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radix-tree: ensure counts are initialised

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radix_tree_join() was freeing nodes with a non-zero ->exceptional count,
and radix_tree_split() wasn't zeroing ->exceptional when it allocated
the new node.  Fix this by making all callers of radix_tree_node_alloc()
pass in the new counts (and some other always-initialised fields), which
will prevent the problem recurring if in future we decide to do
something similar.

Link: http://lkml.kernel.org/r/1481667692-14500-3-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthew Wilcox 2016-12-14 15:09:31 -08:00 • committed by Linus Torvalds
parent bbe9d71f2c
commit e8de434076
2 changed files with 61 additions and 25 deletions
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45
tools/testing/radix-tree/multiorder.c
View file

@ -355,7 +355,7 @@ void multiorder_tagged_iteration(void)
item_kill_tree(&tree);
}
static void __multiorder_join(unsigned long index,
static void multiorder_join1(unsigned long index,
unsigned order1, unsigned order2)
{
unsigned long loc;
@ -373,7 +373,7 @@ static void __multiorder_join(unsigned long index,
item_kill_tree(&tree);
}
static void __multiorder_join2(unsigned order1, unsigned order2)
static void multiorder_join2(unsigned order1, unsigned order2)
{
RADIX_TREE(tree, GFP_KERNEL);
struct radix_tree_node *node;
@ -393,6 +393,39 @@ static void __multiorder_join2(unsigned order1, unsigned order2)
item_kill_tree(&tree);
}
/*
* This test revealed an accounting bug for exceptional entries at one point.
* Nodes were being freed back into the pool with an elevated exception count
* by radix_tree_join() and then radix_tree_split() was failing to zero the
* count of exceptional entries.
*/
static void multiorder_join3(unsigned int order)
{
RADIX_TREE(tree, GFP_KERNEL);
struct radix_tree_node *node;
void **slot;
struct radix_tree_iter iter;
unsigned long i;
for (i = 0; i < (1 << order); i++) {
radix_tree_insert(&tree, i, (void *)0x12UL);
}
radix_tree_join(&tree, 0, order, (void *)0x16UL);
rcu_barrier();
radix_tree_split(&tree, 0, 0);
radix_tree_for_each_slot(slot, &tree, &iter, 0) {
radix_tree_iter_replace(&tree, &iter, slot, (void *)0x12UL);
}
__radix_tree_lookup(&tree, 0, &node, NULL);
assert(node->exceptional == node->count);
item_kill_tree(&tree);
}
static void multiorder_join(void)
{
int i, j, idx;
@ -400,16 +433,20 @@ static void multiorder_join(void)
for (idx = 0; idx < 1024; idx = idx * 2 + 3) {
for (i = 1; i < 15; i++) {
for (j = 0; j < i; j++) {
__multiorder_join(idx, i, j);
multiorder_join1(idx, i, j);
}
}
}
for (i = 1; i < 15; i++) {
for (j = 0; j < i; j++) {
__multiorder_join2(i, j);
multiorder_join2(i, j);
}
}
for (i = 3; i < 10; i++) {
multiorder_join3(i);
}
}
static void check_mem(unsigned old_order, unsigned new_order, unsigned alloc)