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 locking fixes from Ingo Molnar:
"Two lockdep fixes for bugs introduced by the cross-release dependency
tracking feature - plus a commit that disables it because performance
regressed in an absymal fashion on some systems"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/lockdep: Disable cross-release features for now
locking/selftest: Avoid false BUG report
locking/lockdep: Fix stacktrace mess
+25
-31
+21
-29
kernel/locking/lockdep.c
+21
-29
kernel/locking/lockdep.c
···
1873
1873
struct held_lock *next, int distance, struct stack_trace *trace,
1874
1874
int (*save)(struct stack_trace *trace))
1875
1875
{
1876
-
struct lock_list *entry;
1877
-
int ret;
1878
-
struct lock_list this;
1879
1876
struct lock_list *uninitialized_var(target_entry);
1877
+
struct lock_list *entry;
1878
+
struct lock_list this;
1879
+
int ret;
1880
1880
1881
1881
/*
1882
1882
* Prove that the new <prev> -> <next> dependency would not
···
1890
1890
this.class = hlock_class(next);
1891
1891
this.parent = NULL;
1892
1892
ret = check_noncircular(&this, hlock_class(prev), &target_entry);
1893
-
if (unlikely(!ret))
1893
+
if (unlikely(!ret)) {
1894
+
if (!trace->entries) {
1895
+
/*
1896
+
* If @save fails here, the printing might trigger
1897
+
* a WARN but because of the !nr_entries it should
1898
+
* not do bad things.
1899
+
*/
1900
+
save(trace);
1901
+
}
1894
1902
return print_circular_bug(&this, target_entry, next, prev, trace);
1903
+
}
1895
1904
else if (unlikely(ret < 0))
1896
1905
return print_bfs_bug(ret);
1897
1906
···
1947
1938
return print_bfs_bug(ret);
1948
1939
1949
1940
1950
-
if (save && !save(trace))
1941
+
if (!trace->entries && !save(trace))
1951
1942
return 0;
1952
1943
1953
1944
/*
···
1967
1958
if (!ret)
1968
1959
return 0;
1969
1960
1970
-
/*
1971
-
* Debugging printouts:
1972
-
*/
1973
-
if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
1974
-
graph_unlock();
1975
-
printk("\n new dependency: ");
1976
-
print_lock_name(hlock_class(prev));
1977
-
printk(KERN_CONT " => ");
1978
-
print_lock_name(hlock_class(next));
1979
-
printk(KERN_CONT "\n");
1980
-
dump_stack();
1981
-
if (!graph_lock())
1982
-
return 0;
1983
-
}
1984
1961
return 2;
1985
1962
}
1986
1963
···
1981
1986
{
1982
1987
int depth = curr->lockdep_depth;
1983
1988
struct held_lock *hlock;
1984
-
struct stack_trace trace;
1985
-
int (*save)(struct stack_trace *trace) = save_trace;
1989
+
struct stack_trace trace = {
1990
+
.nr_entries = 0,
1991
+
.max_entries = 0,
1992
+
.entries = NULL,
1993
+
.skip = 0,
1994
+
};
1986
1995
1987
1996
/*
1988
1997
* Debugging checks.
···
2017
2018
*/
2018
2019
if (hlock->read != 2 && hlock->check) {
2019
2020
int ret = check_prev_add(curr, hlock, next,
2020
-
distance, &trace, save);
2021
+
distance, &trace, save_trace);
2021
2022
if (!ret)
2022
2023
return 0;
2023
-
2024
-
/*
2025
-
* Stop saving stack_trace if save_trace() was
2026
-
* called at least once:
2027
-
*/
2028
-
if (save && ret == 2)
2029
-
save = NULL;
2030
2024
2031
2025
/*
2032
2026
* Stop after the first non-trylock entry,
+2
-2
lib/Kconfig.debug
+2
-2
lib/Kconfig.debug
···
1092
1092
select DEBUG_MUTEXES
1093
1093
select DEBUG_RT_MUTEXES if RT_MUTEXES
1094
1094
select DEBUG_LOCK_ALLOC
1095
-
select LOCKDEP_CROSSRELEASE
1096
-
select LOCKDEP_COMPLETIONS
1095
+
select LOCKDEP_CROSSRELEASE if BROKEN
1096
+
select LOCKDEP_COMPLETIONS if BROKEN
1097
1097
select TRACE_IRQFLAGS
1098
1098
default n
1099
1099
help
+2
lib/locking-selftest.c
+2
lib/locking-selftest.c
···
2031
2031
print_testname("mixed read-lock/lock-write ABBA");
2032
2032
pr_cont(" |");
2033
2033
dotest(rlock_ABBA1, FAILURE, LOCKTYPE_RWLOCK);
2034
+
#ifdef CONFIG_PROVE_LOCKING
2034
2035
/*
2035
2036
* Lockdep does indeed fail here, but there's nothing we can do about
2036
2037
* that now. Don't kill lockdep for it.
2037
2038
*/
2038
2039
unexpected_testcase_failures--;
2040
+
#endif
2039
2041
2040
2042
pr_cont(" |");
2041
2043
dotest(rwsem_ABBA1, FAILURE, LOCKTYPE_RWSEM);