x1bc
default_idle_call+0x2c/0x30
do_idle+0x144/0x234
cpu_startup_entry+0x20/0x24
rest_init+0x27c/0x290
start_kernel+0x430/0x45c
irq event stamp: 12177
hardirqs last enabled at (12177): [<ffffff800881d804>] _raw_spin_unlock_irq+0x2c/0x4c
hardirqs last disabled at (12176): [<ffffff800881d638>] _raw_spin_lock_irq+0x1c/0x60
softirqs last enabled at (11948): [<ffffff8008081da8>] __do_softirq+0x160/0x4ec
softirqs last disabled at (11935): [<ffffff80080ec948>] irq_exit+0xa0/0xfc
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&(&rchan->lock)->rlock);
<Interrupt>
lock(&(&rchan->lock)->rlock);
*** DEADLOCK ***
3 locks held by reboot/2779:
#0: 00000000bfabfa74 (reboot_mutex){+.+.}, at: sys_reboot+0xdc/0x208
#1: 00000000c75d8c3a (&dev->mutex){....}, at: device_shutdown+0xc8/0x1c4
#2: 00000000ebec58ec (&dev->mutex){....}, at: device_shutdown+0xd8/0x1c4
stack backtrace:
CPU: 6 PID: 2779 Comm: reboot Tainted: G W 4.18.0-rc1-salvator-x-00002-g9203dbec90a68103 #41
Hardware name: Renesas Salvator-X 2nd version board based on r8a7795 ES2.0+ (DT)
Call trace:
dump_backtrace+0x0/0x148
show_stack+0x14/0x1c
dump_stack+0xb0/0xf0
print_usage_bug.part.26+0x1c4/0x27c
mark_lock+0x38c/0x610
__lock_acquire+0x3fc/0x14d4
lock_acquire+0x208/0x238
_raw_spin_lock+0x40/0x54
rcar_dmac_shutdown+0x58/0x6c
platform_drv_shutdown+0x20/0x2c
device_shutdown+0x160/0x1c4
kernel_restart_prepare+0x34/0x3c
kernel_restart+0x14/0x5c
sys_reboot+0x160/0x208
el0_svc_naked+0x30/0x34
rcar_dmac_stop_all_chan() takes the channel lock while stopping a
channel, but does not disable interrupts, leading to a deadlock when a
DMAC interrupt comes in. Before, the same code block was called from an
interrupt handler, hence taking the spinlock was sufficient.
Fix this by disabling local interrupts while taking the spinlock.
Fixes: 9203dbec90a68103 ("dmaengine: rcar-dmac: don't use DMAC error interrupt")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
drivers/dma/sh/rcar-dmac.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 279c930c4a7635e0..4e4d183190bd0c9c 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -823,9 +823,9 @@ static void rcar_dmac_stop_all_chan(struct rcar_dmac *dmac)
struct rcar_dmac_chan *chan = &dmac->channels[i];
/* Stop and reinitialize the channel. */
- spin_lock(&chan->lock);
+ spin_lock_irq(&chan->lock);
rcar_dmac_chan_halt(chan);
- spin_unlock(&chan->lock);
+ spin_unlock_irq(&chan->lock);
}
}
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2018-07-09 16:51 dmaengine: rcar-dmac: Disable interrupts while stopping channels Vinod Koul
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