28 Jun, 2011
1 commit
-
Kill tracehook_notify_death(), reimplement the logic in its caller,
exit_notify().Also, change the exec_id's check to use thread_group_leader() instead
of task_detached(), this is more clear. This logic only applies to
the exiting leader, a sub-thread must never change its exit_signal.Note: when the traced group leader exits the exit_signal-or-SIGCHLD
logic looks really strange:- we notify the tracer even if !thread_group_empty() but
do_wait(WEXITED) can't work until all threads exit- if the tracer is real_parent, it is not clear why can't
we use ->exit_signal event if !thread_group_empty()-v2: do not try to fix the 2nd oddity to avoid the subtle behavior
change mixed with reorganization, suggested by Tejun.Signed-off-by: Oleg Nesterov
Reviewed-by: Tejun Heo
23 Jun, 2011
6 commits
-
tracehook.h is on the way out. Rename tracehook_tracer_task() to
ptrace_parent() and move it from tracehook.h to ptrace.h.Signed-off-by: Tejun Heo
Cc: Christoph Hellwig
Cc: John Johansen
Cc: Stephen Smalley
Signed-off-by: Oleg Nesterov -
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 clone and exec related tracehooks.
tracehook_prepare_clone()
tracehook_finish_clone()
tracehook_report_clone()
tracehook_report_clone_complete()
tracehook_unsafe_exec()The changes are mostly trivial - logic is moved to the caller and
comments are merged and adjusted appropriately.The only exception is in check_unsafe_exec() where LSM_UNSAFE_PTRACE*
are OR'd to bprm->unsafe instead of setting it, which produces the
same result as the field is always zero on entry. It also tests
p->ptrace instead of (p->ptrace & PT_PTRACED) for consistency, which
also gives the same result.This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo
Cc: Christoph Hellwig
Signed-off-by: Oleg Nesterov -
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
Cc: Christoph Hellwig
Cc: Martin Schwidefsky
Signed-off-by: Oleg Nesterov -
Move SIGTRAP on exec(2) logic from tracehook_report_exec() to
ptrace_event(). This is part of changes to make ptrace_event()
smarter and handle ptrace event related details in one place.This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo
Signed-off-by: Oleg Nesterov -
This patch implements ptrace_event_enabled() which tests whether a
given PTRACE_EVENT_* is enabled and use it to simplify ptrace_event()
and tracehook_prepare_clone().PT_EVENT_FLAG() macro is added which calculates PT_TRACE_* flag from
PTRACE_EVENT_*. This is used to define PT_TRACE_* flags and by
ptrace_event_enabled() to find the matching flag.This is used to make ptrace_event() and tracehook_prepare_clone()
simpler.* ptrace_event() callers were responsible for providing mask to test
whether the event was enabled. This patch implements
ptrace_event_enabled() and make ptrace_event() drop @mask and
determine whether the event is enabled from @event. Note that
@event is constant and this conversion doesn't add runtime overhead.All conversions except tracehook_report_clone_complete() are
trivial. tracehook_report_clone_complete() used to use 0 for @mask
(always enabled) but now tests whether the specified event is
enabled. This doesn't cause any behavior difference as it's
guaranteed that the event specified by @trace is enabled.* tracehook_prepare_clone() now only determines which event is
applicable and use ptrace_event_enabled() for enable test.This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo
Signed-off-by: Oleg Nesterov -
task_ptrace(task) simply dereferences task->ptrace and isn't even used
consistently only adding confusion. Kill it and directly access
->ptrace instead.This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo
Signed-off-by: Oleg Nesterov
05 Jun, 2011
1 commit
-
Remove the following three noop tracehooks in signals.c.
* tracehook_force_sigpending()
* tracehook_get_signal()
* tracehook_finish_jctl()The code area is about to be updated and these hooks don't do anything
other than obfuscating the logic.Signed-off-by: Tejun Heo
Signed-off-by: Oleg Nesterov
21 May, 2011
1 commit
-
* 'ptrace' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc: (41 commits)
signal: trivial, fix the "timespec declared inside parameter list" warning
job control: reorganize wait_task_stopped()
ptrace: fix signal->wait_chldexit usage in task_clear_group_stop_trapping()
signal: sys_sigprocmask() needs retarget_shared_pending()
signal: cleanup sys_sigprocmask()
signal: rename signandsets() to sigandnsets()
signal: do_sigtimedwait() needs retarget_shared_pending()
signal: introduce do_sigtimedwait() to factor out compat/native code
signal: sys_rt_sigtimedwait: simplify the timeout logic
signal: cleanup sys_rt_sigprocmask()
x86: signal: sys_rt_sigreturn() should use set_current_blocked()
x86: signal: handle_signal() should use set_current_blocked()
signal: sigprocmask() should do retarget_shared_pending()
signal: sigprocmask: narrow the scope of ->siglock
signal: retarget_shared_pending: optimize while_each_thread() loop
signal: retarget_shared_pending: consider shared/unblocked signals only
signal: introduce retarget_shared_pending()
ptrace: ptrace_check_attach() should not do s/STOPPED/TRACED/
signal: Turn SIGNAL_STOP_DEQUEUED into GROUP_STOP_DEQUEUED
signal: do_signal_stop: Remove the unneeded task_clear_group_stop_pending()
...
