[alsa-devel] [PATCH] ASoC: samsung: Prevent clk_get_rate() calls in atomic context
Sylwester Nawrocki
s.nawrocki at samsung.com
Thu Feb 7 15:20:41 CET 2019
This patch moves clk_get_rate() call from trigger() to hw_params()
callback to avoid calling sleeping clk API from atomic context
and prevent deadlock as indicated below.
Before this change clk_get_rate() was being called with same
spinlock held as the one passed to the clk API when registering
clocks exposed by the I2S driver.
[ 82.109780] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:908
[ 82.117009] in_atomic(): 1, irqs_disabled(): 128, pid: 1554, name: speaker-test
[ 82.124235] 3 locks held by speaker-test/1554:
[ 82.128653] #0: cc8c5328 (snd_pcm_link_rwlock){...-}, at: snd_pcm_stream_lock_irq+0x20/0x38
[ 82.137058] #1: ec9eda17 (&(&substream->self_group.lock)->rlock){..-.}, at: snd_pcm_ioctl+0x900/0x1268
[ 82.146417] #2: 6ac279bf (&(&pri_dai->spinlock)->rlock){..-.}, at: i2s_trigger+0x64/0x6d4
[ 82.154650] irq event stamp: 8144
[ 82.157949] hardirqs last enabled at (8143): [<c0a0f574>] _raw_read_unlock_irq+0x24/0x5c
[ 82.166089] hardirqs last disabled at (8144): [<c0a0f6a8>] _raw_read_lock_irq+0x18/0x58
[ 82.174063] softirqs last enabled at (8004): [<c01024e4>] __do_softirq+0x3a4/0x66c
[ 82.181688] softirqs last disabled at (7997): [<c012d730>] irq_exit+0x140/0x168
[ 82.188964] Preemption disabled at:
[ 82.188967] [<00000000>] (null)
[ 82.195728] CPU: 6 PID: 1554 Comm: speaker-test Not tainted 5.0.0-rc5-00192-ga6e6caca8f03 #191
[ 82.204302] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[ 82.210376] [<c0111a54>] (unwind_backtrace) from [<c010d8f4>] (show_stack+0x10/0x14)
[ 82.218084] [<c010d8f4>] (show_stack) from [<c09ef004>] (dump_stack+0x90/0xc8)
[ 82.225278] [<c09ef004>] (dump_stack) from [<c0152980>] (___might_sleep+0x22c/0x2c8)
[ 82.232990] [<c0152980>] (___might_sleep) from [<c0a0a2e4>] (__mutex_lock+0x28/0xa3c)
[ 82.240788] [<c0a0a2e4>] (__mutex_lock) from [<c0a0ad80>] (mutex_lock_nested+0x1c/0x24)
[ 82.248763] [<c0a0ad80>] (mutex_lock_nested) from [<c04923dc>] (clk_prepare_lock+0x78/0xec)
[ 82.257079] [<c04923dc>] (clk_prepare_lock) from [<c049538c>] (clk_core_get_rate+0xc/0x5c)
[ 82.265309] [<c049538c>] (clk_core_get_rate) from [<c0766b18>] (i2s_trigger+0x490/0x6d4)
[ 82.273369] [<c0766b18>] (i2s_trigger) from [<c074fec4>] (soc_pcm_trigger+0x100/0x140)
[ 82.281254] [<c074fec4>] (soc_pcm_trigger) from [<c07378a0>] (snd_pcm_do_start+0x2c/0x30)
[ 82.289400] [<c07378a0>] (snd_pcm_do_start) from [<c07376cc>] (snd_pcm_action_single+0x38/0x78)
[ 82.298065] [<c07376cc>] (snd_pcm_action_single) from [<c073a450>] (snd_pcm_ioctl+0x910/0x1268)
[ 82.306734] [<c073a450>] (snd_pcm_ioctl) from [<c0292344>] (do_vfs_ioctl+0x90/0x9ec)
[ 82.314443] [<c0292344>] (do_vfs_ioctl) from [<c0292cd4>] (ksys_ioctl+0x34/0x60)
[ 82.321808] [<c0292cd4>] (ksys_ioctl) from [<c0101000>] (ret_fast_syscall+0x0/0x28)
[ 82.329431] Exception stack(0xeb875fa8 to 0xeb875ff0)
[ 82.334459] 5fa0: 00033c18 b6e31000 00000004 00004142 00033d80 00033d80
[ 82.342605] 5fc0: 00033c18 b6e31000 00008000 00000036 00008000 00000000 beea38a8 00008000
[ 82.350748] 5fe0: b6e3142c beea384c b6da9a30 b6c9212c
[ 82.355789]
[ 82.357245] ======================================================
[ 82.363397] WARNING: possible circular locking dependency detected
[ 82.369551] 5.0.0-rc5-00192-ga6e6caca8f03 #191 Tainted: G W
[ 82.376395] ------------------------------------------------------
[ 82.382548] speaker-test/1554 is trying to acquire lock:
[ 82.387834] 6d2007f4 (prepare_lock){+.+.}, at: clk_prepare_lock+0x78/0xec
[ 82.394593]
[ 82.394593] but task is already holding lock:
[ 82.400398] 6ac279bf (&(&pri_dai->spinlock)->rlock){..-.}, at: i2s_trigger+0x64/0x6d4
[ 82.408197]
[ 82.408197] which lock already depends on the new lock.
