From c09eb2e578eb1668bbc84dc07e8d8bd6f04b9a02 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 26 Sep 2022 17:33:38 +0200 Subject: bpf: Adjust kprobe_multi entry_ip for CONFIG_X86_KERNEL_IBT Martynas reported bpf_get_func_ip returning +4 address when CONFIG_X86_KERNEL_IBT option is enabled. When CONFIG_X86_KERNEL_IBT is enabled we'll have endbr instruction at the function entry, which screws return value of bpf_get_func_ip() helper that should return the function address. There's short term workaround for kprobe_multi bpf program made by Alexei [1], but we need this fixup also for bpf_get_attach_cookie, that returns cookie based on the entry_ip value. Moving the fixup in the fprobe handler, so both bpf_get_func_ip and bpf_get_attach_cookie get expected function address when CONFIG_X86_KERNEL_IBT option is enabled. Also renaming kprobe_multi_link_handler entry_ip argument to fentry_ip so it's clearer this is an ftrace __fentry__ ip. [1] commit 7f0059b58f02 ("selftests/bpf: Fix kprobe_multi test.") Cc: Peter Zijlstra Reported-by: Martynas Pumputis Acked-by: Andrii Nakryiko Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20220926153340.1621984-5-jolsa@kernel.org Signed-off-by: Alexei Starovoitov --- tools/testing/selftests/bpf/progs/kprobe_multi.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'tools/testing') diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi.c b/tools/testing/selftests/bpf/progs/kprobe_multi.c index 08f95a8155d1..98c3399e15c0 100644 --- a/tools/testing/selftests/bpf/progs/kprobe_multi.c +++ b/tools/testing/selftests/bpf/progs/kprobe_multi.c @@ -36,15 +36,13 @@ __u64 kretprobe_test6_result = 0; __u64 kretprobe_test7_result = 0; __u64 kretprobe_test8_result = 0; -extern bool CONFIG_X86_KERNEL_IBT __kconfig __weak; - static void kprobe_multi_check(void *ctx, bool is_return) { if (bpf_get_current_pid_tgid() >> 32 != pid) return; __u64 cookie = test_cookie ? bpf_get_attach_cookie(ctx) : 0; - __u64 addr = bpf_get_func_ip(ctx) - (CONFIG_X86_KERNEL_IBT ? 4 : 0); + __u64 addr = bpf_get_func_ip(ctx); #define SET(__var, __addr, __cookie) ({ \ if (((const void *) addr == __addr) && \ -- cgit v1.2.3