Simon Marchi [Sat, 21 Jan 2017 01:39:08 +0000 (20:39 -0500)]
Fix python-interactive with Python 3.6
New in v2:
- Define PyMem_RawMalloc as PyMem_Malloc for Python < 3.4 and use
PyMem_RawMalloc in the code.
Since Python 3.4, the callback installed in PyOS_ReadlineFunctionPointer
should return a value allocated with PyMem_RawMalloc instead of
PyMem_Malloc. The reason is that PyMem_Malloc must be called with the
Python Global Interpreter Lock (GIL) held, which is not the case in the
context where this function is called. PyMem_RawMalloc was introduced
for cases like this.
In Python 3.6, it looks like they added an assert to verify that
PyMem_Malloc was not called without the GIL. The consequence is that
typing anything in the python-interactive mode of gdb crashes the
process. The same behavior was observed with the official package on
Arch Linux as well as with a manual Python build on Ubuntu 14.04.
This is what is shown with a debug build of Python 3.6 (the error with a
non-debug build is far less clear):
(gdb) pi
>>> print(1)
Fatal Python error: Python memory allocator called without holding the GIL
#0 0x00007ffff618bc37 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007ffff618f028 in abort () from /lib/x86_64-linux-gnu/libc.so.6
#2 0x00007ffff6b104d6 in Py_FatalError (msg=msg@entry=0x7ffff6ba15b8 "Python memory allocator called without holding the GIL") at Python/pylifecycle.c:1457
#3 0x00007ffff6a37a68 in _PyMem_DebugCheckGIL () at Objects/obmalloc.c:1972
#4 0x00007ffff6a3804e in _PyMem_DebugFree (ctx=0x7ffff6e65290 <_PyMem_Debug+48>, ptr=0x24f8830) at Objects/obmalloc.c:1994
#5 0x00007ffff6a38e1d in PyMem_Free (ptr=<optimized out>) at Objects/obmalloc.c:442
#6 0x00007ffff6b866c6 in _PyFaulthandler_Fini () at ./Modules/faulthandler.c:1369
#7 0x00007ffff6b104bd in Py_FatalError (msg=msg@entry=0x7ffff6ba15b8 "Python memory allocator called without holding the GIL") at Python/pylifecycle.c:1431
#8 0x00007ffff6a37a68 in _PyMem_DebugCheckGIL () at Objects/obmalloc.c:1972
#9 0x00007ffff6a37aa3 in _PyMem_DebugMalloc (ctx=0x7ffff6e65290 <_PyMem_Debug+48>, nbytes=5) at Objects/obmalloc.c:1980
#10 0x00007ffff6a38d91 in PyMem_Malloc (size=<optimized out>) at Objects/obmalloc.c:418
#11 0x000000000064dbe2 in gdbpy_readline_wrapper (sys_stdin=0x7ffff6514640 <_IO_2_1_stdin_>, sys_stdout=0x7ffff6514400 <_IO_2_1_stdout_>, prompt=0x7ffff4d4f7d0 ">>> ")
at /home/emaisin/src/binutils-gdb/gdb/python/py-gdb-readline.c:75
The documentation is very clear about it [1] and it was also mentioned
in the "What's New In Python 3.4" page [2].
Yao Qi [Fri, 20 Jan 2017 13:00:52 +0000 (13:00 +0000)]
Throw SJ/LJ exception on error in disassembly
PR 20939 reports that GDB will abort on memory error in disassembly,
(gdb) disassemble 0x0,+4
Dump of assembler code from 0x0 to 0x4:
terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'
0x0000000000000000: Aborted
(gdb) guile (print (arch-disassemble arch 0 #:size 4))^M
terminate called after throwing an instance of 'gdb_exception_RETURN_MASK_ERROR'^M
ERROR: Process no longer exists
This patch fixes PR 20939 by catching C++ exception, throwing SJ/LJ
exception in the call back passed to C functions of opcodes, and
catching SJ/LJ exception in gdb, and throw exception.
rather than "backport" the fix to this PR I posted for mainline
https://sourceware.org/ml/gdb-patches/2017-01/msg00288.html because the
fix for mainline includes 1) some changes to opcodes, 2) some refactors
in C++. All of them are risky to backport to 7.12 branch.
With this patch applied to 7.12 branch, GDB doesn't abort on memory error
in disassembly. It fixes some test failures in gdb.guile/scm-disasm.exp
and gdb.python/py-arch.exp on aarch64-linux.
-ERROR: Process no longer exists
-UNRESOLVED: gdb.guile/scm-disasm.exp: test bad memory access
+PASS: gdb.guile/scm-disasm.exp: test bad memory access
-ERROR: Process no longer exists
-UNRESOLVED: gdb.python/py-arch.exp: test bad memory access
+PASS: gdb.python/py-arch.exp: test bad memory access
I'll add the scm-disasm test to master later.
gdb:
2017-01-20 Yao Qi <yao.qi@linaro.org>
PR gdb/20939
* disasm.c (dis_asm_memory_error): Catch the error and rethrow
it as a SJ/LJ exception. Add GDB_NOEXCEPT.
(disasm_print_insn_noexcept): New function.
(disasm_print_insn): New function.
(gdb_pretty_print_insn): Call disasm_print_insn instead of
gdbarch_print_insn.
(gdb_print_insn): Likewise.
(gdb_buffered_insn_length): Likewise.
* event-top.c (GDB_NOEXCEPT): Move it to ...
* exceptions.h (GDB_NOEXCEPT): ... here.
* guile/scm-disasm.c (gdbscm_disasm_memory_error): Remove.
(gdbscm_print_insn_from_port): Don't set di.memory_errro_func.
Call disasm_print_insn rather than gdbarch_print_insn.
projects / thirdparty / binutils-gdb.git / log
