EXT4-fs error (device loop3): ext4_get_branch:178: inode #11: block 4294967295: comm syz.3.607: invalid block
EXT4-fs error (device loop3): ext4_free_branches:1023: inode #11: comm syz.3.607: invalid indirect mapped block 4294967295 (level 1)
EXT4-fs error (device loop3): ext4_free_branches:1023: inode #11: comm syz.3.607: invalid indirect mapped block 4294967295 (level 1)
EXT4-fs (loop3): 2 truncates cleaned up
==================================================================
BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff88e326ea of 28 bytes by task 5450 on cpu 0:
 vsnprintf+0x2ce/0x890 lib/vsprintf.c:2826
 va_format lib/vsprintf.c:1715 [inline]
 pointer+0x833/0xcf0 lib/vsprintf.c:2496
 vsnprintf+0x491/0x890 lib/vsprintf.c:2878
 vscnprintf+0x41/0x90 lib/vsprintf.c:2939
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2475
 _fat_msg+0xa4/0xd0 fs/fat/misc.c:62
 fat_fill_super+0x17c7/0x1ce0 fs/fat/inode.c:1688
 vfat_fill_super+0x24/0x30 fs/fat/namei_vfat.c:1197
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1681
 get_tree_bdev+0x1f/0x30 fs/super.c:1704
 vfat_get_tree+0x1c/0x30 fs/fat/namei_vfat.c:1202
 vfs_get_tree+0x54/0x1d0 fs/super.c:1804
 do_new_mount+0x207/0x680 fs/namespace.c:3902
 path_mount+0x4a4/0xb20 fs/namespace.c:4226
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4427
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4427
 x64_sys_call+0xd36/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88e326f8 of 8 bytes by task 5444 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2475
 __ext4_msg+0x18f/0x1a0 fs/ext4/super.c:981
 ext4_orphan_cleanup+0x938/0xa00 fs/ext4/orphan.c:497
 __ext4_fill_super fs/ext4/super.c:5605 [inline]
 ext4_fill_super+0x3171/0x34e0 fs/ext4/super.c:5724
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1681
 get_tree_bdev+0x1f/0x30 fs/super.c:1704
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5756
 vfs_get_tree+0x54/0x1d0 fs/super.c:1804
 do_new_mount+0x207/0x680 fs/namespace.c:3902
 path_mount+0x4a4/0xb20 fs/namespace.c:4226
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4427
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4427
 x64_sys_call+0xd36/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000ffffe091 -> 0x65727574616e6769

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5444 Comm: syz.3.607 Not tainted 6.16.0-rc6-syzkaller-00281-gf4a40a4282f4 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================
ALSA: seq fatal error: cannot create timer (-19)