syzbot

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BUG: KCSAN: data-race in ext4_itable_unused_count / ext4_itable_unused_set

write to 0xffff8881025e505c of 2 bytes by task 26354 on cpu 0:
 ext4_itable_unused_set+0x1b/0x80 fs/ext4/super.c:403
 __ext4_new_inode+0x1b2c/0x2f70 fs/ext4/ialloc.c:1203
 ext4_symlink+0x2c3/0x700 fs/ext4/namei.c:3465
 vfs_symlink+0x23a/0x300 fs/namei.c:4172
 do_symlinkat+0xeb/0x280 fs/namei.c:4202
 __do_sys_symlink fs/namei.c:4223 [inline]
 __se_sys_symlink fs/namei.c:4221 [inline]
 __x64_sys_symlink+0x32/0x40 fs/namei.c:4221
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881025e505c of 2 bytes by task 26352 on cpu 1:
 ext4_itable_unused_count+0x18/0x80 fs/ext4/super.c:347
 __ext4_get_inode_loc+0x608/0x920 fs/ext4/inode.c:4404
 ext4_get_inode_loc fs/ext4/inode.c:4456 [inline]
 ext4_reserve_inode_write+0xb8/0x1f0 fs/ext4/inode.c:5743
 ext4_xattr_set_handle+0x36f/0x1110 fs/ext4/xattr.c:2336
 ext4_initxattrs+0x66/0xb0 fs/ext4/xattr_security.c:44
 security_inode_init_security+0x1a9/0x260 security/security.c:1098
 ext4_init_security+0x30/0x40 fs/ext4/xattr_security.c:58
 __ext4_new_inode+0x29a1/0x2f70 fs/ext4/ialloc.c:1321
 ext4_symlink+0x2c3/0x700 fs/ext4/namei.c:3465
 vfs_symlink+0x23a/0x300 fs/namei.c:4172
 do_symlinkat+0xeb/0x280 fs/namei.c:4202
 __do_sys_symlink fs/namei.c:4223 [inline]
 __se_sys_symlink fs/namei.c:4221 [inline]
 __x64_sys_symlink+0x32/0x40 fs/namei.c:4221
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x020e -> 0x020d

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 26352 Comm: syz-executor.5 Not tainted 5.13.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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