old-cross-binutils/gdb/testsuite/gdb.base/execl-update-breakpoints.exp
Pedro Alves 2a7f3dffce Fix PR19548: Breakpoint re-set inserts breakpoints when it shouldn't
PR19548 shows that we still have problems related to 13fd3ff343:

 [PR17431: following execs with "breakpoint always-inserted on"]
 https://sourceware.org/ml/gdb-patches/2014-09/msg00733.html

The problem this time is that we currently update the global location
list and try to insert breakpoint locations after re-setting _each_
breakpoint in turn.

Say:

 - We have _more_ than one breakpoint set.  Let's assume 2.

 - There's a breakpoint with a pre-exec address that ends up being an
   unmapped address after the exec.

 - That breakpoint is NOT the first in the breakpoint list.

Then when handling an exec, and we re-set the first breakpoint in the
breakpoint list, we mistakently try to install the old pre-exec /
un-re-set locations of the other breakpoint, which fails:

 (gdb) continue
 Continuing.
 process 28295 is executing new program: (...)/execl-update-breakpoints2
 Error in re-setting breakpoint 1: Warning:
 Cannot insert breakpoint 2.
 Cannot access memory at address 0x1000764

 Breakpoint 1, main (argc=1, argv=0x7fffffffd368) at /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.base/execl-update-breakpoints.c:34
 34        len = strlen (argv[0]);
 (gdb)

Fix this by deferring the global location list update till after all
breakpoints are re-set.

Tested on x86_64 Fedora 20, native and gdbserver.

gdb/ChangeLog:
2016-02-09  Pedro Alves  <palves@redhat.com>

	PR breakpoints/19548
	* breakpoint.c (create_overlay_event_breakpoint): Don't update
	global location list here.
	(create_longjmp_master_breakpoint)
	(create_std_terminate_master_breakpoint)
	(create_exception_master_breakpoint, create_jit_event_breakpoint)
	(update_breakpoint_locations):
	(breakpoint_re_set): Update global location list after all
	breakpoints are re-set.

gdb/testsuite/ChangeLog:
2016-02-09  Pedro Alves  <palves@redhat.com>

	PR breakpoints/19548
	* gdb.base/execl-update-breakpoints.c (some_function): New
	function.
	(main): Call it.
	* gdb.base/execl-update-breakpoints.exp: Add a second breakpoint.
	Tighten expected GDB output.
2016-02-09 12:12:17 +00:00

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# Copyright 2014-2016 Free Software Foundation, Inc.
# 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/>.
# Test that when following an exec, we don't try to insert breakpoints
# in the new image at the addresses the symbols had before the exec.
standard_testfile
# Build two copies of the program, each linked at a different address.
# The address of "main" in the first binary should end up being an
# unmapped address in the second binary.
set objfile ${binfile}.o
set exec1 ${binfile}1
set exec2 ${binfile}2
if { [gdb_compile [file join $srcdir $subdir $srcfile] $objfile \
object [list debug]] != "" } {
untested "compile failed"
return -1
}
set opts1_ld [list debug ldflags=-Wl,-Ttext-segment=0x1000000]
set opts1_gold [list debug ldflags=-Wl,-Ttext=0x1000000]
set opts2_ld [list debug ldflags=-Wl,-Ttext-segment=0x2000000]
set opts2_gold [list debug ldflags=-Wl,-Ttext=0x2000000]
if { [gdb_compile $objfile $exec1 executable $opts1_ld] != "" } {
# Old gold linker versions don't support -Ttext-segment. Fall
# back to -Ttext.
if { [gdb_compile $objfile $exec1 executable $opts1_gold] != ""
|| [gdb_compile $objfile $exec2 executable $opts2_gold] != ""} {
untested "link failed"
return -1
}
} elseif { [gdb_compile $objfile $exec2 executable $opts2_ld] != "" } {
untested "link failed"
return -1
}
# First check whether the address of "main" in exec1 is readable in
# exec2. If it is, then skip the test as unsupported.
clean_restart ${exec1}
if ![runto_main] then {
fail "Couldn't run to main"
return -1
}
set addr ""
set test "main address first"
gdb_test_multiple "p/x &main" $test {
-re " = (0x\[0-9a-f\]+)\r\n$gdb_prompt $" {
set addr $expect_out(1,string)
pass $test
}
}
clean_restart ${exec2}
if ![runto_main] then {
fail "Couldn't run to main"
return -1
}
set cannot_access 0
set test "probe memory access"
gdb_test_multiple "x $addr" $test {
-re "Cannot access memory at address .*$gdb_prompt $" {
set cannot_access 1
pass $test
}
-re ".*$gdb_prompt $" {
pass $test
}
}
if {!$cannot_access} {
unsupported "main address is readable in second binary"
return
}
# The test proper. ALWAYS_INSERTED indicates whether testing in
# "breakpoint always-inserted" mode.
proc test { always_inserted } {
global exec1
global gdb_prompt
clean_restart ${exec1}
gdb_test_no_output "set breakpoint always-inserted $always_inserted"
if ![runto_main] then {
fail "Couldn't run to main"
return -1
}
# Set a second breakpoint (whose original address also ends up
# unmmapped after the exec), for PR 19548.
gdb_test "break some_function" "Breakpoint .*"
# PR17431: with always-inserted on, we'd see:
# (gdb) continue
# Continuing.
# Warning:
# Cannot insert breakpoint 1.
# Cannot access memory at address 0x10000ff
# PR 19548: with more than one breakpoint, we'd see:
# (gdb) continue
# Continuing.
# process (...) is executing new program: (...)/execl-update-breakpoints2
# Error in re-setting breakpoint 1: Warning:
# Cannot insert breakpoint 2.
# Cannot access memory at address 0x1000764
set not_nl "\[^\r\n\]*"
set regex ""
append regex \
"^continue\r\n" \
"Continuing\\.\r\n" \
"${not_nl} is executing new program: ${not_nl}\r\n" \
"(Reading ${not_nl} from remote target\\.\\.\\.\r\n)*" \
"\r\n" \
"Breakpoint 1, main.*$gdb_prompt $"
set message "continue across exec"
gdb_test_multiple "continue" $message {
-re $regex {
pass $message
}
}
}
foreach always_inserted { "off" "on" } {
with_test_prefix "always-inserted $always_inserted" {
test $always_inserted
}
}