# Summary Bug hit again, workaround works again, this time with a strace. I suspect the workaround has a drawback: the characters it eats are lost for the script. Next time I'll try dd to "lose" only one character.
Thank you for your attention. # Details The bug has hit again. Here is a selected portion of strace head /proc/7514/fd/4 open("/proc/7514/fd/4", O_RDONLY) = 3 read(3, "\n", 8192) = 1 fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 14), ...}) = 0 write(1, "\n", 1 ) = 1 read(3, "a", 8192) = 1 read(3, "a", 8192) = 1 read(3, "*", 8192) = 1 read(3, "\177", 8192) = 1 read(3, "e", 8192) = 1 read(3, "e", 8192) = 1 read(3, "\r", 8192) = 1 read(3, ^Cstrace: Process 14679 detached <detached ...> The characters return by read() are what I typed on the terminal hosting the stuck /usr/bin/script. I think that script unlocked itself (i.e. the bug went away) as soon as the first read() returned, but I'm not sure. Thank you for your attention. strace head /proc/7514/fd/4 execve("/usr/bin/head", ["head", "/proc/7514/fd/4"], [/* 31 vars */]) = 0 brk(NULL) = 0x18a8000 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff26a1f6000 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=123250, ...}) = 0 mmap(NULL, 123250, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff26a1d7000 close(3) = 0 access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or directory) open("/lib/x86_64-linux-gnu/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\0`\t\2\0\0\0\0\0"..., 832) = 832 fstat(3, {st_mode=S_IFREG|0755, st_size=1868984, ...}) = 0 mmap(NULL, 3971584, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7ff269c09000 mprotect(0x7ff269dc9000, 2097152, PROT_NONE) = 0 mmap(0x7ff269fc9000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1c0000) = 0x7ff269fc9000 mmap(0x7ff269fcf000, 14848, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7ff269fcf000 close(3) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff26a1d6000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff26a1d5000 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff26a1d4000 arch_prctl(ARCH_SET_FS, 0x7ff26a1d5700) = 0 mprotect(0x7ff269fc9000, 16384, PROT_READ) = 0 mprotect(0x608000, 4096, PROT_READ) = 0 mprotect(0x7ff26a1f8000, 4096, PROT_READ) = 0 munmap(0x7ff26a1d7000, 123250) = 0 brk(NULL) = 0x18a8000 brk(0x18c9000) = 0x18c9000 open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3 fstat(3, {st_mode=S_IFREG|0644, st_size=3001856, ...}) = 0 mmap(NULL, 3001856, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7ff26992c000 close(3) = 0 open("/proc/7514/fd/4", O_RDONLY) = 3 read(3, "\n", 8192) = 1 fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 14), ...}) = 0 write(1, "\n", 1 ) = 1 read(3, "a", 8192) = 1 read(3, "a", 8192) = 1 read(3, "*", 8192) = 1 read(3, "\177", 8192) = 1 read(3, "e", 8192) = 1 read(3, "e", 8192) = 1 read(3, "\r", 8192) = 1 read(3, ^Cstrace: Process 14679 detached <detached ...> -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1558236 Title: /usr/bin/script freezes and eats all CPU, has to be killed, which kills shell and programs inside To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/util-linux/+bug/1558236/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs