Hi Lianbo,

thanks for the review.

On 2022/07/25 15:30, lijiang wrote:
> Hi, Kazu
> Thank  you for the fix.
>
> On Fri, Jul 22, 2022 at 12:45 PM HAGIO KAZUHITO(萩尾 一仁) <k-hagio-ab@nec.com>
> wrote:
>
>> Without the patch, the following gcc-11 compliation warning is emitted
>> for symbols.c:
>>
>> symbols.c: In function 'cmd_p':
>> symbols.c:7412:38: warning: writing 1 byte into a region of size 0
>> [-Wstringop-overflow=]
>>   7412 |                         *(cpuspec-1) = ':';
>>        |                         ~~~~~~~~~~~~~^~~~~
>>
>
>
> I have one question about it:
> This issue only appears in gcc-11 and earlier, I tested it with gcc-12, but
> it disappeared. It's interesting.
I think that the warning is a false detection.  This patch has no behavior
change, just a cosmetic change to avoid the warning.  I'm not sure, but it
might be a gcc bug and fixed in gcc-12.

Thanks,
Kazu

>
> In addition, a new warning was found(gcc-12), but it is not related to this
> patch.
> ...
> gcc -c -g -DX86_64 -DLZO -DGDB_10_2 -g -O2 lkcd_v1.c -DMCLX -Wall -O2
> -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security
> lkcd_v1.c: In function ‘dump_lkcd_environment_v1’:
> lkcd_v1.c:252:20: warning: the comparison will always evaluate as ‘true’
> for the address of ‘dh_panic_string’ will never be NULL [-Waddress]
>    252 |                 dh && dh->dh_panic_string &&
>        |                    ^~
> In file included from lkcd_v1.c:21:
> lkcd_vmdump_v1.h:108:30: note: ‘dh_panic_string’ declared here
>    108 |         char                 dh_panic_string[DUMP_PANIC_LEN];
>        |                              ^~~~~~~~~~~~~~~
> gcc -c -g -DX86_64 -DLZO -DGDB_10_2 -g -O2 lkcd_v2_v3.c -DMCLX -Wall -O2
> -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security
> lkcd_v2_v3.c: In function ‘dump_lkcd_environment_v2_v3’:
> lkcd_v2_v3.c:310:20: warning: the comparison will always evaluate as ‘true’
> for the address of ‘dh_panic_string’ will never be NULL [-Waddress]
>    310 |                 dh && dh->dh_panic_string &&
>        |                    ^~
> In file included from lkcd_v2_v3.c:21:
> lkcd_vmdump_v2_v3.h:205:30: note: ‘dh_panic_string’ declared here
>    205 |         char                 dh_panic_string[DUMP_PANIC_LEN];
>        |                              ^~~~~~~~~~~~~~~
> gcc -c -g -DX86_64 -DLZO -DGDB_10_2 -g -O2 lkcd_v5.c -DMCLX -Wall -O2
> -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security
> lkcd_v5.c: In function ‘dump_lkcd_environment_v5’:
> lkcd_v5.c:273:20: warning: the comparison will always evaluate as ‘true’
> for the address of ‘dh_panic_string’ will never be NULL [-Waddress]
>    273 |                 dh && dh->dh_panic_string &&
>        |                    ^~
> In file included from lkcd_v5.c:20:
> lkcd_dump_v5.h:163:30: note: ‘dh_panic_string’ declared here
>    163 |         char                 dh_panic_string[DUMP_PANIC_LEN];
>        |                              ^~~~~~~~~~~~~~~
> gcc -c -g -DX86_64 -DLZO -DGDB_10_2 -g -O2 lkcd_v7.c -DMCLX -Wall -O2
> -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security
> lkcd_v7.c: In function ‘dump_lkcd_environment_v7’:
> lkcd_v7.c:350:20: warning: the comparison will always evaluate as ‘true’
> for the address of ‘dh_panic_string’ will never be NULL [-Waddress]
>    350 |                 dh && dh->dh_panic_string &&
>        |                    ^~
> In file included from lkcd_v7.c:21:
> lkcd_dump_v5.h:163:30: note: ‘dh_panic_string’ declared here
>    163 |         char                 dh_panic_string[DUMP_PANIC_LEN];
>        |                              ^~~~~~~~~~~~~~~
> gcc -c -g -DX86_64 -DLZO -DGDB_10_2 -g -O2 lkcd_v8.c -DMCLX -Wall -O2
> -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security
> lkcd_v8.c: In function ‘dump_lkcd_environment_v8’:
> lkcd_v8.c:546:20: warning: the comparison will always evaluate as ‘true’
> for the address of ‘dh_panic_string’ will never be NULL [-Waddress]
>    546 |                 dh && dh->dh_panic_string &&
>        |                    ^~
> In file included from lkcd_v8.c:23:
> lkcd_dump_v8.h:165:30: note: ‘dh_panic_string’ declared here
>    165 |         char                 dh_panic_string[DUMP_PANIC_LEN];
> ...
>
> Thanks.
> Lianbo
>
>
>> Signed-off-by: Kazuhito Hagio <k-hagio-ab@nec.com>
>> ---
>>   symbols.c | 6 +++---
>>   1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/symbols.c b/symbols.c
>> index bee1faf..42c4eb4 100644
>> --- a/symbols.c
>> +++ b/symbols.c
>> @@ -7351,7 +7351,7 @@ cmd_p(void)
>>          unsigned radix;
>>          int do_load_module_filter;
>>          char buf1[BUFSIZE];
>> -       char *cpuspec;
>> +       char *cpuspec, *p;
>>
>>          do_load_module_filter = radix = 0;
>>
>> @@ -7386,7 +7386,7 @@ cmd_p(void)
>>           if (argerrs || !args[optind])
>>                   cmd_usage(pc->curcmd, SYNOPSIS);
>>
>> -       cpuspec = strrchr(args[optind], ':');
>> +       p = cpuspec = strrchr(args[optind], ':');
>>          if (cpuspec)
>>                  *cpuspec++ = NULLCHAR;
>>
>> @@ -7409,7 +7409,7 @@ cmd_p(void)
>>                                sp->name);
>>                  else
>>                          /* maybe a valid C expression (e.g. ':') */
>> -                       *(cpuspec-1) = ':';
>> +                       *p = ':';
>>          }
>>
>>          process_gdb_output(concat_args(buf1, 0, TRUE), radix,
>> --
>> 2.31.1
>>