From d5b201ed4feb7a11da242a97669424efeb724031 Mon Sep 17 00:00:00 2001 From: Mykyta Yatsenko Date: Thu, 30 Jul 2026 17:17:39 -0700 Subject: tracing: Make per-template BTF id lists file-local DECLARE_EVENT_CLASS emitted __bpf_trace_btf_ids_ through BTF_ID_LIST_GLOBAL, i.e. a global symbol named after the event class. The class name is not unique across the kernel, so the symbol multiply-defines whenever two translation units instantiate the same class. Switch to the file-local BTF_ID_LIST: the list is reached only through the event_class_.btf_ids pointer, initialised in the same unit, so tracefs readers never reference the symbol by name and resolve_btfids still fills the now-local .BTF_ids entries. The handcrafted syscall classes are the one cross-unit consumer: give them their own local BTF_ID_LIST rather than importing the generated sys_{enter,exit} lists. Link: https://patch.msgid.link/20260730-b4-fix_btf_tracefs-v2-1-6b66da8dc103@meta.com Fixes: eadc0725ab8d3 ("tracing: Expose tracepoint BTF ids via tracefs") Reported-by: Mark Brown Closes: https://lore.kernel.org/all/ff58b01c-3f5e-4d55-be82-609d2faaf12e@sirena.org.uk/ Signed-off-by: Mykyta Yatsenko Acked-by: Andrii Nakryiko Signed-off-by: Steven Rostedt --- include/trace/trace_events.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'include/trace') diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h index 09ad57ac4b73..93011f800d0f 100644 --- a/include/trace/trace_events.h +++ b/include/trace/trace_events.h @@ -398,7 +398,7 @@ static inline notrace int trace_event_get_offsets_##call( \ #define _TRACE_PERF_INIT(call) #endif /* CONFIG_PERF_EVENTS */ -#ifdef CONFIG_BPF_EVENTS +#if defined(CONFIG_BPF_EVENTS) && defined(CONFIG_DEBUG_INFO_BTF) /* * Per-template BTF id list, populated at link time by resolve_btfids: * [0] FUNC __bpf_trace_ (the BPF dispatcher) @@ -406,8 +406,7 @@ static inline notrace int trace_event_get_offsets_##call( \ * Exposed via the events///btf_ids tracefs file. */ #define _TRACE_BTF_IDS_DECLARE(call) \ - extern u32 __bpf_trace_btf_ids_##call[]; \ - BTF_ID_LIST_GLOBAL(__bpf_trace_btf_ids_##call, 2) \ + BTF_ID_LIST(__bpf_trace_btf_ids_##call) \ BTF_ID(func, __bpf_trace_##call) \ BTF_ID(struct, trace_event_raw_##call) @@ -417,7 +416,7 @@ static inline notrace int trace_event_get_offsets_##call( \ #else #define _TRACE_BTF_IDS_DECLARE(call) #define _TRACE_BTF_IDS_INIT(call) -#endif /* CONFIG_BPF_EVENTS */ +#endif /* CONFIG_BPF_EVENTS && CONFIG_DEBUG_INFO_BTF */ #include "stages/stage6_event_callback.h" -- cgit