* [PATCH] clk: fix a missing-free bug in clk_cpy_name()
@ 2019-05-31 1:14 Gen Zhang
2019-06-05 6:38 ` Jiri Slaby
0 siblings, 1 reply; 8+ messages in thread
From: Gen Zhang @ 2019-05-31 1:14 UTC (permalink / raw)
To: mturquette, sboyd; +Cc: linux-clk, linux-kernel
In clk_cpy_name(), '*dst_p'('parent->name'and 'parent->fw_name') and
'dst' are allcoted by kstrdup_const(). According to doc: "Strings
allocated by kstrdup_const should be freed by kfree_const". So
'parent->name', 'parent->fw_name' and 'dst' should be freed.
Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
---
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index aa51756..85c4d3f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3435,6 +3435,7 @@ static int clk_cpy_name(const char **dst_p, const char *src, bool must_exist)
if (!dst)
return -ENOMEM;
+ kfree_const(dst);
return 0;
}
@@ -3491,6 +3492,8 @@ static int clk_core_populate_parent_map(struct clk_core *core)
kfree_const(parents[i].name);
kfree_const(parents[i].fw_name);
} while (--i >= 0);
+ kfree_const(parent->name);
+ kfree_const(parent->fw_name);
kfree(parents);
return ret;
---
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH] clk: fix a missing-free bug in clk_cpy_name()
2019-05-31 1:14 [PATCH] clk: fix a missing-free bug in clk_cpy_name() Gen Zhang
@ 2019-06-05 6:38 ` Jiri Slaby
2019-06-05 16:00 ` Gen Zhang
0 siblings, 1 reply; 8+ messages in thread
From: Jiri Slaby @ 2019-06-05 6:38 UTC (permalink / raw)
To: Gen Zhang, mturquette, sboyd; +Cc: linux-clk, linux-kernel
On 31. 05. 19, 3:14, Gen Zhang wrote:
> In clk_cpy_name(), '*dst_p'('parent->name'and 'parent->fw_name') and
> 'dst' are allcoted by kstrdup_const(). According to doc: "Strings
> allocated by kstrdup_const should be freed by kfree_const". So
> 'parent->name', 'parent->fw_name' and 'dst' should be freed.
>
> Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
> ---
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index aa51756..85c4d3f 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -3435,6 +3435,7 @@ static int clk_cpy_name(const char **dst_p, const char *src, bool must_exist)
> if (!dst)
> return -ENOMEM;
>
> + kfree_const(dst);
So you are now returning a freed pointer in dst_p?
> return 0;
> }
>
> @@ -3491,6 +3492,8 @@ static int clk_core_populate_parent_map(struct clk_core *core)
> kfree_const(parents[i].name);
> kfree_const(parents[i].fw_name);
> } while (--i >= 0);
> + kfree_const(parent->name);
> + kfree_const(parent->fw_name);
Both of them were just freed in the loop above, no?
thanks,
--
js
suse labs
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] clk: fix a missing-free bug in clk_cpy_name()
2019-06-05 6:38 ` Jiri Slaby
@ 2019-06-05 16:00 ` Gen Zhang
2019-06-06 20:16 ` Stephen Boyd
0 siblings, 1 reply; 8+ messages in thread
From: Gen Zhang @ 2019-06-05 16:00 UTC (permalink / raw)
To: Jiri Slaby; +Cc: mturquette, sboyd, linux-clk, linux-kernel
On Wed, Jun 05, 2019 at 08:38:00AM +0200, Jiri Slaby wrote:
> On 31. 05. 19, 3:14, Gen Zhang wrote:
> > In clk_cpy_name(), '*dst_p'('parent->name'and 'parent->fw_name') and
> > 'dst' are allcoted by kstrdup_const(). According to doc: "Strings
> > allocated by kstrdup_const should be freed by kfree_const". So
> > 'parent->name', 'parent->fw_name' and 'dst' should be freed.
> >
> > Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
> > ---
> > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > index aa51756..85c4d3f 100644
> > --- a/drivers/clk/clk.c
> > +++ b/drivers/clk/clk.c
> > @@ -3435,6 +3435,7 @@ static int clk_cpy_name(const char **dst_p, const char *src, bool must_exist)
> > if (!dst)
> > return -ENOMEM;
> >
> > + kfree_const(dst);
>
> So you are now returning a freed pointer in dst_p?
