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Re: [PATCH 2/3] kfifo: fix a memory leak in dma example

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[view original message]
From: Andrea Righi
Subject: [PATCH 1/3] kfifo: fix kernel BUG in dma example
Date: Friday, August 13, 2010 - 12:59 pm

The scatterlist is used uninitialized in kfifo_dma_in_prepare(). This
triggers the following bug if CONFIG_DEBUG_SG=y:

  ------------[ cut here ]------------
  kernel BUG at include/linux/scatterlist.h:65!
  invalid opcode: 0000 [#1] PREEMPT SMP
  ...
  Call Trace:
   [<ffffffff810a1eab>] setup_sgl+0x6b/0xe0
   [<ffffffffa03d7000>] ? example_init+0x0/0x265 [dma_example]
   [<ffffffff810a2021>] __kfifo_dma_in_prepare+0x21/0x30
   [<ffffffffa03d7124>] example_init+0x124/0x265 [dma_example]
   [<ffffffff810f9c55>] ? trace_module_notify+0x25/0x370
   [<ffffffff81110c6e>] ? free_pages_prepare+0x11e/0x1e0
   [<ffffffff8106f2b1>] ? get_parent_ip+0x11/0x50
   [<ffffffff810f9c55>] ? trace_module_notify+0x25/0x370
   [<ffffffff810b65fd>] ? trace_hardirqs_on+0xd/0x10
   [<ffffffff814beade>] ? mutex_unlock+0xe/0x10
   [<ffffffff810f9c71>] ? trace_module_notify+0x41/0x370
   [<ffffffff810a77d5>] ? __blocking_notifier_call_chain+0x45/0x80
   [<ffffffff81137b7a>] ? vfree+0x2a/0x30
   [<ffffffff810a6ac3>] ? up_read+0x23/0x40
   [<ffffffff810a77f5>] ? __blocking_notifier_call_chain+0x65/0x80
   [<ffffffff810001e3>] do_one_initcall+0x43/0x180
   [<ffffffff810c577a>] sys_init_module+0xba/0x200
   [<ffffffff8103819b>] system_call_fastpath+0x16/0x1b
  RIP  [<ffffffff810a1e31>] setup_sgl_buf+0x1a1/0x1b0
   RSP <ffff88006720dc98>
  ---[ end trace a72b979fd3c1d3a5 ]---

Add the proper initialization to avoid the bug.

Signed-off-by: Andrea Righi <arighi@develer.com>
---
 samples/kfifo/dma-example.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c
index b9482c2..03433ca 100644
--- a/samples/kfifo/dma-example.c
+++ b/samples/kfifo/dma-example.c
@@ -45,6 +45,7 @@ static int __init example_init(void)
 
 	printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
 
+	sg_init_table(sg, ARRAY_SIZE(sg));
 	ret = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), FIFO_SIZE);
 	printk(KERN_INFO "DMA sgl entries: %d\n", ...
[ message continues ]
[view original message]
From: Andrea Righi
Subject: [PATCH 2/3] kfifo: fix a memory leak in dma example
Date: Friday, August 13, 2010 - 12:59 pm

We use a dynamically allocated kfifo in the dma example, so we need to
free it when unloading the module.

Signed-off-by: Andrea Righi <arighi@develer.com>
---
 samples/kfifo/dma-example.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c
index 03433ca..3682278 100644
--- a/samples/kfifo/dma-example.c
+++ b/samples/kfifo/dma-example.c
@@ -105,9 +105,7 @@ static int __init example_init(void)
 
 static void __exit example_exit(void)
 {
-#ifdef DYNAMIC
-	kfifo_free(&test);
-#endif
+	kfifo_free(&fifo);
 }
 
 module_init(example_init);
-- 
1.7.0.4

--


[ message continues ]
[view original message]
From: Stefani Seibold
Subject: Re: [PATCH 2/3] kfifo: fix a memory leak in dma example
Date: Friday, August 13, 2010 - 1:42 pm

We use a dynamically allocated kfifo in the dma example, so we need to
free it when unloading the module.

