3.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Upstream commit 910ffdb18a6408e14febbb6e4b6840fd2c928c82.
Cleanup and preparation for the next change.
signal_wake_up(resume => true) is overused. None of ptrace/jctl callers
actually want to wakeup a TASK_WAKEKILL task, but they can't specify the
necessary mask.
Turn signal_wake_up() into signal_wake_up_state(state), reintroduce
signal_wake_up() as a trivial helper, and add ptrace_signal_wake_up()
which adds __TASK_TRACED.
This way ptrace_signal_wake_up() can work "inside" ptrace_request()
even if the tracee doesn't have the TASK_WAKEKILL bit set.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/sched.h | 11 ++++++++++-
kernel/ptrace.c | 4 ++--
kernel/signal.c | 12 +++---------
3 files changed, 15 insertions(+), 12 deletions(-)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2564,7 +2564,16 @@ static inline void thread_group_cputime_
extern void recalc_sigpending_and_wake(struct task_struct *t);
extern void recalc_sigpending(void);
-extern void signal_wake_up(struct task_struct *t, int resume_stopped);
+extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
+
+static inline void signal_wake_up(struct task_struct *t, bool resume)
+{
+ signal_wake_up_state(t, resume ? TASK_WAKEKILL : 0);
+}
+static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
+{
+ signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
+}
/*
* Wrappers for p->thread_info->cpu access. No-op on UP.
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -92,7 +92,7 @@ void __ptrace_unlink(struct task_struct
* TASK_KILLABLE sleeps.
*/
if (child->group_stop & GROUP_STOP_PENDING || task_is_traced(child))
- signal_wake_up(child, task_is_traced(child));
+ ptrace_signal_wake_up(child, true);
spin_unlock(&child->sighand->siglock);
}
@@ -245,7 +245,7 @@ static int ptrace_attach(struct task_str
*/
if (task_is_stopped(task)) {
task->group_stop |= GROUP_STOP_PENDING | GROUP_STOP_TRAPPING;
- signal_wake_up(task, 1);
+ signal_wake_up_state(task, __TASK_STOPPED);
wait_trap = true;
}
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -631,23 +631,17 @@ int dequeue_signal(struct task_struct *t
* No need to set need_resched since signal event passing
* goes through ->blocked
*/
-void signal_wake_up(struct task_struct *t, int resume)
+void signal_wake_up_state(struct task_struct *t, unsigned int state)
{
- unsigned int mask;
-
set_tsk_thread_flag(t, TIF_SIGPENDING);
-
/*
- * For SIGKILL, we want to wake it up in the stopped/traced/killable
+ * TASK_WAKEKILL also means wake it up in the stopped/traced/killable
* case. We don't check t->state here because there is a race with it
* executing another processor and just now entering stopped state.
* By using wake_up_state, we ensure the process will wake up and
* handle its death signal.
*/
- mask = TASK_INTERRUPTIBLE;
- if (resume)
- mask |= TASK_WAKEKILL;
- if (!wake_up_state(t, mask))
+ if (!wake_up_state(t, state | TASK_INTERRUPTIBLE))
kick_process(t);
}
--
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