The patch titled
ptrace: use safer wake up on ptrace_detach()
has been added to the -mm tree. Its filename is
ptrace-use-safer-wake-up-on-ptrace_detach.patch
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See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: ptrace: use safer wake up on ptrace_detach()
From: Tejun Heo <tj@xxxxxxxxxx>
The wake_up_process() call in ptrace_detach() is spurious and not
interlocked with the tracee state. IOW, the tracee could be running or
sleeping in any place in the kernel by the time wake_up_process() is
called. This can lead to the tracee waking up unexpectedly which can be
dangerous.
The wake_up is spurious and should be removed but for now reduce its
toxicity by only waking up if the tracee is in TRACED or STOPPED state.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Roland McGrath <roland@xxxxxxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/ptrace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN kernel/ptrace.c~ptrace-use-safer-wake-up-on-ptrace_detach kernel/ptrace.c
--- a/kernel/ptrace.c~ptrace-use-safer-wake-up-on-ptrace_detach
+++ a/kernel/ptrace.c
@@ -313,7 +313,7 @@ int ptrace_detach(struct task_struct *ch
child->exit_code = data;
dead = __ptrace_detach(current, child);
if (!child->exit_state)
- wake_up_process(child);
+ wake_up_state(child, TASK_TRACED | TASK_STOPPED);
}
write_unlock_irq(&tasklist_lock);
_
Patches currently in -mm which might be from tj@xxxxxxxxxx are
linux-next.patch
ptrace-use-safer-wake-up-on-ptrace_detach.patch
mm-numa-aware-alloc_task_struct_node.patch
mm-numa-aware-alloc_thread_info_node.patch
kthread-numa-aware-kthread_create_on_cpu.patch
kthread-use-kthread_create_on_cpu.patch
smp-move-smp-setup-functions-to-kernel-smpc.patch
scatterlist-new-helper-functions.patch
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