old-cross-binutils/gdb/gdbserver/server.h
Pedro Alves 465a859e0a Fix gdbserver crash exposed by gdb.threads/process-dies-while-handling-bp.exp
Running that test in a loop, I found a gdbserver core dump with the
following back trace:

 Core was generated by `../gdbserver/gdbserver --once --multi :2346'.
 Program terminated with signal SIGSEGV, Segmentation fault.
 #0  0x0000000000406ab6 in inferior_regcache_data (inferior=0x0) at src/gdb/gdbserver/inferiors.c:236
 236       return inferior->regcache_data;
 (gdb) up
 #1  0x0000000000406d7f in get_thread_regcache (thread=0x0, fetch=1) at src/gdb/gdbserver/regcache.c:31
 31        regcache = (struct regcache *) inferior_regcache_data (thread);
 (gdb) bt
 #0  0x0000000000406ab6 in inferior_regcache_data (inferior=0x0) at src/gdb/gdbserver/inferiors.c:236
 #1  0x0000000000406d7f in get_thread_regcache (thread=0x0, fetch=1) at src/gdb/gdbserver/regcache.c:31
 #2  0x0000000000409271 in prepare_resume_reply (buf=0x20dd593 "", ptid=..., status=0x20edce0) at src/gdb/gdbserver/remote-utils.c:1147
 #3  0x000000000040ab0a in vstop_notif_reply (event=0x20edcc0, own_buf=0x20dd590 "T05") at src/gdb/gdbserver/server.c:183
 #4  0x0000000000426b38 in notif_write_event (notif=0x66e6c0 <notif_stop>, own_buf=0x20dd590 "T05") at src/gdb/gdbserver/notif.c:69
 #5  0x0000000000426c55 in handle_notif_ack (own_buf=0x20dd590 "T05", packet_len=8) at src/gdb/gdbserver/notif.c:113
 #6  0x000000000041118f in handle_v_requests (own_buf=0x20dd590 "T05", packet_len=8, new_packet_len=0x7fff742c77b8)
     at src/gdb/gdbserver/server.c:2862
 #7  0x0000000000413850 in process_serial_event () at src/gdb/gdbserver/server.c:4148
 #8  0x0000000000413945 in handle_serial_event (err=0, client_data=0x0) at src/gdb/gdbserver/server.c:4196
 #9  0x000000000041a1ef in handle_file_event (event_file_desc=5) at src/gdb/gdbserver/event-loop.c:429
 #10 0x00000000004199b6 in process_event () at src/gdb/gdbserver/event-loop.c:184
 #11 0x000000000041a735 in start_event_loop () at src/gdb/gdbserver/event-loop.c:547
 #12 0x00000000004123d2 in captured_main (argc=4, argv=0x7fff742c7ac8) at src/gdb/gdbserver/server.c:3562
 #13 0x000000000041252e in main (argc=4, argv=0x7fff742c7ac8) at src/gdb/gdbserver/server.c:3631

Clearly this means that a thread pushed a stop reply in the event
queue, and then before GDB confused the event, the whole process died,
along with its thread.  But the pending thread event was left
dangling.  When GDB fetched that event, gdbserver looked up the
corresponding thread, but found NULL; not expecting this, gdbserver
crashes when it tries to read this thread's registers.

gdb/gdbserver/
2015-08-21  Pedro Alves  <palves@redhat.com>

	PR gdb/18749
	* inferiors.c (remove_thread): Discard any pending stop reply for
	this thread.
	* server.c (remove_all_on_match_pid): Rename to ...
	(remove_all_on_match_ptid): ... this.  Work with a filter ptid
	instead of a pid.
	(discard_queued_stop_replies): Change parameter to a ptid.  Now
	extern.
	(handle_v_kill, kill_inferior_callback)
	(process_serial_event): Adjust.
	(captured_main): Call initialize_notif before starting the
	program, thus before threads are created.
	* server.h (discard_queued_stop_replies): Declare.
2015-08-21 19:52:36 +01:00

135 lines
3.6 KiB
C

/* Common definitions for remote server for GDB.
Copyright (C) 1993-2015 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef SERVER_H
#define SERVER_H
#include "common-defs.h"
gdb_static_assert (sizeof (CORE_ADDR) >= sizeof (void *));
#ifdef __MINGW32CE__
#include "wincecompat.h"
#endif
#include "version.h"
#if !HAVE_DECL_STRERROR
#ifndef strerror
extern char *strerror (int); /* X3.159-1989 4.11.6.2 */
#endif
#endif
#if !HAVE_DECL_PERROR
#ifndef perror
extern void perror (const char *);
#endif
#endif
#if !HAVE_DECL_VASPRINTF
extern int vasprintf(char **strp, const char *fmt, va_list ap);
#endif
#if !HAVE_DECL_VSNPRINTF
int vsnprintf(char *str, size_t size, const char *format, va_list ap);
#endif
#ifdef IN_PROCESS_AGENT
# define PROG "ipa"
#else
# define PROG "gdbserver"
#endif
#include "buffer.h"
#include "xml-utils.h"
#include "regcache.h"
#include "gdb_signals.h"
#include "target.h"
#include "mem-break.h"
#include "gdbthread.h"
#include "inferiors.h"
/* Target-specific functions */
void initialize_low ();
/* Public variables in server.c */
extern ptid_t cont_thread;
extern ptid_t general_thread;
extern int server_waiting;
extern int pass_signals[];
extern int program_signals[];
extern int program_signals_p;
extern int disable_packet_vCont;
extern int disable_packet_Tthread;
extern int disable_packet_qC;
extern int disable_packet_qfThreadInfo;
extern int run_once;
extern int multi_process;
extern int report_fork_events;
extern int report_vfork_events;
extern int non_stop;
extern int extended_protocol;
/* True if the "swbreak+" feature is active. In that case, GDB wants
us to report whether a trap is explained by a software breakpoint
and for the server to handle PC adjustment if necessary on this
target. Only enabled if the target supports it. */
extern int swbreak_feature;
/* True if the "hwbreak+" feature is active. In that case, GDB wants
us to report whether a trap is explained by a hardware breakpoint.
Only enabled if the target supports it. */
extern int hwbreak_feature;
extern int disable_randomization;
#if USE_WIN32API
#include <winsock2.h>
typedef SOCKET gdb_fildes_t;
#else
typedef int gdb_fildes_t;
#endif
#include "event-loop.h"
/* Functions from server.c. */
extern int handle_serial_event (int err, gdb_client_data client_data);
extern int handle_target_event (int err, gdb_client_data client_data);
/* Get rid of the currently pending stop replies that match PTID. */
extern void discard_queued_stop_replies (ptid_t ptid);
#include "remote-utils.h"
#include "utils.h"
#include "debug.h"
/* Maximum number of bytes to read/write at once. The value here
is chosen to fill up a packet (the headers account for the 32). */
#define MAXBUFBYTES(N) (((N)-32)/2)
/* Buffer sizes for transferring memory, registers, etc. Set to a constant
value to accomodate multiple register formats. This value must be at least
as large as the largest register set supported by gdbserver. */
#define PBUFSIZ 16384
#endif /* SERVER_H */