Messages in this thread Patch in this message | | | From | Hao Wu <> | Subject | [PATCH v1] signal.c: repeatedly set the TIF_SIGPENDING flag | Date | Wed, 23 Feb 2022 21:35:40 +0800 |
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The recalc_sigpending_and_wake() function calls recalc_sigpending_tsk() and signal_wake_up(), both of which set the TIF_SIGPENDING flag, so when recalc_sigpending_tsk() returns true, the TIF_SIGPENDING flag will be set twice.
Maybe we can take away the set TIF_SIGPENDING logic from recalc_sigpending_tsk(), so that recalc_sigpending_tsk() just determines whether the TIF_SIGPENDING flag needs to be set, and the actual set TIF_SIGPENDING flag logic is executed outside.
kernel/signal.c:175: recalc_sigpending_and_wake() kernel/signal.c:154: recalc_sigpending_tsk()
Signed-off-by: Hao Wu <guoyuanchao1202@gmail.com> --- kernel/signal.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/kernel/signal.c b/kernel/signal.c index 9b04631acde8..6c5a00cd7e9a 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -157,7 +157,6 @@ static bool recalc_sigpending_tsk(struct task_struct *t) PENDING(&t->pending, &t->blocked) || PENDING(&t->signal->shared_pending, &t->blocked) || cgroup_task_frozen(t)) { - set_tsk_thread_flag(t, TIF_SIGPENDING); return true; } @@ -181,8 +180,11 @@ void recalc_sigpending_and_wake(struct task_struct *t) void recalc_sigpending(void) { - if (!recalc_sigpending_tsk(current) && !freezing(current)) + if (recalc_sigpending_tsk(current)) { + set_tsk_thread_flag(t, TIF_SIGPENDING); + } else if (!freezing(current)) { clear_thread_flag(TIF_SIGPENDING); + } } EXPORT_SYMBOL(recalc_sigpending); @@ -2325,7 +2327,9 @@ static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t * So check for any that we should take before resuming user mode. * This sets TIF_SIGPENDING, but never clears it. */ - recalc_sigpending_tsk(current); + if (recalc_sigpending_tsk(current)) { + set_tsk_thread_flag(t, TIF_SIGPENDING); + } } static void ptrace_do_notify(int signr, int exit_code, int why) 2.32.0
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