This is a note to let you know that I've just added the patch titled
Btrfs: fix crash regarding to ulist_add_merge
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
btrfs-fix-crash-regarding-to-ulist_add_merge.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 35f0399db6658f465b00893bdd13b992a0acfef0 Mon Sep 17 00:00:00 2001
From: Liu Bo <[email protected]>
Date: Fri, 28 Jun 2013 12:37:45 +0800
Subject: Btrfs: fix crash regarding to ulist_add_merge
From: Liu Bo <[email protected]>
commit 35f0399db6658f465b00893bdd13b992a0acfef0 upstream.
Several users reported this crash of NULL pointer or general protection,
the story is that we add a rbtree for speedup ulist iteration, and we
use krealloc() to address ulist growth, and krealloc() use memcpy to copy
old data to new memory area, so it's OK for an array as it doesn't use
pointers while it's not OK for a rbtree as it uses pointers.
So krealloc() will mess up our rbtree and it ends up with crash.
Reviewed-by: Wang Shilong <[email protected]>
Signed-off-by: Liu Bo <[email protected]>
Signed-off-by: Josef Bacik <[email protected]>
Cc: BJ Quinn <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/btrfs/ulist.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
--- a/fs/btrfs/ulist.c
+++ b/fs/btrfs/ulist.c
@@ -205,6 +205,10 @@ int ulist_add_merge(struct ulist *ulist,
u64 new_alloced = ulist->nodes_alloced + 128;
struct ulist_node *new_nodes;
void *old = NULL;
+ int i;
+
+ for (i = 0; i < ulist->nnodes; i++)
+ rb_erase(&ulist->nodes[i].rb_node, &ulist->root);
/*
* if nodes_alloced == ULIST_SIZE no memory has been allocated
@@ -224,6 +228,17 @@ int ulist_add_merge(struct ulist *ulist,
ulist->nodes = new_nodes;
ulist->nodes_alloced = new_alloced;
+
+ /*
+ * krealloc actually uses memcpy, which does not copy rb_node
+ * pointers, so we have to do it ourselves. Otherwise we may
+ * be bitten by crashes.
+ */
+ for (i = 0; i < ulist->nnodes; i++) {
+ ret = ulist_rbtree_insert(ulist, &ulist->nodes[i]);
+ if (ret < 0)
+ return ret;
+ }
}
ulist->nodes[ulist->nnodes].val = val;
ulist->nodes[ulist->nnodes].aux = aux;
Patches currently in stable-queue which might be from [email protected] are
queue-3.10/btrfs-fix-crash-regarding-to-ulist_add_merge.patch
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