loop3: detected capacity change from 0 to 2048
EXT4-fs warning (device loop3): read_mmp_block:107: Error -117 while reading MMP block 0
==================================================================
BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff8412f679 of 1 bytes by task 15093 on cpu 0:
 vsnprintf+0xe8f/0xed0
 vscnprintf+0x29/0x80 lib/vsprintf.c:2900
 printk_sprint kernel/printk/printk.c:2075 [inline]
 vprintk_store+0x606/0xb80 kernel/printk/printk.c:2185
 vprintk_emit+0xac/0x390 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
 autofs_fill_super+0xa5c/0xf20 fs/autofs/inode.c:283
 mount_nodev+0x4f/0xd0 fs/super.c:1414
 autofs_mount+0x25/0x30 fs/autofs/init.c:13
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:610
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1498
 do_new_mount fs/namespace.c:2988 [inline]
 path_mount+0x11ec/0x1d20 fs/namespace.c:3318
 do_mount fs/namespace.c:3331 [inline]
 __do_sys_mount fs/namespace.c:3539 [inline]
 __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3516
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3516
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffffff8412f678 of 8 bytes by task 15092 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:587 [inline]
 data_push_tail+0x138/0x470 kernel/printk/printk_ringbuffer.c:672
 data_alloc+0xbc/0x2b0 kernel/printk/printk_ringbuffer.c:1043
 prb_reserve+0x920/0xbf0 kernel/printk/printk_ringbuffer.c:1549
 vprintk_store+0x53a/0xb80 kernel/printk/printk.c:2175
 vprintk_emit+0xac/0x390 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
 __ext4_warning+0x130/0x140 fs/ext4/super.c:937
 read_mmp_block+0x21d/0x3e0 fs/ext4/mmp.c:106
 ext4_multi_mount_protect+0x104/0x640 fs/ext4/mmp.c:296
 ext4_fill_super+0x4a3b/0x7830 fs/ext4/super.c:4642
 mount_bdev+0x1e8/0x290 fs/super.c:1368
 ext4_mount+0x2d/0x40 fs/ext4/super.c:6515
 legacy_get_tree+0x70/0xc0 fs/fs_context.c:610
 vfs_get_tree+0x4a/0x1a0 fs/super.c:1498
 do_new_mount fs/namespace.c:2988 [inline]
 path_mount+0x11ec/0x1d20 fs/namespace.c:3318
 do_mount fs/namespace.c:3331 [inline]
 __do_sys_mount fs/namespace.c:3539 [inline]
 __se_sys_mount+0x24b/0x2f0 fs/namespace.c:3516
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3516
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000ffffe260 -> 0x00000000ffffe20a

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 15092 Comm: syz-executor.3 Not tainted 5.15.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
loop3: detected capacity change from 0 to 2048
EXT4-fs warning (device loop3): read_mmp_block:107: Error -117 while reading MMP block 0