show history
set history expansion
set history save
sethistory size 256
保存在 ~/.gdb_history
干掉的进程会重建
__epoll_wait_nocancel ()
怎么建立的？不要忽略！！
ctrl+f
(gdb)
[root@red54apple gdbtest]# gdb
GNU gdb Fedora (6.8-37.el5)
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
(gdb) attach 4992
Attaching to process 4992
Reading symbols from /opt/backup/mynginx/workdir/nginx-1.0.5/objs/nginx...done.
Reading symbols from /lib64/libpthread.so.0...done.
[Thread debugging using libthread_db enabled]
[New Thread 0x2b8b4d052520 (LWP 4992)]
Loaded symbols for /lib64/libpthread.so.0
Reading symbols from /lib64/libcrypt.so.1...done.
Loaded symbols for /lib64/libcrypt.so.1
Reading symbols from /lib64/libm.so.6...done.
Loaded symbols for /lib64/libm.so.6
Reading symbols from /lib64/libcrypto.so.6...done.
Loaded symbols for /lib64/libcrypto.so.6
Reading symbols from /usr/lib64/libz.so.1...done.
Loaded symbols for /usr/lib64/libz.so.1
Reading symbols from /lib64/libc.so.6...done.
Loaded symbols for /lib64/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib64/libdl.so.2...done.
Loaded symbols for /lib64/libdl.so.2
Reading symbols from /lib64/libnss_files.so.2...done.
Loaded symbols for /lib64/libnss_files.so.2
0x0000003b6e23079a in sigsuspend () from /lib64/libc.so.6
(gdb) info proc
process 4992
cmdline = 'nginx: master process /usr/local/nginx/objs/nginx'
cwd = '/root/gdbtest'
exe = '/opt/backup/mynginx/workdir/nginx-1.0.5/objs/nginx'
(gdb) q
The program is running. Quit anyway (and detach it)? (y or n) y
Detaching from program: /opt/backup/mynginx/workdir/nginx-1.0.5/objs/nginx, process 4992
[root@red54apple gdbtest]# pidof /usr/local/nginx/objs/nginx
5000 4999 4998 4997 4996 4995 4994 4993 4992
[root@red54apple gdbtest]#
[root@red54apple gdbtest]#
[root@red54apple gdbtest]# gdb
GNU gdb Fedora (6.8-37.el5)
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
(gdb) attach 4999
Attaching to process 4999
Reading symbols from /opt/backup/mynginx/workdir/nginx-1.0.5/objs/nginx...done.
Reading symbols from /lib64/libpthread.so.0...done.
[Thread debugging using libthread_db enabled]
[New Thread 0x2b8b4d052520 (LWP 4999)]
Loaded symbols for /lib64/libpthread.so.0
Reading symbols from /lib64/libcrypt.so.1...done.
Loaded symbols for /lib64/libcrypt.so.1
Reading symbols from /lib64/libm.so.6...done.
Loaded symbols for /lib64/libm.so.6
Reading symbols from /lib64/libcrypto.so.6...done.
Loaded symbols for /lib64/libcrypto.so.6
Reading symbols from /usr/lib64/libz.so.1...done.
Loaded symbols for /usr/lib64/libz.so.1
Reading symbols from /lib64/libc.so.6...done.
Loaded symbols for /lib64/libc.so.6
Reading symbols from /lib64/ld-linux-x86-64.so.2...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Reading symbols from /lib64/libdl.so.2...done.
Loaded symbols for /lib64/libdl.so.2
Reading symbols from /lib64/libnss_files.so.2...done.
Loaded symbols for /lib64/libnss_files.so.2
0x0000003b6e2d3fd3 in __epoll_wait_nocancel () from /lib64/libc.so.6
(gdb) info proc
process 4999
cmdline = 'nginx: worker process'
cwd = '/root/gdbtest'
exe = '/opt/backup/mynginx/workdir/nginx-1.0.5/objs/nginx'
(gdb) info args
No symbol table info available.
(gdb) b proc
Function "proc" not defined.
Make breakpoint pending on future shared library load? (y or [n]) n
(gdb) x proc
No symbol "proc" in current context.
(gdb) info *proc
Undefined info command: "*proc". Try "help info".
(gdb) info program
Using the running image of attached Thread 0x2b8b4d052520 (LWP 4999).
Program stopped at 0x6e2d3fd3.
(gdb) x 0x2b8b4d052520
0x2b8b4d052520: 0x4d052520
(gdb) x/c 0x2b8b4d052520
0x2b8b4d052520: 32 ' '
(gdb) x/i 0x2b8b4d052520
0x2b8b4d052520: and %ah,0x2b8b4d05(%rip) # 0x2b8b7890722b
(gdb) p port.6281
No symbol "port" in current context.
