mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-10-11 11:09:13 +00:00
9b57fb7e35
The 'if' keyword is a define that expands to complex code when
CONFIG_PROFILE_ALL_BRANCHES is selected, which causes a 'perf test LLVM'
failure like:
$ ./perf test LLVM
35: LLVM search and compile :
35.1: Basic BPF llvm compile : Ok
35.2: kbuild searching : Ok
35.3: Compile source for BPF prologue generation: FAILED!
35.4: Compile source for BPF relocation : Skip
The only affected test case is bpf-script-test-prologue.c
because it uses kernel headers and has 'if' inside.
This patch undefines 'if' to make it passes perf test.
More detailed analysis from a message in this thread, also by Wang:
The problem is caused by following relocation information:
$ readelf -a ./llvmsubtest3
...
[ 5] _ftrace_branch PROGBITS 0000000000000000 00000260
00000000000000a0 0000000000000000 WA 0 0 4
...
Relocation section '.relfunc=null_lseek file->f_mode offset orig' at
offset 0x490 contains 4 entries:
Offset Info Type Sym. Value Sym. Name
000000000038 000b00000001 unrecognized: 1 0000000000000000 _ftrace_branch
0000000000b0 000b00000001 unrecognized: 1 0000000000000000 _ftrace_branch
000000000128 000b00000001 unrecognized: 1 0000000000000000 _ftrace_branch
0000000001c0 000b00000001 unrecognized: 1 0000000000000000 _ftrace_branch
Relocation section '.rel_ftrace_branch' at offset 0x4d0 contains 8 entries:
Offset Info Type Sym. Value Sym. Name
000000000000 000200000001 unrecognized: 1 0000000000000000 .L__func__.bpf_func__n
000000000008 000100000001 unrecognized: 1 0000000000000015 .L.str
000000000028 000200000001 unrecognized: 1 0000000000000000 .L__func__.bpf_func__n
000000000030 000100000001 unrecognized: 1 0000000000000015 .L.str
000000000050 000200000001 unrecognized: 1 0000000000000000 .L__func__.bpf_func__n
000000000058 000100000001 unrecognized: 1 0000000000000015 .L.str
000000000078 000200000001 unrecognized: 1 0000000000000000 .L__func__.bpf_func__n
000000000080 000100000001 unrecognized: 1 0000000000000015 .L.str
...
So I think the failure is because you enabled CONFIG_PROFILE_ALL_BRANCHES.
I can reproduce your buggy result by selecting
CONFIG_PROFILE_ALL_BRANCHES in my kbuild:
$ ./perf test LLVM
35: LLVM search and compile :
35.1: Basic BPF llvm compile : Ok
35.2: kbuild searching : Ok
35.3: Compile source for BPF prologue generation: FAILED!
35.4: Compile source for BPF relocation : Skip
Simply undef CONFIG_PROFILE_ALL_BRANCHES in clang opts not working
because it is introduced by "#include <uapi/linux/fs.h>", which override
cmdline options. So I think the best way is to undefine 'if' inside BPF
script.
Reported-and-Tested-by: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/20170620183203.2517-1-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
|
||
|---|---|---|
| .. | ||
| attr | ||
| .gitignore | ||
| attr.c | ||
| attr.py | ||
| backward-ring-buffer.c | ||
| bitmap.c | ||
| bp_signal.c | ||
| bp_signal_overflow.c | ||
| bpf-script-example.c | ||
| bpf-script-test-kbuild.c | ||
| bpf-script-test-prologue.c | ||
| bpf-script-test-relocation.c | ||
| bpf.c | ||
| Build | ||
| builtin-test.c | ||
| clang.c | ||
| code-reading.c | ||
| cpumap.c | ||
| dso-data.c | ||
| dwarf-unwind.c | ||
| event-times.c | ||
| event_update.c | ||
| evsel-roundtrip-name.c | ||
| evsel-tp-sched.c | ||
| expr.c | ||
| fdarray.c | ||
| hists_common.c | ||
| hists_common.h | ||
| hists_cumulate.c | ||
| hists_filter.c | ||
| hists_link.c | ||
| hists_output.c | ||
| is_printable_array.c | ||
| keep-tracking.c | ||
| kmod-path.c | ||
| llvm.c | ||
| llvm.h | ||
| make | ||
| mmap-basic.c | ||
| mmap-thread-lookup.c | ||
| openat-syscall-all-cpus.c | ||
| openat-syscall-tp-fields.c | ||
| openat-syscall.c | ||
| parse-events.c | ||
| parse-no-sample-id-all.c | ||
| perf-hooks.c | ||
| perf-record.c | ||
| perf-targz-src-pkg | ||
| pmu.c | ||
| python-use.c | ||
| sample-parsing.c | ||
| sdt.c | ||
| stat.c | ||
| sw-clock.c | ||
| switch-tracking.c | ||
| task-exit.c | ||
| tests.h | ||
| thread-map.c | ||
| thread-mg-share.c | ||
| topology.c | ||
| unit_number__scnprintf.c | ||
| vmlinux-kallsyms.c | ||