linux-stable/include/linux/profile.h
Tetsuo Handa 0a7fbde518 profiling: remove profile=sleep support
commit b88f55389a upstream.

The kernel sleep profile is no longer working due to a recursive locking
bug introduced by commit 42a20f86dc ("sched: Add wrapper for get_wchan()
to keep task blocked")

Booting with the 'profile=sleep' kernel command line option added or
executing

  # echo -n sleep > /sys/kernel/profiling

after boot causes the system to lock up.

Lockdep reports

  kthreadd/3 is trying to acquire lock:
  ffff93ac82e08d58 (&p->pi_lock){....}-{2:2}, at: get_wchan+0x32/0x70

  but task is already holding lock:
  ffff93ac82e08d58 (&p->pi_lock){....}-{2:2}, at: try_to_wake_up+0x53/0x370

with the call trace being

   lock_acquire+0xc8/0x2f0
   get_wchan+0x32/0x70
   __update_stats_enqueue_sleeper+0x151/0x430
   enqueue_entity+0x4b0/0x520
   enqueue_task_fair+0x92/0x6b0
   ttwu_do_activate+0x73/0x140
   try_to_wake_up+0x213/0x370
   swake_up_locked+0x20/0x50
   complete+0x2f/0x40
   kthread+0xfb/0x180

However, since nobody noticed this regression for more than two years,
let's remove 'profile=sleep' support based on the assumption that nobody
needs this functionality.

Fixes: 42a20f86dc ("sched: Add wrapper for get_wchan() to keep task blocked")
Cc: stable@vger.kernel.org # v5.16+
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-19 05:45:39 +02:00

135 lines
2.6 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_PROFILE_H
#define _LINUX_PROFILE_H
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/cpumask.h>
#include <linux/cache.h>
#include <asm/errno.h>
#define CPU_PROFILING 1
#define SCHED_PROFILING 2
#define KVM_PROFILING 4
struct proc_dir_entry;
struct notifier_block;
#if defined(CONFIG_PROFILING) && defined(CONFIG_PROC_FS)
void create_prof_cpu_mask(void);
int create_proc_profile(void);
#else
static inline void create_prof_cpu_mask(void)
{
}
static inline int create_proc_profile(void)
{
return 0;
}
#endif
enum profile_type {
PROFILE_TASK_EXIT,
PROFILE_MUNMAP
};
#ifdef CONFIG_PROFILING
extern int prof_on __read_mostly;
/* init basic kernel profiler */
int profile_init(void);
int profile_setup(char *str);
void profile_tick(int type);
int setup_profiling_timer(unsigned int multiplier);
/*
* Add multiple profiler hits to a given address:
*/
void profile_hits(int type, void *ip, unsigned int nr_hits);
/*
* Single profiler hit:
*/
static inline void profile_hit(int type, void *ip)
{
/*
* Speedup for the common (no profiling enabled) case:
*/
if (unlikely(prof_on == type))
profile_hits(type, ip, 1);
}
struct task_struct;
struct mm_struct;
/* task is in do_exit() */
void profile_task_exit(struct task_struct * task);
/* task is dead, free task struct ? Returns 1 if
* the task was taken, 0 if the task should be freed.
*/
int profile_handoff_task(struct task_struct * task);
/* sys_munmap */
void profile_munmap(unsigned long addr);
int task_handoff_register(struct notifier_block * n);
int task_handoff_unregister(struct notifier_block * n);
int profile_event_register(enum profile_type, struct notifier_block * n);
int profile_event_unregister(enum profile_type, struct notifier_block * n);
#else
#define prof_on 0
static inline int profile_init(void)
{
return 0;
}
static inline void profile_tick(int type)
{
return;
}
static inline void profile_hits(int type, void *ip, unsigned int nr_hits)
{
return;
}
static inline void profile_hit(int type, void *ip)
{
return;
}
static inline int task_handoff_register(struct notifier_block * n)
{
return -ENOSYS;
}
static inline int task_handoff_unregister(struct notifier_block * n)
{
return -ENOSYS;
}
static inline int profile_event_register(enum profile_type t, struct notifier_block * n)
{
return -ENOSYS;
}
static inline int profile_event_unregister(enum profile_type t, struct notifier_block * n)
{
return -ENOSYS;
}
#define profile_task_exit(a) do { } while (0)
#define profile_handoff_task(a) (0)
#define profile_munmap(a) do { } while (0)
#endif /* CONFIG_PROFILING */
#endif /* _LINUX_PROFILE_H */