Signed-off-by: Andrea Righi <arighi@develer.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
---
 samples/kfifo/dma-example.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c
index 03433ca..3682278 100644
--- a/samples/kfifo/dma-example.c
+++ b/samples/kfifo/dma-example.c
@@ -105,9 +105,7 @@ static int __init example_init(void)
 
 static void __exit example_exit(void)
 {
-#ifdef DYNAMIC
-	kfifo_free(&test);
-#endif
+	kfifo_free(&fifo);
 }
 
 module_init(example_init);


--


[ message continues ]
[view original message]
From: Andrea Righi
Subject: [PATCH 3/3] kfifo: add explicit error checking in all the examples
Date: Friday, August 13, 2010 - 12:59 pm

Provide a check in all the kfifo examples to validate the correct
execution of each testcase.

 [ Andrew: this depends on kfifo-add-explicit-error-checking-in-byte-stream-example.patch ]

Signed-off-by: Andrea Righi <arighi@develer.com>
---
 samples/kfifo/bytestream-example.c |    7 ++-
 samples/kfifo/dma-example.c        |  106 +++++++++++++++++++++++-------------
 samples/kfifo/inttype-example.c    |   43 ++++++++++++---
 samples/kfifo/record-example.c     |   39 ++++++++++++-
 4 files changed, 144 insertions(+), 51 deletions(-)

diff --git a/samples/kfifo/bytestream-example.c b/samples/kfifo/bytestream-example.c
index a94e694..178061e 100644
--- a/samples/kfifo/bytestream-example.c
+++ b/samples/kfifo/bytestream-example.c
@@ -44,7 +44,7 @@ static struct kfifo test;
 static DECLARE_KFIFO(test, unsigned char, FIFO_SIZE);
 #endif
 
-static unsigned char expected_result[FIFO_SIZE] = {
+static const unsigned char expected_result[FIFO_SIZE] = {
 	 3,  4,  5,  6,  7,  8,  9,  0,
 	 1, 20, 21, 22, 23, 24, 25, 26,
 	27, 28, 29, 30, 31, 32, 33, 34,
@@ -90,9 +90,14 @@ static int __init testfunc(void)
 
 	printk(KERN_INFO "queue len: %u\n", kfifo_len(&test));
 
+	/* show the first value without removing from the fifo */
+	if (kfifo_peek(&test, &i))
+		printk(KERN_INFO "%d\n", i);
+
 	/* check the correctness of all values in the fifo */
 	j = 0;
 	while (kfifo_get(&test, &i)) {
+		printk(KERN_INFO "item = %d\n", i);
 		if (i != expected_result[j++]) {
 			printk(KERN_WARNING "value mismatch: test failed\n");
 			return -EIO;
diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c
index 3682278..ee03a4f 100644
--- a/samples/kfifo/dma-example.c
+++ b/samples/kfifo/dma-example.c
@@ -29,8 +29,8 @@ static int __init example_init(void)
 	printk(KERN_INFO "DMA fifo test start\n");
 
 	if (kfifo_alloc(&fifo, FIFO_SIZE, GFP_KERNEL)) {
-		printk(KERN_ERR "error kfifo_alloc\n");
-		return 1;
+		printk(KERN_WARNING "error kfifo_alloc\n");
+		return -ENOMEM;
 	}
 ...
[ message continues ]
[view original message]
From: Stefani Seibold
Subject: Re: [PATCH 3/3] kfifo: add explicit error checking in all the examples
Date: Friday, August 13, 2010 - 1:49 pm

Provide a check in all the kfifo examples to validate the correct
execution of each testcase.

 [ Andrew: this depends on kfifo-add-explicit-error-checking-in-byte-stream-example.patch ]

Signed-off-by: Andrea Righi <arighi@develer.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
---
 samples/kfifo/bytestream-example.c |    7 ++-
 samples/kfifo/dma-example.c        |  106 +++++++++++++++++++++++-------------
 samples/kfifo/inttype-example.c    |   43 ++++++++++++---
 samples/kfifo/record-example.c     |   39 ++++++++++++-
 4 files changed, 144 insertions(+), 51 deletions(-)

diff --git a/samples/kfifo/bytestream-example.c b/samples/kfifo/bytestream-example.c
index a94e694..178061e 100644
--- a/samples/kfifo/bytestream-example.c
+++ b/samples/kfifo/bytestream-example.c
@@ -44,7 +44,7 @@ static struct kfifo test;
 static DECLARE_KFIFO(test, unsigned char, FIFO_SIZE);
 #endif
 
