From: Wei Liu <wei.liu2@citrix.com>
To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
Dario Faggioli <dario.faggioli@citrix.com>,
Wei Liu <wei.liu2@citrix.com>,
Ian Campbell <ian.campbell@citrix.com>
Subject: Re: [PATCH v3 10/10] libxl: fix caller of libxl_cpupool functions
Date: Wed, 15 Jul 2015 18:16:43 +0100 [thread overview]
Message-ID: <20150715171643.GI12455@zion.uk.xensource.com> (raw)
In-Reply-To: <21925.18402.35455.636018@mariner.uk.xensource.com>
On Tue, Jul 14, 2015 at 06:33:22PM +0100, Ian Jackson wrote:
> Wei Liu writes ("[PATCH v3 10/10] libxl: fix caller of libxl_cpupool functions"):
> > Coverity complains cpupool_info leaks a string in failure path. Instead
> > of fixing that path, we rely on the callers (two public APIs at the
> > moment) of cpupool_info correctly call libxl_cpupoolinfo_dispose in
> > their failure path to dispose of any resources.
>
> > diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
> > index 38aff8d..02b4a26 100644
> > --- a/tools/libxl/libxl.c
> > +++ b/tools/libxl/libxl.c
> > @@ -771,8 +771,11 @@ libxl_cpupoolinfo * libxl_list_cpupool(libxl_ctx *ctx, int *nb_pool_out)
> >
> > poolid = 0;
> > for (i = 0;; i++) {
> > - if (cpupool_info(gc, &info, poolid, false))
> > + libxl_cpupoolinfo_init(&info);
> > + if (cpupool_info(gc, &info, poolid, false)) {
> > + libxl_cpupoolinfo_dispose(&info);
> > break;
> > + }
>
> I'm not convinced by this change.
>
> I think that this function has broken error handling: if cpupool_info
> fails, it simply ignores the error.
>
I think the semantics of this function is to get back as many cpupool
info as it can.
Unfortunately the failing of cpupool_info can either mean the cpupool id
does not exist or other internal errors. So not cleaning up is the
right thing to do (speaking from semantics point of view).
I think I need to overhaul cpupool_info a bit if we want to make this
API better.
I'm not sure if it is possible to interleave pool ids. If so, we need a
way to get back the exact number of cpupools. Dario?
Wei.
> To fix this, it would have to clean up the array properly.
>
> Furthermore, I don't understand why it uses the temporary variable
> `info'. Surely it could have cpupool_info write directly into the
> right array slot. If it did that, then the error handling path would
> work to free up any failure.
>
>
> By putting both these fixes in the same patch, you have denied me the
> opportunity to ack the other change, which is fine ...
>
> Ian.
next prev parent reply other threads:[~2015-07-15 17:16 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-14 16:41 [PATCH v3 00/10] xl/libxl: fix issues discovered by coverity Wei Liu
2015-07-14 16:41 ` [PATCH v3 01/10] libxl: don't check s!=NULL in libxl__abs_path Wei Liu
2015-07-14 17:19 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 02/10] libxl: turn two malloc's to libxl__malloc Wei Liu
2015-07-14 17:19 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 03/10] libxl: make libxl__strdup handle NULL Wei Liu
2015-07-14 17:21 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 04/10] libxl: avoid leaking in libxl__initia_device_remove Wei Liu
2015-07-14 17:21 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 05/10] libxl: localtime(3) can return NULL Wei Liu
2015-07-14 17:22 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 06/10] libxl: qmp_init_handler " Wei Liu
2015-07-14 17:23 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 07/10] xl: correct handling of extra_config in main_cpupoolcreate Wei Liu
2015-07-14 17:23 ` Ian Jackson
2015-09-11 10:59 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 08/10] xl: correctly handle null extra config in main_config_update Wei Liu
2015-07-14 17:23 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 09/10] xl: fix a typo in error string in create_domain Wei Liu
2015-07-14 17:24 ` Ian Jackson
2015-07-14 16:41 ` [PATCH v3 10/10] libxl: fix caller of libxl_cpupool functions Wei Liu
2015-07-14 17:33 ` Ian Jackson
2015-07-15 17:16 ` Wei Liu [this message]
2015-07-16 8:57 ` Dario Faggioli
2015-07-16 9:07 ` Wei Liu
2015-07-16 9:33 ` Juergen Gross
2015-07-16 9:30 ` Juergen Gross
2015-07-16 12:49 ` Dario Faggioli
2015-07-15 10:23 ` [PATCH v3 00/10] xl/libxl: fix issues discovered by coverity Ian Campbell
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