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author | Andrew Burgess <aburgess@redhat.com> | 2022-07-20 13:00:40 +0100 |
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committer | Andrew Burgess <aburgess@redhat.com> | 2022-07-25 19:26:24 +0100 |
commit | 554128418b4f1328bb956d5926f24bfd56fd45ea (patch) | |
tree | abb729ac8648540d29b432f9c54ae4d4d6672311 | |
parent | e4146092c3f147b8c395febc771edd7de23f724d (diff) | |
download | gdb-554128418b4f1328bb956d5926f24bfd56fd45ea.zip gdb-554128418b4f1328bb956d5926f24bfd56fd45ea.tar.gz gdb-554128418b4f1328bb956d5926f24bfd56fd45ea.tar.bz2 |
gdb: fix use of uninitialised gdb_printing_disassembler::m_in_comment
Simon pointed out that gdb_printing_disassembler::m_in_comment can be
used uninitialised by the Python disassembler API code. This issue
was spotted when GDB was built with the undefined behaviour sanitizer,
and causes the gdb.python/py-disasm.exp test to fail like this:
(gdb) PASS: gdb.python/py-disasm.exp: global_disassembler=GlobalPreInfoDisassembler: python add_global_disassembler(GlobalPreInfoDisassembler)
disassemble main
Dump of assembler code for function main:
0x0000555555555119 <+0>: push %rbp
0x000055555555511a <+1>: mov %rsp,%rbp
0x000055555555511d <+4>: nop
/home/user/src/binutils-gdb/gdb/disasm.h:144:12: runtime error: load of value 118, which is not a valid value for type 'bool'
The problem is that in disasmpy_builtin_disassemble we create a new
instance of gdbpy_disassembler, which is a sub-class of
gdb_printing_disassembler, however, the m_in_comment field is never
initialised.
This commit fixes the issue by providing a default initialisation
value for m_in_comment in disasm.h. As we only ever disassemble a
single instruction in disasmpy_builtin_disassemble then we don't need
to worry about reseting m_in_comment back to false after the single
instruction has been disassembled.
With this commit the above issue is resolved and
gdb.python/py-disasm.exp now passes.
-rw-r--r-- | gdb/disasm.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/gdb/disasm.h b/gdb/disasm.h index 2921d53..09cb392 100644 --- a/gdb/disasm.h +++ b/gdb/disasm.h @@ -166,7 +166,7 @@ private: uses styled output and emits a start of comment character. It is up to the code that uses this disassembler class to reset this flag back to false at a suitable time (e.g. at the end of every line). */ - bool m_in_comment; + bool m_in_comment = false; }; /* A basic disassembler that doesn't actually print anything. */ |