Message-Id: <m0valaC-0004O6C@chiark.greenend.org.uk>
Date: Thu, 19 Dec 96 16:44 GMT
From: Ian Jackson <ian@chiark.greenend.org.uk>
To: Debian bugs submission address <submit@bugs.debian.org>
Subject: strace fails to trace run-amok pine

Package: strace
Version: 3.1-8

I tried to strace a Pine which had gone out of control using up all of
the CPU because of an ungraceful disconnect by its user:

-root@chiark:~> strace -p 21370
[ nothing happens.  I wait 30 secs, then hit ^C ]
-root@chiark:~> strace -p21370
[ again ]
-root@chiark:~> strace strace -p21370
execve("/usr/bin/strace", ["strace", "-p21370"], [/* 39 vars */]) = 0
mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40006000
mprotect(0x40000000, 20079, PROT_READ|PROT_WRITE|PROT_EXEC) = 0
mprotect(0x8048000, 68308, PROT_READ|PROT_WRITE|PROT_EXEC) = 0
stat("/etc/ld.so.cache", {st_mode=S_IFREG|0644, st_size=4339, ...}) = 0
open("/etc/ld.so.cache", O_RDONLY)      = 3
mmap(0, 4339, PROT_READ, MAP_SHARED, 3, 0) = 0x40007000
close(3)                                = 0
stat("/etc/ld.so.preload", 0xbffffa70)  = -1 ENOENT (No such file or directory)
open("/lib/libc.so.5.4.13", O_RDONLY)   = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3"..., 4096) = 4096
mmap(0, 753664, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40009000
mmap(0x40009000, 522803, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0x40009000
mmap(0x40089000, 21580, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x7f000) = 0x40089000
mmap(0x4008f000, 203440, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x4008f000
close(3)                                = 0
mprotect(0x40009000, 522803, PROT_READ|PROT_WRITE|PROT_EXEC) = 0
munmap(0x40007000, 4339)                = 0
mprotect(0x8048000, 68308, PROT_READ|PROT_EXEC) = 0
mprotect(0x40009000, 522803, PROT_READ|PROT_EXEC) = 0
mprotect(0x40000000, 20079, PROT_READ|PROT_EXEC) = 0
personality(PER_LINUX)                  = 0
geteuid()                               = 0
getuid()                                = 0
getgid()                                = 0
getegid()                               = 0
brk(0x80673cc)                          = 0x80673cc
brk(0x8068000)                          = 0x8068000
stat("/etc/locale/C/libc.cat", 0xbfffe5b4) = -1 ENOENT (No such file or directory)
stat("/usr/lib/locale/C/libc.cat", 0xbfffe5b4) = -1 ENOENT (No such file or directory)
stat("/usr/lib/locale/libc/C", 0xbfffe5b4) = -1 ENOENT (No such file or directory)
stat("/usr/share/locale/C/libc.cat", 0xbfffe5b4) = -1 ENOENT (No such file or directory)
stat("/usr/local/share/locale/C/libc.cat", 0xbfffe5b4) = -1 ENOENT (No such file or directory)
getpid()                                = 22773
getuid()                                = 0
getgid()                                = 0
getuid()                                = 0
geteuid()                               = 0
setreuid(0, 0)                          = 0
getuid()                                = 0
geteuid()                               = 0
setreuid(0, 0)                          = 0
ptrace(PTRACE_ATTACH, 21370, 0x1, 0)    = 0
sigaction(SIGTTOU, {SIG_IGN}, NULL)     = 0
sigaction(SIGTTIN, {SIG_IGN}, NULL)     = 0
sigaction(SIGHUP, {0x804a330, [], 0}, NULL) = 0
sigaction(SIGINT, {0x804a330, [], 0}, NULL) = 0
--- SIGCHLD (Child exited) ---
sigaction(SIGQUIT, {0x804a330, [], 0}, NULL) = 0
sigaction(SIGPIPE, {0x804a330, [], 0}, NULL) = 0
sigaction(SIGTERM, {0x804a330, [], 0}, NULL) = 0
sigprocmask(SIG_SETMASK, [], NULL)      = 0
wait4(-1, [WIFSTOPPED(s) && WSTOPSIG(s) == SIGSTOP], 0, NULL) = 21370
sigprocmask(SIG_BLOCK, [HUP INT QUIT PIPE TERM], NULL) = 0
ptrace(PTRACE_SYSCALL, 21370, 0x1, 0)   = 0
sigprocmask(SIG_SETMASK, [], NULL)      = 0
wait4(-1,  <unfinished ...>
[ Again, I press ^C after a while. ]
-root@chiark:~> kill -QUIT 21370
-root@chiark:~> 

I was using a fairly standard 2.0.21 kernel.

Ian.