[ 82.416343]
[ 82.416343] the existing dependency chain (in reverse order) is:
[ 82.423795]
[ 82.423795] -> #1 (&(&pri_dai->spinlock)->rlock){..-.}:
[ 82.430472] clk_mux_set_parent+0x34/0xb8
[ 82.434975] clk_core_set_parent_nolock+0x1c4/0x52c
[ 82.440347] clk_set_parent+0x38/0x6c
[ 82.444509] of_clk_set_defaults+0xc8/0x308
[ 82.449186] of_clk_add_provider+0x84/0xd0
[ 82.453779] samsung_i2s_probe+0x408/0x5f8
[ 82.458376] platform_drv_probe+0x48/0x98
[ 82.462879] really_probe+0x224/0x3f4
[ 82.467037] driver_probe_device+0x70/0x1c4
[ 82.471716] bus_for_each_drv+0x44/0x8c
[ 82.476049] __device_attach+0xa0/0x138
[ 82.480382] bus_probe_device+0x88/0x90
[ 82.484715] deferred_probe_work_func+0x6c/0xbc
[ 82.489741] process_one_work+0x200/0x740
[ 82.494246] worker_thread+0x2c/0x4c8
[ 82.498408] kthread+0x128/0x164
[ 82.502131] ret_from_fork+0x14/0x20
[ 82.506204] (null)
[ 82.508976]
[ 82.508976] -> #0 (prepare_lock){+.+.}:
[ 82.514264] __mutex_lock+0x60/0xa3c
[ 82.518336] mutex_lock_nested+0x1c/0x24
[ 82.522756] clk_prepare_lock+0x78/0xec
[ 82.527088] clk_core_get_rate+0xc/0x5c
[ 82.531421] i2s_trigger+0x490/0x6d4
[ 82.535494] soc_pcm_trigger+0x100/0x140
[ 82.539913] snd_pcm_do_start+0x2c/0x30
[ 82.544246] snd_pcm_action_single+0x38/0x78
[ 82.549012] snd_pcm_ioctl+0x910/0x1268
[ 82.553345] do_vfs_ioctl+0x90/0x9ec
[ 82.557417] ksys_ioctl+0x34/0x60
[ 82.561229] ret_fast_syscall+0x0/0x28
[ 82.565477] 0xbeea384c
[ 82.568421]
[ 82.568421] other info that might help us debug this:
[ 82.568421]
[ 82.576394] Possible unsafe locking scenario:
[ 82.576394]
[ 82.582285] CPU0 CPU1
[ 82.586792] ---- ----
[ 82.591297] lock(&(&pri_dai->spinlock)->rlock);
[ 82.595977] lock(prepare_lock);
[ 82.601782] lock(&(&pri_dai->spinlock)->rlock);
[ 82.608975] lock(prepare_lock);
[ 82.612268]
[ 82.612268] *** DEADLOCK ***
Fixes: 647d04f8e07a ("ASoC: samsung: i2s: Ensure the RCLK rate is properly determined")
Reported-by: Krzysztof Kozłowski <krzk at kernel.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki at samsung.com>
---
sound/soc/samsung/i2s.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index d6c62aa13041..ce00fe2f6aae 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -700,6 +700,7 @@ static int i2s_hw_params(struct snd_pcm_substream *substream,
{
struct i2s_dai *i2s = to_info(dai);
u32 mod, mask = 0, val = 0;
+ struct clk *rclksrc;
unsigned long flags;
WARN_ON(!pm_runtime_active(dai->dev));
@@ -782,6 +783,10 @@ static int i2s_hw_params(struct snd_pcm_substream *substream,
i2s->frmclk = params_rate(params);
+ rclksrc = i2s->clk_table[CLK_I2S_RCLK_SRC];
+ if (rclksrc && !IS_ERR(rclksrc))
+ i2s->rclk_srcrate = clk_get_rate(rclksrc);
+
return 0;
}
@@ -886,11 +891,6 @@ static int config_setup(struct i2s_dai *i2s)
return 0;
if (!(i2s->quirks & QUIRK_NO_MUXPSR)) {
- struct clk *rclksrc = i2s->clk_table[CLK_I2S_RCLK_SRC];
-
- if (rclksrc && !IS_ERR(rclksrc))
- i2s->rclk_srcrate = clk_get_rate(rclksrc);
-
psr = i2s->rclk_srcrate / i2s->frmclk / rfs;
writel(((psr - 1) << 8) | PSR_PSREN, i2s->addr + I2SPSR);
dev_dbg(&i2s->pdev->dev,
--
2.20.1
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