locking fixes

Linus,

Please pull the latest locking-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking-urgent-for-linus

# HEAD: b50776ae011cfd26df3cc2b4af8b2dc3b683e553 locking/atomics: Don't assume that scripts are executable

A lockdep warning fix and a script execution fix when atomics are generated.

Thanks,

Ingo

------------------>
Andrew Morton (1):
locking/atomics: Don't assume that scripts are executable

Bart Van Assche (1):
locking/lockdep: Make lockdep_unregister_key() honor 'debug_locks' again

 kernel/locking/lockdep.c      | 9 +++++----
 scripts/atomic/gen-atomics.sh | 2 +-
 2 files changed, 6 insertions(+), 5 deletions(-)

index e16766ff184b..e221be724fe8 100644
@@ -4907,8 +4907,9 @@ void lockdep_unregister_key(struct lock_class_key *key)
 		return;
 
 	raw_local_irq_save(flags);
-	arch_spin_lock(&lockdep_lock);
-	current->lockdep_recursion = 1;
+	if (!graph_lock())
+		goto out_irq;
+
 	pf = get_pending_free();
 	hlist_for_each_entry_rcu(k, hash_head, hash_entry) {
 		if (k == key) {

@@ -4920,8 +4921,8 @@ void lockdep_unregister_key(struct lock_class_key *key)
 	WARN_ON_ONCE(!found);
 	__lockdep_free_key_range(pf, key, 1);
 	call_rcu_zapped(pf);
-	current->lockdep_recursion = 0;
-	arch_spin_unlock(&lockdep_lock);
+	graph_unlock();
+out_irq:
 	raw_local_irq_restore(flags);
 
 	/* Wait until is_dynamic_key() has finished accessing k->hash_entry. */

index 27400b0cd732..000dc6437893 100644
@@ -13,7 +13,7 @@ gen-atomic-long.sh              asm-generic/atomic-long.h
 gen-atomic-fallback.sh          linux/atomic-fallback.h
 EOF
 while read script header; do
-	${ATOMICDIR}/${script} ${ATOMICTBL} > ${LINUXDIR}/include/${header}
+	/bin/sh ${ATOMICDIR}/${script} ${ATOMICTBL} > ${LINUXDIR}/include/${header}
 	HASH="$(sha1sum ${LINUXDIR}/include/${header})"
 	HASH="${HASH%% *}"
 	printf "// %s\n" "${HASH}" >> ${LINUXDIR}/include/${header}

Hmm. I've pulled this, but looking at it, I think it's worth noting something...

Yeah, agreed that this is all a bit weird. The status quo right now is:

- scripts/atomic/gen-atomics.sh is a completely standalone, external script which isn't even tied into any Makefile mechanism to build the kernel.

- To generate the headers one has to explicitly call scripts/atomic/gen-atomics.sh, and it's not even executable, so the incantation is even more weird:

         $ . scripts/atomic/gen-atomics.sh

So I agree that the UI of all this should be improved, I suspect we should do the following improvements:

- make gen-atomics.sh executable

- add a "make headers_gen_atomics" target to the main Makefile

- call gen-atomics.sh via the build system and thus have access to $CONFIG_SHELL and such and don't have assumptions about the shell environment.

Arguably /bin/sh tends to exist during the build, everywhere. What usually results in the use of CONFIG_SHELL isn't /bin/sh per se but specific shell variant assumptions such as /bin/bash and the resulting occasional Bashism in the scripts - there are systems with non-bash shells by default and so.

Thanks,

Ingo