root@panda-maverick:~# ifconfig usb0 up
root@panda-maverick:~# strace ifconfig usb0 down
execve("/sbin/ifconfig", ["ifconfig", "usb0", "down"], [/* 15 vars */]) = 0
brk(0) = 0x1e000
uname({sys="Linux", node="panda-maverick", ...}) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40017000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=16970, ...}) = 0
mmap2(NULL, 16970, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40019000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/libgcc_s.so.1", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\320%\0\0004\0\0\0"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0644, st_size=38488, ...}) = 0
mmap2(NULL, 37140, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x40021000
mmap2(0x40029000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x8) = 0x40029000
close(3) = 0
access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory)
open("/lib/libc.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\301V\1\0004\0\0\0"..., 512) = 512
fstat64(3, {st_mode=S_IFREG|0755, st_size=988620, ...}) = 0
mmap2(NULL, 1025308, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x4002b000
mprotect(0x40118000, 32768, PROT_NONE) = 0
mmap2(0x40120000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0xed) = 0x40120000
mmap2(0x40123000, 9500, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x40123000
close(3) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x4001e000
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40126000
set_tls(0x401264c0, 0x4002091c, 0x40126b98, 0x401264c0, 0x40020000) = 0
mprotect(0x40120000, 8192, PROT_READ) = 0
mprotect(0x40029000, 4096, PROT_READ) = 0
mprotect(0x1b000, 4096, PROT_READ) = 0
mprotect(0x4001f000, 4096, PROT_READ) = 0
munmap(0x40019000, 16970) = 0
brk(0) = 0x1e000
brk(0x3f000) = 0x3f000
open("/usr/lib/locale/locale-archive", O_RDONLY|O_LARGEFILE) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=1539648, ...}) = 0
mmap2(NULL, 1539648, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40127000
close(3) = 0
uname({sys="Linux", node="panda-maverick", ...}) = 0
access("/proc/net", R_OK) = 0
access("/proc/net/unix", R_OK) = 0
socket(PF_FILE, SOCK_DGRAM, 0) = 3
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4
access("/proc/net/if_inet6", R_OK) = 0
socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP) = 5
access("/proc/net/ax25", R_OK) = -1 ENOENT (No such file or directory)
access("/proc/net/nr", R_OK) = -1 ENOENT (No such file or directory)
access("/proc/net/rose", R_OK) = -1 ENOENT (No such file or directory)
access("/proc/net/ipx", R_OK) = -1 ENOENT (No such file or directory)
access("/proc/net/appletalk", R_OK) = -1 ENOENT (No such file or directory)
access("/proc/sys/net/econet", R_OK) = -1 ENOENT (No such file or directory)
access("/proc/sys/net/ash", R_OK) = -1 ENOENT (No such file or directory)
access("/proc/net/x25", R_OK) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/locale.alias", O_RDONLY) = 6
fstat64(6, {st_mode=S_IFREG|0644, st_size=2570, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40019000
read(6, "# Locale name alias data base.\n#"..., 4096) = 2570
read(6, "", 4096) = 0
close(6) = 0
munmap(0x40019000, 4096) = 0
open("/usr/share/locale/en_US.UTF-8/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en_US.utf8/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en_US/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en.UTF-8/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en.utf8/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en_US.UTF-8/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en_US.utf8/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en_US/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en.UTF-8/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en.utf8/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale-langpack/en/LC_MESSAGES/net-tools.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
ioctl(4, SIOCGIFFLAGS, {ifr_name="usb0", ifr_flags=IFF_UP|IFF_BROADCAST|IFF_RUNNING|IFF_MULTICAST}) = 0
ioctl(4, SIOCSIFFLAGS
--> hangs
When it doesn't hangs it'll let your kernel very unstable, at the point you can't run any other process:
INFO: task ifconfig:557 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
