From 4a556533cf0256613c412b9627fa8b8edfa7674a Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Thu, 6 Oct 2016 12:53:52 +0100 Subject: [PATCH] Fix PR11094: JIT breakpoint is not properly recreated on reruns Even though this was supposedly in the gdb 7.2 timeframe, the testcase in PR11094 crashes current GDB with a segfault: Program received signal SIGSEGV, Segmentation fault. 0x00000000005ee894 in event_location_to_string (location=0x0) at src/gdb/location.c:412 412 if (EL_STRING (location) == NULL) (top-gdb) bt #0 0x00000000005ee894 in event_location_to_string (location=0x0) at src/gdb/location.c:412 #1 0x000000000057411a in print_breakpoint_location (b=0x18288e0, loc=0x0) at src/gdb/breakpoint.c:6201 #2 0x000000000057483f in print_one_breakpoint_location (b=0x18288e0, loc=0x182cf10, loc_number=0, last_loc=0x7fffffffd258, allflag=1) at src/gdb/breakpoint.c:6473 #3 0x00000000005751e1 in print_one_breakpoint (b=0x18288e0, last_loc=0x7fffffffd258, allflag=1) at src/gdb/breakpoint.c:6707 #4 0x000000000057589c in breakpoint_1 (args=0x0, allflag=1, filter=0x0) at src/gdb/breakpoint.c:6947 #5 0x0000000000575aa8 in maintenance_info_breakpoints (args=0x0, from_tty=0) at src/gdb/breakpoint.c:7026 [...] This is GDB trying to print the location spec of the JIT event breakpoint, but that's an internal breakpoint without one. If I add a NULL check, then we see that the JIT breakpoint is now pending (because its location has shlib_disabled set): (gdb) maint info breakpoints Num Type Disp Enb Address What [...] -8 jit events keep y inf 1 [...] But that's incorrect. GDB should have managed to recreate the JIT breakpoint's location for the second run. So the problem is elsewhere. The problem is that if the JIT loads at the same address on the second run, we never recreate the JIT breakpoint, because we hit this early return: static int jit_breakpoint_re_set_internal (struct gdbarch *gdbarch, struct jit_program_space_data *ps_data) { [...] if (ps_data->cached_code_address == addr) return 0; [...] delete_breakpoint (ps_data->jit_breakpoint); [...] ps_data->jit_breakpoint = create_jit_event_breakpoint (gdbarch, addr); Fix this by deleting the breakpoint and discarding the cached code address when the objfile where the previous JIT breakpoint was found is deleted/unloaded in the first place. The test that was originally added for PR11094 doesn't trip on this because: #1 - It doesn't test the case of the JIT descriptor's address _not_ changing between reruns. #2 - And then it doesn't do "maint info breakpoints", or really anything with the JIT at all. #3 - and even then, to trigger the problem the JIT descriptor needs to be in a separate library, while the current test puts it in the main program. The patch extends the test to cover all combinations of these scenarios. gdb/ChangeLog: 2016-10-06 Pedro Alves * jit.c (free_objfile_data): Delete the JIT breakpoint and clear the cached code address. gdb/testsuite/ChangeLog: 2016-10-06 Pedro Alves * gdb.base/jit-simple-dl.c: New file. * gdb.base/jit-simple-jit.c: New file, factored out from ... * gdb.base/jit-simple.c: ... this. * gdb.base/jit-simple.exp (jit_run): Delete. (build_jit): New proc. (jit_test_reread): Recompile either the main program or the shared library, depending on what is being tested. Skip changing address if caller wants to. Compare before/after addresses. If testing standalone, explicitly load the binary. Test "maint info breakpoints". (top level): Add "standalone vs shared lib" and "change address" vs "same address" axes. --- gdb/ChangeLog | 5 + gdb/jit.c | 6 +- gdb/testsuite/ChangeLog | 15 +++ gdb/testsuite/gdb.base/jit-simple-dl.c | 25 +++++ gdb/testsuite/gdb.base/jit-simple-jit.c | 50 ++++++++++ gdb/testsuite/gdb.base/jit-simple.c | 43 +++----- gdb/testsuite/gdb.base/jit-simple.exp | 125 +++++++++++++++++++++--- 7 files changed, 226 insertions(+), 43 deletions(-) create mode 100644 gdb/testsuite/gdb.base/jit-simple-dl.c create mode 100644 gdb/testsuite/gdb.base/jit-simple-jit.c diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 084ab130418..3f222d6b963 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2016-10-06 Pedro Alves + + * jit.c (free_objfile_data): Delete the JIT breakpoint and clear + the cached code address. + 2016-10-06 Doug Evans * features/aarch64-core.xml (cpsr_flags): Elide "type" and specify diff --git a/gdb/jit.c b/gdb/jit.c index 81a2c26ccf6..03b6bd80c69 