mirror of https://gitee.com/openkylin/linux.git
60 Commits
Author | SHA1 | Message | Date |
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Wang Nan | 361f2b1d1d |
perf bpf: Allow BPF program attach to uprobe events
This patch adds a new syntax to the BPF object section name to support probing at uprobe event. Now we can use BPF program like this: SEC( "exec=/lib64/libc.so.6;" "libcwrite=__write" ) int libcwrite(void *ctx) { return 1; } Where, in section name of a program, before the main config string, we can use 'key=value' style options. Now the only option key is "exec", for uprobes. Signed-off-by: Wang Nan <wangnan0@huawei.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1447675815-166222-4-git-send-email-wangnan0@huawei.com [ Changed the separator from \n to ; ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Wang Nan | ba1fae431e |
perf test: Add 'perf test BPF'
This patch adds BPF testcase for testing BPF event filtering. By utilizing the result of 'perf test LLVM', this patch compiles the eBPF sample program then test its ability. The BPF script in 'perf test LLVM' lets only 50% samples generated by epoll_pwait() to be captured. This patch runs that system call for 111 times, so the result should contain 56 samples. Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446817783-86722-8-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Wang Nan | d3e0ce3930 |
perf bpf: Improve BPF related error messages
A series of bpf loader related error codes were introduced to help error reporting. Functions were improved to return these new error codes. Functions which return pointers were adjusted to encode error codes into return value using the ERR_PTR() interface. bpf_loader_strerror() was improved to convert these error messages to strings. It checks the error codes and calls libbpf_strerror() and strerror_r() accordingly, so caller don't need to consider checking the range of the error code. In bpf__strerror_load(), print kernel version of running kernel and the object's 'version' section to notify user how to fix his/her program. v1 -> v2: Use macro for error code. Fetch error message based on array index, eliminate for-loop. Print version strings. Before: # perf record -e ./test_kversion_nomatch_program.o sleep 1 event syntax error: './test_kversion_nomatch_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP After: # perf record -e ./test_kversion_nomatch_program.o ls event syntax error: './test_kversion_nomatch_program.o' \___ 'version' (4.4.0) doesn't match running kernel (4.3.0) SKIP Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446818289-87444-1-git-send-email-wangnan0@huawei.com [ Add 'static inline' to bpf__strerror_prepare_load() when LIBBPF is disabled ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Wang Nan | 6371ca3b54 |
bpf tools: Improve libbpf error reporting
In this patch, a series of libbpf specific error numbers and libbpf_strerror() are introduced to help reporting errors. Functions are updated to pass correct the error number through the CHECK_ERR() macro. All users of bpf_object__open{_buffer}() and bpf_program__title() in perf are modified accordingly. In addition, due to the error codes changing, bpf__strerror_load() is also modified to use them. bpf__strerror_head() is also changed accordingly so it can parse libbpf errors. bpf_loader_strerror() is introduced for that purpose, and will be improved by the following patch. load_program() is improved not to dump log buffer if it is empty. log buffer is also used to deduce whether the error was caused by an invalid program or other problem. v1 -> v2: - Using macro for error code. - Fetch error message based on array index, eliminate for-loop. - Use log buffer to detect the reason of failure. 3 new error code are introduced to replace LIBBPF_ERRNO__LOAD. In v1: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_kversion_nomatch_program.o ls event syntax error: './test_kversion_nomatch_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP # perf record -e ./test_big_program.o ls event syntax error: './test_big_program.o' \___ Failed to load program: Validate your program and check 'license'/'version' sections in your object SKIP In v2: # perf record -e ./test_ill_program.o ls event syntax error: './test_ill_program.o' \___ Kernel verifier blocks program loading SKIP # perf record -e ./test_kversion_nomatch_program.o event syntax error: './test_kversion_nomatch_program.o' \___ Incorrect kernel version SKIP (Will be further improved by following patches) # perf record -e ./test_big_program.o event syntax error: './test_big_program.o' \___ Program too big SKIP Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446817783-86722-2-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Wang Nan | 7a0119468c |
perf bpf: Mute libbpf when '-v' not set
