I used Masami's address which did not work. Sorry about that. Should be ok
now.
On Mon, 31 Aug 2020, Miroslav Benes wrote:
> Commit fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
> missed to remove ops from new ftrace_ops_trampoline_list in
> ftrace_startup() if ftrace_hash_ipmodify_enable() fails there. It may
> lead to BUG if such ops come from a module which may be removed.
>
> Moreover, the trampoline itself is not freed in this case.
>
> Fix it by calling ftrace_trampoline_free() during the rollback.
>
> Fixes: fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines")
> Signed-off-by: Miroslav Benes <mbe...@suse.cz>
> ---
>
> It would be fair to add
>
> Fixes: f8b8be8a310a ("ftrace, kprobes: Support IPMODIFY flag to find IP
> modify conflict")
>
> too. The situation was a bit more complicated back then though since
> RCU-tasks support was missing.
>
> kernel/trace/ftrace.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 275441254bb5..656d7cb5a78c 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -2862,6 +2862,8 @@ int ftrace_startup(struct ftrace_ops *ops, int command)
> __unregister_ftrace_function(ops);
> ftrace_start_up--;
> ops->flags &= ~FTRACE_OPS_FL_ENABLED;
> + if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
> + ftrace_trampoline_free(ops);
> return ret;
> }
>
> --
> 2.28.0
>
