[GIT pull] locking/urgent for v6.11-rc2

From: Thomas Gleixner
Date: Sun Aug 04 2024 - 09:06:01 EST


Linus,

please pull the latest locking/urgent branch from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-urgent-2024-08-04

up to: 224fa3552029: jump_label: Fix the fix, brown paper bags galore


Two fixes for locking and jump labels:

- Ensure that the atomic_cmpxchg() conditions are correct and evaluating
to true on any non-zero value except 1. The missing check of the
return value leads to inconsisted state of the jump label counter.

- Add a missing type conversion in the paravirt spinlock code which
makes loongson build again.


Thanks,

tglx

------------------>
Peter Zijlstra (1):
jump_label: Fix the fix, brown paper bags galore

Uros Bizjak (1):
locking/pvqspinlock: Correct the type of "old" variable in pv_kick_node()


kernel/jump_label.c | 4 ++--
kernel/locking/qspinlock_paravirt.h | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 4ad5ed8adf96..6dc76b590703 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -236,7 +236,7 @@ void static_key_disable_cpuslocked(struct static_key *key)
}

jump_label_lock();
- if (atomic_cmpxchg(&key->enabled, 1, 0))
+ if (atomic_cmpxchg(&key->enabled, 1, 0) == 1)
jump_label_update(key);
jump_label_unlock();
}
@@ -289,7 +289,7 @@ static void __static_key_slow_dec_cpuslocked(struct static_key *key)
return;

guard(mutex)(&jump_label_mutex);
- if (atomic_cmpxchg(&key->enabled, 1, 0))
+ if (atomic_cmpxchg(&key->enabled, 1, 0) == 1)
jump_label_update(key);
else
WARN_ON_ONCE(!static_key_slow_try_dec(key));
diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qspinlock_paravirt.h
index f5a36e67b593..ac2e22502741 100644
--- a/kernel/locking/qspinlock_paravirt.h
+++ b/kernel/locking/qspinlock_paravirt.h
@@ -357,7 +357,7 @@ static void pv_wait_node(struct mcs_spinlock *node, struct mcs_spinlock *prev)
static void pv_kick_node(struct qspinlock *lock, struct mcs_spinlock *node)
{
struct pv_node *pn = (struct pv_node *)node;
- enum vcpu_state old = vcpu_halted;
+ u8 old = vcpu_halted;
/*
* If the vCPU is indeed halted, advance its state to match that of
* pv_wait_node(). If OTOH this fails, the vCPU was running and will