syzbot reported warning message:

Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d6/0x29e lib/dump_stack.c:118 register_lock_class+0xf06/0x1520 kernel/locking/lockdep.c:893 __lock_acquire+0xfd/0x2ae0 kernel/locking/lockdep.c:4320 lock_acquire+0x148/0x720 kernel/locking/lockdep.c:5029 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:354 [inline] exfat_cache_inval_inode+0x30/0x280 fs/exfat/cache.c:226 exfat_evict_inode+0x124/0x270 fs/exfat/inode.c:660 evict+0x2bb/0x6d0 fs/inode.c:576 exfat_fill_super+0x1e07/0x27d0 fs/exfat/super.c:681 get_tree_bdev+0x3e9/0x5f0 fs/super.c:1342 vfs_get_tree+0x88/0x270 fs/super.c:1547 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x179d/0x29e0 fs/namespace.c:3192 do_mount fs/namespace.c:3205 [inline] __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount+0x126/0x180 fs/namespace.c:3390 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9

If exfat_read_root() returns an error, spinlock is used in exfat_evict_inode() without initialization. This patch combines exfat_cache_init_inode() with exfat_inode_init_once() to initialize spinlock by slab constructor.

Fixes: c35b6810c495 ("exfat: add exfat cache") Cc: stable@vger.kernel.org # v5.7+ Reported-by: syzbot syzbot+b91107320911a26c9a95@syzkaller.appspotmail.com Signed-off-by: Namjae Jeon namjae.jeon@samsung.com --- fs/exfat/cache.c | 11 ----------- fs/exfat/exfat_fs.h | 3 ++- fs/exfat/inode.c | 2 -- fs/exfat/super.c | 5 ++++- 4 files changed, 6 insertions(+), 15 deletions(-)

diff --git a/fs/exfat/cache.c b/fs/exfat/cache.c index 03d0824fc368..5a2f119b7e8c 100644 --- a/fs/exfat/cache.c +++ b/fs/exfat/cache.c @@ -17,7 +17,6 @@ #include "exfat_raw.h" #include "exfat_fs.h"

-#define EXFAT_CACHE_VALID 0 #define EXFAT_MAX_CACHE 16

struct exfat_cache { @@ -61,16 +60,6 @@ void exfat_cache_shutdown(void) kmem_cache_destroy(exfat_cachep); }

-void exfat_cache_init_inode(struct inode *inode) -{ - struct exfat_inode_info *ei = EXFAT_I(inode); - - spin_lock_init(&ei->cache_lru_lock); - ei->nr_caches = 0; - ei->cache_valid_id = EXFAT_CACHE_VALID + 1; - INIT_LIST_HEAD(&ei->cache_lru); -} - static inline struct exfat_cache *exfat_cache_alloc(void) { return kmem_cache_alloc(exfat_cachep, GFP_NOFS); diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index e586daf5a2e7..b8f0e829ecbd 100644 --- a/fs/exfat/exfat_fs.h +++ b/fs/exfat/exfat_fs.h @@ -248,6 +248,8 @@ struct exfat_sb_info { struct rcu_head rcu; };

+#define EXFAT_CACHE_VALID 0 + /* * EXFAT file system inode in-memory data */ @@ -426,7 +428,6 @@ extern const struct dentry_operations exfat_utf8_dentry_ops; /* cache.c */ int exfat_cache_init(void); void exfat_cache_shutdown(void); -void exfat_cache_init_inode(struct inode *inode); void exfat_cache_inval_inode(struct inode *inode); int exfat_get_cluster(struct inode *inode, unsigned int cluster, unsigned int *fclus, unsigned int *dclus, diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c index 687f77653187..730373e0965a 100644 --- a/fs/exfat/inode.c +++ b/fs/exfat/inode.c @@ -608,8 +608,6 @@ static int exfat_fill_inode(struct inode *inode, struct exfat_dir_entry *info) ei->i_crtime = info->crtime; inode->i_atime = info->atime;

- exfat_cache_init_inode(inode); - return 0; }

diff --git a/fs/exfat/super.c b/fs/exfat/super.c index b29935a91b9b..3ffdce5c7384 100644 --- a/fs/exfat/super.c +++ b/fs/exfat/super.c @@ -375,7 +375,6 @@ static int exfat_read_root(struct inode *inode) inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime = current_time(inode); exfat_truncate_atime(&inode->i_atime); - exfat_cache_init_inode(inode); return 0; }

@@ -762,6 +761,10 @@ static void exfat_inode_init_once(void *foo) { struct exfat_inode_info *ei = (struct exfat_inode_info *)foo;

+ spin_lock_init(&ei->cache_lru_lock); + ei->nr_caches = 0; + ei->cache_valid_id = EXFAT_CACHE_VALID + 1; + INIT_LIST_HEAD(&ei->cache_lru); INIT_HLIST_NODE(&ei->i_hash_fat); inode_init_once(&ei->vfs_inode); }