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ftrace: Free the trampoline when ftrace_startup() fails 

Commit fc0ea795f5 ("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: fc0ea795f5 ("ftrace: Add symbols for ftrace trampolines")
Fixes: f8b8be8a31 ("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>
This commit is contained in:
Miroslav Benes 2020-08-31 14:26:31 +02:00 committed by Steven Rostedt (VMware)
parent 3031313eb3
commit d5e47505e0
1 changed files with 2 additions and 0 deletions
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2
kernel/trace/ftrace.c
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@ -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;
}