Commit 12cc126d authored Dec 03, 2020 by Andrii Nakryiko Committed by Alexei Starovoitov Dec 03, 2020

bpf: Fix bpf_put_raw_tracepoint()'s use of __module_address()



__module_address() needs to be called with preemption disabled or with
module_mutex taken. preempt_disable() is enough for read-only uses, which is
what this fix does. Also, module_put() does internal check for NULL, so drop
it as well.

Fixes: a38d1107 ("bpf: support raw tracepoints in modules")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201203204634.1325171-2-andrii@kernel.org

parent cadd6480

kernel/trace/bpf_trace.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -2060,10 +2060,12 @@ struct bpf_raw_event_map bpf_get_raw_tracepoint(const char name)

		void bpf_put_raw_tracepoint(struct bpf_raw_event_map *btp)
		{
		struct module *mod = __module_address((unsigned long)btp);
		struct module *mod;

		if (mod)
		preempt_disable();
		mod = __module_address((unsigned long)btp);
		module_put(mod);
		preempt_enable();
		}

		static __always_inline

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