diff options
| author | Mykyta Yatsenko <yatsenko@meta.com> | 2026-07-30 17:17:39 -0700 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2026-08-05 22:02:29 -0400 |
| commit | d5b201ed4feb7a11da242a97669424efeb724031 (patch) | |
| tree | 4d42d8fd6abb228e89fa0a37eb9e9b20139bf839 /kernel/trace/trace_syscalls.c | |
| parent | efdcfd9b4f4f07aa70663ee02a79dbdf980bf582 (diff) | |
tracing: Make per-template BTF id lists file-local
DECLARE_EVENT_CLASS emitted __bpf_trace_btf_ids_<call> 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_<call>.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 <broonie@kernel.org>
Closes: https://lore.kernel.org/all/ff58b01c-3f5e-4d55-be82-609d2faaf12e@sirena.org.uk/
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_syscalls.c')
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 27 |
1 files changed, 14 insertions, 13 deletions
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 48ef1a93e576..e35744049e3f 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -9,6 +9,7 @@ #include <linux/ftrace.h> #include <linux/perf_event.h> #include <linux/xarray.h> +#include <linux/btf_ids.h> #include <asm/syscall.h> #include "trace_output.h" @@ -1303,15 +1304,15 @@ struct trace_event_functions exit_syscall_print_funcs = { .trace = print_syscall_exit, }; -#ifdef CONFIG_BPF_EVENTS -/* - * BTF id lists generated by DECLARE_EVENT_CLASS for the sys_enter and - * sys_exit tracepoints. The auto-generated event_class_sys_{enter,exit} - * is unused (per-syscall events share the handcrafted classes below), - * but the id lists themselves are global and reusable. - */ -extern u32 __bpf_trace_btf_ids_sys_enter[]; -extern u32 __bpf_trace_btf_ids_sys_exit[]; +#if defined(CONFIG_BPF_EVENTS) && defined(CONFIG_DEBUG_INFO_BTF) +/* BTF id lists for the shared sys_enter/sys_exit dispatcher tracepoints. */ +BTF_ID_LIST(syscall_enter_btf_ids) +BTF_ID(func, __bpf_trace_sys_enter) +BTF_ID(struct, trace_event_raw_sys_enter) + +BTF_ID_LIST(syscall_exit_btf_ids) +BTF_ID(func, __bpf_trace_sys_exit) +BTF_ID(struct, trace_event_raw_sys_exit) #endif struct trace_event_class __refdata event_class_syscall_enter = { @@ -1320,8 +1321,8 @@ struct trace_event_class __refdata event_class_syscall_enter = { .fields_array = syscall_enter_fields_array, .get_fields = syscall_get_enter_fields, .raw_init = init_syscall_trace, -#ifdef CONFIG_BPF_EVENTS - .btf_ids = __bpf_trace_btf_ids_sys_enter, +#if defined(CONFIG_BPF_EVENTS) && defined(CONFIG_DEBUG_INFO_BTF) + .btf_ids = syscall_enter_btf_ids, #endif }; @@ -1335,8 +1336,8 @@ struct trace_event_class __refdata event_class_syscall_exit = { }, .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields), .raw_init = init_syscall_trace, -#ifdef CONFIG_BPF_EVENTS - .btf_ids = __bpf_trace_btf_ids_sys_exit, +#if defined(CONFIG_BPF_EVENTS) && defined(CONFIG_DEBUG_INFO_BTF) + .btf_ids = syscall_exit_btf_ids, #endif }; |