linux-toradex.git/include/linux/tracehook.h, branch tegra-10.9.9

signals: tracehook_notify_jctl change

2009-09-24T14:21:00+00:00

This changes tracehook_notify_jctl() so it's called with the siglock held,
and changes its argument and return value definition.  These clean-ups
make it a better fit for what new tracing hooks need to check.

Tracing needs the siglock here, held from the time TASK_STOPPED was set,
to avoid potential SIGCONT races if it wants to allow any blocking in its
tracing hooks.

This also folds the finish_stop() function into its caller
do_signal_stop().  The function is short, called only once and only
unconditionally.  It aids readability to fold it in.

[oleg@redhat.com: do not call tracehook_notify_jctl() in TASK_STOPPED state]
[oleg@redhat.com: introduce tracehook_finish_jctl() helper]
Signed-off-by: Roland McGrath 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ptrace: tracehook_unsafe_exec(): remove the stale comment

2009-06-18T20:03:49+00:00

tracehook_unsafe_exec() doesn't need task_lock(), remove the old comment.

Signed-off-by: Oleg Nesterov 
Acked-by: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ptrace: tracehook_report_clone: fix false positives

2009-06-05T01:07:40+00:00

The "trace || CLONE_PTRACE" check in tracehook_report_clone() is not right,

- If the untraced task does clone(CLONE_PTRACE) the new child is not traced,
  we must not queue SIGSTOP.

- If we forked the traced task, but the tracer exits and untraces both the
  forking task and the new child (after copy_process() drops tasklist_lock),
  we should not queue SIGSTOP too.

Change the code to check task_ptrace() != 0 instead. This is still racy, but
the race is harmless.

We can race with another tracer attaching to this child, or the tracer can
exit and detach in parallel. But giwen that we didn't do wake_up_new_task()
yet, the child must have the pending SIGSTOP anyway.

Signed-off-by: Oleg Nesterov 
Acked-by: Roland McGrath 
Cc: Christoph Hellwig 
Cc: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tracehook_notify_death: use task_detached() helper

2009-04-03T02:05:00+00:00

Now that task_detached() is exported, change tracehook_notify_death() to
use this helper, nobody else checks ->exit_signal == -1 by hand.

Signed-off-by: Oleg Nesterov 
Cc: "Eric W. Biederman" 
Cc: "Metzger, Markus T" 
Acked-by: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

signals: remove 'handler' parameter to tracehook functions

2009-04-03T02:04:58+00:00

Container-init must behave like global-init to processes within the
container and hence it must be immune to unhandled fatal signals from
within the container (i.e SIG_DFL signals that terminate the process).

But the same container-init must behave like a normal process to processes
in ancestor namespaces and so if it receives the same fatal signal from a
process in ancestor namespace, the signal must be processed.

Implementing these semantics requires that send_signal() determine pid
namespace of the sender but since signals can originate from workqueues/
interrupt-handlers, determining pid namespace of sender may not always be
possible or safe.

This patchset implements the design/simplified semantics suggested by
Oleg Nesterov.  The simplified semantics for container-init are:

	- container-init must never be terminated by a signal from a
	  descendant process.

	- container-init must never be immune to SIGKILL from an ancestor
	  namespace (so a process in parent namespace must always be able
	  to terminate a descendant container).

	- container-init may be immune to unhandled fatal signals (like
	  SIGUSR1) even if they are from ancestor namespace. SIGKILL/SIGSTOP
	  are the only reliable signals to a container-init from ancestor
	  namespace.

This patch:

Based on an earlier patch submitted by Oleg Nesterov and comments from
Roland McGrath (http://lkml.org/lkml/2008/11/19/258).

The handler parameter is currently unused in the tracehook functions.
Besides, the tracehook functions are called with siglock held, so the
functions can check the handler if they later need to.

Removing the parameter simiplifies changes to sig_ignored() in a follow-on
patch.

Signed-off-by: Sukadev Bhattiprolu 
Acked-by: Roland McGrath 
Signed-off-by: Oleg Nesterov 
Cc: "Eric W. Biederman" 
Cc: Daniel Lezcano 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tracehook: comment pasto fixes

2008-09-05T21:39:38+00:00

Fix some pasto's in comments in the new linux/tracehook.h and
asm-generic/syscall.h files.

Reported-by: Wenji Huang 
Signed-off-by: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tracehook: fix CLONE_PTRACE

2008-08-08T00:18:47+00:00

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

tracehook: kerneldoc fix

2008-08-05T00:23:43+00:00

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

tracehook: fix exit_signal=0 case

2008-08-01T19:01:11+00:00

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

tracehook: comment fixes

2008-07-26T21:41:26+00:00

This fixes some typos and errors in  comments.
No code changes.

Signed-off-by: Roland McGrath