Fix pressing down in the TUI (Re: [RFC 8.3 0/3] Some style fixes)

Simon Marchi simark@simark.ca
Sun Mar 24 15:35:00 GMT 2019


On 2019-03-16 1:58 p.m., Eli Zaretskii wrote:
>> Cc: tromey@adacore.com, gdb-patches@sourceware.org
>> From: Pedro Alves <palves@redhat.com>
>> Date: Fri, 15 Mar 2019 13:56:39 +0000
>>
>>>> I think this should return false if open_source_file fails?
>>>
>>> How could it fail if input.is_open returns non-zero?  Are you thinking
>>> about some race, whereby something deletes the file after the
>>> constructor for 'input' returns?
>>
>> Yes, something like that.  The possibility is small, but non-zero
>> that it could fail.  And if it does, we end up with s->nlines
>> uninitialized again.
> 
> OK, pushed with that change to both branches.
> 
> Thanks.

Hi all,

I get an AddressSanitizer failure, and bisecting points to this commit.

I simply "start" an executable, and there is a use-after-free happening when
trying to print the stop location.  See the dump below.

Simon

$ ./gdb -nx --data-directory=data-directory ./a.out
(gdb) start
Temporary breakpoint 1 at 0x1130: file test.cpp, line 12.
Starting program: /home/simark/build/binutils-gdb/gdb/a.out

Temporary breakpoint 1, main () at test.cpp:12
=================================================================
==26068==ERROR: AddressSanitizer: heap-use-after-free on address 0x6210003d4100 at pc 0x7fed89a34681 bp 0x7ffd8d185d80 sp 0x7ffd8d185528
READ of size 2 at 0x6210003d4100 thread T0
    #0 0x7fed89a34680 in __interceptor_strlen /build/gcc/src/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:301
    #1 0x55b6edf6c2f7 in std::char_traits<char>::length(char const*) /usr/include/c++/8.2.1/bits/char_traits.h:320
    #2 0x55b6edf6c9b2 in std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&) /usr/include/c++/8.2.1/bits/basic_string.h:516
    #3 0x55b6ef09121b in source_cache::get_source_lines(symtab*, int, int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*) /home/simark/src/binutils-gdb/gdb/source-cache.c:214
    #4 0x55b6ef0a15cb in print_source_lines_base /home/simark/src/binutils-gdb/gdb/source.c:1340
    #5 0x55b6ef0a2045 in print_source_lines(symtab*, int, int, enum_flags<print_source_lines_flag>) /home/simark/src/binutils-gdb/gdb/source.c:1415
    #6 0x55b6ef112c87 in print_frame_info(frame_info*, int, print_what, int, int) /home/simark/src/binutils-gdb/gdb/stack.c:914
    #7 0x55b6ef10e90d in print_stack_frame(frame_info*, int, print_what, int) /home/simark/src/binutils-gdb/gdb/stack.c:180
    #8 0x55b6ee9592f8 in print_stop_location /home/simark/src/binutils-gdb/gdb/infrun.c:7853
    #9 0x55b6ee95948f in print_stop_event(ui_out*) /home/simark/src/binutils-gdb/gdb/infrun.c:7870
    #10 0x55b6ef34b962 in tui_on_normal_stop /home/simark/src/binutils-gdb/gdb/tui/tui-interp.c:98
    #11 0x55b6ee01a14d in std::_Function_handler<void (bpstats*, int), void (*)(bpstats*, int)>::_M_invoke(std::_Any_data const&, bpstats*&&, int&&) /usr/include/c++/8.2.1/bits/std_function.h:297
    #12 0x55b6ee965415 in std::function<void (bpstats*, int)>::operator()(bpstats*, int) const /usr/include/c++/8.2.1/bits/std_function.h:687
    #13 0x55b6ee962f1b in gdb::observers::observable<bpstats*, int>::notify(bpstats*, int) const /home/simark/src/binutils-gdb/gdb/common/observable.h:106
    #14 0x55b6ee95a6e7 in normal_stop() /home/simark/src/binutils-gdb/gdb/infrun.c:8142
    #15 0x55b6ee93f236 in fetch_inferior_event(void*) /home/simark/src/binutils-gdb/gdb/infrun.c:3782
    #16 0x55b6ee8f2641 in inferior_event_handler(inferior_event_type, void*) /home/simark/src/binutils-gdb/gdb/inf-loop.c:43
    #17 0x55b6eea2a1f0 in handle_target_event /home/simark/src/binutils-gdb/gdb/linux-nat.c:4358
    #18 0x55b6ee7045f1 in handle_file_event /home/simark/src/binutils-gdb/gdb/event-loop.c:733
    #19 0x55b6ee704e89 in gdb_wait_for_event /home/simark/src/binutils-gdb/gdb/event-loop.c:859
    #20 0x55b6ee7027b5 in gdb_do_one_event() /home/simark/src/binutils-gdb/gdb/event-loop.c:322
    #21 0x55b6ee702907 in start_event_loop() /home/simark/src/binutils-gdb/gdb/event-loop.c:371
    #22 0x55b6eeadfc16 in captured_command_loop /home/simark/src/binutils-gdb/gdb/main.c:331
    #23 0x55b6eeae2ef9 in captured_main /home/simark/src/binutils-gdb/gdb/main.c:1174
    #24 0x55b6eeae30c2 in gdb_main(captured_main_args*) /home/simark/src/binutils-gdb/gdb/main.c:1190
    #25 0x55b6edf4fa89 in main /home/simark/src/binutils-gdb/gdb/gdb.c:32
    #26 0x7fed88ad8222 in __libc_start_main (/usr/lib/libc.so.6+0x24222)
    #27 0x55b6edf4f86d in _start (/home/simark/build/binutils-gdb/gdb/gdb+0x197186d)

