[PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

Subsystems: networking drivers, the rest

STALE5543d

8 messages, 3 authors, 2011-08-10 · open the first message on its own page

[PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

From: <hidden>
Date: 2011-08-09 16:42:00 

From: Wang Shaoyan <redacted>

  drivers/net/gianfar_ethtool.c:765: warning: the frame size of 2048 bytes is larger than 1024 bytes

Signed-off-by: Wang Shaoyan <redacted>
---
 drivers/net/gianfar_ethtool.c |   20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/net/gianfar_ethtool.c b/drivers/net/gianfar_ethtool.c
index 6e35069..134fe1b 100644
--- a/drivers/net/gianfar_ethtool.c
+++ b/drivers/net/gianfar_ethtool.c
@@ -686,10 +686,21 @@ static int gfar_ethflow_to_filer_table(struct gfar_private *priv, u64 ethflow, u
 {
 	unsigned int last_rule_idx = priv->cur_filer_idx;
 	unsigned int cmp_rqfpr;
-	unsigned int local_rqfpr[MAX_FILER_IDX + 1];
-	unsigned int local_rqfcr[MAX_FILER_IDX + 1];
+	unsigned int *local_rqfpr;
+	unsigned int *local_rqfcr;
 	int i = 0x0, k = 0x0;
 	int j = MAX_FILER_IDX, l = 0x0;
+	int ret = 1;
+
+	local_rqfpr = kmalloc(sizeof(unsigned int) * (MAX_FILER_IDX + 1),
+		GFP_KERNEL);
+	local_rqfcr = kmalloc(sizeof(unsigned int) * (MAX_FILER_IDX + 1),
+		GFP_KERNEL);
+	if (!local_rqfpr || !local_rqfcr) {
+		pr_err("Out of memory\n");
+		ret = 0;
+		got err;
+	}
 
 	switch (class) {
 	case TCP_V4_FLOW:
@@ -765,7 +776,10 @@ static int gfar_ethflow_to_filer_table(struct gfar_private *priv, u64 ethflow, u
 		priv->cur_filer_idx = priv->cur_filer_idx - 1;
 	}
 
-	return 1;
+err:
+	kfree(local_rqfcr);
+	kfree(local_rqfpr);
+	return ret;
 }
 
 static int gfar_set_hash_opts(struct gfar_private *priv, struct ethtool_rxnfc *cmd)
-- 
1.7.0.4

Re: [PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

From: Eric Dumazet <hidden>
Date: 2011-08-09 16:53:08 

Le mercredi 10 août 2011 à 00:39 +0800, stufever@gmail.com a écrit :
quoted hunk
From: Wang Shaoyan <redacted>

  drivers/net/gianfar_ethtool.c:765: warning: the frame size of 2048 bytes is larger than 1024 bytes

Signed-off-by: Wang Shaoyan <redacted>
---
 drivers/net/gianfar_ethtool.c |   20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/net/gianfar_ethtool.c b/drivers/net/gianfar_ethtool.c
index 6e35069..134fe1b 100644
--- a/drivers/net/gianfar_ethtool.c
+++ b/drivers/net/gianfar_ethtool.c
@@ -686,10 +686,21 @@ static int gfar_ethflow_to_filer_table(struct gfar_private *priv, u64 ethflow, u
 {
 	unsigned int last_rule_idx = priv->cur_filer_idx;
 	unsigned int cmp_rqfpr;
-	unsigned int local_rqfpr[MAX_FILER_IDX + 1];
-	unsigned int local_rqfcr[MAX_FILER_IDX + 1];
+	unsigned int *local_rqfpr;
+	unsigned int *local_rqfcr;
 	int i = 0x0, k = 0x0;
 	int j = MAX_FILER_IDX, l = 0x0;
+	int ret = 1;
+
+	local_rqfpr = kmalloc(sizeof(unsigned int) * (MAX_FILER_IDX + 1),
+		GFP_KERNEL);
+	local_rqfcr = kmalloc(sizeof(unsigned int) * (MAX_FILER_IDX + 1),
+		GFP_KERNEL);
+	if (!local_rqfpr || !local_rqfcr) {
+		pr_err("Out of memory\n");
	Please remove this pr_err(), kmalloc() will complain already.
quoted hunk
+		ret = 0;
+		got err;
+	}
 
 	switch (class) {
 	case TCP_V4_FLOW:
@@ -765,7 +776,10 @@ static int gfar_ethflow_to_filer_table(struct gfar_private *priv, u64 ethflow, u
 		priv->cur_filer_idx = priv->cur_filer_idx - 1;
 	}
 
