Sounds like it might be this [1] patch.
Thanks, I inlined it.
Roland, OK to commit? Then I can commit the previous patch with a
good concious; after I test it obviously...
Summary: Double free and memory loss probing partition table
Original Submission: While GNU Mach reads the partition table, the
second assert in linux/dev/glue:free_pages is triggered. This
particular assert checks for double frees. I have traced the problem
back to getblk and __brelse: if linux_auto_config is true (which it is
when partitions are being probed), a static buffer is used to hold the
BH structure. If getblk is called a second time (i.e. before the first
block is released), the buffer is overriden. This results in a double
free, a memory leak (as the buffer in the first BH is never released)
and a consistency problem as code which uses the first buffer will now
see different data. This is the case in
linux/dev/drivers/block/genhd.c:msdos_partition which calls bread
then, before freeing the block, calls extended_partition which also
calls bread. In reality, there is no reason to not use kalloc and
kfree here. In kern/statup.c:setup_main, we see that vm_mem_bootstrap
which calls kmem_init is called long before
linux/dev/init/main.c:linux_init is invoked by
i386/i386at/machine_init:machine_init.
This attached patch changes getblk and __brelse to always use kalloc
and kfree and adds asserts to kern/kalloc.c to make sure that kalloc,
kfree and kget are only called after kmem_init has been called.
Apply the patch using -p0
2004-09-07 Neal H. Walfield <[EMAIL PROTECTED]>
* linux/dev/glue/block.c (__brelse): Unconditionally kfree BH.
(getblk): Unconditionally kalloc BH.
* kern/kalloc.c [!NDEBUG] (kalloc_init_called): New static
variable.
(kalloc_init): Assert that kalloc_init_called is zero.
[! NDEBUG] Set kalloc_init_called to 1 on success.
(kalloc): Assert that kalloc_init_called is non-zero.
(kget): Likewise.
(kfree): Likewise.
Index: linux/dev/glue/block.c
===================================================================
RCS file: /cvsroot/hurd/gnumach/linux/dev/glue/Attic/block.c,v
retrieving revision 1.8.2.2
diff -u -p -r1.8.2.2 block.c
--- linux/dev/glue/block.c 19 Jan 2004 01:44:31 -0000 1.8.2.2
+++ linux/dev/glue/block.c 7 Sep 2004 15:08:17 -0000
@@ -354,22 +354,17 @@ struct buffer_head *
getblk (kdev_t dev, int block, int size)
{
struct buffer_head *bh;
- static struct buffer_head bhead;
assert (size <= PAGE_SIZE);
- if (! linux_auto_config)
- bh = (struct buffer_head *) kalloc (sizeof (struct buffer_head));
- else
- bh = &bhead;
+ bh = (struct buffer_head *) kalloc (sizeof (struct buffer_head));
if (bh)
{
memset (bh, 0, sizeof (struct buffer_head));
bh->b_data = alloc_buffer (size);
if (! bh->b_data)
{
- if (! linux_auto_config)
- kfree ((vm_offset_t) bh, sizeof (struct buffer_head));
+ kfree ((vm_offset_t) bh, sizeof (struct buffer_head));
return NULL;
}
bh->b_dev = dev;
@@ -385,8 +380,7 @@ void
__brelse (struct buffer_head *bh)
{
free_buffer (bh->b_data, bh->b_size);
- if (! linux_auto_config)
- kfree ((vm_offset_t) bh, sizeof (*bh));
+ kfree ((vm_offset_t) bh, sizeof (*bh));
}
/* Allocate a buffer of SIZE bytes and fill it with data
Index: kern/kalloc.c
===================================================================
RCS file: /cvsroot/hurd/gnumach/kern/kalloc.c,v
retrieving revision 1.1.1.1
diff -u -p -r1.1.1.1 kalloc.c
--- kern/kalloc.c 25 Feb 1997 21:28:23 -0000 1.1.1.1
+++ kern/kalloc.c 7 Sep 2004 15:08:17 -0000
@@ -106,12 +106,18 @@ unsigned long k_zone_max[16] = {
* This initializes all of the zones.
*/
+#ifndef NDEBUG
+static int kalloc_init_called;
+#endif
+
void kalloc_init()
{
vm_offset_t min, max;
vm_size_t size;
register int i;
+ assert (! kalloc_init_called);
+
kalloc_map = kmem_suballoc(kernel_map, &min, &max,
kalloc_map_size, FALSE);
@@ -142,6 +148,10 @@ void kalloc_init()
size >= PAGE_SIZE ? ZONE_COLLECTABLE : 0,
k_zone_name[i]);
}
+
+#ifndef NDEBUG
+ kalloc_init_called = 1;
+#endif
}
vm_offset_t kalloc(size)
@@ -153,6 +163,8 @@ vm_offset_t kalloc(size)
/* compute the size of the block that we will actually allocate */
+ assert (kalloc_init_called);
+
allocsize = size;
if (size < kalloc_max) {
allocsize = MINSIZE;
@@ -185,6 +197,8 @@ vm_offset_t kget(size)
register vm_size_t allocsize;
vm_offset_t addr;
+ assert (kalloc_init_called);
+
/* compute the size of the block that we will actually allocate */
allocsize = size;
@@ -219,6 +233,8 @@ kfree(data, size)
register int zindex;
register vm_size_t freesize;
+ assert (kalloc_init_called);
+
freesize = size;
if (size < kalloc_max) {
freesize = MINSIZE;
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