0x6210003d4100 is located 0 bytes inside of 4096-byte region [0x6210003d4100,0x6210003d5100)
freed by thread T0 here:
    #0 0x7fed89a8ac19 in __interceptor_free /build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cc:66
    #1 0x55b6edfe12df in xfree<char> /home/simark/src/binutils-gdb/gdb/common/common-utils.h:60
    #2 0x55b6edfea675 in gdb::xfree_deleter<char>::operator()(char*) const /home/simark/src/binutils-gdb/gdb/common/gdb_unique_ptr.h:34
    #3 0x55b6edfe532c in std::unique_ptr<char, gdb::xfree_deleter<char> >::reset(char*) /usr/include/c++/8.2.1/bits/unique_ptr.h:382
    #4 0x55b6edfe7329 in std::unique_ptr<char, gdb::xfree_deleter<char> >::operator=(std::unique_ptr<char, gdb::xfree_deleter<char> >&&) /usr/include/c++/8.2.1/bits/unique_ptr.h:289
    #5 0x55b6ef09ec2b in find_and_open_source(char const*, char const*, std::unique_ptr<char, gdb::xfree_deleter<char> >*) /home/simark/src/binutils-gdb/gdb/source.c:990
    #6 0x55b6ef09f56a in open_source_file(symtab*) /home/simark/src/binutils-gdb/gdb/source.c:1069
    #7 0x55b6ef090f78 in source_cache::get_source_lines(symtab*, int, int, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >*) /home/simark/src/binutils-gdb/gdb/source-cache.c:205
    #8 0x55b6ef0a15cb in print_source_lines_base /home/simark/src/binutils-gdb/gdb/source.c:1340
    #9 0x55b6ef0a2045 in print_source_lines(symtab*, int, int, enum_flags<print_source_lines_flag>) /home/simark/src/binutils-gdb/gdb/source.c:1415
    #10 0x55b6ef112c87 in print_frame_info(frame_info*, int, print_what, int, int) /home/simark/src/binutils-gdb/gdb/stack.c:914
    #11 0x55b6ef10e90d in print_stack_frame(frame_info*, int, print_what, int) /home/simark/src/binutils-gdb/gdb/stack.c:180
    #12 0x55b6ee9592f8 in print_stop_location /home/simark/src/binutils-gdb/gdb/infrun.c:7853
    #13 0x55b6ee95948f in print_stop_event(ui_out*) /home/simark/src/binutils-gdb/gdb/infrun.c:7870
    #14 0x55b6ef34b962 in tui_on_normal_stop /home/simark/src/binutils-gdb/gdb/tui/tui-interp.c:98
    #15 0x55b6ee01a14d in std::_Function_handler<void (bpstats*, int), void (*)(bpstats*, int)>::_M_invoke(std::_Any_data const&, bpstats*&&, int&&) /usr/include/c++/8.2.1/bits/std_function.h:297
    #16 0x55b6ee965415 in std::function<void (bpstats*, int)>::operator()(bpstats*, int) const /usr/include/c++/8.2.1/bits/std_function.h:687
    #17 0x55b6ee962f1b in gdb::observers::observable<bpstats*, int>::notify(bpstats*, int) const /home/simark/src/binutils-gdb/gdb/common/observable.h:106
    #18 0x55b6ee95a6e7 in normal_stop() /home/simark/src/binutils-gdb/gdb/infrun.c:8142
    #19 0x55b6ee93f236 in fetch_inferior_event(void*) /home/simark/src/binutils-gdb/gdb/infrun.c:3782
    #20 0x55b6ee8f2641 in inferior_event_handler(inferior_event_type, void*) /home/simark/src/binutils-gdb/gdb/inf-loop.c:43
    #21 0x55b6eea2a1f0 in handle_target_event /home/simark/src/binutils-gdb/gdb/linux-nat.c:4358
    #22 0x55b6ee7045f1 in handle_file_event /home/simark/src/binutils-gdb/gdb/event-loop.c:733
    #23 0x55b6ee704e89 in gdb_wait_for_event /home/simark/src/binutils-gdb/gdb/event-loop.c:859
    #24 0x55b6ee7027b5 in gdb_do_one_event() /home/simark/src/binutils-gdb/gdb/event-loop.c:322
    #25 0x55b6ee702907 in start_event_loop() /home/simark/src/binutils-gdb/gdb/event-loop.c:371
    #26 0x55b6eeadfc16 in captured_command_loop /home/simark/src/binutils-gdb/gdb/main.c:331
    #27 0x55b6eeae2ef9 in captured_main /home/simark/src/binutils-gdb/gdb/main.c:1174
    #28 0x55b6eeae30c2 in gdb_main(captured_main_args*) /home/simark/src/binutils-gdb/gdb/main.c:1190
    #29 0x55b6edf4fa89 in main /home/simark/src/binutils-gdb/gdb/gdb.c:32

