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locking/lockdep: Improve noinstr vs errors 

Better handle the failure paths.

  vmlinux.o: warning: objtool: debug_locks_off()+0x23: call to console_verbose() leaves .noinstr.text section
  vmlinux.o: warning: objtool: debug_locks_off()+0x19: call to __kasan_check_write() leaves .noinstr.text section

  debug_locks_off+0x19/0x40:
  instrument_atomic_write at include/linux/instrumented.h:86
  (inlined by) __debug_locks_off at include/linux/debug_locks.h:17
  (inlined by) debug_locks_off at lib/debug_locks.c:41

Fixes: 6eebad1ad3 ("lockdep: __always_inline more for noinstr")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210621120120.784404944@infradead.org
This commit is contained in:
Peter Zijlstra 2021-06-21 13:12:38 +02:00 committed by Ingo Molnar
parent 1f008d46f1
commit 49faa77759
3 changed files with 6 additions and 2 deletions
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2
include/linux/debug_locks.h
View File

@ -27,8 +27,10 @@ extern int debug_locks_off(void);
int __ret = 0; \
\
if (!oops_in_progress && unlikely(c)) { \
instrumentation_begin(); \
if (debug_locks_off() && !debug_locks_silent) \
WARN(1, "DEBUG_LOCKS_WARN_ON(%s)", #c); \
instrumentation_end(); \
__ret = 1; \
} \
__ret; \

4
kernel/locking/lockdep.c
View File

@ -843,7 +843,7 @@ static int count_matching_names(struct lock_class *new_class)
}
/* used from NMI context -- must be lockless */
static __always_inline struct lock_class *
static noinstr struct lock_class *
look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)
{
struct lockdep_subclass_key *key;
@ -851,12 +851,14 @@ look_up_lock_class(const struct lockdep_map *lock, unsigned int subclass)
struct lock_class *class;
if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
instrumentation_begin();
debug_locks_off();
printk(KERN_ERR
"BUG: looking up invalid subclass: %u\n", subclass);
printk(KERN_ERR
"turning off the locking correctness validator.\n");
dump_stack();
instrumentation_end();
return NULL;
}

2
lib/debug_locks.c
View File

@ -36,7 +36,7 @@ EXPORT_SYMBOL_GPL(debug_locks_silent);
/*
* Generic 'turn off all lock debugging' function:
*/
noinstr int debug_locks_off(void)
int debug_locks_off(void)
{
if (debug_locks && __debug_locks_off()) {
if (!debug_locks_silent) {