100644 --- a/gdb/jit.c +++ b/gdb/jit.c @@ -1482,7 +1482,11 @@ free_objfile_data (struct objfile *objfile, void *data) = ((struct jit_program_space_data *) program_space_data (objfile->pspace, jit_program_space_data)); if (ps_data != NULL && ps_data->objfile == objfile) - ps_data->objfile = NULL; + { + ps_data->objfile = NULL; + delete_breakpoint (ps_data->jit_breakpoint); + ps_data->cached_code_address = 0; + } } xfree (data); diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 5335344a06a..b27ca79eb19 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,18 @@ +2016-10-06 Pedro Alves + + * gdb.base/jit-simple-dl.c: New file. + * gdb.base/jit-simple-jit.c: New file, factored out from ... + * gdb.base/jit-simple.c: ... this. + * gdb.base/jit-simple.exp (jit_run): Delete. + (build_jit): New proc. + (jit_test_reread): Recompile either the main program or the shared + library, depending on what is being tested. Skip changing address + if caller wants to. Compare before/after addresses. If testing + standalone, explicitly load the binary. Test "maint info + breakpoints". + (top level): Add "standalone vs shared lib" and "change address" + vs "same address" axes. + 2016-10-06 Pedro Alves * gdb.base/jit-simple.exp (top level) Delete get_compiler_info diff --git a/gdb/testsuite/gdb.base/jit-simple-dl.c b/gdb/testsuite/gdb.base/jit-simple-dl.c new file mode 100644 index 00000000000..074dcddb3bd --- /dev/null +++ b/gdb/testsuite/gdb.base/jit-simple-dl.c @@ -0,0 +1,25 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 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 . */ + +/* A stub program that links with a simple library that uses the JIT + API. */ + +int +main (void) +{ + return 0; +} diff --git a/gdb/testsuite/gdb.base/jit-simple-jit.c b/gdb/testsuite/gdb.base/jit-simple-jit.c new file mode 100644 index 00000000000..93b846c13f0 --- /dev/null +++ b/gdb/testsuite/gdb.base/jit-simple-jit.c @@ -0,0 +1,50 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2012-2016 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 . */ + +/* Simple library using the JIT API. */ + +#include + +struct jit_code_entry +{ + struct jit_code_entry *next_entry; + struct jit_code_entry *prev_entry; + const char *symfile_addr; + uint64_t symfile_size; +}; + +struct jit_descriptor +{ + uint32_t version; + /* This type should be jit_actions_t, but we use uint32_t + to be explicit about the bitwidth. */ + uint32_t action_flag; + struct jit_code_entry *relevant_entry; + struct jit_code_entry *first_entry; +}; + +#ifdef SPACER +/* This exists to change the address of __jit_debug_descriptor. */ +int spacer = 4; +#endif + +struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 }; + +void +__jit_debug_register_code (void) +{ +} diff --git a/gdb/testsuite/gdb.base/jit-simple.c b/gdb/testsuite/gdb.base/jit-simple.c index 3893c3d7d8b..9f1d27b7ac9 100644 --- a/gdb/testsuite/gdb.base/jit-simple.c +++ b/gdb/testsuite/gdb.base/jit-simple.c @@ -1,37 +1,26 @@ -/* Simple program using the JIT API. */ +/* This testcase is part of GDB, the GNU debugger. -#include + Copyright 2016 Free Software Foundation, Inc. -struct jit_code_entry -{ - struct jit_code_entry *next_entry; - struct jit_code_entry *prev_entry; - const char *symfile_addr; - uint64_t symfile_size; -}; + 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. -struct jit_descriptor -{ - uint32_t version; - /* This type should be jit_actions_t, but we use uint32_t - to be explicit about the bitwidth. */ - uint32_t action_flag; - struct jit_code_entry *relevant_entry; - struct jit_code_entry *first_entry; -}; + 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. -#ifdef SPACER -/* This exists to change the address of __jit_debug_descriptor. */ -int spacer = 4; -#endif + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ -struct jit_descriptor __jit_debug_descriptor = { 1, 0, 0, 0 }; +/* Simple standalone program using the JIT API. */ -void __jit_debug_register_code() -{ -} +#include "jit-simple-jit.c" -int main() +int +main (void) { return 0; } diff --git a/gdb/testsuite/gdb.base/jit-simple.exp b/gdb/testsuite/gdb.base/jit-simple.exp index 6fe6011baa1..c1a079a67a8 100644 --- a/gdb/testsuite/gdb.base/jit-simple.exp +++ b/gdb/testsuite/gdb.base/jit-simple.exp @@ -13,6 +13,17 @@ # You should have received a copy of the GNU General Public License # along with this program. If not, see . +# Test re-running an inferior with a JIT descriptor, where the JIT +# descriptor changes address between runs. +# http://sourceware.org/bugzilla/show_bug.cgi?id=13431 + +# Test both the case of the JIT reader being included in the main +# program directly, and the case of the JIT reader being split out to +# a shared library. + +# For completeness, also test when the JIT descriptor does not change +# address between runs. + if {[skip_shlib_tests]} { untested jit-simple.exp return -1 @@ -20,25 +31,81 @@ if {[skip_shlib_tests]} { standard_testfile -if {[build_executable $testfile.exp $testfile $srcfile debug] == -1} { +set libname $testfile-jit +set srcfile_lib $srcdir/$subdir/$libname.c +set binfile_lib [standard_output_file $libname.so] + +# Build a standalone JIT binary. + +proc build_standalone_jit {{options ""}} { + global testfile srcfile binfile + + lappend options "debug" + + if {[build_executable $testfile.exp $testfile $srcfile $options] == -1} { + return -1 + } + + return 0 +} + +# Build the shared library JIT. + +proc build_shared_jit {{options ""}} { + global testfile + global srcfile_lib binfile_lib + + lappend options "debug additional_flags=-fPIC" + if { [gdb_compile_shlib $srcfile_lib $binfile_lib $options] != "" } { + return -1 + } + + return 0 +} + +if {[build_standalone_jit] == -1} { + untested "could not compile $binfile" + return +} + +if {[build_shared_jit] == -1} { + untested "could not compile $binfile_lib" + return +} + +# Built the program that loads the JIT library. +set srcfile_dl $testfile-dl.c +set binfile_dl $binfile-dl +set options [list debug shlib=${binfile_lib}] +if {[gdb_compile ${srcdir}/${subdir}/${srcfile_dl} $binfile_dl executable \ + [list debug shlib=$binfile_lib]] == -1 } { untested jit-simple.exp return -1 } -# Test re-running an inferior with a JIT descriptor, where the JIT -# descriptor changes address between runs. -# http://sourceware.org/bugzilla/show_bug.cgi?id=13431 -proc jit_test_reread {} { - global testfile binfile subdir srcfile srcdir +# STANDALONE is true when the JIT reader is included directly in the +# main program. False when the JIT reader is in a separate shared +# library. If CHANGE_ADDR is true, force changing the JIT descriptor +# changes address between runs. +proc jit_test_reread {standalone change_addr} { + global testfile binfile subdir srcfile srcdir binfile_lib binfile_dl global hex with_test_prefix "initial run" { - clean_restart $testfile + if {$standalone} { + clean_restart $binfile + } else { + clean_restart $binfile_dl + } runto_main set addr_before [get_hexadecimal_valueof "&__jit_debug_descriptor" 0 \ "get address of __jit_debug_descriptor"] + + gdb_test "maint info breakpoints" \ + "jit events keep y $hex <__jit_debug_register_code>.*" \ + "maint info breakpoints shows jit breakpoint" } with_test_prefix "second run" { @@ -47,21 +114,49 @@ proc jit_test_reread {} { # second, gdb might not reload the executable automatically. sleep 1 - gdb_rename_execfile $binfile ${binfile}x - if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug additional_flags=-DSPACER}] != "" } { - fail "recompile" - return - } else { - pass "recompile" + if ${change_addr} { + set options "additional_flags=-DSPACER" + if {$standalone} { + gdb_rename_execfile $binfile ${binfile}x + set res [build_standalone_jit $options] + } else { + gdb_rename_execfile $binfile_lib ${binfile_lib}x + set res [build_shared_jit $options] + } + if { $res == -1 } { + fail "recompile" + return + } else { + pass "recompile" + } } runto_main set addr_after [get_hexadecimal_valueof "&__jit_debug_descriptor" 0 \ "get address of __jit_debug_descriptor"] + + # This used to crash in the JIT-in-shared-library case: + # https://sourceware.org/bugzilla/show_bug.cgi?id=11094 + gdb_test "maint info breakpoints" \ + "jit events keep y $hex <__jit_debug_register_code>.*" \ + "maint info breakpoints shows jit breakpoint" } - gdb_assert {$addr_before != $addr_after} "address changed" + if ${change_addr} { + gdb_assert {$addr_before != $addr_after} "address changed" + } else { + gdb_assert {$addr_before == $addr_after} "address didn't change" + } } -jit_test_reread +foreach standalone {1 0} { + with_test_prefix [expr ($standalone)?"standalone":"shared"] { + with_test_prefix "change addr" { + jit_test_reread $standalone 1 + } + with_test_prefix "same addr" { + jit_test_reread $standalone 0 + } + } +} -- 2.30.2