(gdb) shell ps -ef|grep nginx
root 4992 1 0 Sep22 ? 00:00:00 nginx: master process /usr/local/nginx/objs/nginx
nobody 4993 4992 0 Sep22 ? 00:00:00 nginx: worker process
nobody 4994 4992 0 Sep22 ? 00:00:00 nginx: worker process
nobody 4995 4992 0 Sep22 ? 00:00:00 nginx: worker process
nobody 4996 4992 0 Sep22 ? 00:00:00 nginx: worker process
nobody 4997 4992 0 Sep22 ? 00:00:00 nginx: worker process
nobody 4998 4992 0 Sep22 ? 00:00:00 nginx: worker process
nobody 4999 4992 0 Sep22 ? 00:00:00 nginx: worker process
nobody 5000 4992 0 Sep22 ? 00:00:00 nginx: worker process
root 5121 5082 0 00:15 pts/1 00:00:00 bash -c ps -ef|grep nginx
root 5123 5121 0 00:15 pts/1 00:00:00 grep nginx
(gdb) attach 4992
A program is being debugged already. Kill it? (y or n) y
Attaching to program: /opt/backup/mynginx/workdir/nginx-1.0.5/objs/nginx, process 4992
[Thread debugging using libthread_db enabled]
[New Thread 0x2b8b4d052520 (LWP 4992)]
Loaded symbols for /lib64/libpthread.so.0
Loaded symbols for /lib64/libcrypt.so.1
Loaded symbols for /lib64/libm.so.6
Loaded symbols for /lib64/libcrypto.so.6
Loaded symbols for /usr/lib64/libz.so.1
Loaded symbols for /lib64/libc.so.6
Loaded symbols for /lib64/ld-linux-x86-64.so.2
Loaded symbols for /lib64/libdl.so.2
Loaded symbols for /lib64/libnss_files.so.2
ngx_vslprintf (buf=0x6d881c "",
last=0xffffffffffffffff <Address 0xffffffffffffffff out of bounds>, fmt=0x4ae2fb "%4d/%02d/%02d %02d:%02d:%02d", args=0x7fff1a77bb30)
at src/core/ngx_string.c:157
157 while (*fmt && buf < last) {
(gdb) shell ps -ef|grep nginx
[root@red54apple ~]# gdb GNU gdb Fedora (6.8-37.el5) Copyright (C) 2008 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-redhat-linux-gnu". (gdb) shell pidof /usr/local/nginx/objs/nginx 5283 5279 5222 5000 4996 4995 4994 4993 4992 (gdb) x/i $pc No registers. (gdb) show reg Undefined show command: "reg". Try "help show". (gdb) attach 5283 Attaching to process 5283 Reading symbols from /opt/backup/mynginx/workdir/nginx-1.0.5/objs/nginx...done. Reading symbols from /lib64/libpthread.so.0...done. [Thread debugging using libthread_db enabled] [New Thread 0x2b8b4d052520 (LWP 5283)] Loaded symbols for /lib64/libpthread.so.0 Reading symbols from /lib64/libcrypt.so.1...done. Loaded symbols for /lib64/libcrypt.so.1 Reading symbols from /lib64/libm.so.6...done. Loaded symbols for /lib64/libm.so.6 Reading symbols from /lib64/libcrypto.so.6...done. Loaded symbols for /lib64/libcrypto.so.6 Reading symbols from /usr/lib64/libz.so.1...done. Loaded symbols for /usr/lib64/libz.so.1 Reading symbols from /lib64/libc.so.6...done. Loaded symbols for /lib64/libc.so.6 Reading symbols from /lib64/ld-linux-x86-64.so.2...done. Loaded symbols for /lib64/ld-linux-x86-64.so.2 Reading symbols from /lib64/libdl.so.2...done. Loaded symbols for /lib64/libdl.so.2 Reading symbols from /lib64/libnss_files.so.2...done. Loaded symbols for /lib64/libnss_files.so.2 0x0000003b6e2d3fd3 in __epoll_wait_nocancel () from /lib64/libc.so.6 (gdb) show reg Undefined show command: "reg". Try "help show". (gdb) info reg rax 0xfffffffffffffffc -4 rbx 0x3b6e01bbc0 255248677824 rcx 0xffffffffffffffff -1 rdx 0x200 512 rsi 0x13cf1370 332338032 rdi 0x16 22 rbp 0x7fff1a77bfb0 0x7fff1a77bfb0 rsp 0x7fff1a77bf28 0x7fff1a77bf28 r8 0x17566ce 24471246 r9 0x4e7b688a 1316710538 r10 0x5 5 r11 0x246 582 r12 0x0 0 r13 0x7fff1a77c550 140733637444944 r14 0x0 0 r15 0x0 0 rip 0x3b6e2d3fd3 0x3b6e2d3fd3 <__epoll_wait_nocancel+10> eflags 0x246 [ PF ZF IF ] cs 0x33 51 ss 0x2b 43 ds 0x0 0 es 0x0 0 fs 0x0 0 gs 0x0 0 fctrl 0x37f 895 fstat 0x0 0 ftag 0xffff 65535 fiseg 0x0 0 fioff 0x0 0 foseg 0x0 0 fooff 0x0 0 fop 0x0 0 mxcsr 0x1f80 [ IM DM ZM OM UM PM ] (gdb) x/i $pc 0x3b6e2d3fd3 <__epoll_wait_nocancel+10>: cmp $0xfffffffffffff001,%rax (gdb) (gdb) x/10i $pc 0x3b6e2d3fd3 <__epoll_wait_nocancel+10>: cmp $0xfffffffffffff001,%rax 0x3b6e2d3fd9 <__epoll_wait_nocancel+16>: jae 0x3b6e2d4038 <epoll_wait+120> 0x3b6e2d3fdb <__epoll_wait_nocancel+18>: retq 0x3b6e2d3fdc <epoll_wait+28>: sub $0x28,%rsp 0x3b6e2d3fe0 <epoll_wait+32>: mov %rdi,0x8(%rsp) 0x3b6e2d3fe5 <epoll_wait+37>: mov %rsi,0x10(%rsp) 0x3b6e2d3fea <epoll_wait+42>: mov %rdx,0x18(%rsp) 0x3b6e2d3fef <epoll_wait+47>: mov %rcx,0x20(%rsp) 0x3b6e2d3ff4 <epoll_wait+52>: callq 0x3b6e2dfa80 <__libc_enable_asynccancel> 0x3b6e2d3ff9 <epoll_wait+57>: mov 0x8(%rsp),%rdi (gdb)