-static unsigned char expected_result[FIFO_SIZE] = {
+static const unsigned char expected_result[FIFO_SIZE] = {
 	 3,  4,  5,  6,  7,  8,  9,  0,
 	 1, 20, 21, 22, 23, 24, 25, 26,
 	27, 28, 29, 30, 31, 32, 33, 34,
@@ -90,9 +90,14 @@ static int __init testfunc(void)
 
 	printk(KERN_INFO "queue len: %u\n", kfifo_len(&test));
 
+	/* show the first value without removing from the fifo */
+	if (kfifo_peek(&test, &i))
+		printk(KERN_INFO "%d\n", i);
+
 	/* check the correctness of all values in the fifo */
 	j = 0;
 	while (kfifo_get(&test, &i)) {
+		printk(KERN_INFO "item = %d\n", i);
 		if (i != expected_result[j++]) {
 			printk(KERN_WARNING "value mismatch: test failed\n");
 			return -EIO;
diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c
index 3682278..ee03a4f 100644
--- a/samples/kfifo/dma-example.c
+++ b/samples/kfifo/dma-example.c
@@ -29,8 +29,8 @@ static int __init example_init(void)
 	printk(KERN_INFO "DMA fifo test start\n");
 
 	if (kfifo_alloc(&fifo, FIFO_SIZE, GFP_KERNEL)) {
-		printk(KERN_ERR "error kfifo_alloc\n");
-		return 1;
+		printk(KERN_WARNING ...
[ message continues ]
[view original message]
From: Stefani Seibold
Subject: Re: [PATCH 1/3] kfifo: fix kernel BUG in dma example
Date: Friday, August 13, 2010 - 1:40 pm

The scatterlist is used uninitialized in kfifo_dma_in_prepare(). This
triggers the following bug if CONFIG_DEBUG_SG=y:

  ------------[ cut here ]------------
  kernel BUG at include/linux/scatterlist.h:65!
  invalid opcode: 0000 [#1] PREEMPT SMP
  ...
  Call Trace:
   [<ffffffff810a1eab>] setup_sgl+0x6b/0xe0
   [<ffffffffa03d7000>] ? example_init+0x0/0x265 [dma_example]
   [<ffffffff810a2021>] __kfifo_dma_in_prepare+0x21/0x30
   [<ffffffffa03d7124>] example_init+0x124/0x265 [dma_example]
   [<ffffffff810f9c55>] ? trace_module_notify+0x25/0x370
   [<ffffffff81110c6e>] ? free_pages_prepare+0x11e/0x1e0
   [<ffffffff8106f2b1>] ? get_parent_ip+0x11/0x50
   [<ffffffff810f9c55>] ? trace_module_notify+0x25/0x370
   [<ffffffff810b65fd>] ? trace_hardirqs_on+0xd/0x10
   [<ffffffff814beade>] ? mutex_unlock+0xe/0x10
   [<ffffffff810f9c71>] ? trace_module_notify+0x41/0x370
   [<ffffffff810a77d5>] ? __blocking_notifier_call_chain+0x45/0x80
   [<ffffffff81137b7a>] ? vfree+0x2a/0x30
   [<ffffffff810a6ac3>] ? up_read+0x23/0x40
   [<ffffffff810a77f5>] ? __blocking_notifier_call_chain+0x65/0x80
   [<ffffffff810001e3>] do_one_initcall+0x43/0x180
   [<ffffffff810c577a>] sys_init_module+0xba/0x200
   [<ffffffff8103819b>] system_call_fastpath+0x16/0x1b
  RIP  [<ffffffff810a1e31>] setup_sgl_buf+0x1a1/0x1b0
   RSP <ffff88006720dc98>
  ---[ end trace a72b979fd3c1d3a5 ]---

Add the proper initialization to avoid the bug.

Signed-off-by: Andrea Righi <arighi@develer.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
---
 samples/kfifo/dma-example.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c
index b9482c2..03433ca 100644
--- a/samples/kfifo/dma-example.c
+++ b/samples/kfifo/dma-example.c
@@ -45,6 +45,7 @@ static int __init example_init(void)
 
 	printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo));
 
+	sg_init_table(sg, ARRAY_SIZE(sg));
 	ret = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), ...
[ message continues ]
Previous thread: [patch 0/3] sched: fixes related to scaling down cpu power with RT tasks by Suresh Siddha on Friday, August 13, 2010 - 12:45 pm. (23 messages)

Next thread: Re: [PATCHv8 04/13] USB: gadget: mass_storage: moved strings handling code to composite by David Brownell on Friday, August 13, 2010 - 1:30 pm. (1 message)