[PATCH v2 3/3] tracing/kprobes: Use APIs that matches symbols without .XXX suffix
From: Song Liu <song@kernel.org>
Date: 2024-08-02 21:09:11
Also in:
live-patching, lkml
Subsystem:
kprobes, the rest, tracing · Maintainers:
Naveen N Rao, "David S. Miller", Masami Hiramatsu, Linus Torvalds, Steven Rostedt
Use the new kallsyms APIs that matches symbols name with .XXX suffix. This allows userspace tools to get kprobes on the expected function name, while the actual symbol has a .llvm.<hash> suffix. This only effects kernel compile with CONFIG_LTO_CLANG. Signed-off-by: Song Liu <song@kernel.org> --- kernel/kprobes.c | 6 +++++- kernel/trace/trace_kprobe.c | 11 ++++++++++- 2 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e85de37d9e1e..99102283b076 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c@@ -70,7 +70,11 @@ static DEFINE_PER_CPU(struct kprobe *, kprobe_instance); kprobe_opcode_t * __weak kprobe_lookup_name(const char *name, unsigned int __unused) { - return ((kprobe_opcode_t *)(kallsyms_lookup_name(name))); + unsigned long addr = kallsyms_lookup_name(name); + + if (IS_ENABLED(CONFIG_LTO_CLANG) && !addr) + addr = kallsyms_lookup_name_without_suffix(name); + return ((kprobe_opcode_t *)(addr)); } /*
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 61a6da808203..d2ad0c561c83 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c@@ -203,6 +203,10 @@ unsigned long trace_kprobe_address(struct trace_kprobe *tk) if (tk->symbol) { addr = (unsigned long) kallsyms_lookup_name(trace_kprobe_symbol(tk)); + + if (IS_ENABLED(CONFIG_LTO_CLANG) && !addr) + addr = kallsyms_lookup_name_without_suffix(trace_kprobe_symbol(tk)); + if (addr) addr += tk->rp.kp.offset; } else {
@@ -766,8 +770,13 @@ static unsigned int number_of_same_symbols(const char *mod, const char *func_nam { struct sym_count_ctx ctx = { .count = 0, .name = func_name }; - if (!mod) + if (!mod) { kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count); + if (IS_ENABLED(CONFIG_LTO_CLANG) && !ctx.count) { + kallsyms_on_each_match_symbol_without_suffix( + count_symbols, func_name, &ctx.count); + } + } module_kallsyms_on_each_symbol(mod, count_mod_symbols, &ctx);
--
2.43.0