diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index a1147e5dd245..9178d5cc0b01 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -189,6 +189,10 @@ static inline void ptrace_init_task(struct task_struct *child, bool ptrace) child->ptrace = current->ptrace; __ptrace_link(child, current->parent); } + +#ifdef CONFIG_HAVE_HW_BREAKPOINT + atomic_set(&child->ptrace_bp_refcnt, 1); +#endif } /** @@ -350,6 +354,13 @@ extern int task_current_syscall(struct task_struct *target, long *callno, unsigned long args[6], unsigned int maxargs, unsigned long *sp, unsigned long *pc); -#endif +#ifdef CONFIG_HAVE_HW_BREAKPOINT +extern int ptrace_get_breakpoints(struct task_struct *tsk); +extern void ptrace_put_breakpoints(struct task_struct *tsk); +#else +static inline void ptrace_put_breakpoints(struct task_struct *tsk) { } +#endif /* CONFIG_HAVE_HW_BREAKPOINT */ + +#endif /* __KERNEL */ #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index 18d63cea2848..781abd137673 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1537,6 +1537,9 @@ struct task_struct { unsigned long memsw_nr_pages; /* uncharged mem+swap usage */ } memcg_batch; #endif +#ifdef CONFIG_HAVE_HW_BREAKPOINT + atomic_t ptrace_bp_refcnt; +#endif }; /* Future-safe accessor for struct task_struct's cpus_allowed. */ diff --git a/kernel/exit.c b/kernel/exit.c index f5d2f63bae0b..8dd874181542 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1016,7 +1016,7 @@ NORET_TYPE void do_exit(long code) /* * FIXME: do that only when needed, using sched_exit tracepoint */ - flush_ptrace_hw_breakpoint(tsk); + ptrace_put_breakpoints(tsk); exit_notify(tsk, group_dead); #ifdef CONFIG_NUMA diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 0fc1eed28d27..dc7ab65f3b36 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -22,6 +22,7 @@ #include #include #include +#include /* @@ -879,3 +880,19 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, return ret; } #endif /* CONFIG_COMPAT */ + +#ifdef CONFIG_HAVE_HW_BREAKPOINT +int ptrace_get_breakpoints(struct task_struct *tsk) +{ + if (atomic_inc_not_zero(&tsk->ptrace_bp_refcnt)) + return 0; + + return -1; +} + +void ptrace_put_breakpoints(struct task_struct *tsk) +{ + if (atomic_dec_and_test(&tsk->ptrace_bp_refcnt)) + flush_ptrace_hw_breakpoint(tsk); +} +#endif /* CONFIG_HAVE_HW_BREAKPOINT */