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tracing: Avoid BTF lookup in atomic context

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The function graph trace formatter can be called from ftrace_dump_one()
with interrupts disabled. When ftrace_dump_on_oops is enabled, the trace
panic notifier can reach ftrace_dump() from the panic path, including the
nmi_panic() path used by the hard lockup detector.

btf_find_func_proto() calls bpf_find_btf_id(), which may initialize vmlinux
BTF under a mutex. Skip the BTF lookup when running in an atomic context
or with interrupts disabled, and fall back to the existing return value
formatting.

Link: https://patch.msgid.link/20260916133218.1282590-2-dolinux.peng@gmail.com
Fixes: ebeed8d4a5 ("tracing/probes: Move finding func-proto API and getting func-param API to trace_btf")
Signed-off-by: pengdonglin <pengdonglin@xiaomi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
pengdonglin 2026-09-16 21:32:15 +08:00 committed by Steven Rostedt
parent 5505be91c9
commit 42643ba35d
1 changed files with 3 additions and 0 deletions
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3
kernel/trace/trace_btf.c
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@ -15,6 +15,9 @@ const struct btf_type *btf_find_func_proto(const char *func_name, struct btf **b
const struct btf_type *t;
s32 id;
if (unlikely(in_atomic() || irqs_disabled()))
return NULL;
id = bpf_find_btf_id(func_name, BTF_KIND_FUNC, btf_p);
if (id < 0)
return NULL;