According to [1], libbpf should be muted. This patch reset info and warning message level to ensure libbpf doesn't output anything even if error happened. [1] http://lkml.kernel.org/r/20151020151255.GF5119@kernel.org Committer note: Before: Testing it with an incompatible kernel version in the .c file that generated foo.o: [root@zoo ~]# perf record -e /tmp/foo.o sleep 1 libbpf: load bpf program failed: Invalid argument libbpf: -- BEGIN DUMP LOG --- libbpf: libbpf: -- END LOG -- libbpf: failed to load program 'fork=_do_fork' libbpf: failed to load object '/tmp/foo.o' event syntax error: '/tmp/foo.o' \___ Invalid argument: Are you root and runing a CONFIG_BPF_SYSCALL kernel? (add -v to see detail) Run 'perf list' for a list of valid events Usage: perf record [<options>] [<command>] or: perf record [<options>] -- <command> [<options>] -e, --event <event> event selector. use 'perf list' to list available events [root@zoo ~]# After: [root@zoo ~]# perf record -e /tmp/foo.o sleep 1 event syntax error: '/tmp/foo.o' \___ Invalid argument: Are you root and runing a CONFIG_BPF_SYSCALL kernel? (add -v to see detail) Run 'perf list' for a list of valid events Usage: perf record [<options>] [<command>] or: perf record [<options>] -- <command> [<options>] -e, --event <event> event selector. use 'perf list' to list available events [root@zoo ~]# This, BTW, need fixing to emit a proper message by validating the version in the foo.o "version" ELF section against the running kernel, warning the user instead of asking the kernel to load a binary that it will refuse due to unmatching kernel version. Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1446547486-229499-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Wang Nan | d509db0473 |
perf tools: Compile scriptlets to BPF objects when passing '.c' to --event
This patch provides infrastructure for passing source files to --event directly using: # perf record --event bpf-file.c command This patch does following works: 1) Allow passing '.c' file to '--event'. parse_events_load_bpf() is expanded to allow caller tell it whether the passed file is source file or object. 2) llvm__compile_bpf() is called to compile the '.c' file, the result is saved into memory. Use bpf_object__open_buffer() to load the in-memory object. Introduces a bpf-script-example.c so we can manually test it: # perf record --clang-opt "-DLINUX_VERSION_CODE=0x40200" --event ./bpf-script-example.c sleep 1 Note that '--clang-opt' must put before '--event'. Futher patches will merge it into a testcase so can be tested automatically. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1444826502-49291-10-git-send-email-wangnan0@huawei.com Signed-off-by: He Kuang <hekuang@huawei.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Wang Nan | 4edf30e39e |
perf bpf: Collect perf_evsel in BPF object files
This patch creates a 'struct perf_evsel' for every probe in a BPF object file(s) and fills 'struct evlist' with them. The previously introduced dummy event is now removed. After this patch, the following command: # perf record --event filter.o ls Can trace on each of the probes defined in filter.o. The core of this patch is bpf__foreach_tev(), which calls a callback function for each 'struct probe_trace_event' event for a bpf program with each associated file descriptors. The add_bpf_event() callback creates evsels by calling parse_events_add_tracepoint(). Since bpf-loader.c will not be built if libbpf is turned off, an empty bpf__foreach_tev() is defined in bpf-loader.h to avoid build errors. Committer notes: Before: # /tmp/oldperf record --event /tmp/foo.o -a usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.198 MB perf.data ] # perf evlist /tmp/foo.o # perf evlist -v /tmp/foo.o: type: 1, size: 112, config: 0x9, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 I.e. we create just the PERF_TYPE_SOFTWARE (type: 1), PERF_COUNT_SW_DUMMY(config 0x9) event, now, with this patch: # perf record --event /tmp/foo.o -a usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.210 MB perf.data ] # perf evlist -v perf_bpf_probe:fork: type: 2, size: 112, config: 0x6bd, { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|PERIOD|RAW, disabled: 1, inherit: 1, mmap: 1, comm: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 # We now have a PERF_TYPE_SOFTWARE (type: 1), but the config states 0x6bd, which is how, after setting up the event via the kprobes interface, the 'perf_bpf_probe:fork' event is accessible via the perf_event_open syscall. This is all transient, as soon as the 'perf record' session ends, these probes will go away. To see how it looks like, lets try doing a neverending session, one that expects a control+C to end: # perf record --event /tmp/foo.o -a So, with that in place, we can use 'perf probe' to see what is in place: # perf probe -l perf_bpf_probe:fork (on _do_fork@acme/git/linux/kernel/fork.c) We also can use debugfs: [root@felicio ~]# cat /sys/kernel/debug/tracing/kprobe_events p:perf_bpf_probe/fork _text+638512 Ok, now lets stop and see if we got some forks: [root@felicio linux]# perf record --event /tmp/foo.o -a ^C[ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.325 MB perf.data (111 samples) ] [root@felicio linux]# perf script sshd 1271 [003] 81797.507678: perf_bpf_probe:fork: (ffffffff8109be30) sshd 18309 [000] 81797.524917: perf_bpf_probe:fork: (ffffffff8109be30) sshd 18309 [001] 81799.381603: perf_bpf_probe:fork: (ffffffff8109be30) sshd 18309 [001] 81799.408635: perf_bpf_probe:fork: (ffffffff8109be30) <SNIP> Sure enough, we have 111 forks :-) Callchains seems to work as well: # perf report --stdio --no-child # To display the perf.data header info, please use --header/--header-only options. # # Total Lost Samples: 0 # # Samples: 562 of event 'perf_bpf_probe:fork' # Event count (approx.): 562 # # Overhead Command Shared Object Symbol # ........ ........ ................ ............ # 44.66% sh [kernel.vmlinux] [k] _do_fork | ---_do_fork entry_SYSCALL_64_fastpath __libc_fork make_child 26.16% make [kernel.vmlinux] [k] _do_fork <SNIP> # Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1444826502-49291-7-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Wang Nan | 1e5e3ee8ff |
perf tools: Load eBPF object into kernel
