From 5c7edcd7ee6b77b88252fe4096dce1a46a60c829 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Thu, 31 Jul 2008 02:04:09 -0700 Subject: tracehook: fix exit_signal=0 case My commit 2b2a1ff64afbadac842bbc58c5166962cf4f7664 introduced a regression (sorry about that) for the odd case of exit_signal=0 (e.g. clone_flags=0). This is not a normal use, but it's used by a case in the glibc test suite. Dying with exit_signal=0 sends no signal, but it's supposed to wake up a parent's blocked wait*() calls (unlike the delayed_group_leader case). This fixes tracehook_notify_death() and its caller to distinguish a "signal 0" wakeup from the delayed_group_leader case (with no wakeup). Signed-off-by: Roland McGrath Tested-by: Serge Hallyn Signed-off-by: Linus Torvalds --- include/linux/tracehook.h | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'include/linux/tracehook.h') diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index b1875582c1a..12532839f50 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -493,16 +493,21 @@ static inline int tracehook_notify_jctl(int notify, int why) * @death_cookie: value to pass to tracehook_report_death() * @group_dead: nonzero if this was the last thread in the group to die * - * Return the signal number to send our parent with do_notify_parent(), or - * zero to send no signal and leave a zombie, or -1 to self-reap right now. + * A return value >= 0 means call do_notify_parent() with that signal + * number. Negative return value can be %DEATH_REAP to self-reap right + * now, or %DEATH_DELAYED_GROUP_LEADER to a zombie without notifying our + * parent. Note that a return value of 0 means a do_notify_parent() call + * that sends no signal, but still wakes up a parent blocked in wait*(). * * Called with write_lock_irq(&tasklist_lock) held. */ +#define DEATH_REAP -1 +#define DEATH_DELAYED_GROUP_LEADER -2 static inline int tracehook_notify_death(struct task_struct *task, void **death_cookie, int group_dead) { if (task->exit_signal == -1) - return task->ptrace ? SIGCHLD : -1; + return task->ptrace ? SIGCHLD : DEATH_REAP; /* * If something other than our normal parent is ptracing us, then @@ -512,21 +517,21 @@ static inline int tracehook_notify_death(struct task_struct *task, if (thread_group_empty(task) && !ptrace_reparented(task)) return task->exit_signal; - return task->ptrace ? SIGCHLD : 0; + return task->ptrace ? SIGCHLD : DEATH_DELAYED_GROUP_LEADER; } /** * tracehook_report_death - task is dead and ready to be reaped * @task: @current task now exiting - * @signal: signal number sent to parent, or 0 or -1 + * @signal: return value from tracheook_notify_death() * @death_cookie: value passed back from tracehook_notify_death() * @group_dead: nonzero if this was the last thread in the group to die * * Thread has just become a zombie or is about to self-reap. If positive, * @signal is the signal number just sent to the parent (usually %SIGCHLD). - * If @signal is -1, this thread will self-reap. If @signal is 0, this is - * a delayed_group_leader() zombie. The @death_cookie was passed back by - * tracehook_notify_death(). + * If @signal is %DEATH_REAP, this thread will self-reap. If @signal is + * %DEATH_DELAYED_GROUP_LEADER, this is a delayed_group_leader() zombie. + * The @death_cookie was passed back by tracehook_notify_death(). * * If normal reaping is not inhibited, @task->exit_state might be changing * in parallel. -- cgit v1.2.3 From 115a326c1e5cab457924356123bbfd7d783ecf9d Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Mon, 4 Aug 2008 13:56:01 -0700 Subject: tracehook: kerneldoc fix My last change to tracehook.h made it confuse the kerneldoc parser. Move the #define's before the comment so it's happy again. Signed-off-by: Roland McGrath Acked-by: Randy Dunlap Signed-off-by: Linus Torvalds --- include/linux/tracehook.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux/tracehook.h') diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 12532839f50..ab3ef7aefa9 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -487,6 +487,9 @@ static inline int tracehook_notify_jctl(int notify, int why) return notify || (current->ptrace & PT_PTRACED); } +#define DEATH_REAP -1 +#define DEATH_DELAYED_GROUP_LEADER -2 + /** * tracehook_notify_death - task is dead, ready to notify parent * @task: @current task now exiting @@ -501,8 +504,6 @@ static inline int tracehook_notify_jctl(int notify, int why) * * Called with write_lock_irq(&tasklist_lock) held. */ -#define DEATH_REAP -1 -#define DEATH_DELAYED_GROUP_LEADER -2 static inline int tracehook_notify_death(struct task_struct *task, void **death_cookie, int group_dead) { -- cgit v1.2.3 From 5861bbfcc10fc0358abf52c7d22850c8d180f0b0 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Thu, 7 Aug 2008 16:55:03 -0700 Subject: tracehook: fix CLONE_PTRACE In the change in commit 09a05394fe2448a4139b014936330af23fa7ec83, I overlooked two nits in the logic and this broke using CLONE_PTRACE when PTRACE_O_TRACE* are not being used. A parent that is itself traced at all but not using PTRACE_O_TRACE*, using CLONE_PTRACE would have its new child fail to be traced. A parent that is not itself traced at all that uses CLONE_PTRACE (which should be a no-op in this case) would confuse the bookkeeping and lead to a crash at exit time. This restores the missing checks and fixes both failure modes. Reported-by: Eduardo Habkost Signed-off-by: Roland McGrath --- include/linux/tracehook.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/tracehook.h') diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index ab3ef7aefa9..b48d8196957 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -280,7 +280,7 @@ static inline void tracehook_report_clone(int trace, struct pt_regs *regs, unsigned long clone_flags, pid_t pid, struct task_struct *child) { - if (unlikely(trace)) { + if (unlikely(trace) || unlikely(clone_flags & CLONE_PTRACE)) { /* * The child starts up with an immediate SIGSTOP. */ -- cgit v1.2.3