2020-06-22 15:38:10

by Colin King

Subject: [PATCH][next] mm/zswap: fix a couple of memory leaks and rework kzalloc failure check

From: Colin Ian King <[email protected]>

kzalloc failures return NULL on out of memory errors, so replace the
IS_ERR_OR_NULL check with the usual null pointer check. Fix two memory
leaks with on acomp and acomp_ctx by ensuring these objects are free'd
on the error return path.

Addresses-Coverity: ("Resource leak")
Fixes: d4f86abd6e35 ("mm/zswap: move to use crypto_acomp API for hardware acceleration")
Signed-off-by: Colin Ian King <[email protected]>
---
mm/zswap.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/mm/zswap.c b/mm/zswap.c
index 0d914ba6b4a0..14839cbac7ff 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -433,23 +433,23 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
return 0;

acomp_ctx = kzalloc(sizeof(*acomp_ctx), GFP_KERNEL);
- if (IS_ERR_OR_NULL(acomp_ctx)) {
+ if (!acomp_ctx) {
pr_err("Could not initialize acomp_ctx\n");
return -ENOMEM;
}
acomp = crypto_alloc_acomp(pool->tfm_name, 0, 0);
- if (IS_ERR_OR_NULL(acomp)) {
+ if (!acomp) {
pr_err("could not alloc crypto acomp %s : %ld\n",
pool->tfm_name, PTR_ERR(acomp));
- return -ENOMEM;
+ goto free_acomp_ctx;
}
acomp_ctx->acomp = acomp;

req = acomp_request_alloc(acomp_ctx->acomp);
- if (IS_ERR_OR_NULL(req)) {
+ if (!req) {
pr_err("could not alloc crypto acomp %s : %ld\n",
pool->tfm_name, PTR_ERR(acomp));
- return -ENOMEM;
+ goto free_acomp;
}
acomp_ctx->req = req;

@@ -462,6 +462,12 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
*per_cpu_ptr(pool->acomp_ctx, cpu) = acomp_ctx;

return 0;
+
+free_acomp:
+ kfree(acomp);
+free_acomp_ctx:
+ kfree(acomp_ctx);
+ return -ENOMEM;
}

static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node)
--
2.27.0

2020-06-22 18:31:02

by Dan Carpenter

Subject: Re: [PATCH][next] mm/zswap: fix a couple of memory leaks and rework kzalloc failure check

On Mon, Jun 22, 2020 at 04:35:46PM +0100, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> kzalloc failures return NULL on out of memory errors, so replace the
> IS_ERR_OR_NULL check with the usual null pointer check. Fix two memory
> leaks with on acomp and acomp_ctx by ensuring these objects are free'd
> on the error return path.
>
> Addresses-Coverity: ("Resource leak")
> Fixes: d4f86abd6e35 ("mm/zswap: move to use crypto_acomp API for hardware acceleration")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> mm/zswap.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/mm/zswap.c b/mm/zswap.c
> index 0d914ba6b4a0..14839cbac7ff 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -433,23 +433,23 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
> return 0;
>
> acomp_ctx = kzalloc(sizeof(*acomp_ctx), GFP_KERNEL);
> - if (IS_ERR_OR_NULL(acomp_ctx)) {
> + if (!acomp_ctx) {
> pr_err("Could not initialize acomp_ctx\n");
> return -ENOMEM;
> }
> acomp = crypto_alloc_acomp(pool->tfm_name, 0, 0);
> - if (IS_ERR_OR_NULL(acomp)) {
> + if (!acomp) {

This should be IS_ERR(acomp). Please preserve the error code.

> pr_err("could not alloc crypto acomp %s : %ld\n",
> pool->tfm_name, PTR_ERR(acomp));
> - return -ENOMEM;
> + goto free_acomp_ctx;
> }
> acomp_ctx->acomp = acomp;
>
> req = acomp_request_alloc(acomp_ctx->acomp);
> - if (IS_ERR_OR_NULL(req)) {
> + if (!req) {
> pr_err("could not alloc crypto acomp %s : %ld\n",
> pool->tfm_name, PTR_ERR(acomp));
> - return -ENOMEM;
> + goto free_acomp;
> }
> acomp_ctx->req = req;
>
> @@ -462,6 +462,12 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node)
> *per_cpu_ptr(pool->acomp_ctx, cpu) = acomp_ctx;
>
> return 0;
> +
> +free_acomp:
> + kfree(acomp);

