ubifs: Fix memory leak in alloc_wbufs()

[ Upstream commit 4a1ff3c5d04b9079b4f768d9a71b51c4af578dd2 ]

kmemleak reported a sequence of memory leaks, and show them as following:

  unreferenced object 0xffff8881575f8400 (size 1024):
    comm "mount", pid 19625, jiffies 4297119604 (age 20.383s)
    hex dump (first 32 bytes):
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    backtrace:
      [<ffffffff8176cecd>] __kmalloc+0x4d/0x150
      [<ffffffffa0406b2b>] ubifs_mount+0x307b/0x7170 [ubifs]
      [<ffffffff819fa8fd>] legacy_get_tree+0xed/0x1d0
      [<ffffffff81936f2d>] vfs_get_tree+0x7d/0x230
      [<ffffffff819b2bd4>] path_mount+0xdd4/0x17b0
      [<ffffffff819b37aa>] __x64_sys_mount+0x1fa/0x270
      [<ffffffff83c14295>] do_syscall_64+0x35/0x80
      [<ffffffff83e0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

  unreferenced object 0xffff8881798a6e00 (size 512):
    comm "mount", pid 19677, jiffies 4297121912 (age 37.816s)
    hex dump (first 32 bytes):
      6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
      6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    backtrace:
      [<ffffffff8176cecd>] __kmalloc+0x4d/0x150
      [<ffffffffa0418342>] ubifs_wbuf_init+0x52/0x480 [ubifs]
      [<ffffffffa0406ca5>] ubifs_mount+0x31f5/0x7170 [ubifs]
      [<ffffffff819fa8fd>] legacy_get_tree+0xed/0x1d0
      [<ffffffff81936f2d>] vfs_get_tree+0x7d/0x230
      [<ffffffff819b2bd4>] path_mount+0xdd4/0x17b0
      [<ffffffff819b37aa>] __x64_sys_mount+0x1fa/0x270
      [<ffffffff83c14295>] do_syscall_64+0x35/0x80
      [<ffffffff83e0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

The problem is that the ubifs_wbuf_init() returns an error in the
loop which in the alloc_wbufs(), then the wbuf->buf and wbuf->inodes
that were successfully alloced before are not freed.

Fix it by adding error hanging path in alloc_wbufs() which frees
the memory alloced before when ubifs_wbuf_init() returns an error.

Fixes: 1e51764a3c2a ("UBIFS: add new flash file system")
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index d0c9a09..32cb147 100644 (file)
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -833,7 +833,7 @@ static int alloc_wbufs(struct ubifs_info *c)
                INIT_LIST_HEAD(&c->jheads[i].buds_list);
                err = ubifs_wbuf_init(c, &c->jheads[i].wbuf);
                if (err)
-                       return err;
+                       goto out_wbuf;
 
                c->jheads[i].wbuf.sync_callback = &bud_wbuf_callback;
                c->jheads[i].wbuf.jhead = i;
@@ -841,7 +841,7 @@ static int alloc_wbufs(struct ubifs_info *c)
                c->jheads[i].log_hash = ubifs_hash_get_desc(c);
                if (IS_ERR(c->jheads[i].log_hash)) {
                        err = PTR_ERR(c->jheads[i].log_hash);
-                       goto out;
+                       goto out_log_hash;
                }
        }
 
@@ -854,9 +854,18 @@ static int alloc_wbufs(struct ubifs_info *c)
 
        return 0;
 
-out:
-       while (i--)
+out_log_hash:
+       kfree(c->jheads[i].wbuf.buf);
+       kfree(c->jheads[i].wbuf.inodes);
+
+out_wbuf:
+       while (i--) {
+               kfree(c->jheads[i].wbuf.buf);
+               kfree(c->jheads[i].wbuf.inodes);
                kfree(c->jheads[i].log_hash);
+       }
+       kfree(c->jheads);
+       c->jheads = NULL;
 
        return err;
 }