mirror/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

ptrace: kill trivial tracehooks

Browse Source 
At this point, tracehooks aren't useful to mainline kernel and mostly
just add an extra layer of obfuscation.  Although they have comments,
without actual in-kernel users, it is difficult to tell what are their
assumptions and they're actually trying to achieve.  To mainline
kernel, they just aren't worth keeping around.

This patch kills the following trivial tracehooks.

* Ones testing whether task is ptraced.  Replace with ->ptrace test.

	tracehook_expect_breakpoints()
	tracehook_consider_ignored_signal()
	tracehook_consider_fatal_signal()

* ptrace_event() wrappers.  Call directly.

	tracehook_report_exec()
	tracehook_report_exit()
	tracehook_report_vfork_done()

* ptrace_release_task() wrapper.  Call directly.

	tracehook_finish_release_task()

* noop

	tracehook_prepare_release_task()
	tracehook_report_death()

This doesn't introduce any behavior change.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This commit is contained in:
Tejun Heo
2011-06-17 16:50:37 +02:00
committed by Oleg Nesterov
parent f3c04b934d
commit a288eecce5
7 changed files with 11 additions and 171 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
kernel/exit.c
View File

@@ -169,7 +169,6 @@ void release_task(struct task_struct * p)
struct task_struct *leader;
int zap_leader;
repeat:
tracehook_prepare_release_task(p);
/* don't need to get the RCU readlock here - the process is dead and
* can't be modifying its own credentials. But shut RCU-lockdep up */
rcu_read_lock();
@@ -179,7 +178,7 @@ repeat:
proc_flush_task(p);
write_lock_irq(&tasklist_lock);
tracehook_finish_release_task(p);
ptrace_release_task(p);
__exit_signal(p);
/*
@@ -868,8 +867,6 @@ static void exit_notify(struct task_struct *tsk, int group_dead)
wake_up_process(tsk->signal->group_exit_task);
write_unlock_irq(&tasklist_lock);
tracehook_report_death(tsk, signal, cookie, group_dead);
/* If the process is dead, release it - nobody will wait for it */
if (signal == DEATH_REAP)
release_task(tsk);
@@ -924,7 +921,7 @@ NORET_TYPE void do_exit(long code)
*/
set_fs(USER_DS);
tracehook_report_exit(&code);
ptrace_event(PTRACE_EVENT_EXIT, code);
validate_creds_for_do_exit(tsk);

2
kernel/fork.c
View File

@@ -1527,7 +1527,7 @@ long do_fork(unsigned long clone_flags,
freezer_do_not_count();
wait_for_completion(&vfork);
freezer_count();
tracehook_report_vfork_done(p, nr);
ptrace_event(PTRACE_EVENT_VFORK_DONE, nr);
}
} else {
nr = PTR_ERR(p);

8
kernel/signal.c
View File

@@ -87,7 +87,7 @@ static int sig_ignored(struct task_struct *t, int sig, int from_ancestor_ns)
/*
* Tracers may want to know about even ignored signals.
*/
return !tracehook_consider_ignored_signal(t, sig);
return !t->ptrace;
}
/*
@@ -493,7 +493,8 @@ int unhandled_signal(struct task_struct *tsk, int sig)
return 1;
if (handler != SIG_IGN && handler != SIG_DFL)
return 0;
return !tracehook_consider_fatal_signal(tsk, sig);
/* if ptraced, let the tracer determine */
return !tsk->ptrace;
}
/*
@@ -981,8 +982,7 @@ static void complete_signal(int sig, struct task_struct *p, int group)
if (sig_fatal(p, sig) &&
!(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
!sigismember(&t->real_blocked, sig) &&
(sig == SIGKILL ||
!tracehook_consider_fatal_signal(t, sig))) {
(sig == SIGKILL || !t->ptrace)) {
/*
* This signal will be fatal to the whole group.
*/