From: Taylor Blau <me@ttaylorr.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Jeff Hostetler via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org, Jeff Hostetler <jeffhost@microsoft.com>
Subject: Re: [PATCH 1/7] trace2: fix memory leak of thread name
Date: Thu, 16 Sep 2021 00:19:42 -0400 [thread overview]
Message-ID: <YULF3hoaDxA9ENdO@nand.local> (raw)
In-Reply-To: <xmqqa6kdwo24.fsf@gitster.g>
On Wed, Sep 15, 2021 at 02:01:39PM -0700, Junio C Hamano wrote:
> "Jeff Hostetler via GitGitGadget" <gitgitgadget@gmail.com> writes:
>
> > From: Jeff Hostetler <jeffhost@microsoft.com>
> >
> > Do not leak the thread name (contained within the thread context) when
> > a thread terminates.
> >
> > Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
> > ---
> > trace2/tr2_tls.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/trace2/tr2_tls.c b/trace2/tr2_tls.c
> > index 067c23755fb..7da94aba522 100644
> > --- a/trace2/tr2_tls.c
> > +++ b/trace2/tr2_tls.c
> > @@ -95,6 +95,7 @@ void tr2tls_unset_self(void)
> >
> > pthread_setspecific(tr2tls_key, NULL);
> >
> > + strbuf_release(&ctx->thread_name);
> > free(ctx->array_us_start);
> > free(ctx);
> > }
>
> So the idea is create allocates a new instance, and unset is to
> release the resource held by it?
>
> This is not a problem in _this_ patch but more about the base code
> that is being fixed here, but using strbuf as thread_name member
> sends a strong signal that it is designed to be inexpensive to
> change thread_name after a context is created by create_self. If
> it is not the case, the member should be "const char *", which may
> be computed using a temporary strbuf in create_self() and taken from
> the strbuf with strbuf_detach(), I would think.
It looks like we do not change the contents of the thread_name buffer
anywhere. I assume that we store the strbuf in struct tr2tls_thread_ctx
because we do some string formatting in tr2tls_create_self().
But there we could easily say ctx->thread_name = strbuf_release(&buf).
More concerning to me is that we use signed integers to keep track of nr
and alloc of array_us_start. But both of these are separate issues and
don't need to be dealt with here.
Thanks,
Taylor
next prev parent reply other threads:[~2021-09-16 4:20 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-15 20:36 [PATCH 0/7] Builtin FSMonitor Part 1 Jeff Hostetler via GitGitGadget
2021-09-15 20:36 ` [PATCH 1/7] trace2: fix memory leak of thread name Jeff Hostetler via GitGitGadget
2021-09-15 21:01 ` Junio C Hamano
2021-09-16 4:19 ` Taylor Blau [this message]
2021-09-16 5:35 ` Ævar Arnfjörð Bjarmason
2021-09-16 5:43 ` Taylor Blau
2021-09-16 8:01 ` Ævar Arnfjörð Bjarmason
2021-09-16 15:35 ` Jeff Hostetler
2021-09-16 15:47 ` Ævar Arnfjörð Bjarmason
2021-09-16 19:13 ` Junio C Hamano
2021-09-15 20:36 ` [PATCH 2/7] simple-ipc: preparations for supporting binary messages Jeff Hostetler via GitGitGadget
2021-09-15 20:43 ` Eric Sunshine
2021-09-17 16:52 ` Jeff Hostetler