Thanks for your reply. I re-examined the code, and this kfree is
incorrect and it should be deleted.
>
> > return 0;
> > }
> >
> > @@ -3491,6 +3492,8 @@ static int clk_core_populate_parent_map(struct clk_core *core)
> > kfree_const(parents[i].name);
> > kfree_const(parents[i].fw_name);
> > } while (--i >= 0);
> > + kfree_const(parent->name);
> > + kfree_const(parent->fw_name);
>
> Both of them were just freed in the loop above, no?
for (i = 0, parent = parents; i < num_parents; i++, parent++)
Is 'parent' the same as the one from the loop above?
Moreover, should 'parents[i].name' and 'parents[i].fw_name' be freed by
kfree_const()?
Thanks
Gen
>
> thanks,
> --
> js
> suse labs
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] clk: fix a missing-free bug in clk_cpy_name()
2019-06-05 16:00 ` Gen Zhang
@ 2019-06-06 20:16 ` Stephen Boyd
2019-06-07 1:52 ` Gen Zhang
0 siblings, 1 reply; 8+ messages in thread
From: Stephen Boyd @ 2019-06-06 20:16 UTC (permalink / raw)
To: Gen Zhang, Jiri Slaby; +Cc: mturquette, linux-clk, linux-kernel
Quoting Gen Zhang (2019-06-05 09:00:43)
> On Wed, Jun 05, 2019 at 08:38:00AM +0200, Jiri Slaby wrote:
> > On 31. 05. 19, 3:14, Gen Zhang wrote:
> > > In clk_cpy_name(), '*dst_p'('parent->name'and 'parent->fw_name') and
> > > 'dst' are allcoted by kstrdup_const(). According to doc: "Strings
> > > allocated by kstrdup_const should be freed by kfree_const". So
> > > 'parent->name', 'parent->fw_name' and 'dst' should be freed.
> > >
> > > Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
> > > ---
> > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > > index aa51756..85c4d3f 100644
> > > --- a/drivers/clk/clk.c
> > > +++ b/drivers/clk/clk.c
> > > @@ -3435,6 +3435,7 @@ static int clk_cpy_name(const char **dst_p, const char *src, bool must_exist)
> > > if (!dst)
> > > return -ENOMEM;
> > >
> > > + kfree_const(dst);
> >
> > So you are now returning a freed pointer in dst_p?
> Thanks for your reply. I re-examined the code, and this kfree is
> incorrect and it should be deleted.
> >
> > > return 0;
> > > }
> > >
> > > @@ -3491,6 +3492,8 @@ static int clk_core_populate_parent_map(struct clk_core *core)
> > > kfree_const(parents[i].name);
> > > kfree_const(parents[i].fw_name);
> > > } while (--i >= 0);
> > > + kfree_const(parent->name);
> > > + kfree_const(parent->fw_name);
> >
> > Both of them were just freed in the loop above, no?
> for (i = 0, parent = parents; i < num_parents; i++, parent++)
> Is 'parent' the same as the one from the loop above?
Yes. Did it change somehow?
>
> Moreover, should 'parents[i].name' and 'parents[i].fw_name' be freed by
> kfree_const()?
>
Yes? They're allocated with kstrdup_const() in clk_cpy_name(), or
they're NULL by virtue of the kcalloc and then kfree_const() does
nothing.
I'm having a hard time following what this patch is trying to fix. It
looks unnecessary though so I'm going to drop it from the clk review
queue.
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] clk: fix a missing-free bug in clk_cpy_name()
2019-06-06 20:16 ` Stephen Boyd
@ 2019-06-07 1:52 ` Gen Zhang
2019-06-07 9:10 ` Jiri Slaby
0 siblings, 1 reply; 8+ messages in thread
From: Gen Zhang @ 2019-06-07 1:52 UTC (permalink / raw)
To: Stephen Boyd; +Cc: Jiri Slaby, mturquette, linux-clk, linux-kernel
On Thu, Jun 06, 2019 at 01:16:45PM -0700, Stephen Boyd wrote:
> Quoting Gen Zhang (2019-06-05 09:00:43)
> > On Wed, Jun 05, 2019 at 08:38:00AM +0200, Jiri Slaby wrote:
> > > On 31. 05. 19, 3:14, Gen Zhang wrote:
> > > > In clk_cpy_name(), '*dst_p'('parent->name'and 'parent->fw_name') and
> > > > 'dst' are allcoted by kstrdup_const(). According to doc: "Strings
> > > > allocated by kstrdup_const should be freed by kfree_const". So
> > > > 'parent->name', 'parent->fw_name' and 'dst' should be freed.
