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authorPeter Zijlstra <peterz@infradead.org>2020-09-30 11:49:37 +0200
committerIngo Molnar <mingo@kernel.org>2020-10-09 08:53:08 +0200
commit2bb8945bcc1a768f2bc402a16c9610bba8d5187d (patch)
treebf7547f8e6361941a5838adeba9d80c2e55825f4 /kernel/locking
parent583090b1b8232e6eae243a9009699666153a13a9 (diff)
lockdep: Fix usage_traceoverflow
Basically print_lock_class_header()'s for loop is out of sync with the the size of of ->usage_traces[]. Also clean things up a bit while at it, to avoid such mishaps in the future. Fixes: 23870f122768 ("locking/lockdep: Fix "USED" <- "IN-NMI" inversions") Reported-by: Qian Cai <cai@redhat.com> Debugged-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Qian Cai <cai@redhat.com> Link: https://lkml.kernel.org/r/20200930094937.GE2651@hirez.programming.kicks-ass.net
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/lockdep.c32
-rw-r--r--kernel/locking/lockdep_internals.h7
2 files changed, 20 insertions, 19 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 2facbbd146ec..a430fbb01eb1 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -585,6 +585,8 @@ static const char *usage_str[] =
#include "lockdep_states.h"
#undef LOCKDEP_STATE
[LOCK_USED] = "INITIAL USE",
+ [LOCK_USED_READ] = "INITIAL READ USE",
+ /* abused as string storage for verify_lock_unused() */
[LOCK_USAGE_STATES] = "IN-NMI",
};
#endif
@@ -1939,7 +1941,7 @@ static void print_lock_class_header(struct lock_class *class, int depth)
#endif
printk(KERN_CONT " {\n");
- for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
+ for (bit = 0; bit < LOCK_TRACE_STATES; bit++) {
if (class->usage_mask & (1 << bit)) {
int len = depth;
@@ -3969,7 +3971,7 @@ static int separate_irq_context(struct task_struct *curr,
static int mark_lock(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit)
{
- unsigned int old_mask, new_mask, ret = 1;
+ unsigned int new_mask, ret = 1;
if (new_bit >= LOCK_USAGE_STATES) {
DEBUG_LOCKS_WARN_ON(1);
@@ -3996,30 +3998,26 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
if (unlikely(hlock_class(this)->usage_mask & new_mask))
goto unlock;
- old_mask = hlock_class(this)->usage_mask;
hlock_class(this)->usage_mask |= new_mask;
- /*
- * Save one usage_traces[] entry and map both LOCK_USED and
- * LOCK_USED_READ onto the same entry.
- */
- if (new_bit == LOCK_USED || new_bit == LOCK_USED_READ) {
- if (old_mask & (LOCKF_USED | LOCKF_USED_READ))
- goto unlock;
- new_bit = LOCK_USED;
+ if (new_bit < LOCK_TRACE_STATES) {
+ if (!(hlock_class(this)->usage_traces[new_bit] = save_trace()))
+ return 0;
}
- if (!(hlock_class(this)->usage_traces[new_bit] = save_trace()))
- return 0;
-
switch (new_bit) {
+ case 0 ... LOCK_USED-1:
+ ret = mark_lock_irq(curr, this, new_bit);
+ if (!ret)
+ return 0;
+ break;
+
case LOCK_USED:
debug_atomic_dec(nr_unused_locks);
break;
+
default:
- ret = mark_lock_irq(curr, this, new_bit);
- if (!ret)
- return 0;
+ break;
}
unlock:
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index b0be1560ed17..de49f9e1c11b 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -20,9 +20,12 @@ enum lock_usage_bit {
#undef LOCKDEP_STATE
LOCK_USED,
LOCK_USED_READ,
- LOCK_USAGE_STATES
+ LOCK_USAGE_STATES,
};
+/* states after LOCK_USED_READ are not traced and printed */
+static_assert(LOCK_TRACE_STATES == LOCK_USAGE_STATES);
+
#define LOCK_USAGE_READ_MASK 1
#define LOCK_USAGE_DIR_MASK 2
#define LOCK_USAGE_STATE_MASK (~(LOCK_USAGE_READ_MASK | LOCK_USAGE_DIR_MASK))
@@ -121,7 +124,7 @@ static const unsigned long LOCKF_USED_IN_IRQ_READ =
extern struct list_head all_lock_classes;
extern struct lock_chain lock_chains[];
-#define LOCK_USAGE_CHARS (1+LOCK_USAGE_STATES/2)
+#define LOCK_USAGE_CHARS (2*XXX_LOCK_USAGE_STATES + 1)
extern void get_usage_chars(struct lock_class *class,
char usage[LOCK_USAGE_CHARS]);