From 5c13e2388bf3426fd69a89eb46e50469e9624e56 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Fri, 18 Aug 2023 11:34:32 -0700 Subject: [PATCH] f2fs: avoid false alarm of circular locking ====================================================== WARNING: possible circular locking dependency detected 6.5.0-rc5-syzkaller-00353-gae545c3283dc #0 Not tainted ------------------------------------------------------ syz-executor273/5027 is trying to acquire lock: ffff888077fe1fb0 (&fi->i_sem){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2133 [inline] ffff888077fe1fb0 (&fi->i_sem){+.+.}-{3:3}, at: f2fs_add_inline_entry+0x300/0x6f0 fs/f2fs/inline.c:644 but task is already holding lock: ffff888077fe07c8 (&fi->i_xattr_sem){.+.+}-{3:3}, at: f2fs_down_read fs/f2fs/f2fs.h:2108 [inline] ffff888077fe07c8 (&fi->i_xattr_sem){.+.+}-{3:3}, at: f2fs_add_dentry+0x92/0x230 fs/f2fs/dir.c:783 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&fi->i_xattr_sem){.+.+}-{3:3}: down_read+0x9c/0x470 kernel/locking/rwsem.c:1520 f2fs_down_read fs/f2fs/f2fs.h:2108 [inline] f2fs_getxattr+0xb1e/0x12c0 fs/f2fs/xattr.c:532 __f2fs_get_acl+0x5a/0x900 fs/f2fs/acl.c:179 f2fs_acl_create fs/f2fs/acl.c:377 [inline] f2fs_init_acl+0x15c/0xb30 fs/f2fs/acl.c:420 f2fs_init_inode_metadata+0x159/0x1290 fs/f2fs/dir.c:558 f2fs_add_regular_entry+0x79e/0xb90 fs/f2fs/dir.c:740 f2fs_add_dentry+0x1de/0x230 fs/f2fs/dir.c:788 f2fs_do_add_link+0x190/0x280 fs/f2fs/dir.c:827 f2fs_add_link fs/f2fs/f2fs.h:3554 [inline] f2fs_mkdir+0x377/0x620 fs/f2fs/namei.c:781 vfs_mkdir+0x532/0x7e0 fs/namei.c:4117 do_mkdirat+0x2a9/0x330 fs/namei.c:4140 __do_sys_mkdir fs/namei.c:4160 [inline] __se_sys_mkdir fs/namei.c:4158 [inline] __x64_sys_mkdir+0xf2/0x140 fs/namei.c:4158 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (&fi->i_sem){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3142 [inline] check_prevs_add kernel/locking/lockdep.c:3261 [inline] validate_chain kernel/locking/lockdep.c:3876 [inline] __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5144 lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 down_write+0x93/0x200 kernel/locking/rwsem.c:1573 f2fs_down_write fs/f2fs/f2fs.h:2133 [inline] f2fs_add_inline_entry+0x300/0x6f0 fs/f2fs/inline.c:644 f2fs_add_dentry+0xa6/0x230 fs/f2fs/dir.c:784 f2fs_do_add_link+0x190/0x280 fs/f2fs/dir.c:827 f2fs_add_link fs/f2fs/f2fs.h:3554 [inline] f2fs_mkdir+0x377/0x620 fs/f2fs/namei.c:781 vfs_mkdir+0x532/0x7e0 fs/namei.c:4117 ovl_do_mkdir fs/overlayfs/overlayfs.h:196 [inline] ovl_mkdir_real+0xb5/0x370 fs/overlayfs/dir.c:146 ovl_workdir_create+0x3de/0x820 fs/overlayfs/super.c:309 ovl_make_workdir fs/overlayfs/super.c:711 [inline] ovl_get_workdir fs/overlayfs/super.c:864 [inline] ovl_fill_super+0xdab/0x6180 fs/overlayfs/super.c:1400 vfs_get_super+0xf9/0x290 fs/super.c:1152 vfs_get_tree+0x88/0x350 fs/super.c:1519 do_new_mount fs/namespace.c:3335 [inline] path_mount+0x1492/0x1ed0 fs/namespace.c:3662 do_mount fs/namespace.c:3675 [inline] __do_sys_mount fs/namespace.c:3884 [inline] __se_sys_mount fs/namespace.c:3861 [inline] __x64_sys_mount+0x293/0x310 fs/namespace.c:3861 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- rlock(&fi->i_xattr_sem); lock(&fi->i_sem); lock(&fi->i_xattr_sem); lock(&fi->i_sem); Cc: Reported-and-tested-by: syzbot+e5600587fa9cbf8e3826@syzkaller.appspotmail.com Fixes: 5eda1ad1aaff "f2fs: fix deadlock in i_xattr_sem and inode page lock" Tested-by: Guenter Roeck Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/f2fs.h | 24 +++++++++++++++--------- fs/f2fs/inline.c | 3 ++- 2 files changed, 17 insertions(+), 10 deletions(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index c602ff2403b6..c0b7417f1d87 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -2122,15 +2122,6 @@ static inline int f2fs_down_read_trylock(struct f2fs_rwsem *sem) return down_read_trylock(&sem->internal_rwsem); } -#ifdef CONFIG_DEBUG_LOCK_ALLOC -static inline void f2fs_down_read_nested(struct f2fs_rwsem *sem, int subclass) -{ - down_read_nested(&sem->internal_rwsem, subclass); -} -#else -#define f2fs_down_read_nested(sem, subclass) f2fs_down_read(sem) -#endif - static inline void f2fs_up_read(struct f2fs_rwsem *sem) { up_read(&sem->internal_rwsem); @@ -2141,6 +2132,21 @@ static inline void f2fs_down_write(struct f2fs_rwsem *sem) down_write(&sem->internal_rwsem); } +#ifdef CONFIG_DEBUG_LOCK_ALLOC +static inline void f2fs_down_read_nested(struct f2fs_rwsem *sem, int subclass) +{ + down_read_nested(&sem->internal_rwsem, subclass); +} + +static inline void f2fs_down_write_nested(struct f2fs_rwsem *sem, int subclass) +{ + down_write_nested(&sem->internal_rwsem, subclass); +} +#else +#define f2fs_down_read_nested(sem, subclass) f2fs_down_read(sem) +#define f2fs_down_write_nested(sem, subclass) f2fs_down_write(sem) +#endif + static inline int f2fs_down_write_trylock(struct f2fs_rwsem *sem) { return down_write_trylock(&sem->internal_rwsem); diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c index 4638fee16a91..0d185ad5e469 100644 --- a/fs/f2fs/inline.c +++ b/fs/f2fs/inline.c @@ -641,7 +641,8 @@ int f2fs_add_inline_entry(struct inode *dir, const struct f2fs_filename *fname, } if (inode) { - f2fs_down_write(&F2FS_I(inode)->i_sem); + f2fs_down_write_nested(&F2FS_I(inode)->i_sem, + SINGLE_DEPTH_NESTING); page = f2fs_init_inode_metadata(inode, dir, fname, ipage); if (IS_ERR(page)) { err = PTR_ERR(page);