From: Shuah Khan <skhan@linuxfoundation.org>
To: peterz@infradead.org, mingo@redhat.com, will@kernel.org,
kvalo@codeaurora.org, davem@davemloft.net, kuba@kernel.org
Cc: netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
linux-kernel@vger.kernel.org, ath10k@lists.infradead.org,
Shuah Khan <skhan@linuxfoundation.org>
Subject: [PATCH v3 0/3] Add lockdep_assert_not_held()
Date: Fri, 26 Feb 2021 17:06:57 -0700 [thread overview]
Message-ID: <cover.1614383025.git.skhan@linuxfoundation.org> (raw)
Some kernel functions must not be called holding a specific lock. Doing
so could lead to locking problems. Currently these routines call
lock_is_held() to check for lock hold followed by WARN_ON.
Adding a common lockdep interface will help reduce the duplication of this
logic in the rest of the kernel.
Add lockdep_assert_not_held() to be used in these functions to detect
incorrect calls while holding a lock.
lockdep_assert_not_held() provides the opposite functionality of
lockdep_assert_held() which is used to assert calls that require
holding a specific lock.
The need for lockdep_assert_not_held() came up in a discussion on
ath10k patch. ath10k_drain_tx() and i915_vma_pin_ww() are examples
of functions that can use lockdep_assert_not_held().
Link: https://lore.kernel.org/lkml/37a29c383bff2fb1605241ee6c7c9be3784fb3c6.1613171185.git.skhan@linuxfoundation.org/
Link: https://lore.kernel.org/linux-wireless/871rdmu9z9.fsf@codeaurora.org/
This patch series adds lockdep_assert_not_held() and uses it in the
second patch in ath10k_drain_tx() function.
Changes since v2:
-- Fixed coding style issues
-- Patch 2 uses new lock states in __lock_is_held() and
lock_is_held_type
Patch 1 incorporates suggestions from Peter Zijlstra on v1 series
to avoid misfires when lockdep_off() is employed.
Patch 2 Johannes Berg's suggestions as it make it easier to read and
maintain the lock states. These are defines and a enum to avoid changes
to lock_is_held_type() and lockdep_is_held() return types.
Patch 2 is a separate patch because it adds defines to lockdep.h and
kernel/locking/lockdep.c now includes lockdep.h - decided make this
a separate patch just in case issues related to header dependencies
pop up. I can combine Patches 1&2 if that is preferred.
Patch 3 uses the new interface in ath10k_drain_tx() function. Added
Kalle Valo's Ack from v1 for this change.
Tested on the mainline from yesterday.
Shuah Khan (3):
lockdep: add lockdep_assert_not_held()
lockdep: add lockdep lock state defines
ath10k: detect conf_mutex held ath10k_drain_tx() calls
drivers/net/wireless/ath/ath10k/mac.c | 2 ++
include/linux/lockdep.h | 18 +++++++++++++++---
kernel/locking/lockdep.c | 15 ++++++++++-----
3 files changed, 27 insertions(+), 8 deletions(-)
--
2.27.0
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next reply other threads:[~2021-02-27 0:07 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-27 0:06 Shuah Khan [this message]
2021-02-27 0:06 ` [PATCH v3 1/3] lockdep: add lockdep_assert_not_held() Shuah Khan
2021-02-27 0:06 ` [PATCH v3 2/3] lockdep: add lockdep lock state defines Shuah Khan
2021-02-27 0:07 ` [PATCH v3 3/3] ath10k: detect conf_mutex held ath10k_drain_tx() calls Shuah Khan
2021-03-01 8:38 ` [PATCH v3 0/3] Add lockdep_assert_not_held() Peter Zijlstra
2021-03-01 8:45 ` Kalle Valo
2021-03-01 9:36 ` Peter Zijlstra
2021-03-01 11:02 ` Kalle Valo
2021-03-01 16:04 ` Shuah Khan
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