From: Yao Qi <qiyaoltc@gmail.com>
To: gdb-patches@sourceware.org
Subject: [PATCH] Wake up interruptible_select in remote_fileio ctrl-c handler
Date: Thu, 19 May 2016 14:38:00 -0000 [thread overview]
Message-ID: <1463668660-9205-1-git-send-email-yao.qi@linaro.org> (raw)
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 <remote_fileio_ctrl_c_signal_handler(int)>) at /home/yao/SourceCode/gnu/gdb/git/gdb/remote-fileio.c:325
#1 0x00000000004495de in remote_fileio_ctrl_c_signal_handler (signo=<optimised out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/remote-fileio.c:349
#2 <signal handler called>
#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=<optimised out>, 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=<optimised out>, 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.
I don't have the test env to run testsuite against targets support
remote fileio.
2016-05-19 Yao Qi <yao.qi@linaro.org>
PR remote/19998
* remote-fileio.c (remote_fileio_ctrl_c_signal_handler): Call
quit_serial_event_set.
---
gdb/remote-fileio.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/gdb/remote-fileio.c b/gdb/remote-fileio.c
index 44817df..29c5ca3 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
--
1.9.1
next reply other threads:[~2016-05-19 14:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-19 14:38 Yao Qi [this message]
2016-06-01 8:35 ` Yao Qi
2016-06-01 11:52 ` Pedro Alves
2016-06-01 13:42 ` Yao Qi
2016-06-01 14:15 ` Pedro Alves
[not found] ` <CAH=s-PMDdhETFmMxMdbanHfRM-r13cyxiERdmaDRD5iQgZmzjA@mail.gmail.com>
2016-06-01 15:38 ` Pedro Alves
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