previously allocated by thread T0 here:
    #0 0x7fed89a8b019 in __interceptor_malloc /build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cc:86
    #1 0x7fed88af983f in realpath@@GLIBC_2.3 (/usr/lib/libc.so.6+0x4583f)
    #2 0x7fed899dbbbc in __interceptor_canonicalize_file_name /build/gcc/src/gcc/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:3297
    #3 0x55b6ee376a03 in gdb_realpath(char const*) /home/simark/src/binutils-gdb/gdb/common/pathstuff.c:72
    #4 0x55b6ef09ec12 in find_and_open_source(char const*, char const*, std::unique_ptr<char, gdb::xfree_deleter<char> >*) /home/simark/src/binutils-gdb/gdb/source.c:990
    #5 0x55b6ef09f56a in open_source_file(symtab*) /home/simark/src/binutils-gdb/gdb/source.c:1069
    #6 0x55b6ef0a0f12 in print_source_lines_base /home/simark/src/binutils-gdb/gdb/source.c:1270
    #7 0x55b6ef0a2045 in print_source_lines(symtab*, int, int, enum_flags<print_source_lines_flag>) /home/simark/src/binutils-gdb/gdb/source.c:1415
    #8 0x55b6ef112c87 in print_frame_info(frame_info*, int, print_what, int, int) /home/simark/src/binutils-gdb/gdb/stack.c:914
    #9 0x55b6ef10e90d in print_stack_frame(frame_info*, int, print_what, int) /home/simark/src/binutils-gdb/gdb/stack.c:180
    #10 0x55b6ee9592f8 in print_stop_location /home/simark/src/binutils-gdb/gdb/infrun.c:7853
    #11 0x55b6ee95948f in print_stop_event(ui_out*) /home/simark/src/binutils-gdb/gdb/infrun.c:7870
    #12 0x55b6ef34b962 in tui_on_normal_stop /home/simark/src/binutils-gdb/gdb/tui/tui-interp.c:98
    #13 0x55b6ee01a14d in std::_Function_handler<void (bpstats*, int), void (*)(bpstats*, int)>::_M_invoke(std::_Any_data const&, bpstats*&&, int&&) /usr/include/c++/8.2.1/bits/std_function.h:297
    #14 0x55b6ee965415 in std::function<void (bpstats*, int)>::operator()(bpstats*, int) const /usr/include/c++/8.2.1/bits/std_function.h:687
    #15 0x55b6ee962f1b in gdb::observers::observable<bpstats*, int>::notify(bpstats*, int) const /home/simark/src/binutils-gdb/gdb/common/observable.h:106
    #16 0x55b6ee95a6e7 in normal_stop() /home/simark/src/binutils-gdb/gdb/infrun.c:8142
    #17 0x55b6ee93f236 in fetch_inferior_event(void*) /home/simark/src/binutils-gdb/gdb/infrun.c:3782
    #18 0x55b6ee8f2641 in inferior_event_handler(inferior_event_type, void*) /home/simark/src/binutils-gdb/gdb/inf-loop.c:43
    #19 0x55b6eea2a1f0 in handle_target_event /home/simark/src/binutils-gdb/gdb/linux-nat.c:4358
    #20 0x55b6ee7045f1 in handle_file_event /home/simark/src/binutils-gdb/gdb/event-loop.c:733
    #21 0x55b6ee704e89 in gdb_wait_for_event /home/simark/src/binutils-gdb/gdb/event-loop.c:859
    #22 0x55b6ee7027b5 in gdb_do_one_event() /home/simark/src/binutils-gdb/gdb/event-loop.c:322
    #23 0x55b6ee702907 in start_event_loop() /home/simark/src/binutils-gdb/gdb/event-loop.c:371
    #24 0x55b6eeadfc16 in captured_command_loop /home/simark/src/binutils-gdb/gdb/main.c:331
    #25 0x55b6eeae2ef9 in captured_main /home/simark/src/binutils-gdb/gdb/main.c:1174
    #26 0x55b6eeae30c2 in gdb_main(captured_main_args*) /home/simark/src/binutils-gdb/gdb/main.c:1190
    #27 0x55b6edf4fa89 in main /home/simark/src/binutils-gdb/gdb/gdb.c:32
    #28 0x7fed88ad8222 in __libc_start_main (/usr/lib/libc.so.6+0x24222)



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