This patch utilizes bpf_object__load() provided by libbpf to load all objects into kernel. Committer notes: Testing it: When using an incorrect kernel version number, i.e., having this in your eBPF proggie: int _version __attribute__((section("version"), used)) = 0x40100; For a 4.3.0-rc6+ kernel, say, this happens and needs checking at event parsing time, to provide a better error report to the user: # perf record --event /tmp/foo.o sleep 1 libbpf: load bpf program failed: Invalid argument libbpf: -- BEGIN DUMP LOG --- libbpf: libbpf: -- END LOG -- libbpf: failed to load program 'fork=_do_fork' libbpf: failed to load object '/tmp/foo.o' event syntax error: '/tmp/foo.o' \___ Invalid argument: Are you root and runing a CONFIG_BPF_SYSCALL kernel? (add -v to see detail) Run 'perf list' for a list of valid events Usage: perf record [<options>] [<command>] or: perf record [<options>] -- <command> [<options>] -e, --event <event> event selector. use 'perf list' to list available events If we instead make it match, i.e. use 0x40300 on this v4.3.0-rc6+ kernel, the whole process goes thru: # perf record --event /tmp/foo.o -a usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.202 MB perf.data ] # perf evlist -v /tmp/foo.o: type: 1, size: 112, config: 0x9, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 # Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1444826502-49291-6-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Wang Nan | aa3abf30bb |
perf tools: Create probe points for BPF programs
This patch introduces bpf__{un,}probe() functions to enable callers to create kprobe points based on section names a BPF program. It parses the section names in the program and creates corresponding 'struct perf_probe_event' structures. The parse_perf_probe_command() function is used to do the main parsing work. The resuling 'struct perf_probe_event' is stored into program private data for further using. By utilizing the new probing API, this patch creates probe points during event parsing. To ensure probe points be removed correctly, register an atexit hook so even perf quit through exit() bpf__clear() is still called, so probing points are cleared. Note that bpf_clear() should be registered before bpf__probe() is called, so failure of bpf__probe() can still trigger bpf__clear() to remove probe points which are already probed. strerror style error reporting scaffold is created by this patch. bpf__strerror_probe() is the first error reporting function in bpf-loader.c. Committer note: Trying it: To build a test eBPF object file: I am testing using a script I built from the 'perf test -v LLVM' output: $ cat ~/bin/hello-ebpf export KERNEL_INC_OPTIONS="-nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.8.3/include -I/home/acme/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated -I/home/acme/git/linux/include -Iinclude -I/home/acme/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/acme/git/linux/include/uapi -Iinclude/generated/uapi -include /home/acme/git/linux/include/linux/kconfig.h" export WORKING_DIR=/lib/modules/4.2.0/build export CLANG_SOURCE=- export CLANG_OPTIONS=-xc OBJ=/tmp/foo.o rm -f $OBJ echo '__attribute__((section("fork=do_fork"), used)) int fork(void *ctx) {return 0;} char _license[] __attribute__((section("license"), used)) = "GPL";int _version __attribute__((section("version"), used)) = 0x40100;' | \ clang -D__KERNEL__ $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o /tmp/foo.o && file $OBJ --- First asking to put a probe in a function not present in the kernel (misses the initial _): $ perf record --event /tmp/foo.o sleep 1 Probe point 'do_fork' not found. event syntax error: '/tmp/foo.o' \___ You need to check probing points in BPF file (add -v to see detail) Run 'perf list' for a list of valid events Usage: perf record [<options>] [<command>] or: perf record [<options>] -- <command> [<options>] -e, --event <event> event selector. use 'perf list' to list available events $ --- Now, with "__attribute__((section("fork=_do_fork"), used)): $ grep _do_fork /proc/kallsyms ffffffff81099ab0 T _do_fork $ perf record --event /tmp/foo.o sleep 1 Failed to open kprobe_events: Permission denied event syntax error: '/tmp/foo.o' \___ Permission denied --- Cool, we need to provide some better hints, "kprobe_events" is too low level, one doesn't strictly need to know the precise details of how these things are put in place, so something that shows the command needed to fix the permissions would be more helpful. Lets try as root instead: # perf record --event /tmp/foo.o sleep 1 Lowering default frequency rate to 1000. Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate. [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.013 MB perf.data ] # perf evlist /tmp/foo.o [root@felicio ~]# perf evlist -v /tmp/foo.o: type: 1, size: 112, config: 0x9, { sample_period, sample_freq }: 1000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 --- Signed-off-by: Wang Nan <wangnan0@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1444826502-49291-5-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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Wang Nan | 69d262a93a |
perf ebpf: Add the libbpf glue
The 'bpf-loader.[ch]' files are introduced in this patch. Which will be the interface between perf and libbpf. bpf__prepare_load() resides in bpf-loader.c. Following patches will enrich these two files. Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1444826502-49291-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |