Commit d5e47505 authored Aug 31, 2020 by Miroslav Benes Committed by Steven Rostedt (VMware) Sep 18, 2020

ftrace: Free the trampoline when ftrace_startup() fails

Commit fc0ea795 ("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: fc0ea795 ("ftrace: Add symbols for ftrace trampolines")
Fixes: f8b8be8a ("ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict")
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent 3031313e

kernel/trace/ftrace.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}

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