From c5f51572a7fdff5be9e67c231de593155f394ab3 Mon Sep 17 00:00:00 2001 From: Chengming Zhou Date: Wed, 29 Jul 2020 02:05:54 +0800 Subject: ftrace: Do not let direct or IPMODIFY ftrace_ops be added to module and set trampolines When inserting a module, we find all ftrace_ops referencing it on the ftrace_ops_list. But FTRACE_OPS_FL_DIRECT and FTRACE_OPS_FL_IPMODIFY flags are special, and should not be set automatically. So warn and skip ftrace_ops that have these two flags set and adding new code. Also check if only one ftrace_ops references the module, in which case we can use a trampoline as an optimization. Link: https://lkml.kernel.org/r/20200728180554.65203-2-zhouchengming@bytedance.com Signed-off-by: Chengming Zhou Signed-off-by: Muchun Song Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index d052f856f1cf..f433cb44300a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6199,9 +6199,17 @@ static int referenced_filters(struct dyn_ftrace *rec) for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) { if (ops_references_rec(ops, rec)) { + if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT)) + continue; + if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY)) + continue; cnt++; if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) rec->flags |= FTRACE_FL_REGS; + if (cnt == 1 && ops->trampoline) + rec->flags |= FTRACE_FL_TRAMP; + else + rec->flags &= ~FTRACE_FL_TRAMP; } } -- cgit v1.2.3