From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yonghong Song Subject: Re: [PATCH bpf-next] samples/bpf: fix kprobe attachment issue on x64 Date: Sun, 29 Apr 2018 17:00:23 -0700 Message-ID: <4524f1c3-a63c-1fb1-ee53-94350e0dc280@fb.com> References: <20180429220631.2925150-1-yhs@fb.com> <20180429232031.5p2y4s274inymf4b@ast-mbp> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Cc: , , , To: Alexei Starovoitov Return-path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:40636 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754382AbeD3AA6 (ORCPT ); Sun, 29 Apr 2018 20:00:58 -0400 In-Reply-To: <20180429232031.5p2y4s274inymf4b@ast-mbp> Content-Language: en-US Sender: netdev-owner@vger.kernel.org List-ID: On 4/29/18 4:20 PM, Alexei Starovoitov wrote: > On Sun, Apr 29, 2018 at 03:06:31PM -0700, Yonghong Song wrote: >> Commit d5a00528b58c ("syscalls/core, syscalls/x86: Rename >> struct pt_regs-based sys_*() to __x64_sys_*()") renamed a lot >> of syscall function sys_*() to __x64_sys_*(). >> This caused several kprobe based samples/bpf tests failing. >> >> This patch fixed the problem by using __x64_sys_*(), >> instead of sys_*(), in bpf program SEC annotations if >> the target arch is __TARGET_ARCH_x86. >> >> Fixes: d5a00528b58c ("syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()") >> Signed-off-by: Yonghong Song >> --- >> samples/bpf/map_perf_test_kern.c | 32 +++++++++++++++++++++++ >> samples/bpf/test_current_task_under_cgroup_kern.c | 4 +++ >> samples/bpf/test_map_in_map_kern.c | 4 +++ >> samples/bpf/test_probe_write_user_kern.c | 4 +++ >> samples/bpf/trace_output_kern.c | 4 +++ >> samples/bpf/tracex2_kern.c | 4 +++ >> 6 files changed, 52 insertions(+) >> >> diff --git a/samples/bpf/map_perf_test_kern.c b/samples/bpf/map_perf_test_kern.c >> index 2b2ffb9..79f4320 100644 >> --- a/samples/bpf/map_perf_test_kern.c >> +++ b/samples/bpf/map_perf_test_kern.c >> @@ -95,7 +95,11 @@ struct bpf_map_def SEC("maps") lru_hash_lookup_map = { >> .max_entries = MAX_ENTRIES, >> }; >> >> +#ifdef __TARGET_ARCH_x86 >> +SEC("kprobe/__x64_sys_getuid") >> +#else >> SEC("kprobe/sys_getuid") >> +#endif > > I think it would be better to hack bpf_load.c to add __x64_ > automatically when it matches "sys_" in the beginning of kprobe name. I thought this before but there a few outliers for the particular kernel configuration I have for latest bpf-next: drivers/video/fbdev/core/sysfillrect.c: void sys_fillrect(struct fb_info *p, const struct fb_fillrect *rect) drivers/video/fbdev/core/syscopyarea.c: void sys_copyarea(struct fb_info *p, const struct fb_copyarea *area) drivers/video/fbdev/core/sysimgblt.c: void sys_imageblit(struct fb_info *p, const struct fb_image *image) I am not sure whether any other outliers for other configurations or in the future somebody could introduces a kernel function sys_ but not a syscall. That is why I took the approach as in the patch.