-	return 1;
+err:
+	kfree(local_rqfcr);
+	kfree(local_rqfpr);
+	return ret;
 }
 
You should now track all "return 0;" done in this function to make sure
no memory leak is added by your patch.

Re: [PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

From: Joe Perches <joe@perches.com>
Date: 2011-08-09 17:52:10 

On Tue, 2011-08-09 at 18:53 +0200, Eric Dumazet wrote:
Le mercredi 10 août 2011 à 00:39 +0800, stufever@gmail.com a écrit :
[]
quoted
+	if (!local_rqfpr || !local_rqfcr) {
+		pr_err("Out of memory\n");
	Please remove this pr_err(), kmalloc() will complain already.
Always?
I know there's a trace option, but is it always on?

Re: [PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

From: Eric Dumazet <hidden>
Date: 2011-08-09 17:59:42 

Le mardi 09 août 2011 à 10:52 -0700, Joe Perches a écrit :
On Tue, 2011-08-09 at 18:53 +0200, Eric Dumazet wrote:
quoted
Le mercredi 10 août 2011 à 00:39 +0800, stufever@gmail.com a écrit :
[]
quoted
quoted
+	if (!local_rqfpr || !local_rqfcr) {
+		pr_err("Out of memory\n");
	Please remove this pr_err(), kmalloc() will complain already.
Always?
I know there's a trace option, but is it always on?
Yes, unless caller added ___GFP_NOWARN in gfp :

ptr = kmalloc(size, GFP_KERNEL | ___GFP_NOWARN);

Re: [PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

From: Joe Perches <joe@perches.com>
Date: 2011-08-09 18:12:30 

On Tue, 2011-08-09 at 19:59 +0200, Eric Dumazet wrote:
Le mardi 09 août 2011 à 10:52 -0700, Joe Perches a écrit :
quoted
On Tue, 2011-08-09 at 18:53 +0200, Eric Dumazet wrote:
quoted
Le mercredi 10 août 2011 à 00:39 +0800, stufever@gmail.com a écrit :
[]
quoted
quoted
+	if (!local_rqfpr || !local_rqfcr) {
+		pr_err("Out of memory\n");
	Please remove this pr_err(), kmalloc() will complain already.
Always?
I know there's a trace option, but is it always on?
Yes, unless caller added ___GFP_NOWARN in gfp :
ptr = kmalloc(size, GFP_KERNEL | ___GFP_NOWARN);
Isn't that true only for slub?

Do you know where this get emitted?
I looked cursorily but I don't see it.

Re: [PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

From: Eric Dumazet <hidden>
Date: 2011-08-09 18:24:23 

Le mardi 09 août 2011 à 11:12 -0700, Joe Perches a écrit :
On Tue, 2011-08-09 at 19:59 +0200, Eric Dumazet wrote:
quoted
Le mardi 09 août 2011 à 10:52 -0700, Joe Perches a écrit :
quoted
On Tue, 2011-08-09 at 18:53 +0200, Eric Dumazet wrote:
quoted
Le mercredi 10 août 2011 à 00:39 +0800, stufever@gmail.com a écrit :
[]
quoted
quoted
+	if (!local_rqfpr || !local_rqfcr) {
+		pr_err("Out of memory\n");
	Please remove this pr_err(), kmalloc() will complain already.
Always?
I know there's a trace option, but is it always on?
Yes, unless caller added ___GFP_NOWARN in gfp :
ptr = kmalloc(size, GFP_KERNEL | ___GFP_NOWARN);
Isn't that true only for slub?
nope, this is page allocation, so common to slab/slub/...