> > > >
> > > > Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
> > > > ---
> > > > diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> > > > index aa51756..85c4d3f 100644
> > > > --- a/drivers/clk/clk.c
> > > > +++ b/drivers/clk/clk.c
> > > > @@ -3435,6 +3435,7 @@ static int clk_cpy_name(const char **dst_p, const char *src, bool must_exist)
> > > > if (!dst)
> > > > return -ENOMEM;
> > > >
> > > > + kfree_const(dst);
> > >
> > > So you are now returning a freed pointer in dst_p?
> > Thanks for your reply. I re-examined the code, and this kfree is
> > incorrect and it should be deleted.
> > >
> > > > return 0;
> > > > }
> > > >
> > > > @@ -3491,6 +3492,8 @@ static int clk_core_populate_parent_map(struct clk_core *core)
> > > > kfree_const(parents[i].name);
> > > > kfree_const(parents[i].fw_name);
> > > > } while (--i >= 0);
> > > > + kfree_const(parent->name);
> > > > + kfree_const(parent->fw_name);
> > >
> > > Both of them were just freed in the loop above, no?
> > for (i = 0, parent = parents; i < num_parents; i++, parent++)
> > Is 'parent' the same as the one from the loop above?
>
> Yes. Did it change somehow?
parent++?
>
> >
> > Moreover, should 'parents[i].name' and 'parents[i].fw_name' be freed by
> > kfree_const()?
> >
>
> Yes? They're allocated with kstrdup_const() in clk_cpy_name(), or
> they're NULL by virtue of the kcalloc and then kfree_const() does
> nothing.
I re-examined clk_cpy_name(). They are the second parameter of
clk_cpy_name(). The first parameter is allocated, not the second one.
So 'parent->name' and 'parent->fw_name' should be freed, not
'parents[i].name' or 'parents[i].fw_name'. Am I totally misunderstanding
this clk_cpy_name()? :-(
Thanks
Gen
>
> I'm having a hard time following what this patch is trying to fix. It
> looks unnecessary though so I'm going to drop it from the clk review
> queue.
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] clk: fix a missing-free bug in clk_cpy_name()
2019-06-07 1:52 ` Gen Zhang
@ 2019-06-07 9:10 ` Jiri Slaby
2019-06-07 12:07 ` Gen Zhang
0 siblings, 1 reply; 8+ messages in thread
From: Jiri Slaby @ 2019-06-07 9:10 UTC (permalink / raw)
To: Gen Zhang, Stephen Boyd; +Cc: mturquette, linux-clk, linux-kernel
On 07. 06. 19, 3:52, Gen Zhang wrote:
>>>>> @@ -3491,6 +3492,8 @@ static int clk_core_populate_parent_map(struct clk_core *core)
>>>>> kfree_const(parents[i].name);
>>>>> kfree_const(parents[i].fw_name);
>>>>> } while (--i >= 0);
>>>>> + kfree_const(parent->name);
>>>>> + kfree_const(parent->fw_name);
>>>>
>>>> Both of them were just freed in the loop above, no?
>>> for (i = 0, parent = parents; i < num_parents; i++, parent++)
>>> Is 'parent' the same as the one from the loop above?
>>
>> Yes. Did it change somehow?
> parent++?
parent++ is done after the loop body. Or what do you mean?
>>> Moreover, should 'parents[i].name' and 'parents[i].fw_name' be freed by
>>> kfree_const()?
>>>
>>
>> Yes? They're allocated with kstrdup_const() in clk_cpy_name(), or
>> they're NULL by virtue of the kcalloc and then kfree_const() does
>> nothing.
> I re-examined clk_cpy_name(). They are the second parameter of
> clk_cpy_name(). The first parameter is allocated, not the second one.
> So 'parent->name' and 'parent->fw_name' should be freed, not
> 'parents[i].name' or 'parents[i].fw_name'. Am I totally misunderstanding
> this clk_cpy_name()? :-(
The second parameter (the source) is parent_data[i].*, not parents[i].*
(the destination). parent->fw_name and parent->name are properly freed
in the do {} while loop as parents[i].name and parents[i].fw_name, given
i hasn't changed yet. I am not sure what you mean at all. Are you
uncertain about the C code flow?
thanks,
--
js
suse labs
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH] clk: fix a missing-free bug in clk_cpy_name()
2019-06-07 9:10 ` Jiri Slaby
@ 2019-06-07 12:07 ` Gen Zhang
0 siblings, 0 replies; 8+ messages in thread
From: Gen Zhang @ 2019-06-07 12:07 UTC (permalink / raw)
To: Jiri Slaby; +Cc: Stephen Boyd, mturquette, linux-clk, linux-kernel
On Fri, Jun 07, 2019 at 11:10:37AM +0200, Jiri Slaby wrote:
> On 07. 06. 19, 3:52, Gen Zhang wrote:
> >>>>> @@ -3491,6 +3492,8 @@ static int clk_core_populate_parent_map(struct clk_core *core)
> >>>>> kfree_const(parents[i].name);
> >>>>> kfree_const(parents[i].fw_name);
> >>>>> } while (--i >= 0);
> >>>>> + kfree_const(parent->name);
> >>>>> + kfree_const(parent->fw_name);
> >>>>
> >>>> Both of them were just freed in the loop above, no?
> >>> for (i = 0, parent = parents; i < num_parents; i++, parent++)
> >>> Is 'parent' the same as the one from the loop above?
> >>
> >> Yes. Did it change somehow?
> > parent++?
>
> parent++ is done after the loop body. Or what do you mean?
>
> >>> Moreover, should 'parents[i].name' and 'parents[i].fw_name' be freed by
> >>> kfree_const()?
> >>>
> >>
> >> Yes? They're allocated with kstrdup_const() in clk_cpy_name(), or
> >> they're NULL by virtue of the kcalloc and then kfree_const() does
> >> nothing.
> > I re-examined clk_cpy_name(). They are the second parameter of
> > clk_cpy_name(). The first parameter is allocated, not the second one.
> > So 'parent->name' and 'parent->fw_name' should be freed, not
> > 'parents[i].name' or 'parents[i].fw_name'. Am I totally misunderstanding
> > this clk_cpy_name()? :-(
>
> The second parameter (the source) is parent_data[i].*, not parents[i].*
> (the destination). parent->fw_name and parent->name are properly freed
> in the do {} while loop as parents[i].name and parents[i].fw_name, given
> i hasn't changed yet. I am not sure what you mean at all. Are you
> uncertain about the C code flow?
>
> thanks,
> --
> js
> suse labs
Thanks your patient explainaton. I think I need some time to figure out
this part of code.
Thanks
Gen
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] clk: fix a missing-free bug in clk_cpy_name()
@ 2019-05-27 14:04 Gen Zhang
0 siblings, 0 replies; 8+ messages in thread
From: Gen Zhang @ 2019-05-27 14:04 UTC (permalink / raw)
To: mturquette, sboyd; +Cc: linux-clk, linux-kernel
In clk_cpy_name(), '*dst_p'('parent->name'and 'parent->fw_name') and
'dst' are allcoted by kstrdup_const(). According to doc: "Strings
allocated by kstrdup_const should be freed by kfree_const". So
'parent->name', 'parent->fw_name' and 'dst' should be freed.
Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
---
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index aa51756..85c4d3f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3435,6 +3435,7 @@ static int clk_cpy_name(const char **dst_p, const char *src, bool must_exist)
if (!dst)
return -ENOMEM;
+ kfree_const(dst);
return 0;
}
@@ -3491,6 +3492,8 @@ static int clk_core_populate_parent_map(struct clk_core *core)
kfree_const(parents[i].name);
kfree_const(parents[i].fw_name);
} while (--i >= 0);
+ kfree_const(parent->name);
+ kfree_const(parent->fw_name);
kfree(parents);
return ret;
---
^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2019-06-07 12:07 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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2019-05-31 1:14 [PATCH] clk: fix a missing-free bug in clk_cpy_name() Gen Zhang
2019-06-05 6:38 ` Jiri Slaby
2019-06-05 16:00 ` Gen Zhang
2019-06-06 20:16 ` Stephen Boyd
2019-06-07 1:52 ` Gen Zhang
2019-06-07 9:10 ` Jiri Slaby
2019-06-07 12:07 ` Gen Zhang
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2019-05-27 14:04 Gen Zhang
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