From ce48c146495a1a50e48cdbfbfaba3e708be7c07c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 22 Jan 2018 22:53:28 +0100 Subject: 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 Tested-by: Tejun Heo Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20180122215328.GP3397@worktop Signed-off-by: Ingo Molnar --- include/linux/jump_label.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/jump_label.h') 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. -- cgit