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([2804:14d:8084:993e:2d5d:7adb:2b6:a50e]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-30293e2e3c0sm3788165eec.3.2026.05.14.08.20.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 14 May 2026 08:20:14 -0700 (PDT) Message-ID: <4c825e40-13af-4ce7-9169-de2737643ab8@redhat.com> Date: Thu, 14 May 2026 12:20:10 -0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/6] gdb/record: Refactor record history To: "Schimpe, Christina" , "gdb-patches@sourceware.org" References: <20260423152604.171356-1-guinevere@redhat.com> <20260423152604.171356-2-guinevere@redhat.com> <9de15785-0595-417b-b14d-fe5820738231@redhat.com> <23236510-ef59-4396-91eb-5763725f01cc@redhat.com> From: Guinevere Larsen In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 4_xAnQw_GVODXHbeCAIKUt-Wf7kXgUhEYXjN-VTNSJI_1778772015 X-Mimecast-Originator: redhat.com Content-Type: multipart/alternative; boundary="------------9GXWl0x0wlLKo0DHJTavhBRm" Content-Language: en-US X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: gdb-patches-bounces~public-inbox=simark.ca@sourceware.org This is a multi-part message in MIME format. --------------9GXWl0x0wlLKo0DHJTavhBRm Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/13/26 4:54 AM, Schimpe, Christina wrote: >>>>>> + record_full_incomplete_instruction.effects.shrink_to_fit (); >>>>>> + record_full_list.push_back (record_full_incomplete_instruction); >>> I think this line will at some point call the default copy constructor of >> record_full_mem_entry >>> and record_full_reg_entry, which have those buffers: >>> >>> gdb_byte buf[sizeof (gdb_byte *)]; >>> >>> IIUC you'll only have a shallow copy. Should we use a std::move instead >> here? >> Might be worth, yeah... >>> I further wonder if this problem might be related to the double free issues >> you >>> describe in patch #3. Would you mind checking? >> I did check it! When I was working on patch #3, I disabled copy >> construction, only allowed move constructor/assignment because I >> specifically thought that the vector push_back was the reason for the >> double frees, but it still happened. > That's weird, it would have perfectly explained it. > So with std::move we still have this problem? > Would you mind sharing some backtrace of this double free error ? Huh... I guess I must have done something wrong when I tried this the last time I just redid the changes to make the cleanup function into the destructors and now things just worked. I'll polish it a bit and send a v3 with that update! Thanks for getting me to try it again :) -- Cheers, Guinevere Larsen It/she --------------9GXWl0x0wlLKo0DHJTavhBRm Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit
On 5/13/26 4:54 AM, Schimpe, Christina wrote:
+  record_full_incomplete_instruction.effects.shrink_to_fit ();
+  record_full_list.push_back (record_full_incomplete_instruction);

I think this line will at some point call the default copy constructor of

record_full_mem_entry

and record_full_reg_entry, which have those buffers:

gdb_byte buf[sizeof (gdb_byte *)];

IIUC you'll only have a shallow copy. Should we use a std::move instead

here?
Might be worth, yeah...

I further wonder if this problem might be related to the double free issues

you

describe in patch #3. Would you mind checking?

I did check it! When I was working on patch #3, I disabled copy
construction, only allowed move constructor/assignment because I
specifically thought that the vector push_back was the reason for the
double frees, but it still happened.

That's weird, it would have perfectly explained it.
So with std::move we still have this problem?
Would you mind sharing some backtrace of this double free error ?

Huh... I guess I must have done something wrong when I tried this the last time

I just redid the changes to make the cleanup function into the destructors and now things just worked. I'll polish it a bit and send a v3 with that update! Thanks for getting me to try it again :)

-- 
Cheers,
Guinevere Larsen
It/she
--------------9GXWl0x0wlLKo0DHJTavhBRm--