31 Mar, 2011
1 commit
-
Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: Lucas De Marchi
23 Mar, 2011
1 commit
-
tracehook_notify_jctl() aids in determining whether and what to report
to the parent when a task is stopped or continued. The function also
adds an extra requirement that siglock may be released across it,
which is currently unused and quite difficult to satisfy in
well-defined manner.As job control and the notifications are about to receive major
overhaul, remove the tracehook and open code it. If ever necessary,
let's factor it out after the overhaul.* Oleg spotted incorrect CLD_CONTINUED/STOPPED selection when ptraced.
Fixed.Signed-off-by: Tejun Heo
Cc: Oleg Nesterov
Cc: Roland McGrath
28 Oct, 2010
1 commit
-
Oleg Nesterov pointed out we have to prevent multiple-threads-inside-exec
itself and we can reuse ->cred_guard_mutex for it. Yes, concurrent
execve() has no worth.Let's move ->cred_guard_mutex from task_struct to signal_struct. It
naturally prevent multiple-threads-inside-exec.Signed-off-by: KOSAKI Motohiro
Reviewed-by: Oleg Nesterov
Acked-by: Roland McGrath
Acked-by: David Howells
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Dec, 2009
1 commit
-
Suggested by Roland.
Change tracehook_report_syscall_exit() to look at step flag and send the
trap signal if needed.This change affects ia64, microblaze, parisc, powerpc, sh. They pass
nonzero "step" argument to tracehook but since it was ignored the tracee
reports via ptrace_notify(), this is not right and not consistent.- PTRACE_SETSIGINFO doesn't work
- if the tracer resumes the tracee with signr != 0 the new signal
is generated rather than delivering it- If PT_TRACESYSGOOD is set the tracee reports the wrong exit_code
I don't have a powerpc machine, but I think this test-case should see the
difference:#include
#include
#include
#include
#includeint main(void)
{
int pid, status;if (!(pid = fork())) {
assert(ptrace(PTRACE_TRACEME) == 0);
kill(getpid(), SIGSTOP);getppid();
return 0;
}assert(pid == wait(&status));
assert(ptrace(PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACESYSGOOD) == 0);assert(ptrace(PTRACE_SYSCALL, pid, 0,0) == 0);
assert(pid == wait(&status));assert(ptrace(PTRACE_SINGLESTEP, pid, 0,0) == 0);
assert(pid == wait(&status));if (status == 0x57F)
return 0;printf("kernel bug: status=%X shouldn't have 0x80\n", status);
return 1;
}Signed-off-by: Oleg Nesterov
Acked-by: Roland McGrath
Cc:
Cc: Ingo Molnar
Cc: Thomas Gleixner
Cc: "H. Peter Anvin"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Sep, 2009
1 commit
-
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
19 Jun, 2009
1 commit
-
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
05 Jun, 2009
1 commit
-
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
03 Apr, 2009
2 commits
-
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 -
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
06 Sep, 2008
1 commit
-
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
08 Aug, 2008
1 commit
-
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
05 Aug, 2008
1 commit
-
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
02 Aug, 2008
1 commit
-
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
27 Jul, 2008
18 commits
-
This fixes some typos and errors in comments.
No code changes.Signed-off-by: Roland McGrath
-
This adds asm-generic/syscall.h, which documents what a real
asm-ARCH/syscall.h file should define. This is not used yet, but will
provide all the machine-dependent details of examining a user system call
about to begin, in progress, or just ended.Each arch should add an asm-ARCH/syscall.h that defines all the entry
points documented in asm-generic/syscall.h, as short inlines if possible.