The kfree() isn't correct. It needs to be:

crypto_free_acomp(acomp);

> +free_acomp_ctx:
> + kfree(acomp_ctx);
> + return -ENOMEM;

regards,
dan carpenter

2020-06-22 19:57:54

by Song Bao Hua (Barry Song)

Subject: RE: [PATCH][next] mm/zswap: fix a couple of memory leaks and rework kzalloc failure check

> -----Original Message-----
> From: Dan Carpenter [mailto:[email protected]]
> Sent: Tuesday, June 23, 2020 6:28 AM
> To: Colin King <[email protected]>
> Cc: Seth Jennings <[email protected]>; Dan Streetman
> <[email protected]>; Vitaly Wool <[email protected]>; Andrew
> Morton <[email protected]>; Song Bao Hua (Barry Song)
> <[email protected]>; Stephen Rothwell <[email protected]>;
> [email protected]; [email protected];
> [email protected]
> Subject: Re: [PATCH][next] mm/zswap: fix a couple of memory leaks and
> rework kzalloc failure check
>
> On Mon, Jun 22, 2020 at 04:35:46PM +0100, Colin King wrote:
> > From: Colin Ian King <[email protected]>
> >
> > kzalloc failures return NULL on out of memory errors, so replace the
> > IS_ERR_OR_NULL check with the usual null pointer check. Fix two memory
> > leaks with on acomp and acomp_ctx by ensuring these objects are free'd
> > on the error return path.
> >
> > Addresses-Coverity: ("Resource leak")
> > Fixes: d4f86abd6e35 ("mm/zswap: move to use crypto_acomp API for
> hardware acceleration")
> > Signed-off-by: Colin Ian King <[email protected]>


Colin, thanks for your patch. I am sorry I did the same thing with you here:
https://lkml.org/lkml/2020/6/22/347


> > ---
> > mm/zswap.c | 16 +++++++++++-----
> > 1 file changed, 11 insertions(+), 5 deletions(-)
> >
> > diff --git a/mm/zswap.c b/mm/zswap.c
> > index 0d914ba6b4a0..14839cbac7ff 100644
> > --- a/mm/zswap.c
> > +++ b/mm/zswap.c
> > @@ -433,23 +433,23 @@ static int zswap_cpu_comp_prepare(unsigned int
> cpu, struct hlist_node *node)
> > return 0;
> >
> > acomp_ctx = kzalloc(sizeof(*acomp_ctx), GFP_KERNEL);
> > - if (IS_ERR_OR_NULL(acomp_ctx)) {
> > + if (!acomp_ctx) {
> > pr_err("Could not initialize acomp_ctx\n");
> > return -ENOMEM;
> > }
> > acomp = crypto_alloc_acomp(pool->tfm_name, 0, 0);
> > - if (IS_ERR_OR_NULL(acomp)) {
> > + if (!acomp) {
>
> This should be IS_ERR(acomp). Please preserve the error code.
>
> > pr_err("could not alloc crypto acomp %s : %ld\n",
> > pool->tfm_name, PTR_ERR(acomp));
> > - return -ENOMEM;
> > + goto free_acomp_ctx;
> > }
> > acomp_ctx->acomp = acomp;
> >
> > req = acomp_request_alloc(acomp_ctx->acomp);
> > - if (IS_ERR_OR_NULL(req)) {
> > + if (!req) {
> > pr_err("could not alloc crypto acomp %s : %ld\n",
> > pool->tfm_name, PTR_ERR(acomp));
> > - return -ENOMEM;
> > + goto free_acomp;
> > }
> > acomp_ctx->req = req;
> >
> > @@ -462,6 +462,12 @@ static int zswap_cpu_comp_prepare(unsigned int
> cpu, struct hlist_node *node)
> > *per_cpu_ptr(pool->acomp_ctx, cpu) = acomp_ctx;
> >
> > return 0;
> > +
> > +free_acomp:
> > + kfree(acomp);
>
> The kfree() isn't correct. It needs to be:
>
> crypto_free_acomp(acomp);
>
> > +free_acomp_ctx:
> > + kfree(acomp_ctx);
> > + return -ENOMEM;
>
> regards,
> dan carpenter

2020-06-23 11:17:05

by Colin King

Subject: Re: [PATCH][next] mm/zswap: fix a couple of memory leaks and rework kzalloc failure check

