Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull lockdep fix from Thomas Gleixner:
"A single fix for the stack trace caching logic in lockdep, where the
duplicate avoidance managed to store no back trace at all"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/lockdep: Fix stack trace caching logic
+10
-6
+10
-6
kernel/locking/lockdep.c
+10
-6
kernel/locking/lockdep.c
···
1822
1822
*/
1823
1823
static int
1824
1824
check_prev_add(struct task_struct *curr, struct held_lock *prev,
1825
-
struct held_lock *next, int distance, int trylock_loop)
1825
+
struct held_lock *next, int distance, int *stack_saved)
1826
1826
{
1827
1827
struct lock_list *entry;
1828
1828
int ret;
···
1883
1883
}
1884
1884
}
1885
1885
1886
-
if (!trylock_loop && !save_trace(&trace))
1887
-
return 0;
1886
+
if (!*stack_saved) {
1887
+
if (!save_trace(&trace))
1888
+
return 0;
1889
+
*stack_saved = 1;
1890
+
}
1888
1891
1889
1892
/*
1890
1893
* Ok, all validations passed, add the new lock
···
1910
1907
* Debugging printouts:
1911
1908
*/
1912
1909
if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
1910
+
/* We drop graph lock, so another thread can overwrite trace. */
1911
+
*stack_saved = 0;
1913
1912
graph_unlock();
1914
1913
printk("\n new dependency: ");
1915
1914
print_lock_name(hlock_class(prev));
···
1934
1929
check_prevs_add(struct task_struct *curr, struct held_lock *next)
1935
1930
{
1936
1931
int depth = curr->lockdep_depth;
1937
-
int trylock_loop = 0;
1932
+
int stack_saved = 0;
1938
1933
struct held_lock *hlock;
1939
1934
1940
1935
/*
···
1961
1956
*/
1962
1957
if (hlock->read != 2 && hlock->check) {
1963
1958
if (!check_prev_add(curr, hlock, next,
1964
-
distance, trylock_loop))
1959
+
distance, &stack_saved))
1965
1960
return 0;
1966
1961
/*
1967
1962
* Stop after the first non-trylock entry,
···
1984
1979
if (curr->held_locks[depth].irq_context !=
1985
1980
curr->held_locks[depth-1].irq_context)
1986
1981
break;
1987
-
trylock_loop = 1;
1988
1982
}
1989
1983
return 1;
1990
1984
out_bug: