Messages in this thread | | | Subject | Re: perf test BPF failing on 4.15.0-rc6 | From | "Wangnan (F)" <> | Date | Wed, 3 Jan 2018 12:42:13 +0800 |
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Unable to reproduce. In my kernel configuration, SyS_epoll_wait is not inlined at all.
From the log you sent, it seems that all 3 instances are attached. This testcase should work if the last one (SyS_epoll_wait) get probed correctly.
Could you please have a look if the 3rd kprobe event (p:perf_bpf_probe/func_2 _text+2845824) works?
Thank you.
On 2018/1/3 2:59, Arnaldo Carvalho de Melo wrote: > Hi Wang, > > I just updated my machine to Fedora 27 and 4.15.0-rc6 and the > only test failing for me is: > > [root@jouet linux]# perf test bpf > 39: BPF filter : > 39.1: Basic BPF filtering : FAILED! > 39.2: BPF pinning : Skip > 39.3: BPF prologue generation : Skip > 39.4: BPF relocation checker : Skip > [root@jouet linux]# > > I haven't checked but perhaps the problem is that SyS_epoll_wait seems > to now be inlined in three places and perhaps the eBPF proggie is being > added to just one of them? > > Seemingly relevant excerpt: > > Open Debuginfo file: /lib/modules/4.15.0-rc6/build/vmlinux > Try to find probe point from debuginfo. > Matched function: SyS_epoll_wait [2f40eb7] > found inline addr: 0xffffffff812b6ff1 > Probe point found: compat_SyS_epoll_pwait+129 > found inline addr: 0xffffffff812b6de7 > Probe point found: SyS_epoll_pwait+135 > found inline addr: 0xffffffff812b6c80 > Probe point found: SyS_epoll_wait+0 > Found 3 probe_trace_events. > > - Arnaldo > > P.S.: Full -v output: > > [root@jouet linux]# uname -a > Linux jouet 4.15.0-rc6 #4 SMP Tue Jan 2 14:30:53 -03 2018 x86_64 x86_64 x86_64 GNU/Linux > [root@jouet linux]# gcc -v > Using built-in specs. > COLLECT_GCC=/usr/bin/gcc > COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-redhat-linux/7/lto-wrapper > OFFLOAD_TARGET_NAMES=nvptx-none > OFFLOAD_TARGET_DEFAULT=1 > Target: x86_64-redhat-linux > Configured with: ../configure --enable-bootstrap --enable-languages=c,c++,objc,obj-c++,fortran,ada,go,lto --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared --enable-threads=posix --enable-checking=release --enable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-gcc-major-version-only --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl --enable-libmpx --enable-offload-targets=nvptx-none --without-cuda-driver --enable-gnu-indirect-function --with-tune=generic --with-arch_32=i686 --build=x86_64-redhat-linux > Thread model: posix > gcc version 7.2.1 20170915 (Red Hat 7.2.1-2) (GCC) > [root@jouet linux]# clang -v > clang version 6.0.0 (http://llvm.org/git/clang.git 56cc8f8880db2ebc433eeb6b6a707c101467a186) (http://llvm.org/git/llvm.git 3656d83960a4f3fedf6d8f19043abf52379f78c3) > Target: x86_64-unknown-linux-gnu > Thread model: posix > InstalledDir: /usr/local/bin > Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/7 > Selected GCC installation: /usr/lib/gcc/x86_64-redhat-linux/7 > Candidate multilib: .;@m64 > Candidate multilib: 32;@m32 > Selected multilib: .;@m64 > [root@jouet linux]# perf test -v BPF > 39: BPF filter : > 39.1: Basic BPF filtering : > --- start --- > test child forked, pid 24304 > Kernel build dir is set to /lib/modules/4.15.0-rc6/build > set env: KBUILD_DIR=/lib/modules/4.15.0-rc6/build > unset env: KBUILD_OPTS > include option is set to -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/7/include -I/home/acme/git/linux/arch/x86/include -I./arch/x86/include/generated -I/home/acme/git/linux/include -I./include -I/home/acme/git/linux/arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I/home/acme/git/linux/include/uapi -I./include/generated/uapi -include /home/acme/git/linux/include/linux/kconfig.h > set env: NR_CPUS=4 > set env: LINUX_VERSION_CODE=0x40f00 > set env: CLANG_EXEC=/usr/local/bin/clang > set env: CLANG_OPTIONS=-xc > set env: KERNEL_INC_OPTIONS= -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/7/include -I/home/acme/git/linux/arch/x86/include -I./arch/x86/include/generated -I/home/acme/git/linux/include -I./include -I/home/acme/git/linux/arch/x86/include/uapi -I./arch/x86/include/generated/uapi -I/home/acme/git/linux/include/uapi -I./include/generated/uapi -include /home/acme/git/linux/include/linux/kconfig.h > set env: WORKING_DIR=/lib/modules/4.15.0-rc6/build > set env: CLANG_SOURCE=- > llvm compiling command template: echo '/* > * bpf-script-example.c > * Test basic LLVM building > */ > #ifndef LINUX_VERSION_CODE > # error Need LINUX_VERSION_CODE > # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig' > #endif > #define BPF_ANY 0 > #define BPF_MAP_TYPE_ARRAY 2 > #define BPF_FUNC_map_lookup_elem 1 > #define BPF_FUNC_map_update_elem 2 > > static void *(*bpf_map_lookup_elem)(void *map, void *key) = > (void *) BPF_FUNC_map_lookup_elem; > static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) = > (void *) BPF_FUNC_map_update_elem; > > struct bpf_map_def { > unsigned int type; > unsigned int key_size; > unsigned int value_size; > unsigned int max_entries; > }; > > #define SEC(NAME) __attribute__((section(NAME), used)) > struct bpf_map_def SEC("maps") flip_table = { > .type = BPF_MAP_TYPE_ARRAY, > .key_size = sizeof(int), > .value_size = sizeof(int), > .max_entries = 1, > }; > > SEC("func=SyS_epoll_wait") > int bpf_func__SyS_epoll_wait(void *ctx) > { > int ind =0; > int *flag = bpf_map_lookup_elem(&flip_table, &ind); > int new_flag; > if (!flag) > return 0; > /* flip flag and store back */ > new_flag = !*flag; > bpf_map_update_elem(&flip_table, &ind, &new_flag, BPF_ANY); > return new_flag; > } > char _license[] SEC("license") = "GPL"; > int _version SEC("version") = LINUX_VERSION_CODE; > ' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS -DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o - > libbpf: loading object '[basic_bpf_test]' from buffer > libbpf: section .strtab, size 120, link 0, flags 0, type=3 > libbpf: section .text, size 0, link 0, flags 6, type=1 > libbpf: section func=SyS_epoll_wait, size 192, link 0, flags 6, type=1 > libbpf: found program func=SyS_epoll_wait > libbpf: section .relfunc=SyS_epoll_wait, size 32, link 8, flags 0, type=9 > libbpf: section maps, size 16, link 0, flags 3, type=1 > libbpf: section license, size 4, link 0, flags 3, type=1 > libbpf: license of [basic_bpf_test] is GPL > libbpf: section version, size 4, link 0, flags 3, type=1 > libbpf: kernel version of [basic_bpf_test] is 40f00 > libbpf: section .symtab, size 168, link 1, flags 0, type=2 > libbpf: maps in [basic_bpf_test]: 1 maps in 16 bytes > libbpf: map 0 is "flip_table" > libbpf: collecting relocating info for: 'func=SyS_epoll_wait' > libbpf: relocation: insn_idx=4 > libbpf: relocation: find map 0 (flip_table) for insn 4 > libbpf: relocation: insn_idx=17 > libbpf: relocation: find map 0 (flip_table) for insn 17 > bpf: config program 'func=SyS_epoll_wait' > symbol:SyS_epoll_wait file:(null) line:0 offset:0 return:0 lazy:(null) > bpf: config 'func=SyS_epoll_wait' is ok > Looking at the vmlinux_path (8 entries long) > Using /lib/modules/4.15.0-rc6/build/vmlinux for symbols > Open Debuginfo file: /lib/modules/4.15.0-rc6/build/vmlinux > Try to find probe point from debuginfo. > Matched function: SyS_epoll_wait [2f40eb7] > found inline addr: 0xffffffff812b6ff1 > Probe point found: compat_SyS_epoll_pwait+129 > found inline addr: 0xffffffff812b6de7 > Probe point found: SyS_epoll_pwait+135 > found inline addr: 0xffffffff812b6c80 > Probe point found: SyS_epoll_wait+0 > Found 3 probe_trace_events. > Opening /sys/kernel/debug/tracing//kprobe_events write=1 > Writing event: p:perf_bpf_probe/func _text+2846705 > Writing event: p:perf_bpf_probe/func_1 _text+2846183 > Writing event: p:perf_bpf_probe/func_2 _text+2845824 > libbpf: create map flip_table: fd=3 > add bpf event perf_bpf_probe:func and attach bpf program 4 > registering plugin: /root/.traceevent/plugins/plugin_kvm.so > registering plugin: /root/.traceevent/plugins/plugin_hrtimer.so > registering plugin: /root/.traceevent/plugins/plugin_jbd2.so > registering plugin: /root/.traceevent/plugins/plugin_kmem.so > registering plugin: /root/.traceevent/plugins/plugin_scsi.so > registering plugin: /root/.traceevent/plugins/plugin_sched_switch.so > registering plugin: /root/.traceevent/plugins/plugin_function.so > registering plugin: /root/.traceevent/plugins/plugin_xen.so > registering plugin: /root/.traceevent/plugins/plugin_mac80211.so > registering plugin: /root/.traceevent/plugins/plugin_cfg80211.so > adding perf_bpf_probe:func > adding perf_bpf_probe:func to 0x24e3850 > add bpf event perf_bpf_probe:func_1 and attach bpf program 4 > adding perf_bpf_probe:func_1 > adding perf_bpf_probe:func_1 to 0x1965020 > add bpf event perf_bpf_probe:func_2 and attach bpf program 4 > adding perf_bpf_probe:func_2 > adding perf_bpf_probe:func_2 to 0x19656a0 > mmap size 1052672B > BPF filter result incorrect, expected 56, got 0 samples > Opening /sys/kernel/debug/tracing//kprobe_events write=1 > Opening /sys/kernel/debug/tracing//uprobe_events write=1 > Parsing probe_events: p:perf_bpf_probe/func _text+2846705 > Group:perf_bpf_probe Event:func probe:p > Parsing probe_events: p:perf_bpf_probe/func_1 _text+2846183 > Group:perf_bpf_probe Event:func_1 probe:p > Parsing probe_events: p:perf_bpf_probe/func_2 _text+2845824 > Group:perf_bpf_probe Event:func_2 probe:p > Writing event: -:perf_bpf_probe/func > Opening /sys/kernel/debug/tracing//kprobe_events write=1 > Opening /sys/kernel/debug/tracing//uprobe_events write=1 > Parsing probe_events: p:perf_bpf_probe/func_1 _text+2846183 > Group:perf_bpf_probe Event:func_1 probe:p > Parsing probe_events: p:perf_bpf_probe/func_2 _text+2845824 > Group:perf_bpf_probe Event:func_2 probe:p > Writing event: -:perf_bpf_probe/func_1 > Opening /sys/kernel/debug/tracing//kprobe_events write=1 > Opening /sys/kernel/debug/tracing//uprobe_events write=1 > Parsing probe_events: p:perf_bpf_probe/func_2 _text+2845824 > Group:perf_bpf_probe Event:func_2 probe:p > Writing event: -:perf_bpf_probe/func_2 > test child finished with -1 > ---- end ---- > BPF filter subtest 0: FAILED! > 39.2: BPF pinning : > --- force skipped --- > BPF filter subtest 1: Skip > 39.3: BPF prologue generation : > --- force skipped --- > BPF filter subtest 2: Skip > 39.4: BPF relocation checker : > --- force skipped --- > BPF filter subtest 3: Skip > [root@jouet linux]# > [root@jouet linux]#
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