From: Tom de Vries <tdevries@suse.de>
To: gdb-patches@sourceware.org
Subject: [PATCH] [gdb/server] Emit warning for SIGINT failure
Date: Wed, 9 Nov 2022 21:32:58 +0100 [thread overview]
Message-ID: <20221109203258.26431-1-tdevries@suse.de> (raw)
Consider the executable from test-case gdb.base/interrupt-daemon.exp.
When starting it using gdbserver:
...
$ ./build/gdbserver/gdbserver localhost:2345 \
./outputs/gdb.base/interrupt-daemon/interrupt-daemon
...
and connecting to it using gdb:
...
$ gdb -q -ex "target remote localhost:2345" \
-ex "set follow-fork-mode child" \
-ex "break daemon_main" -ex cont
...
we are setup to do the same as in the test-case: interrupt a running inferior
using ^C.
So let's try:
...
(gdb) continue
Continuing.
^C
...
After pressing ^C, nothing happens. This a known problem, filed as
PR remote/18772.
The problem is that in linux_process_target::request_interrupt, a kill is used
to send a SIGINT, but it fails. And it fails silently.
Make the failure verbose by adding a warning, such that the gdbserver output
becomes more helpful:
...
Process interrupt-daemon created; pid = 15068
Listening on port 2345
Remote debugging from host ::1, port 35148
Detaching from process 15068
Detaching from process 15085
gdbserver: Sending SIGINT to process group of pid 15068 failed: \
No such process
...
Note that the failure can easily be reproduced using the test-case and target
board native-gdbserver:
...
(gdb) continue^M
Continuing.^M
PASS: gdb.base/interrupt-daemon.exp: fg: continue
^CFAIL: gdb.base/interrupt-daemon.exp: fg: ctrl-c stops process (timeout)
...
as reported in PR server/23382.
Tested on x86_64-linux.
---
gdbserver/linux-low.cc | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc
index 0cbfeb99086..f4df02d3ac9 100644
--- a/gdbserver/linux-low.cc
+++ b/gdbserver/linux-low.cc
@@ -5467,7 +5467,10 @@ linux_process_target::request_interrupt ()
{
/* Send a SIGINT to the process group. This acts just like the user
typed a ^C on the controlling terminal. */
- ::kill (-signal_pid, SIGINT);
+ int res = ::kill (-signal_pid, SIGINT);
+ if (res == -1)
+ warning (_("Sending SIGINT to process group of pid %ld failed: %s"),
+ signal_pid, safe_strerror (errno));
}
bool
base-commit: 3abad2f6a637a0c56af70311d94ec66eea1b4852
--
2.35.3
next reply other threads:[~2022-11-09 20:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-09 20:32 Tom de Vries [this message]
2022-11-26 13:34 ` [PING] " Tom de Vries
2022-11-26 20:29 ` Simon Marchi
2022-11-27 9:27 ` Tom de Vries
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