commit 868883583e
Author: Andrew Burgess <aburgess@redhat.com>
Date: Sat Mar 23 16:17:36 2024 +0000
gdb/arch: assert that X86_XSTATE_MPX is not set for x32
added
if (xcr0 & X86_XSTATE_MPX)
{
/* MPX is not available on x32. */
gdb_assert (!is_x32);
regnum = create_feature_i386_64bit_mpx (tdesc.get (), regnum);
}
But x32 is a software convention. There is no x32 mode in hardware and
CPU always returns the 64-bit mode XCR0 value for x32 processes. This
regression was fixed on master branch by
commit bf616be991 (HEAD)
Author: Andrew Burgess <aburgess@redhat.com>
Date: Thu Jan 25 14:25:57 2024 +0000
gdb/gdbserver: share some code relating to target description creation
which used the gdbserver code to clear the X86_XSTATE_MPX bit in XCR0 for
x32. Fix this regression on gdb-15-branch by clearing the X86_XSTATE_MPX
bit in XCR0 for x32 in gdb.
PR gdb/32143
* x86-linux-nat.c (x86_linux_nat_target::read_description): Clear
the X86_XSTATE_MPX bit in XCR0 for x32.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Commit a8caed5d7f handled the tombstone
value -1 used by lld (https://reviews.llvm.org/D81784). The
referenced lld commit also uses the tombstone value -2 for
pre-DWARF-v5
(e618ccbf43).
If not handled, -2 breaks the pc step range calculation and triggers
the assertion:
gdb/infrun.c:2794: internal-error: resume_1: Assertion
`pc_in_thread_step_range (pc, tp)' failed.
This commit adds -2 tombstone value and handles it in the same way as -1.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31727
Cherry-picked from e814012b2b
Approved-By: Tom Tromey <tom@tromey.com>
In PR gdb/32025, a fatal error was reported when sending a SIGINT to gdb while
disassembling.
I managed to reproduce this on aarch64-linux in a Leap 15.5 container using
this trigger patch:
...
gdb_disassembler_memory_reader::dis_asm_read_memory
(bfd_vma memaddr, gdb_byte *myaddr, unsigned int len,
struct disassemble_info *info) noexcept
{
+ set_quit_flag ();
return target_read_code (memaddr, myaddr, len);
}
...
and a simple gdb command line calling the disassemble command:
...
$ gdb -q -batch a.out -ex "disassemble main"
...
The following scenario leads to the fatal error:
- the disassemble command is executed,
- set_quit_flag is called in
gdb_disassembler_memory_reader::dis_asm_read_memory, pretending that a
user pressed ^C,
- target_read_code calls QUIT, which throws a
gdb_exception_quit,
- the exception propagation mechanism reaches c code in libopcodes and a fatal
error triggers because the c code is not compiled with -fexception.
Fix this by:
- wrapping the body of gdb_disassembler_memory_reader::dis_asm_read_memory in
catch_exceptions (which consequently needs moving to a header file), and
- reraising the caught exception in default_print_insn using QUIT.
Tested on aarch64-linux.
Approved-By: Andrew Burgess <aburgess@redhat.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32025
(cherry picked from commit c45c3b4162)
Using 'output' to print arrays larger than max-value-size, with only
repeating elements, can cause gdb to crash:
```
$ cat a.c:
char a[1000000];
int main()
{
return a[0];
}
$ gdb -q a
(gdb) print a
$1 = {0 '\000' <repeats 65536 times>, <unavailable> <repeats 934464 times>}
(gdb) output a
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
```
Using 'print' works, because value::record_latest sets the unavailable
bytes of the value when it's added to the value history.
But 'outout' doesn't do that, so the printing tries to access more bytes
than are available.
The original problem in PR32015 was about using 'print' of a dynamic
array in a D program.
Here the crash happens because for 'print' the value was a struct with
length/ptr fields, which is converted in d-valprint.c into an array.
So value::record_latest didn't have a chance to mark the unavailable
bytes in this case.
To make sure the unavailable bytes always match the contents, this fixes
it by marking the unavailable bytes immediately after the contents are
allocated.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32015
Reviewed-By: Alexandra Petlanova Hajkova <ahajkova@redhat.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>
(cherry picked from commit 8fdd2b2bcd)