2021-09-15 20:36 ` [PATCH 3/7] simple-ipc: move definition of ipc_active_state outside of ifdef Jeff Hostetler via GitGitGadget
2021-09-15 21:06 ` Junio C Hamano
2021-09-17 16:58 ` Jeff Hostetler
2021-09-18 7:03 ` Carlo Arenas
2021-09-20 15:51 ` Junio C Hamano
2021-09-15 20:36 ` [PATCH 4/7] simple-ipc/ipc-win32: add trace2 debugging Jeff Hostetler via GitGitGadget
2021-09-16 5:40 ` Ævar Arnfjörð Bjarmason
2021-09-17 17:27 ` Jeff Hostetler
2021-09-15 20:36 ` [PATCH 5/7] simple-ipc/ipc-win32: add Windows ACL to named pipe Jeff Hostetler via GitGitGadget
2021-09-16 5:47 ` Ævar Arnfjörð Bjarmason
2021-09-17 18:10 ` Jeff Hostetler
2021-09-17 19:14 ` Ævar Arnfjörð Bjarmason
2021-09-15 20:36 ` [PATCH 6/7] run-command: create start_bg_command Jeff Hostetler via GitGitGadget
2021-09-16 4:53 ` Taylor Blau
2021-09-16 4:58 ` Taylor Blau
2021-09-16 5:56 ` Ævar Arnfjörð Bjarmason
2021-09-15 20:36 ` [PATCH 7/7] t/helper/simple-ipc: convert test-simple-ipc to use start_bg_command Jeff Hostetler via GitGitGadget
2021-09-16 5:06 ` Taylor Blau
2021-09-17 19:41 ` Jeff Hostetler
2021-09-18 8:59 ` Ævar Arnfjörð Bjarmason
2021-09-16 5:55 ` Ævar Arnfjörð Bjarmason
2021-09-20 15:36 ` [PATCH v2 0/7] Builtin FSMonitor Part 1 Jeff Hostetler via GitGitGadget
2021-09-20 15:36 ` [PATCH v2 1/7] trace2: add trace2_child_ready() to report on background children Jeff Hostetler via GitGitGadget
2021-09-20 15:36 ` [PATCH v2 2/7] simple-ipc: preparations for supporting binary messages Jeff Hostetler via GitGitGadget
2021-09-20 15:36 ` [PATCH v2 3/7] simple-ipc: move definition of ipc_active_state outside of ifdef Jeff Hostetler via GitGitGadget
2021-09-20 15:36 ` [PATCH v2 4/7] simple-ipc/ipc-win32: add trace2 debugging Jeff Hostetler via GitGitGadget
2021-09-20 15:36 ` [PATCH v2 5/7] simple-ipc/ipc-win32: add Windows ACL to named pipe Jeff Hostetler via GitGitGadget
2021-09-20 15:36 ` [PATCH v2 6/7] run-command: create start_bg_command Jeff Hostetler via GitGitGadget
2021-09-20 15:36 ` [PATCH v2 7/7] t/helper/simple-ipc: convert test-simple-ipc to use start_bg_command Jeff Hostetler via GitGitGadget
2021-09-23 15:03 ` Ævar Arnfjörð Bjarmason
2021-09-23 17:58 ` Jeff Hostetler
2021-09-23 18:37 ` Junio C Hamano
2021-11-04 19:46 ` Adam Dinwoodie
2021-11-04 20:14 ` Ramsay Jones
2021-11-08 14:58 ` Jeff Hostetler
2021-11-08 23:59 ` Johannes Schindelin
2021-11-09 18:53 ` Ramsay Jones
2021-11-09 23:01 ` Johannes Schindelin
2021-11-09 23:34 ` Junio C Hamano
2021-11-10 12:27 ` Johannes Schindelin
2021-11-12 8:56 ` Adam Dinwoodie
2021-11-12 16:01 ` Junio C Hamano
2021-11-12 21:33 ` Adam Dinwoodie
2021-11-16 10:56 ` Johannes Schindelin
2021-11-16 11:02 ` Johannes Schindelin
2021-11-13 19:11 ` Ramsay Jones
2021-11-14 19:34 ` Ramsay Jones
2021-11-14 20:10 ` Adam Dinwoodie
2021-09-23 14:33 ` [PATCH v2 0/7] Builtin FSMonitor Part 1 Ævar Arnfjörð Bjarmason
2021-09-23 17:12 ` Jeff Hostetler
2021-09-23 20:47 ` Ævar Arnfjörð Bjarmason
2021-09-27 13:37 ` Jeff Hostetler
2021-09-23 17:51 ` Taylor Blau
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