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

Subsystems: memory management, the rest, zswap compressed swap caching

STALE2294d

5 messages, 4 authors, 2020-06-23 · open the first message on its own page

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

From: Colin King <hidden>
Date: 2020-06-22 15:36:00

From: Colin Ian King <redacted>

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 <redacted>
---
 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

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

From: Dan Carpenter <hidden>
Date: 2020-06-22 18:28:56

On Mon, Jun 22, 2020 at 04:35:46PM +0100, Colin King wrote:

quoted hunk

From: Colin Ian King <redacted>

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 <redacted>
---
 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.

quoted hunk

 		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);

quoted hunk

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

regards,
dan carpenter

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

From: Song Bao Hua (Barry Song) <hidden>
Date: 2020-06-22 19:55:25

-----Original Message-----
From: Dan Carpenter [mailto:dan.carpenter@oracle.com]
Sent: Tuesday, June 23, 2020 6:28 AM
To: Colin King <redacted>
Cc: Seth Jennings <redacted>; Dan Streetman
[off-list ref]; Vitaly Wool [off-list ref]; Andrew
Morton [off-list ref]; Song Bao Hua (Barry Song)
[off-list ref]; Stephen Rothwell [off-list ref];
linux-mm@kvack.org; kernel-janitors@vger.kernel.org;
linux-kernel@vger.kernel.org
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:

quoted

From: Colin Ian King <redacted>

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")

quoted

Signed-off-by: Colin Ian King <redacted>


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

quoted

---
 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)

quoted

 		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.

quoted

 		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)

quoted

 	*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);

quoted

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

regards,
dan carpenter

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

From: Colin Ian King <hidden>
Date: 2020-06-23 11:12:49

On 22/06/2020 20:55, Song Bao Hua (Barry Song) wrote:

quoted

-----Original Message-----
From: Dan Carpenter [mailto:dan.carpenter@oracle.com]
Sent: Tuesday, June 23, 2020 6:28 AM
To: Colin King <redacted>
Cc: Seth Jennings <redacted>; Dan Streetman
[off-list ref]; Vitaly Wool [off-list ref]; Andrew
Morton [off-list ref]; Song Bao Hua (Barry Song)
[off-list ref]; Stephen Rothwell [off-list ref];
linux-mm@kvack.org; kernel-janitors@vger.kernel.org;
linux-kernel@vger.kernel.org
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:

quoted

From: Colin Ian King <redacted>

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")

quoted

Signed-off-by: Colin Ian King <redacted>


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

quoted

---
 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)

quoted

 		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.

quoted

 		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)

quoted

 	*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);

quoted

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

regards,
dan carpenter

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

From: Vitaly Wool <hidden>
Date: 2020-06-23 14:02:46

On Tue, Jun 23, 2020, 1:12 PM Colin Ian King [off-list ref] wrote:

On 22/06/2020 20:55, Song Bao Hua (Barry Song) wrote:

quoted

-----Original Message-----
From: Dan Carpenter [mailto:dan.carpenter@oracle.com]
Sent: Tuesday, June 23, 2020 6:28 AM
To: Colin King <redacted>
Cc: Seth Jennings <redacted>; Dan Streetman
[off-list ref]; Vitaly Wool [off-list ref]; Andrew
Morton [off-list ref]; Song Bao Hua (Barry Song)
[off-list ref]; Stephen Rothwell [off-list ref];
linux-mm@kvack.org; kernel-janitors@vger.kernel.org;
linux-kernel@vger.kernel.org
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:

quoted

From: Colin Ian King <redacted>

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")

quoted

Signed-off-by: Colin Ian King <redacted>


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

quoted

---
 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)

quoted

            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.

quoted

            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)

quoted

    *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);

quoted

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

regards,
dan carpenter

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