From 03d73f1fd9d89d89bdd021cad26693e4f6abc07a Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Wed, 1 Jun 2016 09:33:40 +0100 Subject: [PATCH] Wake up interruptible_select in remote_fileio ctrl-c handler As reported in PR 19998, after type ctrl-c, GDB hang there and does not send interrupt. It causes a fail in gdb.base/interrupt.exp. All targets support remote fileio should be affected. When we type ctrc-c, SIGINT is handled by remote_fileio_sig_set, as shown below, #0 remote_fileio_sig_set (sigint_func=0x4495d0 ) at /home/yao/SourceCode/gnu/gdb/git/gdb/remote-fileio.c:325 #1 0x00000000004495de in remote_fileio_ctrl_c_signal_handler (signo=) at /home/yao/SourceCode/gnu/gdb/git/gdb/remote-fileio.c:349 #2 #3 0x00007ffff647ed83 in __select_nocancel () at ../sysdeps/unix/syscall-template.S:81 #4 0x00000000005530ce in interruptible_select (n=10, readfds=readfds@entry=0x7fffffffd730, writefds=writefds@entry=0x0, exceptfds=exceptfds@entry=0x0, timeout=timeout@entry=0x0) at /home/yao/SourceCode/gnu/gdb/git/gdb/event-top.c:1017 #5 0x000000000061ab20 in stdio_file_read (file=, buf=0x12d02e0 "\n\022-\001", length_buf=16383) at /home/yao/SourceCode/gnu/gdb/git/gdb/ui-file.c:577 #6 0x000000000044a4dc in remote_fileio_func_read (buf=0x12c0360 "") at /home/yao/SourceCode/gnu/gdb/git/gdb/remote-fileio.c:583 #7 0x0000000000449598 in do_remote_fileio_request (uiout=, buf_arg=buf_arg@entry=0x12c0340) at /home/yao/SourceCode/gnu/gdb/git/gdb/remote-fileio.c:1179 we don't set quit_serial_event, do { res = gdb_select (n, readfds, writefds, exceptfds, timeout); } while (res == -1 && errno == EINTR); if (res == 1 && FD_ISSET (fd, readfds)) { errno = EINTR; return -1; } return res; we can't go out of the loop above, and that is why GDB can't send interrupt. Recently, we stop throwing exception from SIGINT handler (remote_fileio_ctrl_c_signal_handler) https://sourceware.org/ml/gdb-patches/2016-03/msg00372.html, which is correct, because gdb_select is interruptible. However, in the same patch series, we add interruptible_select later as a wrapper to gdb_select, https://sourceware.org/ml/gdb-patches/2016-03/msg00375.html and it is not interruptible (because of the loop in it) unless select/poll-able file descriptors are marked. This fix in this patch is to call quit_serial_event_set, so that we can go out of the loop above, return -1 and set errno to EINTR. 2016-06-01 Yao Qi PR remote/19998 * remote-fileio.c (remote_fileio_ctrl_c_signal_handler): Call quit_serial_event_set. --- gdb/ChangeLog | 6 ++++++ gdb/remote-fileio.c | 2 ++ 2 files changed, 8 insertions(+) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 10c9c05183d..f9dc6f9c61f 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2016-06-01 Yao Qi + + PR remote/19998 + * remote-fileio.c (remote_fileio_ctrl_c_signal_handler): Call + quit_serial_event_set. + 2016-06-01 Joel Brobecker GDB 7.11.1 released. diff --git a/gdb/remote-fileio.c b/gdb/remote-fileio.c index 44817df37b7..29c5ca35896 100644 --- a/gdb/remote-fileio.c +++ b/gdb/remote-fileio.c @@ -348,6 +348,8 @@ remote_fileio_ctrl_c_signal_handler (int signo) { remote_fileio_sig_set (remote_fileio_ctrl_c_signal_handler); remote_fio_ctrl_c_flag = 1; + /* Wake up interruptible_select. */ + quit_serial_event_set (); } static void -- 2.30.2