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| author | Oleg Nesterov <oleg@redhat.com> | 2009-06-04 16:29:09 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-04 18:07:40 -0700 |
| commit | edaba2c5334492f82d39ec35637c6dea5176a977 (patch) | |
| tree | d05ee0eacdb0c725da8374e9c1f38a4808dfdd2e /kernel/ptrace.c | |
| parent | 08f67461c609ad96bf26732b590569e02e322019 (diff) | |
| download | lwn-edaba2c5334492f82d39ec35637c6dea5176a977.tar.gz lwn-edaba2c5334492f82d39ec35637c6dea5176a977.zip | |
ptrace: revert "ptrace_detach: the wrong wakeup breaks the ERESTARTxxx logic"
Commit 95a3540da9c81a5987be810e1d9a83640a366bd5 ("ptrace_detach: the wrong
wakeup breaks the ERESTARTxxx logic") removed the "extra"
wake_up_process() from ptrace_detach(), but as Jan pointed out this breaks
the compatibility.
I believe the changelog is right and this wake_up() is wrong in many
ways, but GDB assumes that ptrace(PTRACE_DETACH, child, 0, 0) always
wakes up the tracee.
Despite the fact this breaks SIGNAL_STOP_STOPPED/group_stop_count logic,
and despite the fact this wake_up_process() can break another
assumption: PTRACE_DETACH with SIGSTOP should leave the tracee in
TASK_STOPPED case. Because the untraced child can dequeue SIGSTOP and
call do_signal_stop() before ptrace_detach() calls wake_up_process().
Revert this change for now. We need some fixes even if we we want to keep
the current behaviour, but these fixes are not for 2.6.30.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/ptrace.c')
| -rw-r--r-- | kernel/ptrace.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 0692ab5a0d67..42c317874cfa 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -304,6 +304,8 @@ int ptrace_detach(struct task_struct *child, unsigned int data) if (child->ptrace) { child->exit_code = data; dead = __ptrace_detach(current, child); + if (!child->exit_state) + wake_up_process(child); } write_unlock_irq(&tasklist_lock); |