Re: [RFC] Fix BFD leak in solib-darwin.c

[John Baldwin <jhb@FreeBSD.org>]

On 2/22/19 9:16 AM, John Baldwin wrote:
> On 2/22/19 8:36 AM, Tom Tromey wrote:
>> commit 192b62ce0b4bb5c61188f570e127a26d2c32f716 ("Use class to manage
>> BFD reference counts") changed darwin_get_dyld_bfd to use:
>>
>> +	dyld_bfd.release ();
>>
>> rather than
>>
>> -      do_cleanups (cleanup);
>>
>> However, using release here leaks the BFD.  Instead I believe reset
>> should be used instead.
>>
>> I can't readily test this, so please take a look and let me know what
>> you think.
>>
>> gdb/ChangeLog
>> 2019-02-22  Tom Tromey  <tromey@adacore.com>
>>
>> 	* solib-darwin.c (darwin_get_dyld_bfd): Use reset, not release.
>> ---
>>  gdb/ChangeLog      | 4 ++++
>>  gdb/solib-darwin.c | 2 +-
>>  2 files changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/gdb/solib-darwin.c b/gdb/solib-darwin.c
>> index d3060604bad..da410ad4660 100644
>> --- a/gdb/solib-darwin.c
>> +++ b/gdb/solib-darwin.c
>> @@ -455,7 +455,7 @@ darwin_get_dyld_bfd ()
>>        if (sub != NULL)
>>  	dyld_bfd = sub;
>>        else
>> -	dyld_bfd.release ();
>> +	dyld_bfd.reset (nullptr);
>>      }
>>    return dyld_bfd;
>>  }
> 
> I haven't tested, but this LGTM.  Simon has noticed several instances of
> this bug where release() was used instead of reset().  (The most recent one
> was in the build-id separate debug file code that I think hasn't been
> committed yet.)  It might be worth doing a quick sweep of current 'release'
> calls (if there aren't too many) to check for other leaks.

I did a quick look and this is the only other one I could find that I think
is also a leak:

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 98f46e0416..055cbc8073 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -2722,7 +2722,7 @@ dwarf2_get_dwz_file (struct dwarf2_per_objfile *dwarf2_per_objfile)
   if (dwz_bfd != NULL)
     {
       if (!build_id_verify (dwz_bfd.get (), buildid_len, buildid))
-       dwz_bfd.release ();
+       dwz_bfd.reset (nullptr);
     }
 
   if (dwz_bfd == NULL)


-- 
John Baldwin