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exfat: fix use of uninitialized spinlock on error path 

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: c35b6810c4 ("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>
zero-sugar-mainline-defconfig
Namjae Jeon 2020-09-29 09:09:49 +09:00
parent d6c9efd924
commit 8ff006e57a
4 changed files with 6 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
fs/exfat/cache.c
View File

@ -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);

3
fs/exfat/exfat_fs.h
View File

@ -248,6 +248,8 @@ struct exfat_sb_info {
struct rcu_head rcu;
};
#define EXFAT_CACHE_VALID 0
/*
* EXFAT file system inode in-memory data
*/
@ -428,7 +430,6 @@ 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,

2
fs/exfat/inode.c
View File

@ -611,8 +611,6 @@ 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;
}

5
fs/exfat/super.c
View File

@ -376,7 +376,6 @@ 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;
}
@ -763,6 +762,10 @@ 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);
}