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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-07-25 01:47:37 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-07-25 10:53:39 -0700 |
| commit | 3d749b9e676b26584a47e75c235aa6f69d0697ae (patch) | |
| tree | 2db2dab84cde07c4872ac5e8d4078f2a3fc4271d /kernel | |
| parent | 364d3c13c17f45da6d638011078d4c4d3070d719 (diff) | |
| download | lwn-3d749b9e676b26584a47e75c235aa6f69d0697ae.tar.gz lwn-3d749b9e676b26584a47e75c235aa6f69d0697ae.zip | |
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 <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/signal.c | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index fdab7b363fa7..39c1706edf03 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(); |