Re: [Qemu-devel] [PATCH] disas: Always initialize read_memory_inner_func properly

[Paolo Bonzini <pbonzini@redhat.com>]

On 27/09/2017 16:58, Thomas Huth wrote:
> I've recently seen this with valgrind while running the HMP tester:
> 
> ==22373== Conditional jump or move depends on uninitialised value(s)
> ==22373==    at 0x4A41FD: arm_disas_set_info (cpu.c:504)
> ==22373==    by 0x3867A7: monitor_disas (disas.c:390)
> ==22373==    by 0x38E80E: memory_dump (monitor.c:1339)
> ==22373==    by 0x38FA43: handle_hmp_command (monitor.c:3123)
> ==22373==    by 0x38FB9E: qmp_human_monitor_command (monitor.c:613)
> ==22373==    by 0x4E3124: qmp_marshal_human_monitor_command (qmp-marshal.c:1736)
> ==22373==    by 0x769678: do_qmp_dispatch (qmp-dispatch.c:104)
> ==22373==    by 0x769678: qmp_dispatch (qmp-dispatch.c:131)
> ==22373==    by 0x38B734: handle_qmp_command (monitor.c:3853)
> ==22373==    by 0x76ED07: json_message_process_token (json-streamer.c:105)
> ==22373==    by 0x78D40A: json_lexer_feed_char (json-lexer.c:323)
> ==22373==    by 0x78D4CD: json_lexer_feed (json-lexer.c:373)
> ==22373==    by 0x38A08D: monitor_qmp_read (monitor.c:3895)
> 
> And indeed, in monitor_disas, the read_memory_inner_func variable was
> not initialized, but arm_disas_set_info() expects this to be NULL
> or a valid pointer. Let's properly set this to NULL in the
> INIT_DISASSEMBLE_INFO to fix it in all functions that use the
> disassemble_info struct.
> 
> Fixes: f7478a92dd9ee2276bfaa5b7317140d3f9d6a53b ("Fix Thumb-1 BE32 execution")
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>  disas.c             | 1 -
>  include/disas/bfd.h | 1 +
>  2 files changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/disas.c b/disas.c
> index d6a1eb9..54eea3f 100644
> --- a/disas.c
> +++ b/disas.c
> @@ -190,7 +190,6 @@ void target_disas(FILE *out, CPUState *cpu, target_ulong code,
>  
>      s.cpu = cpu;
>      s.info.read_memory_func = target_read_memory;
> -    s.info.read_memory_inner_func = NULL;
>      s.info.buffer_vma = code;
>      s.info.buffer_length = size;
>      s.info.print_address_func = generic_print_address;
> diff --git a/include/disas/bfd.h b/include/disas/bfd.h
> index b01e002..d99da68 100644
> --- a/include/disas/bfd.h
> +++ b/include/disas/bfd.h
> @@ -479,6 +479,7 @@ int generic_symbol_at_address(bfd_vma, struct disassemble_info *);
>    (INFO).buffer_vma = 0, \
>    (INFO).buffer_length = 0, \
>    (INFO).read_memory_func = buffer_read_memory, \
> +  (INFO).read_memory_inner_func = NULL, \
>    (INFO).memory_error_func = perror_memory, \
>    (INFO).print_address_func = generic_print_address, \
>    (INFO).print_insn = NULL, \
> 

Queued, thanks.

Paolo