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author | Waiman Long <longman@redhat.com> | 2019-05-21 16:48:43 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-26 09:14:07 +0200 |
commit | 366ae49ed78ccdd66df37c7dcd3be7710511b2cc (patch) | |
tree | 2d24799a85f96d278c5fb64e11f919ae7d18c97a /include/linux | |
parent | 1fb3ce14f28d729af550e731254ff77a77ccce1a (diff) | |
download | linux-stable-366ae49ed78ccdd66df37c7dcd3be7710511b2cc.tar.gz linux-stable-366ae49ed78ccdd66df37c7dcd3be7710511b2cc.tar.bz2 linux-stable-366ae49ed78ccdd66df37c7dcd3be7710511b2cc.zip |
rcu: Force inlining of rcu_read_lock()
[ Upstream commit 6da9f775175e516fc7229ceaa9b54f8f56aa7924 ]
When debugging options are turned on, the rcu_read_lock() function
might not be inlined. This results in lockdep's print_lock() function
printing "rcu_read_lock+0x0/0x70" instead of rcu_read_lock()'s caller.
For example:
[ 10.579995] =============================
[ 10.584033] WARNING: suspicious RCU usage
[ 10.588074] 4.18.0.memcg_v2+ #1 Not tainted
[ 10.593162] -----------------------------
[ 10.597203] include/linux/rcupdate.h:281 Illegal context switch in
RCU read-side critical section!
[ 10.606220]
[ 10.606220] other info that might help us debug this:
[ 10.606220]
[ 10.614280]
[ 10.614280] rcu_scheduler_active = 2, debug_locks = 1
[ 10.620853] 3 locks held by systemd/1:
[ 10.624632] #0: (____ptrval____) (&type->i_mutex_dir_key#5){.+.+}, at: lookup_slow+0x42/0x70
[ 10.633232] #1: (____ptrval____) (rcu_read_lock){....}, at: rcu_read_lock+0x0/0x70
[ 10.640954] #2: (____ptrval____) (rcu_read_lock){....}, at: rcu_read_lock+0x0/0x70
These "rcu_read_lock+0x0/0x70" strings are not providing any useful
information. This commit therefore forces inlining of the rcu_read_lock()
function so that rcu_read_lock()'s caller is instead shown.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/rcupdate.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index e102c5bccbb9..68cbe111420b 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -620,7 +620,7 @@ static inline void rcu_preempt_sleep_check(void) { } * read-side critical sections may be preempted and they may also block, but * only when acquiring spinlocks that are subject to priority inheritance. */ -static inline void rcu_read_lock(void) +static __always_inline void rcu_read_lock(void) { __rcu_read_lock(); __acquire(RCU); |