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authorOleg Nesterov <oleg@redhat.com>2009-06-04 16:29:09 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-06-04 18:07:40 -0700
commitedaba2c5334492f82d39ec35637c6dea5176a977 (patch)
treed05ee0eacdb0c725da8374e9c1f38a4808dfdd2e /kernel/ptrace.c
parent08f67461c609ad96bf26732b590569e02e322019 (diff)
downloadlinux-2.6.34-ux500-edaba2c5334492f82d39ec35637c6dea5176a977.tar.gz
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.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 0692ab5a0d6..42c317874cf 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);