From d5e47505e02666d5b3fe99212e0100791847dc8d Mon Sep 17 00:00:00 2001 From: Miroslav Benes Date: Mon, 31 Aug 2020 14:26:31 +0200 Subject: [PATCH] ftrace: Free the trampoline when ftrace_startup() fails 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. Link: https://lkml.kernel.org/r/20200831122631.28057-1-mbenes@suse.cz Fixes: fc0ea795f53c ("ftrace: Add symbols for ftrace trampolines") Fixes: f8b8be8a310a ("ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict") Signed-off-by: Miroslav Benes Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 2754412..656d7cb 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; } -- 2.7.4