Dear list, I just found `strace -f` hangs forever for me.
$ uname -a CYGWIN_NT-6.1 fracting-PC 2.2.1(0.289/5/3) 2015-08-15 11:00 i686 Cygwin) $ cat parent.sh ./child.sh $ cat child.sh echo haha $ strace -f -o out.txt bash -c parent.sh #hangs forever. I have a few C source test case here, which were originally for a Wine bug, but could reproduce this Cygwin bug: https://bugs.wine-staging.com/show_bug.cgi?id=525#c2 To reproduce: (Ignore the Wine bug report itself, just copy the source. The Wine bug itself is fixed now, with analysis which indicates something is wrong with IsDebuggerPresent(). I refer the bug here since it might help to triage our Cygwin issue if there is something related) gcc spawn-parent.c -o spawn-parent.exe gcc spawn-child.c -o spawn-child.exe gcc dummy.c -o dummy.exe Without strace, the above programs works fine: $ ./spawn-parent.exe from SPAWN parent! from SPAWN dummy! haha this is dummy However, when tracing with `strace -f`, spawn-child.exe hangs: $ strace -f -o /tmp/spawn.nested.strace.txt ./spawn-parent.exe #hangs I read the strace document of Cygwin[1], it said: -f, --trace-children trace child processes (toggle - default true) [1] https://cygwin.com/cygwin-ug-net/strace.html According to my test, `strace` without `-f` works fine, which trace child process, as the document says. Is it a known bug that toggle off child process doesn't work? Or did i miss anything else? (Note, current strace works with my needs, I don't need to toggle off child process tracing at all, just make sure there is not a bug here) Thanks! -- Regards, Qian Hong - http://www.winehq.org -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
