System zones: 
1-2, 19-19
==================================================================
BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff86dc7598 of 8 bytes by task 17303 on cpu 1:
 data_alloc+0x205/0x2b0 kernel/printk/printk_ringbuffer.c:1071
 prb_reserve+0x920/0xbf0 kernel/printk/printk_ringbuffer.c:1549
 vprintk_store+0x560/0xbb0 kernel/printk/printk.c:2175
 vprintk_emit+0xac/0x3c0 kernel/printk/printk.c:2228
 vprintk_default+0x22/0x30 kernel/printk/printk.c:2255
 vprintk+0x7f/0x90 kernel/printk/printk_safe.c:50
 _printk+0x76/0x97 kernel/printk/printk.c:2265
 fat_msg+0x91/0xb9 fs/fat/misc.c:56
 fat_fill_super+0x2903/0x2af0 fs/fat/inode.c:1888
 vfat_fill_super+0x2c/0x40 fs/fat/namei_vfat.c:1051
 mount_bdev+0x1e8/0x290 fs/super.c:1370
 vfat_mount+0x2d/0x40 fs/fat/namei_vfat.c:1058
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:610
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1500
 do_new_mount fs/namespace.c:2994 [inline]
 path_mount+0x11cf/0x1c40 fs/namespace.c:3324
 do_mount fs/namespace.c:3337 [inline]
 __do_sys_mount fs/namespace.c:3545 [inline]
 __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3522
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3522
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffffff86dc7598 of 8 bytes by task 17289 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:587 [inline]
 data_push_tail+0x138/0x470 kernel/printk/printk_ringbuffer.c:672
 data_realloc kernel/printk/printk_ringbuffer.c:1132 [inline]
 prb_reserve_in_last+0x757/0xbe0 kernel/printk/printk_ringbuffer.c:1421
 vprintk_store+0x486/0xbb0 kernel/printk/printk.c:2152
 vprintk_emit+0xac/0x3c0 kernel/printk/printk.c:2228
 vprintk_default+0x22/0x30 kernel/printk/printk.c:2255
 vprintk+0x7f/0x90 kernel/printk/printk_safe.c:50
 _printk+0x76/0x97 kernel/printk/printk.c:2265
 debug_print_tree fs/ext4/block_validity.c:138 [inline]
 ext4_setup_system_zone+0x4b9/0x620 fs/ext4/block_validity.c:265
 __ext4_fill_super+0x4dfb/0x59b0 fs/ext4/super.c:5310
 ext4_fill_super+0xfd/0x2f0 fs/ext4/super.c:5557
 get_tree_bdev+0x2c2/0x3d0 fs/super.c:1295
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1500
 do_new_mount fs/namespace.c:2994 [inline]
 path_mount+0x11cf/0x1c40 fs/namespace.c:3324
 do_mount fs/namespace.c:3337 [inline]
 __do_sys_mount fs/namespace.c:3545 [inline]
 __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3522
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3522
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x000000010000280f -> 0x00000001000037a2

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 17289 Comm: syz-executor.4 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
, 35-38, 46-46
EXT4-fs (loop4): mounted filesystem without journal. Quota mode: none.
ext4 filesystem being mounted at /root/syzkaller-testdir727086134/syzkaller.KQ03fi/136/file0 supports timestamps until 2038 (0x7fffffff)