[GIT PULL] locking fixes

From: Ingo Molnar
Date: Fri Sep 22 2023 - 06:12:15 EST



Linus,

Please pull the latest locking/urgent git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-urgent-2023-09-22

# HEAD: 41b43b6c6e30a832c790b010a06772e793bca193 locking/seqlock: Do the lockdep annotation before locking in do_write_seqcount_begin_nested()

Fix a include/linux/atomic/atomic-arch-fallback.h breakage that generated
incorrect code, and fix a lockdep reporting race that may result in lockups.

Thanks,

Ingo

------------------>
Mark Rutland (1):
locking/atomic: scripts: fix fallback ifdeffery

Sebastian Andrzej Siewior (1):
locking/seqlock: Do the lockdep annotation before locking in do_write_seqcount_begin_nested()


include/linux/atomic/atomic-arch-fallback.h | 10 +---------
include/linux/seqlock.h | 2 +-
scripts/atomic/gen-atomic-fallback.sh | 2 +-
3 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/include/linux/atomic/atomic-arch-fallback.h b/include/linux/atomic/atomic-arch-fallback.h
index 18f5744dfb5d..b83ef19da13d 100644
--- a/include/linux/atomic/atomic-arch-fallback.h
+++ b/include/linux/atomic/atomic-arch-fallback.h
@@ -459,8 +459,6 @@ raw_atomic_read_acquire(const atomic_t *v)
{
#if defined(arch_atomic_read_acquire)
return arch_atomic_read_acquire(v);
-#elif defined(arch_atomic_read)
- return arch_atomic_read(v);
#else
int ret;

@@ -508,8 +506,6 @@ raw_atomic_set_release(atomic_t *v, int i)
{
#if defined(arch_atomic_set_release)
arch_atomic_set_release(v, i);
-#elif defined(arch_atomic_set)
- arch_atomic_set(v, i);
#else
if (__native_word(atomic_t)) {
smp_store_release(&(v)->counter, i);
@@ -2575,8 +2571,6 @@ raw_atomic64_read_acquire(const atomic64_t *v)
{
#if defined(arch_atomic64_read_acquire)
return arch_atomic64_read_acquire(v);
-#elif defined(arch_atomic64_read)
- return arch_atomic64_read(v);
#else
s64 ret;

@@ -2624,8 +2618,6 @@ raw_atomic64_set_release(atomic64_t *v, s64 i)
{
#if defined(arch_atomic64_set_release)
arch_atomic64_set_release(v, i);
-#elif defined(arch_atomic64_set)
- arch_atomic64_set(v, i);
#else
if (__native_word(atomic64_t)) {
smp_store_release(&(v)->counter, i);
@@ -4657,4 +4649,4 @@ raw_atomic64_dec_if_positive(atomic64_t *v)
}

#endif /* _LINUX_ATOMIC_FALLBACK_H */
-// 202b45c7db600ce36198eb1f1fc2c2d5268ace2d
+// 2fdd6702823fa842f9cea57a002e6e4476ae780c
diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 987a59d977c5..e9bd2f65d7f4 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -512,8 +512,8 @@ do { \

static inline void do_write_seqcount_begin_nested(seqcount_t *s, int subclass)
{
- do_raw_write_seqcount_begin(s);
seqcount_acquire(&s->dep_map, subclass, 0, _RET_IP_);
+ do_raw_write_seqcount_begin(s);
}

/**
diff --git a/scripts/atomic/gen-atomic-fallback.sh b/scripts/atomic/gen-atomic-fallback.sh
index c0c8a85d7c81..a45154cefa48 100755
--- a/scripts/atomic/gen-atomic-fallback.sh
+++ b/scripts/atomic/gen-atomic-fallback.sh
@@ -102,7 +102,7 @@ gen_proto_order_variant()
fi

# Allow ACQUIRE/RELEASE/RELAXED ops to be defined in terms of FULL ops
- if [ ! -z "${order}" ]; then
+ if [ ! -z "${order}" ] && ! meta_is_implicitly_relaxed "${meta}"; then
printf "#elif defined(arch_${basename})\n"
printf "\t${retstmt}arch_${basename}(${args});\n"
fi