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my setting: set detach-on-fork off set follow-fork-mode child first I doesn't set any breakpoint, when I press F11 to start debug, after parent called fork() ,the parent should be in hang-up state, the child should be in running state, and I want to continue the parent, but the Resume button is disabled and Suspend is enable,I think that is wrong.
Could you provide a simple test program that we can reproduce the problem with?
(In reply to Marc Khouzam from comment #1) > Could you provide a simple test program that we can reproduce the problem > with? int fork_main (int argc, char ** argv) { int rc = fork(); if (rc < 0) exit(1); else if (rc == 0) { for (;;) { puts("I am child"); sleep(1); } } else { for (;;) { puts("I am parent"); sleep(1); } } return 0; } BTW, if I set breakpoint or not, the problem both exists. the parent kernel stack: [<ffffffff810d50b7>] utrace_stop+0xf7/0x1e0 [<ffffffff810d51e7>] finish_resume_report+0x47/0x100 [<ffffffff810d532b>] utrace_resume+0x8b/0x110 [<ffffffff8100aaa0>] do_notify_resume+0xb0/0xc0 [<ffffffff8100b341>] int_signal+0x12/0x17 [<ffffffffffffffff>] 0xffffffffffffffff the child kernel stack: [<ffffffff810a02a4>] hrtimer_nanosleep+0xc4/0x180 [<ffffffff810a03ce>] sys_nanosleep+0x6e/0x80 [<ffffffff8100b072>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff
# gdb -v GNU gdb (GDB) Red Hat Enterprise Linux (7.2-64.el6_5.2) Copyright (C) 2010 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". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>.
(In reply to jia kai from comment #3) > # gdb -v > GNU gdb (GDB) Red Hat Enterprise Linux (7.2-64.el6_5.2) > Copyright (C) 2010 Free Software Foundation, Inc. That is a really old GDB where multi-process was very new. Many things were fixed since then. I recommend trying a more recent version to see if the behaviour is better.
I tried a new GDB (built from source): GNU gdb (GDB) 7.8 Copyright (C) 2014 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-unknown-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word". the problem still exists. And another problem: 1.add a breakpoint before debug; 2.start debugging, and the program suspended at the breakpoint; 3.delete the breakpoint and continue the program; 4.add the breakpoint(program is running now) at the same position, and after a while the program should be reached here again, but the breakpoint cannot suspend the program now. Thanks.
Using the test program I was not able to reproduce the problem. I get both child and parent being debugged. I use non-stop mode, and I copy pasted set detach-on-fork off set follow-fork-mode child into the gdb console when the program stopped at main.