This lets us write new tracing code that understands user system call
registers, without any new arch-specific work.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This adds tracehook.h inlines to enable a new arch feature in support of
user debugging/tracing. This is not used yet, but it lays the groundwork
for a debugger to be able to wrangle a task that's possibly running,
without interrupting its syscalls in progress.Each arch should define TIF_NOTIFY_RESUME, and in their entry.S code treat
it much like TIF_SIGPENDING. That is, it causes you to take the slow path
when returning to user mode, where you get the full user-mode state
accessible as for signal handling or ptrace. The arch code should check
TIF_NOTIFY_RESUME after handling TIF_SIGPENDING. When it's set, clear it
and then call tracehook_notify_resume().In future, tracing code will call set_notify_resume() when it wants to get
a callback in tracehook_notify_resume().Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This defines a new hook tracehook_force_sigpending() that lets tracing
code decide to force TIF_SIGPENDING on in recalc_sigpending().This is not used yet, so it compiles away to nothing for now. It lays the
groundwork for new tracing code that can interrupt a task synthetically
without actually sending a signal.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This moves the ptrace logic in task death (exit_notify) into tracehook.h
inlines. Some code is rearranged slightly to make things nicer. There is
no change, only cleanup.There is one hook called with the tasklist_lock write-locked, as ptrace
needs. There is also a new hook called after exit_state changes and
without locks. This is a better place for tracing work to be in the
future, since it doesn't delay the whole system with locking.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This defines the tracehook_notify_jctl() hook to formalize the ptrace
effects on the job control notifications. There is no change, only
cleanup.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This defines the tracehook_get_signal() hook to allow tracing code to slip
in before normal signal dequeuing. This lays the groundwork for new
tracing features that can inject synthetic signals outside the normal
queue or control the disposition of delivered signals. The calling
convention lets tracehook_get_signal() decide both exactly what will
happen and what signal number to report in the handler/exit.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This adds standard tracehook.h inlines for arch code to call when
TIF_SYSCALL_TRACE has been set. This replaces having each arch implement
the ptrace guts for its syscall tracing support.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This defines tracehook_consider_fatal_signal() has a fine-grained hook for
deciding to skip the special cases for a fatal signal, as ptrace does.
There is no change, only cleanup.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This defines tracehook_consider_ignored_signal() has a fine-grained hook
for deciding to prevent the normal short-circuit of sending an ignored
signal, as ptrace does. There is no change, only cleanup.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This defines tracehook_signal_handler() as a hook for the arch signal
handling code to call. It gives ptrace the opportunity to stop for a
pseudo-single-step trap immediately after signal handler setup is done.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This adds tracehook_expect_breakpoints() as a formal hook for the nommu
code to use for its, "Is text-poking likely?" check at mmap time. This
names the actual semantics the code means to test, and documents it.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This adds the tracehook_tracer_task() hook to consolidate all forms of
"Who is using ptrace on me?" logic. This is used for "TracerPid:" in
/proc and for permission checks. We also clean up the selinux code the
called an identical accessor.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This moves the ptrace-related logic from release_task into tracehook.h and
ptrace.h inlines. It provides clean hooks both before and after locking
tasklist_lock, for future tracing logic to do more cleanup without the
lock.This also changes release_task() itself in the rare "zap_leader" case to
set the leader to EXIT_DEAD before iterating. This maintains the
invariant that release_task() only ever handles a task in EXIT_DEAD. This
is a common-sense invariant that is already always true except in this one
arcane case of zombie leader whose parent ignores SIGCHLD.This change is harmless and only costs one store in this one rare case.
It keeps the expected state more consisently sane, which is nicer when
debugging weirdness in release_task(). It also lets some future code in
the tracehook entry points rely on this invariant for bookkeeping.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This moves the PTRACE_EVENT_VFORK_DONE tracing into a tracehook.h inline,
tracehook_report_vfork_done(). The change has no effect, just clean-up.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This moves all the ptrace initialization and tracing logic for task
creation into tracehook.h and ptrace.h inlines. It reorganizes the code
slightly, but should not change any behavior.There are four tracehook entry points, at each important stage of task
creation. This keeps the interface from the core fork.c code fairly
clean, while supporting the complex setup required for ptrace or something
like it.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This moves the PTRACE_EVENT_EXIT tracing into a tracehook.h inline,
tracehook_report_exec(). The change has no effect, just clean-up.Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This moves all the ptrace hooks related to exec into tracehook.h inlines.
This also lifts the calls for tracing out of the binfmt load_binary hooks
into search_binary_handler() after it calls into the binfmt module. This
change has no effect, since all the binfmt modules' load_binary functions
did the call at the end on success, and now search_binary_handler() does
it immediately after return if successful. We consolidate the repeated
code, and binfmt modules no longer need to import ptrace_notify().Signed-off-by: Roland McGrath
Cc: Oleg Nesterov
Reviewed-by: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds