From: Oleg Nesterov Date: Fri, 25 Jul 2008 08:47:37 +0000 (-0700) Subject: ptrace: simplify ptrace_stop()->sigkill_pending() path X-Git-Tag: v2.6.27-rc1~349 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3d749b9e676b26584a47e75c235aa6f69d0697ae;p=linux-2.6 ptrace: simplify ptrace_stop()->sigkill_pending() path 1. SIGKILL can't be blocked, remove this check from sigkill_pending(). 2. When ptrace_stop() sees sigkill_pending() == T, it can just return. Kill "int killed" and simplify the code. This also is more correct, the tracer shouldn't see us in TASK_TRACED if we are not going to stop. I strongly believe this code needs further changes. We should do the "was this task killed" check unconditionally, currently it depends on arch_ptrace_stop_needed(). On the other hand, sigkill_pending() isn't very clever. If the task was killed tkill(SIGKILL), the signal can be already dequeued if the caller is do_exit(). Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/signal.c b/kernel/signal.c index fdab7b363f..39c1706edf 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1496,9 +1496,8 @@ static inline int may_ptrace_stop(void) */ static int sigkill_pending(struct task_struct *tsk) { - return ((sigismember(&tsk->pending.signal, SIGKILL) || - sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) && - !unlikely(sigismember(&tsk->blocked, SIGKILL))); + return sigismember(&tsk->pending.signal, SIGKILL) || + sigismember(&tsk->signal->shared_pending.signal, SIGKILL); } /* @@ -1514,8 +1513,6 @@ static int sigkill_pending(struct task_struct *tsk) */ static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info) { - int killed = 0; - if (arch_ptrace_stop_needed(exit_code, info)) { /* * The arch code has something special to do before a @@ -1531,7 +1528,8 @@ static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info) spin_unlock_irq(¤t->sighand->siglock); arch_ptrace_stop(exit_code, info); spin_lock_irq(¤t->sighand->siglock); - killed = sigkill_pending(current); + if (sigkill_pending(current)) + return; } /* @@ -1548,7 +1546,7 @@ static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info) __set_current_state(TASK_TRACED); spin_unlock_irq(¤t->sighand->siglock); read_lock(&tasklist_lock); - if (!unlikely(killed) && may_ptrace_stop()) { + if (may_ptrace_stop()) { do_notify_parent_cldstop(current, CLD_TRAPPED); read_unlock(&tasklist_lock); schedule();