[Bug gdb/23621] New: gdbserver can't intrrupt “SOME” process,kill(pid,2) called by gdbserver didn't send SIGINT to process,what's happening?

[prosup at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=23621

Bug ID: 23621
Summary: gdbserver can't intrrupt “SOME” process,kill(pid,2)
called by gdbserver didn't send SIGINT to
process,what's happening?
Product: gdb
Version: 7.10.1
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: gdb
Assignee: unassigned at sourceware dot org
Reporter: prosup at 163 dot com
Target Milestone: ---

Envirment is:

target:x86_64 client,runs the program which striped

Host:x86_64 server ,has code,toolchain,striped program,symbles file for debug

%gdbserver --multi :1234 </dev/null &> /pathtolog/gdb.log
./someprogram &
[1] PID
%gdb
(gdb)target extended-remote TARGETIP:1234
(gdb)file someprogram
(gdb)setrootfs pathtorootfs
(gdb)...//set lib path etc.
(gdb)attach PID
...//load everything as normal
...//stop somewhere
(gdb)c
^C^CThe target is not responding to interrupt requests.
Stop debugging it? (y or n)

tried to find the root cause:

on the target:

gdb attach to gdbserver(yes I can use gdb on the target right now,but the
target machine shall be released without gdb,symbles,etc. for size).

(gdb) b kill
Breakpoint 1 at 0xf760afb0
(gdb) c
Continuing.

when press ctrl+c from host gdb ,gdbserver will break into the breakpoint

Breakpoint 1, 0xf760afb0 in kill () from /lib/libc.so.6
(gdb)
(gdb) x /32wx 0xffee8070
0xffee8070: 0xfffffe0c 0x00000002 0x00000001 0x00000000

0xfffffe0c = -PID
0x00000002 = SIGINT

some program will get the signalwhen gdbserver continue .
so，kill() is good for "SOME PROGRAM",not all.


And I'v use tcpdump monitored data between gdb/gdbserver.
If kill() worked （for "GOOD" program),gdbserver will send a packet to gdb.

I'v tried [sigmonitor](https://github.com/honkiko/signal-monitor),found out
gdbserver didn't send any sigal to "BAD program" in this case.but I can call
kill(pid,2) int gdbserver debuging gdb process

(gdb) call kill(PID,2)

then dmesg shows like this

[11902.060722] ==========send_signal===========
SIG 2 to 6141[a.out], tgid=6141
...
SIG 19 to 6142[a.out], tgid=6141
[11902.111135] Task Tree of 6142 = {
...

---------------------------------------------------------------------

"BAD program" might be a multi-thread program ,more than 3 thread process can't
be stop,less than 3 is good.

[prosup at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=23621

prosup <prosup at 163 dot com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Target| |x86_64 qemu virtual machine
Component|gdb |server

[prosup at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=23621

prosup <prosup at 163 dot com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Summary|gdbserver can't intrrupt |gdbserver can't intrrupt
|“SOME” process,kill(pid,2) |“SOME” process,kill(pid,2)
|called by gdbserver didn't |called by gdbserver didn't
|send SIGINT to |send SIGINT to process
|process,what's happening? |

[prosup at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=23621

prosup <prosup at 163 dot com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |DUPLICATE

--- Comment #1 from prosup <prosup at 163 dot com> ---
seems the same problem.

*** This bug has been marked as a duplicate of bug 18945 ***