Re: [PATCH v4] lockdep: check that no locks held at freeze time

From: Andrew Morton
Date: Wed Feb 20 2013 - 18:24:51 EST

On Wed, 20 Feb 2013 15:17:16 -0800
Mandeep Singh Baines <msb@xxxxxxxxxxxx> wrote:

> We shouldn't try_to_freeze if locks are held.
> ...
> @@ -43,6 +44,9 @@ extern void thaw_kernel_threads(void);
> + if (!(current->flags & PF_NOFREEZE))
> + debug_check_no_locks_held(current,
> +
> "lock held while trying to freeze");
> ...
> + debug_check_no_locks_held(tsk, "lock held at task exit time");

There doesn't seem much point in adding the `msg' to
debug_check_no_locks_held() - the dump_stack() in
print_held_locks_bug() will tell us the same thing. Maybe just change
the print_held_locks_bug() messages so they stop assuming they were
called from do_exit()?

Also, I wonder if the `tsk' arg is needed. In both callers
tsk==current. Is it likely that we'll ever call
debug_check_no_locks_held() for any task other than `current'?

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