root@panda- maverick: ~# ifconfig usb0 up maverick: ~# strace ifconfig usb0 down "/sbin/ ifconfig" , ["ifconfig", "usb0", "down"], [/* 15 vars */]) = 0 maverick" , ...}) = 0 "/etc/ld. so.nohwcap" , F_OK) = -1 ENOENT (No such file or directory) PROT_WRITE, MAP_PRIVATE| MAP_ANONYMOUS, -1, 0) = 0x40017000 "/etc/ld. so.preload" , R_OK) = -1 ENOENT (No such file or directory) etc/ld. so.cache" , O_RDONLY) = 3 S_IFREG| 0644, st_size=16970, ...}) = 0 "/etc/ld. so.nohwcap" , F_OK) = -1 ENOENT (No such file or directory) lib/libgcc_ s.so.1" , O_RDONLY) = 3 1\1\1\0\ 0\0\0\0\ 0\0\0\0\ 3\0(\0\ 1\0\0\0\ 320%\0\ 0004\0\ 0\0"... , 512) = 512 S_IFREG| 0644, st_size=38488, ...}) = 0 PROT_EXEC, MAP_PRIVATE| MAP_DENYWRITE, 3, 0) = 0x40021000 PROT_WRITE, MAP_PRIVATE| MAP_FIXED| MAP_DENYWRITE, 3, 0x8) = 0x40029000 "/etc/ld. so.nohwcap" , F_OK) = -1 ENOENT (No such file or directory) lib/libc. so.6", O_RDONLY) = 3 1\1\1\0\ 0\0\0\0\ 0\0\0\0\ 3\0(\0\ 1\0\0\0\ 301V\1\ 0004\0\ 0\0"... , 512) = 512 S_IFREG| 0755, st_size=988620, ...}) = 0 PROT_EXEC, MAP_PRIVATE| MAP_DENYWRITE, 3, 0) = 0x4002b000 0x40118000, 32768, PROT_NONE) = 0 PROT_WRITE, MAP_PRIVATE| MAP_FIXED| MAP_DENYWRITE, 3, 0xed) = 0x40120000 PROT_WRITE, MAP_PRIVATE| MAP_FIXED| MAP_ANONYMOUS, -1, 0) = 0x40123000 PROT_WRITE, MAP_PRIVATE| MAP_ANONYMOUS, -1, 0) = 0x4001e000 PROT_WRITE, MAP_PRIVATE| MAP_ANONYMOUS, -1, 0) = 0x40126000 0x40120000, 8192, PROT_READ) = 0 0x40029000, 4096, PROT_READ) = 0 0x4001f000, 4096, PROT_READ) = 0 usr/lib/ locale/ locale- archive" , O_RDONLY| O_LARGEFILE) = 3 S_IFREG| 0644, st_size=1539648, ...}) = 0 maverick" , ...}) = 0 "/proc/ net/unix" , R_OK) = 0 "/proc/ net/if_ inet6", R_OK) = 0 "/proc/ net/ax25" , R_OK) = -1 ENOENT (No such file or directory) "/proc/ net/nr" , R_OK) = -1 ENOENT (No such file or directory) "/proc/ net/rose" , R_OK) = -1 ENOENT (No such file or directory) "/proc/ net/ipx" , R_OK) = -1 ENOENT (No such file or directory) "/proc/ net/appletalk" , R_OK) = -1 ENOENT (No such file or directory) "/proc/ sys/net/ econet" , R_OK) = -1 ENOENT (No such file or directory) "/proc/ sys/net/ ash", R_OK) = -1 ENOENT (No such file or directory) "/proc/ net/x25" , R_OK) = -1 ENOENT (No such file or directory) usr/share/ locale/ locale. alias", O_RDONLY) = 6 S_IFREG| 0644, st_size=2570, ...}) = 0 PROT_WRITE, MAP_PRIVATE| MAP_ANONYMOUS, -1, 0) = 0x40019000 usr/share/ locale/ en_US.UTF- 8/LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale/ en_US.utf8/ LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale/ en_US/LC_ MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale/ en.UTF- 8/LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale/ en.utf8/ LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale/ en/LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale- langpack/ en_US.UTF- 8/LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale- langpack/ en_US.utf8/ LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale- langpack/ en_US/LC_ MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale- langpack/ en.UTF- 8/LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale- langpack/ en.utf8/ LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) usr/share/ locale- langpack/ en/LC_MESSAGES/ net-tools. mo", O_RDONLY) = -1 ENOENT (No such file or directory) IFF_UP| IFF_BROADCAST| IFF_RUNNING| IFF_MULTICAST} ) = 0
root@panda-
execve(
brk(0) = 0x1e000
uname({sys="Linux", node="panda-
access(
mmap2(NULL, 8192, PROT_READ|
access(
open("/
fstat64(3, {st_mode=
mmap2(NULL, 16970, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40019000
close(3) = 0
access(
open("/
read(3, "\177ELF\
fstat64(3, {st_mode=
mmap2(NULL, 37140, PROT_READ|
mmap2(0x40029000, 8192, PROT_READ|
close(3) = 0
access(
open("/
read(3, "\177ELF\
fstat64(3, {st_mode=
mmap2(NULL, 1025308, PROT_READ|
mprotect(
mmap2(0x40120000, 12288, PROT_READ|
mmap2(0x40123000, 9500, PROT_READ|
close(3) = 0
mmap2(NULL, 4096, PROT_READ|
mmap2(NULL, 4096, PROT_READ|
set_tls(0x401264c0, 0x4002091c, 0x40126b98, 0x401264c0, 0x40020000) = 0
mprotect(
mprotect(
mprotect(0x1b000, 4096, PROT_READ) = 0
mprotect(
munmap(0x40019000, 16970) = 0
brk(0) = 0x1e000
brk(0x3f000) = 0x3f000
open("/
fstat64(3, {st_mode=
mmap2(NULL, 1539648, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40127000
close(3) = 0
uname({sys="Linux", node="panda-
access("/proc/net", R_OK) = 0
access(
socket(PF_FILE, SOCK_DGRAM, 0) = 3
socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4
access(
socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP) = 5
access(
access(
access(
access(
access(
access(
access(
access(
open("/
fstat64(6, {st_mode=
mmap2(NULL, 4096, PROT_READ|
read(6, "# Locale name alias data base.\n#"..., 4096) = 2570
read(6, "", 4096) = 0
close(6) = 0
munmap(0x40019000, 4096) = 0
open("/
open("/
open("/
open("/
open("/
open("/
open("/
open("/
open("/
open("/
open("/
open("/
ioctl(4, SIOCGIFFLAGS, {ifr_name="usb0", ifr_flags=
ioctl(4, SIOCSIFFLAGS
--> hangs
When it doesn't hangs it'll let your kernel very unstable, at the point you can't run any other process: kernel/ hung_task_ timeout_ secs" disables this message.
INFO: task ifconfig:557 blocked for more than 120 seconds.
"echo 0 > /proc/sys/