Commit b019b4a6 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'timers-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull timer fix from Thomas Gleixner:
 "A single fix for posix CPU timers.

  When a thread is cloned, the posix CPU timers are not inherited.

  If the parent has a CPU timer armed the corresponding tick dependency
  in the tasks tick_dep_mask is set and copied to the new thread, which
  means the new thread and all decendants will prevent the system to go
  into full NOHZ operation.

  Clear the tick dependency mask in copy_process() to fix this"

* tag 'timers-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  posix-cpu-timers: Clear TICK_DEP_BIT_POSIX_TIMER on clone
parents 33e83ffe b5413156

include/linux/tick.h

+8 −0
Original line number Diff line number Diff line
@@ -251,12 +251,19 @@ static inline void tick_dep_set_task(struct task_struct *tsk, 
	if (tick_nohz_full_enabled())

		tick_nohz_dep_set_task(tsk, bit);

}



static inline void tick_dep_clear_task(struct task_struct *tsk,

				       enum tick_dep_bits bit)

{

	if (tick_nohz_full_enabled())

		tick_nohz_dep_clear_task(tsk, bit);

}



static inline void tick_dep_init_task(struct task_struct *tsk)

{

	atomic_set(&tsk->tick_dep_mask, 0);

}



static inline void tick_dep_set_signal(struct task_struct *tsk,

				       enum tick_dep_bits bit)

{
@@ -290,6 +297,7 @@ static inline void tick_dep_set_task(struct task_struct *tsk, 
				     enum tick_dep_bits bit) { }

static inline void tick_dep_clear_task(struct task_struct *tsk,

				       enum tick_dep_bits bit) { }

static inline void tick_dep_init_task(struct task_struct *tsk) { }

static inline void tick_dep_set_signal(struct task_struct *tsk,

				       enum tick_dep_bits bit) { }

static inline void tick_dep_clear_signal(struct signal_struct *signal,

kernel/fork.c

+2 −0
Original line number Diff line number Diff line
@@ -105,6 +105,7 @@ 
#include <linux/rseq.h>

#include <uapi/linux/pidfd.h>

#include <linux/pidfs.h>

#include <linux/tick.h>



#include <asm/pgalloc.h>

#include <linux/uaccess.h>
@@ -2292,6 +2293,7 @@ __latent_entropy struct task_struct *copy_process( 
	acct_clear_integrals(p);



	posix_cputimers_init(&p->posix_cputimers);

	tick_dep_init_task(p);



	p->io_context = NULL;

	audit_set_context(p, NULL);