diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2018-01-22 22:53:28 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-01-24 10:03:44 +0100 |
| commit | ce48c146495a1a50e48cdbfbfaba3e708be7c07c (patch) | |
| tree | 6aabd7d32c16454175afdb2a20352056d9beb71a | |
| parent | 1f07476ec143bbed7bf0b641749783b1094b4c4f (diff) | |
sched/core: Fix cpu.max vs. cpuhotplug deadlock
Tejun reported the following cpu-hotplug lock (percpu-rwsem) read recursion:
tg_set_cfs_bandwidth()
get_online_cpus()
cpus_read_lock()
cfs_bandwidth_usage_inc()
static_key_slow_inc()
cpus_read_lock()
Reported-by: Tejun Heo <tj@kernel.org>
Tested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180122215328.GP3397@worktop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | include/linux/jump_label.h | 7 | ||||
| -rw-r--r-- | kernel/jump_label.c | 12 | ||||
| -rw-r--r-- | kernel/sched/fair.c | 4 |
3 files changed, 18 insertions, 5 deletions
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index c7b368c734af..e0340ca08d98 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -160,6 +160,8 @@ extern void arch_jump_label_transform_static(struct jump_entry *entry, extern int jump_label_text_reserved(void *start, void *end); extern void static_key_slow_inc(struct static_key *key); extern void static_key_slow_dec(struct static_key *key); +extern void static_key_slow_inc_cpuslocked(struct static_key *key); +extern void static_key_slow_dec_cpuslocked(struct static_key *key); extern void jump_label_apply_nops(struct module *mod); extern int static_key_count(struct static_key *key); extern void static_key_enable(struct static_key *key); @@ -222,6 +224,9 @@ static inline void static_key_slow_dec(struct static_key *key) atomic_dec(&key->enabled); } +#define static_key_slow_inc_cpuslocked(key) static_key_slow_inc(key) +#define static_key_slow_dec_cpuslocked(key) static_key_slow_dec(key) + static inline int jump_label_text_reserved(void *start, void *end) { return 0; @@ -416,6 +421,8 @@ extern bool ____wrong_branch_error(void); #define static_branch_inc(x) static_key_slow_inc(&(x)->key) #define static_branch_dec(x) static_key_slow_dec(&(x)->key) +#define static_branch_inc_cpuslocked(x) static_key_slow_inc_cpuslocked(&(x)->key) +#define static_branch_dec_cpuslocked(x) static_key_slow_dec_cpuslocked(&(x)->key) /* * Normal usage; boolean enable/disable. diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 8594d24e4adc..b4517095db6a 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -79,7 +79,7 @@ int static_key_count(struct static_key *key) } EXPORT_SYMBOL_GPL(static_key_count); -static void static_key_slow_inc_cpuslocked(struct static_key *key) +void static_key_slow_inc_cpuslocked(struct static_key *key) { int v, v1; @@ -180,7 +180,7 @@ void static_key_disable(struct static_key *key) } EXPORT_SYMBOL_GPL(static_key_disable); -static void static_key_slow_dec_cpuslocked(struct static_key *key, +static void __static_key_slow_dec_cpuslocked(struct static_key *key, unsigned long rate_limit, struct delayed_work *work) { @@ -211,7 +211,7 @@ static void __static_key_slow_dec(struct static_key *key, struct delayed_work *work) { cpus_read_lock(); - static_key_slow_dec_cpuslocked(key, rate_limit, work); + __static_key_slow_dec_cpuslocked(key, rate_limit, work); cpus_read_unlock(); } @@ -229,6 +229,12 @@ void static_key_slow_dec(struct static_key *key) } EXPORT_SYMBOL_GPL(static_key_slow_dec); +void static_key_slow_dec_cpuslocked(struct static_key *key) +{ + STATIC_KEY_CHECK_USE(key); + __static_key_slow_dec_cpuslocked(key, 0, NULL); +} + void static_key_slow_dec_deferred(struct static_key_deferred *key) { STATIC_KEY_CHECK_USE(key); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 2fe3aa853e4d..26a71ebcd3c2 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4365,12 +4365,12 @@ static inline bool cfs_bandwidth_used(void) void cfs_bandwidth_usage_inc(void) { - static_key_slow_inc(&__cfs_bandwidth_used); + static_key_slow_inc_cpuslocked(&__cfs_bandwidth_used); } void cfs_bandwidth_usage_dec(void) { - static_key_slow_dec(&__cfs_bandwidth_used); + static_key_slow_dec_cpuslocked(&__cfs_bandwidth_used); } #else /* HAVE_JUMP_LABEL */ static bool cfs_bandwidth_used(void) |