使用strace跟踪df的执行
[root@tir-test-ali_hz ~]# strace df -h
execve("/usr/bin/df", ["df", "-h"], [/* 26 vars */]) = 0
brk(NULL) = 0x6d9000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f430701c000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=42402, ...}) = 0
mmap(NULL, 42402, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f4307011000
close(3) = 0
open("/lib64/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P%\2\0\0\0\0\0"..., 832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=2173512, ...}) = 0
mmap(NULL, 3981792, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f4306a2f000
mprotect(0x7f4306bf2000, 2093056, PROT_NONE) = 0
mmap(0x7f4306df1000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1c2000) = 0x7f4306df1000
mmap(0x7f4306df7000, 16864, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f4306df7000
close(3) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f4307010000
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f430700e000
arch_prctl(ARCH_SET_FS, 0x7f430700e740) = 0
mprotect(0x7f4306df1000, 16384, PROT_READ) = 0
mprotect(0x616000, 4096, PROT_READ) = 0
mprotect(0x7f430701d000, 4096, PROT_READ) = 0
munmap(0x7f4307011000, 42402) = 0
brk(NULL) = 0x6d9000
brk(0x6fa000) = 0x6fa000
brk(NULL) = 0x6fa000
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=106070960, ...}) = 0
mmap(NULL, 106070960, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f4300506000
close(3) = 0
open("/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=2502, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f430701b000
read(3, "# Locale name alias data base.\n#"..., 4096) = 2502
read(3, "", 4096) = 0
close(3) = 0
munmap(0x7f430701b000, 4096) = 0
open("/usr/share/locale/zh_CN.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/zh_CN.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/zh_CN/LC_MESSAGES/coreutils.mo", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=190751, ...}) = 0
mmap(NULL, 190751, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f4306fdf000
close(3) = 0
open("/usr/share/locale/zh.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/zh.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/zh/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/etc/mtab", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0444, st_size=0, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f430701b000
read(3, "rootfs / rootfs rw 0 0\nsysfs /sy"..., 1024) = 1024
read(3, "odev,noexec,relatime,freezer 0 0"..., 1024) = 1024
read(3, "red 0 0\n/dev/vda1 /var/lib/docke"..., 1024) = 577
read(3, "", 1024) = 0
close(3) = 0
munmap(0x7f430701b000, 4096) = 0
open("/usr/lib64/gconv/gconv-modules.cache", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=26254, ...}) = 0
mmap(NULL, 26254, PROT_READ, MAP_SHARED, 3, 0) = 0x7f4307015000
close(3) = 0
stat("/", {st_mode=S_IFDIR|0555, st_size=4096, ...}) = 0
stat("/sys", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0
stat("/proc", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0
stat("/dev", {st_mode=S_IFDIR|0755, st_size=3100, ...}) = 0
stat("/sys/kernel/security", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/dev/shm", {st_mode=S_IFDIR|S_ISVTX|0777, st_size=40, ...}) = 0
stat("/dev/pts", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/run", {st_mode=S_IFDIR|0755, st_size=980, ...}) = 0
stat("/sys/fs/cgroup", {st_mode=S_IFDIR|0755, st_size=340, ...}) = 0
stat("/sys/fs/cgroup/systemd", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/pstore", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/devices", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/memory", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/cpu,cpuacct", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/freezer", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/hugetlb", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/net_cls,net_prio", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/cpuset", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/pids", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/perf_event", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/fs/cgroup/blkio", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/sys/kernel/config", {st_mode=S_IFDIR|0755, st_size=0, ...}) = 0
stat("/", {st_mode=S_IFDIR|0555, st_size=4096, ...}) = 0
stat("/proc/sys/fs/binfmt_misc",
发现卡在stat("/proc/sys/fs/binfmt_misc" 这一步