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authorOleg Nesterov <oleg@redhat.com>2011-04-01 20:13:01 +0200
committerTejun Heo <tj@kernel.org>2011-04-04 02:11:05 +0200
commit321fb561971ba0f10ce18c0f8a4b9fbfc7cef4b9 (patch)
tree4123410887b549284ed32cf5e8fb799fd2540c14
parentee77f075921730b2b465880f9fd4367003bdab39 (diff)
ptrace: ptrace_check_attach() should not do s/STOPPED/TRACED/
After "ptrace: Clean transitions between TASK_STOPPED and TRACED" d79fdd6d96f46fabb779d86332e3677c6f5c2a4f, ptrace_check_attach() should never see a TASK_STOPPED tracee and s/STOPPED/TRACED/ is no longer legal. Add the warning. Note: ptrace_check_attach() can be greatly simplified, in particular it doesn't need tasklist. But I'd prefer another patch for that. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
-rw-r--r--kernel/ptrace.c8
1 files changed, 3 insertions, 5 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 43485866749a..20d5efdeee02 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -112,16 +112,14 @@ int ptrace_check_attach(struct task_struct *child, int kill)
*/
read_lock(&tasklist_lock);
if ((child->ptrace & PT_PTRACED) && child->parent == current) {
- ret = 0;
/*
* child->sighand can't be NULL, release_task()
* does ptrace_unlink() before __exit_signal().
*/
spin_lock_irq(&child->sighand->siglock);
- if (task_is_stopped(child))
- child->state = TASK_TRACED;
- else if (!task_is_traced(child) && !kill)
- ret = -ESRCH;
+ WARN_ON_ONCE(task_is_stopped(child));
+ if (task_is_traced(child) || kill)
+ ret = 0;
spin_unlock_irq(&child->sighand->siglock);
}
read_unlock(&tasklist_lock);