On 6/29/2024 2:39 PM, Brian Inglis via Cygwin wrote:
Reran cygport --debug upload and command hanging was ssh-add -l!
296 72109 [main] ssh-add 63275 win32env_to_cygenv: 0xA000232E0:
TERM_PROGRAM=mintty
189 72298 [main] ssh-add 63275 win32env_to_cygenv: 0xA00023300:
TERM_PROGRAM_VERSION=3.7.1
I was able to reproduce this problem by entering below command with
ffmpeg from https://www.gyan.dev/ffmpeg/builds/ , this ffmpeg build
spams putc. So, without piping its output to `tee', It would not
possible track down any cause among lengthy trace output.
strace mintty -e /bin/timeout 10 sh -c './ffmpeg -h full|& tee'
In summary, When `timeout' expires, `timeout' signals SIGHUP to pgrp of
itself, btw some member of the pgrp may have acquired any of
synchronization object of some part of cygwin internal when a member
process of the pgrp did encounter the signal interrupt from `timeout'.
In my case it was output_mutex of pty.
1565 10693297 [main] timeout 745 kill_pgrp: pid 0, signal 15
2701 15224348 [main] mintty 744
fhandler_pty_master::process_slave_output: bytes read 256
1736 9525442 [sig] sh 746 proc_subproc: args: 4, 1
3137 6700294 [main] tee 748 fhandler_pty_slave::write: pty5,
write(0x7FFFFC780, 1024)
1347 9526789 [sig] sh 746 proc_subproc: clear waiting threads
2084 15226432 [main] mintty 744
fhandler_pty_master::process_slave_output: returning 256
1110 6701404 [main] tee 748 fhandler_pty_slave::write: (1267): pty
output_mutex (0x4C0): waiti
-1 ms
732 9527521 [sig] sh 746 checkstate: child_procs count 2
3648 10696945 [main] timeout 745 open_shared: name cygpid.724, shared
0x1A0050000 (wanted 0x1A
0000), h 0x16C, m 6, created 0
1055 6702459 [main] tee 748 fhandler_pty_slave::write: (1267): pty
output_mutex: acquired
2092 15753306 [main] mintty 744 fhandler_pty_master::close: (2095):
pty output_mutex (0x4AC):
ting -1 ms
And below is a location where `tee' did hang.
#3 0x00007ffd0e408fdf in fhandler_pty_slave::write (this=0x800009a10,
ptr=0x7ffffc780, len=<optimized out>)
at ../../.././winsup/cygwin/fhandler/pty.cc:1268
1268 if (!process_opost_output (get_output_handle (), ptr, towrite,
false,
(gdb) li
1263 termios_printf ("pty%d, write(%p, %lu)", get_minor (), ptr, len);
1264
1265 push_process_state process_state (PID_TTYOU);
1266
1267 acquire_output_mutex (mutex_timeout);
1268 if (!process_opost_output (get_output_handle (), ptr, towrite,
false,
1269 get_ttyp (), is_nonblocking ()))
I ended up prepending two CancelIo call just above of
acquire_output_mutex located in fhandler_pty_master::close of pty.cc.
> CancelIo(get_ttyp()->to_master());
> CancelIo(get_ttyp()->to_master_nat());
acquire_output_mutex (mutex_timeout);
Hope it helps
--
Problem reports: https://cygwin.com/problems.html
FAQ: https://cygwin.com/faq/
Documentation: https://cygwin.com/docs.html
Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
