Re: [PATCH] Fix infinite recursion bug at get_msymbol_address.

["Ali Tamur via gdb-patches" <gdb-patches@sourceware.org>]

If there are no objections, I am planning to check this in a couple days.
Thank you.
Ali

On Wed, Nov 13, 2019 at 10:34 AM Ali Tamur <tamur@google.com> wrote:

> Friendly ping?
>
> On Wed, Nov 6, 2019 at 8:05 PM Ali Tamur <tamur@google.com> wrote:
>
>> The patch 4b610737f0 seems to have introduced the possibility of infinite
>> recursion. I have encountered the problem while debugging a failing
>> in-house
>> test. I am sorry, it is fairly difficult to reduce the test case (and I
>> don't
>> understand most of what is going on) but the stack trace shows a call to
>> objfpy_add_separate_debug_file, which eventually causes
>> lookup_minimal_symbol_by_pc_name to be invoked, which calls
>> get_msymbol_address.
>> Somehow lookup_minimal_symbol_linkage finds the same symbol and the
>> function
>> calls itself with the same parameters. I don't know whether this should be
>> classified as 'it should never happen', but this simple patch makes the
>> test
>> pass and should be harmless, I think.
>>
>> gdb/ChangeLog
>>
>>         * symtab.c (get_msymbol_address): Guard against infinite
>> recursion.
>> ---
>>  gdb/symtab.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/gdb/symtab.c b/gdb/symtab.c
>> index 2c934b9c22..b231cc6e84 100644
>> --- a/gdb/symtab.c
>> +++ b/gdb/symtab.c
>> @@ -6328,7 +6328,7 @@ get_msymbol_address (struct objfile *objf, const
>> struct minimal_symbol *minsym)
>>         {
>>           bound_minimal_symbol found
>>             = lookup_minimal_symbol_linkage (linkage_name, objfile);
>> -         if (found.minsym != nullptr)
>> +         if (found.minsym != nullptr && found.minsym != minsym)
>>             return BMSYMBOL_VALUE_ADDRESS (found);
>>         }
>>      }
>> --
>> 2.24.0.rc1.363.gb1bccd3e3d-goog
>>
>>