On Fri, 2 Nov 2018, Nadav Amit wrote:
> text_mutex is expected to be held before text_poke() is called, but we
> cannot add a lockdep assertion since kgdb does not take it, and instead
> *supposedly* ensures the lock is not taken and will not be acquired by
> any other core while text_poke() is running.
>
> The reason for the "supposedly" comment is that it is not entirely clear
> that this would be the case if gdb_do_roundup is zero.
>
> Add a comment to clarify this behavior, and restore the assertions as
> they were before the recent commit.
>
> This partially reverts commit 9222f606506c ("x86/alternatives:
> Lockdep-enforce text_mutex in text_poke*()")
Alright, what can we do. It's probably better to have this, rather than to
trying to work this around in kgdb to accomodate the rest of the world.
> Cc: Jiri Kosina <jkos...@suse.cz>
> Cc: Andy Lutomirski <l...@kernel.org>
> Cc: Kees Cook <keesc...@chromium.org>
> Cc: Dave Hansen <dave.han...@intel.com>
> Fixes: 9222f606506c ("x86/alternatives: Lockdep-enforce text_mutex in
> text_poke*()")
> Reviewed-by: Masami Hiramatsu <mhira...@kernel.org>
> Tested-by: Masami Hiramatsu <mhira...@kernel.org>
> Suggested-by: Peter Zijlstra <pet...@infradead.org>
> Signed-off-by: Nadav Amit <na...@vmware.com>
Acked-by: Jiri Kosina <jkos...@suse.cz>
Thanks,
--
Jiri Kosina
SUSE Labs
