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Message-ID: <20230301122919.266818-3-chengzhihao1@huawei.com>
Date: Wed, 1 Mar 2023 20:29:19 +0800
From: Zhihao Cheng <chengzhihao1@...wei.com>
To: <richard@....at>, <s.hauer@...gutronix.de>,
<miquel.raynal@...tlin.com>
CC: <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
<chengzhihao1@...wei.com>
Subject: [PATCH -next 2/2] ubifs: dirty_cow_znode: Fix memleak when insert_old_idx() failed
Following process will cause a memleak for copied up znode:
dirty_cow_znode
zn = copy_znode(c, znode);
err = insert_old_idx(c, zbr->lnum, zbr->offs);
if (unlikely(err))
return ERR_PTR(err); // No one refers to zn.
Fetch a reproducer in [Link].
Function copy_znode() is split into 2 parts: resource allocation
and znode replacement, insert_old_idx() is split in similar way,
so resource cleanup could be done in error handling path without
corrupting metadata(mem & disk).
It's okay that old index inserting is put behind of add_idx_dirt(),
old index is used in layout_leb_in_gaps(), so the two processes do
not depend on each other.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216705
Fixes: 1e51764a3c2a ("UBIFS: add new flash file system")
Signed-off-by: Zhihao Cheng <chengzhihao1@...wei.com>
---
fs/ubifs/tnc.c | 137 +++++++++++++++++++++++++++++++------------------
1 file changed, 87 insertions(+), 50 deletions(-)
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index 2df56bbc6865..6b7d95b65f4b 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -44,6 +44,33 @@ enum {
NOT_ON_MEDIA = 3,
};
+static void do_insert_old_idx(struct ubifs_info *c,
+ struct ubifs_old_idx *old_idx)
+{
+ struct ubifs_old_idx *o;
+ struct rb_node **p, *parent = NULL;
+
+ p = &c->old_idx.rb_node;
+ while (*p) {
+ parent = *p;
+ o = rb_entry(parent, struct ubifs_old_idx, rb);
+ if (old_idx->lnum < o->lnum)
+ p = &(*p)->rb_left;
+ else if (old_idx->lnum > o->lnum)
+ p = &(*p)->rb_right;
+ else if (old_idx->offs < o->offs)
+ p = &(*p)->rb_left;
+ else if (old_idx->offs > o->offs)
+ p = &(*p)->rb_right;
+ else {
+ ubifs_err(c, "old idx added twice!");
+ kfree(old_idx);
+ }
+ }
+ rb_link_node(&old_idx->rb, parent, p);
+ rb_insert_color(&old_idx->rb, &c->old_idx);
+}
+
/**
* insert_old_idx - record an index node obsoleted since the last commit start.
* @c: UBIFS file-system description object
@@ -69,35 +96,15 @@ enum {
*/
static int insert_old_idx(struct ubifs_info *c, int lnum, int offs)
{
- struct ubifs_old_idx *old_idx, *o;
- struct rb_node **p, *parent = NULL;
+ struct ubifs_old_idx *old_idx;
old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
if (unlikely(!old_idx))
return -ENOMEM;
old_idx->lnum = lnum;
old_idx->offs = offs;
+ do_insert_old_idx(c, old_idx);
- p = &c->old_idx.rb_node;
- while (*p) {
- parent = *p;
- o = rb_entry(parent, struct ubifs_old_idx, rb);
- if (lnum < o->lnum)
- p = &(*p)->rb_left;
- else if (lnum > o->lnum)
- p = &(*p)->rb_right;
- else if (offs < o->offs)
- p = &(*p)->rb_left;
- else if (offs > o->offs)
- p = &(*p)->rb_right;
- else {
- ubifs_err(c, "old idx added twice!");
- kfree(old_idx);
- return 0;
- }
- }
- rb_link_node(&old_idx->rb, parent, p);
- rb_insert_color(&old_idx->rb, &c->old_idx);
return 0;
}
@@ -199,23 +206,6 @@ static struct ubifs_znode *copy_znode(struct ubifs_info *c,
__set_bit(DIRTY_ZNODE, &zn->flags);
__clear_bit(COW_ZNODE, &zn->flags);
- ubifs_assert(c, !ubifs_zn_obsolete(znode));
- __set_bit(OBSOLETE_ZNODE, &znode->flags);
-
- if (znode->level != 0) {
- int i;
- const int n = zn->child_cnt;
-
- /* The children now have new parent */
- for (i = 0; i < n; i++) {
- struct ubifs_zbranch *zbr = &zn->zbranch[i];
-
- if (zbr->znode)
- zbr->znode->parent = zn;
- }
- }
-
- atomic_long_inc(&c->dirty_zn_cnt);
return zn;
}
@@ -233,6 +223,42 @@ static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
return ubifs_add_dirt(c, lnum, dirt);
}
+/**
+ * replace_znode - replace old znode with new znode.
+ * @c: UBIFS file-system description object
+ * @new_zn: new znode
+ * @old_zn: old znode
+ * @zbr: the branch of parent znode
+ *
+ * Replace old znode with new znode in TNC.
+ */
+static void replace_znode(struct ubifs_info *c, struct ubifs_znode *new_zn,
+ struct ubifs_znode *old_zn, struct ubifs_zbranch *zbr)
+{
+ ubifs_assert(c, !ubifs_zn_obsolete(old_zn));
+ __set_bit(OBSOLETE_ZNODE, &old_zn->flags);
+
+ if (old_zn->level != 0) {
+ int i;
+ const int n = new_zn->child_cnt;
+
+ /* The children now have new parent */
+ for (i = 0; i < n; i++) {
+ struct ubifs_zbranch *child = &new_zn->zbranch[i];
+
+ if (child->znode)
+ child->znode->parent = new_zn;
+ }
+ }
+
+ zbr->znode = new_zn;
+ zbr->lnum = 0;
+ zbr->offs = 0;
+ zbr->len = 0;
+
+ atomic_long_inc(&c->dirty_zn_cnt);
+}
+
/**
* dirty_cow_znode - ensure a znode is not being committed.
* @c: UBIFS file-system description object
@@ -265,21 +291,32 @@ static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
return zn;
if (zbr->len) {
- err = insert_old_idx(c, zbr->lnum, zbr->offs);
- if (unlikely(err))
- return ERR_PTR(err);
+ struct ubifs_old_idx *old_idx;
+
+ old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
+ if (unlikely(!old_idx)) {
+ err = -ENOMEM;
+ goto out;
+ }
+ old_idx->lnum = zbr->lnum;
+ old_idx->offs = zbr->offs;
+
err = add_idx_dirt(c, zbr->lnum, zbr->len);
- } else
- err = 0;
+ if (err) {
+ kfree(old_idx);
+ goto out;
+ }
- zbr->znode = zn;
- zbr->lnum = 0;
- zbr->offs = 0;
- zbr->len = 0;
+ do_insert_old_idx(c, old_idx);
+ }
+
+ replace_znode(c, zn, znode, zbr);
- if (unlikely(err))
- return ERR_PTR(err);
return zn;
+
+out:
+ kfree(zn);
+ return ERR_PTR(err);
}
/**
--
2.31.1
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