linux.git/kernel/ptrace.c, branch v2.6.26-rc7

make generic sys_ptrace unconditional

2008-05-01T17:21:54+00:00

With s390 the last arch switched to the generic sys_ptrace yesterday so
we can now kill the ifdef around it to enforce every new port it using
it instead of introducing new weirdo versions.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Linus Torvalds

ptrace: permit ptracing of /sbin/init

2008-04-30T15:29:38+00:00

Afaics, currently there are no kernel problems with ptracing init, it can't
lose SIGNAL_UNKILLABLE flag and be killed/stopped by accident.

The ability to strace/debug init can be very useful if you try to figure out
why it does not work as expected.

However, admin should know what he does, "gdb /sbin/init 1" stops init, it
can't reap orphaned zombies or take care of /etc/inittab until continued.  It
is even possible to crash init (and thus the whole system) if you wish,
ptracer has full control.

See also the long discussion: http://marc.info/?t=120628018600001

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

ptrace: ptrace_attach: use send_sig_info() instead force_sig_specific()

2008-04-30T15:29:38+00:00

Nobody can block/ignore SIGSTOP, no need to use force_sig_specific() in
ptrace_attach.  Use the "regular" send_sig_info().

With this patch stracing of /sbin/init doesn't clear its SIGNAL_UNKILLABLE,
but not that this makes ptracing of init safe.

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

ptrace: __ptrace_unlink: use the ptrace_reparented() helper

2008-04-30T15:29:38+00:00

Currently __ptrace_unlink() checks list_empty(->ptrace_list) to figure out
whether the child was reparented.  Change the code to use ptrace_reparented()
to make this check more explicit and consistent.

No functional changes.

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

ptrace: conditionalize compat_ptrace_request

2008-04-28T21:14:36+00:00

My recent additions to compat_ptrace_request made it mandatory
for CONFIG_COMPAT arch's to define copy_siginfo_from_user32.
This broke some builds, though they all really should get cleaned
up in that way.

Since all the arch's that actually call compat_ptrace_request have
now been cleaned up to use the generic compat_sys_ptrace, we can
avoid the build problems on the crufty arch's by changing the
conditionals on the definition.

Signed-off-by: Roland McGrath 
Signed-off-by: Linus Torvalds

ptrace: compat_ptrace_request siginfo

2008-04-21T22:53:41+00:00

This adds support for PTRACE_GETSIGINFO and PTRACE_SETSIGINFO in
compat_ptrace_request.  It relies on existing arch definitions for
copy_siginfo_to_user32 and copy_siginfo_from_user32.

On powerpc, this fixes a longstanding regression of 32-bit ptrace
calls on 64-bit kernels vs native calls (64-bit calls or 32-bit
kernels).  This can be seen in a 32-bit call using PTRACE_GETSIGINFO
to examine e.g. siginfo_t.si_addr from a signal that sets it.
(This was broken as of 2.6.24 and, I presume, many or all prior versions.)

Signed-off-by: Roland McGrath 
Signed-off-by: Linus Torvalds

ptrace_check_attach: remove unneeded ->signal != NULL check

2008-02-08T17:22:26+00:00

It is not possible to see the PT_PTRACED task without ->signal/sighand under
tasklist_lock, release_task() does ptrace_unlink() first.  If the task was
already released before, ptrace_attach() can't succeed and set PT_PTRACED.
Remove this check.

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

kill PT_ATTACHED

2008-02-08T17:22:26+00:00

Since the patch

	"Fix ptrace_attach()/ptrace_traceme()/de_thread() race"
	commit f5b40e363ad6041a96e3da32281d8faa191597b9

we set PT_ATTACHED and change child->parent "atomically" wrt task_list lock.

This means we can remove the checks like "PT_ATTACHED && ->parent != ptracer"
which were needed to catch the "ptrace attach is in progress" case.  We can
also remove the flag itself since nobody else uses it.

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

kernel/ptrace.c should #include

2008-02-06T18:41:02+00:00

Every file should include the headers containing the prototypes for its global
functions (in this case sys_ptrace()).

Signed-off-by: Adrian Bunk 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

use __set_task_state() for TRACED/STOPPED tasks

2008-02-06T18:41:00+00:00

1. It is much easier to grep for ->state change if __set_task_state() is used
   instead of the direct assignment.

2. ptrace_stop() and handle_group_stop() use set_task_state() which adds the
   unneeded mb() (btw even if we use mb() it is still possible that do_wait()
   sees the new ->state but not ->exit_code, but this is ok).

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