Re: [PATCH 4/5] ath10k: detect conf_mutex held ath10k_drain_tx() calls
From: Kalle Valo <hidden>
Date: 2021-02-10 08:29:01
Also in:
linux-wireless, lkml
Shuah Khan [off-list ref] writes:
ath10k_drain_tx() must not be called with conf_mutex held as workers can use that also. Add check to detect conf_mutex held calls. Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
The commit log does not answer to "Why?". How did you find this? What actual problem are you trying to solve?
quoted hunk
--- drivers/net/wireless/ath/ath10k/mac.c | 1 + 1 file changed, 1 insertion(+)diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c index 53f92945006f..3545ce7dce0a 100644 --- a/drivers/net/wireless/ath/ath10k/mac.c +++ b/drivers/net/wireless/ath/ath10k/mac.c@@ -4566,6 +4566,7 @@ static void ath10k_mac_op_wake_tx_queue(struct ieee80211_hw *hw, /* Must not be called with conf_mutex held as workers can use that also. */ void ath10k_drain_tx(struct ath10k *ar) { + WARN_ON(lockdep_is_held(&ar->conf_mutex));
Empty line after WARN_ON().
Shouldn't this check debug_locks similarly lockdep_assert_held() does?
#define lockdep_assert_held(l) do { \
WARN_ON(debug_locks && !lockdep_is_held(l)); \
} while (0)
And I suspect you need #ifdef CONFIG_LOCKDEP which should fix the kbuild
bot error.
But honestly I would prefer to have lockdep_assert_not_held() in
include/linux/lockdep.h, much cleaner that way. Also
i915_gem_object_lookup_rcu() could then use the same macro.
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