Do you know where this get emitted?
I looked cursorily but I don't see it.
This is a bit beyond this thread

Look at mm/page_alloc.c

void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)

Re: [PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

From: Joe Perches <joe@perches.com>
Date: 2011-08-09 19:57:19 

On Tue, 2011-08-09 at 20:24 +0200, Eric Dumazet wrote:
Le mardi 09 août 2011 à 11:12 -0700, Joe Perches a écrit :
quoted
On Tue, 2011-08-09 at 19:59 +0200, Eric Dumazet wrote:
quoted
Le mardi 09 août 2011 à 10:52 -0700, Joe Perches a écrit :
quoted
On Tue, 2011-08-09 at 18:53 +0200, Eric Dumazet wrote:
quoted
Le mercredi 10 août 2011 à 00:39 +0800, stufever@gmail.com a écrit :
[]
quoted
quoted
+	if (!local_rqfpr || !local_rqfcr) {
+		pr_err("Out of memory\n");
	Please remove this pr_err(), kmalloc() will complain already.
I think this is fine and should be kept until
some general agreement is made that OOM messages
should be removed generically.

If these are really superfluous, which I doubt a
little because these are emitted at different
KERN_<LEVEL>, (the generic one emits at KERN_WARNING),
there are _thousands_ of these OOM errors in drivers/
alone that could be removed.

$ grep -rP --include=*.[ch] \
	"(printk|\b[a-z]+_\w+)\s*\(.*\".*(alloc|mem)" drivers | \
  wc -l
5147

call it 50% false positive, it's still a lot.

I think one more won't hurt for awhile.

Re: [PATCH] gianfar: reduce stack usage in gianfar_ethtool.c

From: Wang Shaoyan <hidden>
Date: 2011-08-10 02:20:12 

2011/8/10 Eric Dumazet [off-list ref]:
Le mercredi 10 août 2011 à 00:39 +0800, stufever@gmail.com a écrit :
quoted
From: Wang Shaoyan <redacted>

  drivers/net/gianfar_ethtool.c:765: warning: the frame size of 2048 bytes is larger than 1024 bytes

Signed-off-by: Wang Shaoyan <redacted>
---
 drivers/net/gianfar_ethtool.c |   20 +++++++++++++++++---
 1 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/net/gianfar_ethtool.c b/drivers/net/gianfar_ethtool.c
index 6e35069..134fe1b 100644
--- a/drivers/net/gianfar_ethtool.c
+++ b/drivers/net/gianfar_ethtool.c
@@ -686,10 +686,21 @@ static int gfar_ethflow_to_filer_table(struct gfar_private *priv, u64 ethflow, u
 {
      unsigned int last_rule_idx = priv->cur_filer_idx;
      unsigned int cmp_rqfpr;
-     unsigned int local_rqfpr[MAX_FILER_IDX + 1];
-     unsigned int local_rqfcr[MAX_FILER_IDX + 1];
+     unsigned int *local_rqfpr;
+     unsigned int *local_rqfcr;
      int i = 0x0, k = 0x0;
      int j = MAX_FILER_IDX, l = 0x0;
+     int ret = 1;
+
+     local_rqfpr = kmalloc(sizeof(unsigned int) * (MAX_FILER_IDX + 1),
+             GFP_KERNEL);
+     local_rqfcr = kmalloc(sizeof(unsigned int) * (MAX_FILER_IDX + 1),
+             GFP_KERNEL);
+     if (!local_rqfpr || !local_rqfcr) {
+             pr_err("Out of memory\n");
       Please remove this pr_err(), kmalloc() will complain already.
quoted
+             ret = 0;
+             got err;
+     }

      switch (class) {
      case TCP_V4_FLOW:
@@ -765,7 +776,10 @@ static int gfar_ethflow_to_filer_table(struct gfar_private *priv, u64 ethflow, u
              priv->cur_filer_idx = priv->cur_filer_idx - 1;
      }

-     return 1;
+err:
+     kfree(local_rqfcr);
+     kfree(local_rqfpr);
+     return ret;
 }
Thanks, I will do it

You should now track all "return 0;" done in this function to make sure
no memory leak is added by your patch.





-- 
Wang Shaoyan
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