This reverts commit bf26c018490c2fce7fe9b629083b96ce0e6ad019.
The patch was fine but we can no longer race with SIGKILL after
9899d11f "ptrace: ensure arch_ptrace/ptrace_request can never race
with SIGKILL", the __TASK_TRACED tracee can't be woken up and
->ptrace_bps[] can't go away.
Now that ptrace_get_breakpoints/ptrace_put_breakpoints have no
callers, we can kill them and remove task->ptrace_bp_refcnt.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Acked-by: Michael Neuling <mikey@xxxxxxxxxxx>
---
include/linux/ptrace.h | 10 ----------
include/linux/sched.h | 3 ---
kernel/exit.c | 2 +-
kernel/ptrace.c | 16 ----------------
4 files changed, 1 insertions(+), 30 deletions(-)
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 89573a3..07d0df6 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -142,9 +142,6 @@ static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
{
INIT_LIST_HEAD(&child->ptrace_entry);
INIT_LIST_HEAD(&child->ptraced);
-#ifdef CONFIG_HAVE_HW_BREAKPOINT
- atomic_set(&child->ptrace_bp_refcnt, 1);
-#endif
child->jobctl = 0;
child->ptrace = 0;
child->parent = child->real_parent;
@@ -351,11 +348,4 @@ extern int task_current_syscall(struct task_struct *target, long *callno,
unsigned long args[6], unsigned int maxargs,
unsigned long *sp, unsigned long *pc);
-#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
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 178a8d9..ebdba8a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1406,9 +1406,6 @@ struct task_struct {
} memcg_batch;
unsigned int memcg_kmem_skip_account;
#endif
-#ifdef CONFIG_HAVE_HW_BREAKPOINT
- atomic_t ptrace_bp_refcnt;
-#endif
#ifdef CONFIG_UPROBES
struct uprobe_task *utask;
#endif
diff --git a/kernel/exit.c b/kernel/exit.c
index af2eb3c..0636035 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -819,7 +819,7 @@ void do_exit(long code)
/*
* FIXME: do that only when needed, using sched_exit tracepoint
*/
- ptrace_put_breakpoints(tsk);
+ flush_ptrace_hw_breakpoint(tsk);
exit_notify(tsk, group_dead);
#ifdef CONFIG_NUMA
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index aed981a..8cc170b 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -1179,19 +1179,3 @@ 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 */
--
1.5.5.1
--
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