On 22/06/2020 20:55, Song Bao Hua (Barry Song) wrote:
>
>
>> -----Original Message-----
>> From: Dan Carpenter [mailto:[email protected]]
>> Sent: Tuesday, June 23, 2020 6:28 AM
>> To: Colin King <[email protected]>
>> Cc: Seth Jennings <[email protected]>; Dan Streetman
>> <[email protected]>; Vitaly Wool <[email protected]>; Andrew
>> Morton <[email protected]>; Song Bao Hua (Barry Song)
>> <[email protected]>; Stephen Rothwell <[email protected]>;
>> [email protected]; [email protected];
>> [email protected]
>> Subject: Re: [PATCH][next] mm/zswap: fix a couple of memory leaks and
>> rework kzalloc failure check
>>
>> On Mon, Jun 22, 2020 at 04:35:46PM +0100, Colin King wrote:
>>> From: Colin Ian King <[email protected]>
>>>
>>> kzalloc failures return NULL on out of memory errors, so replace the
>>> IS_ERR_OR_NULL check with the usual null pointer check. Fix two memory
>>> leaks with on acomp and acomp_ctx by ensuring these objects are free'd
>>> on the error return path.
>>>
>>> Addresses-Coverity: ("Resource leak")
>>> Fixes: d4f86abd6e35 ("mm/zswap: move to use crypto_acomp API for
>> hardware acceleration")
>>> Signed-off-by: Colin Ian King <[email protected]>
>
>
> Colin, thanks for your patch. I am sorry I did the same thing with you here:
> https://lkml.org/lkml/2020/6/22/347

Thanks for fixing this correctly, I ran out of time yesterday to re-do
the fix.

Colin

>
>
>>> ---
>>> mm/zswap.c | 16 +++++++++++-----
>>> 1 file changed, 11 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/mm/zswap.c b/mm/zswap.c
>>> index 0d914ba6b4a0..14839cbac7ff 100644
>>> --- a/mm/zswap.c
>>> +++ b/mm/zswap.c
>>> @@ -433,23 +433,23 @@ static int zswap_cpu_comp_prepare(unsigned int
>> cpu, struct hlist_node *node)
>>> return 0;
>>>
>>> acomp_ctx = kzalloc(sizeof(*acomp_ctx), GFP_KERNEL);
>>> - if (IS_ERR_OR_NULL(acomp_ctx)) {
>>> + if (!acomp_ctx) {
>>> pr_err("Could not initialize acomp_ctx\n");
>>> return -ENOMEM;
>>> }
>>> acomp = crypto_alloc_acomp(pool->tfm_name, 0, 0);
>>> - if (IS_ERR_OR_NULL(acomp)) {
>>> + if (!acomp) {
>>
>> This should be IS_ERR(acomp). Please preserve the error code.
>>
>>> pr_err("could not alloc crypto acomp %s : %ld\n",
>>> pool->tfm_name, PTR_ERR(acomp));
>>> - return -ENOMEM;
>>> + goto free_acomp_ctx;
>>> }
>>> acomp_ctx->acomp = acomp;
>>>
>>> req = acomp_request_alloc(acomp_ctx->acomp);
>>> - if (IS_ERR_OR_NULL(req)) {
>>> + if (!req) {
>>> pr_err("could not alloc crypto acomp %s : %ld\n",
>>> pool->tfm_name, PTR_ERR(acomp));
>>> - return -ENOMEM;
>>> + goto free_acomp;
>>> }
>>> acomp_ctx->req = req;
>>>
>>> @@ -462,6 +462,12 @@ static int zswap_cpu_comp_prepare(unsigned int
>> cpu, struct hlist_node *node)
>>> *per_cpu_ptr(pool->acomp_ctx, cpu) = acomp_ctx;
>>>
>>> return 0;
>>> +
>>> +free_acomp:
>>> + kfree(acomp);
>>
>> The kfree() isn't correct. It needs to be:
>>
>> crypto_free_acomp(acomp);
>>
>>> +free_acomp_ctx:
>>> + kfree(acomp_ctx);
>>> + return -ENOMEM;
>>
>> regards,
>> dan carpenter
>

2020-06-23 14:05:13

by Vitaly Wool

Subject: Re: [PATCH][next] mm/zswap: fix a couple of memory leaks and rework kzalloc failure check

