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| H A D | stm32_sai_sub.c | diff a14bf98c045bf119b7e779f186528e38c6428830 Thu Jan 09 09:32:54 CET 2020 Olivier Moysan <olivier.moysan@st.com> ASoC: stm32: sai: fix possible circular locking
In current driver, locks can be taken as follows:
- Register access: take a lock on regmap config and then on clock.
- Master clock provider: take a lock on clock and then on regmap config.
This can lead to the circular locking summarized below.
Remove peripheral clock management through regmap framework, and manage
peripheral clock in driver instead. On register access, lock on clock
is taken first, which allows to avoid possible locking issue.
[ 6696.561513] ======================================================
[ 6696.567670] WARNING: possible circular locking dependency detected
[ 6696.573842] 4.19.49 #866 Not tainted
[ 6696.577397] ------------------------------------------------------
[ 6696.583566] pulseaudio/6439 is trying to acquire lock:
[ 6696.588697] 87b0a25b (enable_lock){..-.}, at: clk_enable_lock+0x64/0x128
[ 6696.595377]
[ 6696.595377] but task is already holding lock:
[ 6696.601197] d858f825 (stm32_sai_sub:1342:(sai->regmap_config)->lock){....}
...
[ 6696.812513] Possible unsafe locking scenario:
[ 6696.812513]
[ 6696.818418] CPU0 CPU1
[ 6696.822935] ---- ----
[ 6696.827451] lock(stm32_sai_sub:1342:(sai->regmap_config)->lock);
[ 6696.833618] lock(enable_lock);
[ 6696.839350] lock(stm32_sai_sub:1342:
(sai->regmap_config)->lock);
[ 6696.848035] lock(enable_lock);
Fixes: 03e78a242a15 ("ASoC: stm32: sai: add h7 support")
Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Link: https://lore.kernel.org/r/20200109083254.478-1-olivier.moysan@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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