From: Zhang Xiaoxu zhangxiaoxu5@huawei.com
commit 9b2f20344d450137d015b380ff0c2e2a6a170135 upstream.
The btrfs_alloc_dummy_root() uses ERR_PTR as the error return value rather than NULL, if error happened, there will be a NULL pointer dereference:
BUG: KASAN: null-ptr-deref in btrfs_free_dummy_root+0x21/0x50 [btrfs] Read of size 8 at addr 000000000000002c by task insmod/258926
CPU: 2 PID: 258926 Comm: insmod Tainted: G W 6.1.0-rc2+ #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x34/0x44 kasan_report+0xb7/0x140 kasan_check_range+0x145/0x1a0 btrfs_free_dummy_root+0x21/0x50 [btrfs] btrfs_test_free_space_cache+0x1a8c/0x1add [btrfs] btrfs_run_sanity_tests+0x65/0x80 [btrfs] init_btrfs_fs+0xec/0x154 [btrfs] do_one_initcall+0x87/0x2a0 do_init_module+0xdf/0x320 load_module+0x3006/0x3390 __do_sys_finit_module+0x113/0x1b0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0
Fixes: aaedb55bc08f ("Btrfs: add tests for btrfs_get_extent") CC: stable@vger.kernel.org # 4.9+ Reviewed-by: Anand Jain anand.jain@oracle.com Signed-off-by: Zhang Xiaoxu zhangxiaoxu5@huawei.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/btrfs/tests/btrfs-tests.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/btrfs/tests/btrfs-tests.c +++ b/fs/btrfs/tests/btrfs-tests.c @@ -189,7 +189,7 @@ void btrfs_free_dummy_fs_info(struct btr
void btrfs_free_dummy_root(struct btrfs_root *root) { - if (!root) + if (IS_ERR_OR_NULL(root)) return; /* Will be freed by btrfs_free_fs_roots */ if (WARN_ON(test_bit(BTRFS_ROOT_IN_RADIX, &root->state)))