From d21cb73a9025ffa9ef4f5a0d4051780c264fa02e Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Thu, 28 May 2020 17:21:29 -0300 Subject: [PATCH] perf trace: Grow the syscall table as needed when using libaudit The audit-libs API doesn't provide a way to figure out what is the syscall with the greatest number/id, take that into account when using that method to go on growing the syscall table as we the syscalls go on appearing on the radar. With this the libaudit based method is back working, i.e. when building with: $ make NO_SYSCALL_TABLE=1 O=/tmp/build/perf -C tools/perf install-bin Auto-detecting system features: ... libaudit: [ on ] ... libbfd: [ on ] ... libcap: [ on ] $ ldd ~/bin/perf | grep audit libaudit.so.1 => /lib64/libaudit.so.1 (0x00007faef22df000) $ perf trace is back working, which makes it functional in arches other than x86_64, powerpc, arm64 and s390, that provides these generators: $ find tools/perf/arch/ -name "*syscalltbl*" tools/perf/arch/x86/entry/syscalls/syscalltbl.sh tools/perf/arch/arm64/entry/syscalls/mksyscalltbl tools/perf/arch/s390/entry/syscalls/mksyscalltbl tools/perf/arch/powerpc/entry/syscalls/mksyscalltbl $ Example output forcing the libaudit method on x86_64: # perf trace -e file,nanosleep sleep 0.001 ? ( ): sleep/859090 ... [continued]: execve()) = 0 0.045 ( 0.005 ms): sleep/859090 access(filename: 0x8733e850, mode: R) = -1 ENOENT (No such file or directory) 0.055 ( 0.005 ms): sleep/859090 openat(dfd: CWD, filename: 0x8733ba29, flags: RDONLY|CLOEXEC) = 3 0.079 ( 0.005 ms): sleep/859090 openat(dfd: CWD, filename: 0x87345d20, flags: RDONLY|CLOEXEC) = 3 0.085 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483f58, count: 832) = 832 0.090 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483b50, count: 784) = 784 0.094 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483b20, count: 32) = 32 0.098 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483ad0, count: 68) = 68 0.109 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483a50, count: 784) = 784 0.113 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483730, count: 32) = 32 0.117 ( 0.002 ms): sleep/859090 read(fd: 3, buf: 0x7ffd9d483710, count: 68) = 68 0.320 ( 0.008 ms): sleep/859090 openat(dfd: CWD, filename: 0x872c3660, flags: RDONLY|CLOEXEC) = 3 0.372 ( 1.057 ms): sleep/859090 nanosleep(rqtp: 0x7ffd9d484ac0) = 0 # There are still some limitations when using the libaudit method, that will be fixed at some point, i.e., this works with the mksyscalltbl method but not with libaudit's: # perf trace -e file,*sleep sleep 0.001 event syntax error: '*sleep' \___ parser error Run 'perf list' for a list of valid events Usage: perf trace [] [] or: perf trace [] -- [] or: perf trace record [] [] or: perf trace record [] -- [] -e, --event event/syscall selector. use 'perf list' to list available events # Cc: Adrian Hunter Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-trace.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index 61bafca1018a..4cbb64edc998 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -1748,12 +1748,26 @@ static int trace__read_syscall_info(struct trace *trace, int id) struct syscall *sc; const char *name = syscalltbl__name(trace->sctbl, id); +#ifdef HAVE_SYSCALL_TABLE_SUPPORT if (trace->syscalls.table == NULL) { trace->syscalls.table = calloc(trace->sctbl->syscalls.max_id + 1, sizeof(*sc)); if (trace->syscalls.table == NULL) return -ENOMEM; } +#else + if (id > trace->sctbl->syscalls.max_id || (id == 0 && trace->syscalls.table == NULL)) { + // When using libaudit we don't know beforehand what is the max syscall id + struct syscall *table = realloc(trace->syscalls.table, (id + 1) * sizeof(*sc)); + if (table == NULL) + return -ENOMEM; + + memset(table + trace->sctbl->syscalls.max_id, 0, (id - trace->sctbl->syscalls.max_id) * sizeof(*sc)); + + trace->syscalls.table = table; + trace->sctbl->syscalls.max_id = id; + } +#endif sc = trace->syscalls.table + id; if (sc->nonexistent) return 0; @@ -2077,8 +2091,20 @@ static struct syscall *trace__syscall_info(struct trace *trace, err = -EINVAL; - if (id > trace->sctbl->syscalls.max_id) +#ifdef HAVE_SYSCALL_TABLE_SUPPORT + if (id > trace->sctbl->syscalls.max_id) { +#else + if (id >= trace->sctbl->syscalls.max_id) { + /* + * With libaudit we don't know beforehand what is the max_id, + * so we let trace__read_syscall_info() figure that out as we + * go on reading syscalls. + */ + err = trace__read_syscall_info(trace, id); + if (err) +#endif goto out_cant_read; + } if ((trace->syscalls.table == NULL || trace->syscalls.table[id].name == NULL) && (err = trace__read_syscall_info(trace, id)) != 0)