On Tue, Jun 23, 2020, 1:12 PM Colin Ian King <[email protected]> wrote:
>
> On 22/06/2020 20:55, Song Bao Hua (Barry Song) wrote:
> >
> >
> >> -----Original Message-----
> >> From: Dan Carpenter [mailto:[email protected]]
> >> Sent: Tuesday, June 23, 2020 6:28 AM
> >> To: Colin King <[email protected]>
> >> Cc: Seth Jennings <[email protected]>; Dan Streetman
> >> <[email protected]>; Vitaly Wool <[email protected]>; Andrew
> >> Morton <[email protected]>; Song Bao Hua (Barry Song)
> >> <[email protected]>; Stephen Rothwell <[email protected]>;
> >> [email protected]; [email protected];
> >> [email protected]
> >> Subject: Re: [PATCH][next] mm/zswap: fix a couple of memory leaks and
> >> rework kzalloc failure check
> >>
> >> On Mon, Jun 22, 2020 at 04:35:46PM +0100, Colin King wrote:
> >>> From: Colin Ian King <[email protected]>
> >>>
> >>> kzalloc failures return NULL on out of memory errors, so replace the
> >>> IS_ERR_OR_NULL check with the usual null pointer check. Fix two memory
> >>> leaks with on acomp and acomp_ctx by ensuring these objects are free'd
> >>> on the error return path.
> >>>
> >>> Addresses-Coverity: ("Resource leak")
> >>> Fixes: d4f86abd6e35 ("mm/zswap: move to use crypto_acomp API for
> >> hardware acceleration")
> >>> Signed-off-by: Colin Ian King <[email protected]>
> >
> >
> > Colin, thanks for your patch. I am sorry I did the same thing with you here:
> > https://lkml.org/lkml/2020/6/22/347
>
> Thanks for fixing this correctly, I ran out of time yesterday to re-do
> the fix.
>
> Colin

I think this has gotten out of hand. Barry, could you please come up
with a replacement for the initial patch rather than doing it
incrementally?

Thanks,
Vitaly

>
> >
> >
> >>> ---
> >>> mm/zswap.c | 16 +++++++++++-----
> >>> 1 file changed, 11 insertions(+), 5 deletions(-)
> >>>
> >>> diff --git a/mm/zswap.c b/mm/zswap.c
> >>> index 0d914ba6b4a0..14839cbac7ff 100644
> >>> --- a/mm/zswap.c
> >>> +++ b/mm/zswap.c
> >>> @@ -433,23 +433,23 @@ static int zswap_cpu_comp_prepare(unsigned int
> >> cpu, struct hlist_node *node)
> >>> return 0;
> >>>
> >>> acomp_ctx = kzalloc(sizeof(*acomp_ctx), GFP_KERNEL);
> >>> - if (IS_ERR_OR_NULL(acomp_ctx)) {
> >>> + if (!acomp_ctx) {
> >>> pr_err("Could not initialize acomp_ctx\n");
> >>> return -ENOMEM;
> >>> }
> >>> acomp = crypto_alloc_acomp(pool->tfm_name, 0, 0);
> >>> - if (IS_ERR_OR_NULL(acomp)) {
> >>> + if (!acomp) {
> >>
> >> This should be IS_ERR(acomp). Please preserve the error code.
> >>
> >>> pr_err("could not alloc crypto acomp %s : %ld\n",
> >>> pool->tfm_name, PTR_ERR(acomp));
> >>> - return -ENOMEM;
> >>> + goto free_acomp_ctx;
> >>> }
> >>> acomp_ctx->acomp = acomp;
> >>>
> >>> req = acomp_request_alloc(acomp_ctx->acomp);
> >>> - if (IS_ERR_OR_NULL(req)) {
> >>> + if (!req) {
> >>> pr_err("could not alloc crypto acomp %s : %ld\n",
> >>> pool->tfm_name, PTR_ERR(acomp));
> >>> - return -ENOMEM;
> >>> + goto free_acomp;
> >>> }
> >>> acomp_ctx->req = req;
> >>>
> >>> @@ -462,6 +462,12 @@ static int zswap_cpu_comp_prepare(unsigned int
> >> cpu, struct hlist_node *node)
> >>> *per_cpu_ptr(pool->acomp_ctx, cpu) = acomp_ctx;
> >>>
> >>> return 0;
> >>> +
> >>> +free_acomp:
> >>> + kfree(acomp);
> >>
> >> The kfree() isn't correct. It needs to be:
> >>
> >> crypto_free_acomp(acomp);
> >>
> >>> +free_acomp_ctx:
> >>> + kfree(acomp_ctx);
> >>> + return -ENOMEM;
> >>
> >> regards,
> >> dan carpenter
> >
>