This is a note to let you know that I've just added the patch titled
ASoC: samsung: Use IRQ safe spin lock calls
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
asoc-samsung-use-irq-safe-spin-lock-calls.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 316fa9e09ad76e095b9d7e9350c628b918370a22 Mon Sep 17 00:00:00 2001
From: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Date: Thu, 18 Feb 2016 15:47:13 +0000
Subject: ASoC: samsung: Use IRQ safe spin lock calls
From: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
commit 316fa9e09ad76e095b9d7e9350c628b918370a22 upstream.
Lockdep warns of a potential lock inversion, i2s->lock is held numerous
times whilst we are under the substream lock (snd_pcm_stream_lock). If
we use the IRQ unsafe spin lock calls, you can also end up locking
snd_pcm_stream_lock whilst under i2s->lock (if an IRQ happens whilst we
are holding i2s->lock). This could result in deadlock.
[ 18.147001] CPU0 CPU1
[ 18.151509] ---- ----
[ 18.156022] lock(&(&pri_dai->spinlock)->rlock);
[ 18.160701] local_irq_disable();
[ 18.166622] lock(&(&substream->self_group.lock)->rlock);
[ 18.174595] lock(&(&pri_dai->spinlock)->rlock);
[ 18.181806] <Interrupt>
[ 18.184408] lock(&(&substream->self_group.lock)->rlock);
[ 18.190045]
[ 18.190045] *** DEADLOCK ***
This patch changes to using the irq safe spinlock calls, to avoid this
issue.
Fixes: ce8bcdbb61d9 ("ASoC: samsung: i2s: Protect more registers with a spinlock")
Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Tested-by: Anand Moon <linux.amoon@xxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/soc/samsung/i2s.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -480,10 +480,11 @@ static int i2s_set_sysclk(struct snd_soc
unsigned int cdcon_mask = 1 << i2s_regs->cdclkcon_off;
unsigned int rsrc_mask = 1 << i2s_regs->rclksrc_off;
u32 mod, mask, val = 0;
+ unsigned long flags;
- spin_lock(i2s->lock);
+ spin_lock_irqsave(i2s->lock, flags);
mod = readl(i2s->addr + I2SMOD);
- spin_unlock(i2s->lock);
+ spin_unlock_irqrestore(i2s->lock, flags);
switch (clk_id) {
case SAMSUNG_I2S_OPCLK:
@@ -574,11 +575,11 @@ static int i2s_set_sysclk(struct snd_soc
return -EINVAL;
}
- spin_lock(i2s->lock);
+ spin_lock_irqsave(i2s->lock, flags);
mod = readl(i2s->addr + I2SMOD);
mod = (mod & ~mask) | val;
writel(mod, i2s->addr + I2SMOD);
- spin_unlock(i2s->lock);
+ spin_unlock_irqrestore(i2s->lock, flags);
return 0;
}
@@ -589,6 +590,7 @@ static int i2s_set_fmt(struct snd_soc_da
struct i2s_dai *i2s = to_info(dai);
int lrp_shift, sdf_shift, sdf_mask, lrp_rlow, mod_slave;
u32 mod, tmp = 0;
+ unsigned long flags;
lrp_shift = i2s->variant_regs->lrp_off;
sdf_shift = i2s->variant_regs->sdf_off;
@@ -648,7 +650,7 @@ static int i2s_set_fmt(struct snd_soc_da
return -EINVAL;
}
- spin_lock(i2s->lock);
+ spin_lock_irqsave(i2s->lock, flags);
mod = readl(i2s->addr + I2SMOD);
/*
* Don't change the I2S mode if any controller is active on this
@@ -656,7 +658,7 @@ static int i2s_set_fmt(struct snd_soc_da
*/
if (any_active(i2s) &&
((mod & (sdf_mask | lrp_rlow | mod_slave)) != tmp)) {
- spin_unlock(i2s->lock);
+ spin_unlock_irqrestore(i2s->lock, flags);
dev_err(&i2s->pdev->dev,
"%s:%d Other DAI busy\n", __func__, __LINE__);
return -EAGAIN;
@@ -665,7 +667,7 @@ static int i2s_set_fmt(struct snd_soc_da
mod &= ~(sdf_mask | lrp_rlow | mod_slave);
mod |= tmp;
writel(mod, i2s->addr + I2SMOD);
- spin_unlock(i2s->lock);
+ spin_unlock_irqrestore(i2s->lock, flags);
return 0;
}
@@ -675,6 +677,7 @@ static int i2s_hw_params(struct snd_pcm_
{
struct i2s_dai *i2s = to_info(dai);
u32 mod, mask = 0, val = 0;
+ unsigned long flags;
if (!is_secondary(i2s))
mask |= (MOD_DC2_EN | MOD_DC1_EN);
@@ -743,11 +746,11 @@ static int i2s_hw_params(struct snd_pcm_
return -EINVAL;
}
- spin_lock(i2s->lock);
+ spin_lock_irqsave(i2s->lock, flags);
mod = readl(i2s->addr + I2SMOD);
mod = (mod & ~mask) | val;
writel(mod, i2s->addr + I2SMOD);
- spin_unlock(i2s->lock);
+ spin_unlock_irqrestore(i2s->lock, flags);
samsung_asoc_init_dma_data(dai, &i2s->dma_playback, &i2s->dma_capture);
Patches currently in stable-queue which might be from ckeepax@xxxxxxxxxxxxxxxxxxxxxxxxxxx are
queue-4.4/asoc-samsung-use-irq-safe-spin-lock-calls.patch
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