syzbot

loop4: detected capacity change from 0 to 512
EXT4-fs (loop4): couldn't mount as ext2 due to feature incompatibilities
==================================================================
BUG: KCSAN: data-race in data_push_tail / number

write to 0xffffffff86f3aff3 of 1 bytes by task 3926 on cpu 1:
 number+0x7d0/0xa90 lib/vsprintf.c:562
 vsnprintf+0xa44/0xe20 lib/vsprintf.c:2883
 vscnprintf+0x42/0x80 lib/vsprintf.c:2923
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2128
 vprintk_store+0x56f/0x800 kernel/printk/printk.c:2242
 vprintk_emit+0xd0/0x430 kernel/printk/printk.c:2288
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x83/0x90 kernel/printk/printk_safe.c:50
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 __ext4_error_inode+0x2d5/0x400 fs/ext4/super.c:800
 check_xattrs+0x6ba/0x770 fs/ext4/xattr.c:290
 __xattr_check_inode fs/ext4/xattr.c:311 [inline]
 ext4_xattr_ibody_find+0x1a6/0x390 fs/ext4/xattr.c:2264
 ext4_find_inline_data_nolock+0xb9/0x1f0 fs/ext4/inline.c:147
 ext4_iget_extra_inode+0xdf/0x1a0 fs/ext4/inode.c:4612
 __ext4_iget+0x1148/0x1cc0 fs/ext4/inode.c:4854
 ext4_orphan_get+0x140/0x3e0 fs/ext4/ialloc.c:1390
 ext4_orphan_cleanup+0x5b4/0x9c0 fs/ext4/orphan.c:467
 __ext4_fill_super fs/ext4/super.c:5556 [inline]
 ext4_fill_super+0x35b0/0x38d0 fs/ext4/super.c:5672
 get_tree_bdev+0x2a8/0x3a0 fs/super.c:1303
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5703
 vfs_get_tree+0x51/0x190 fs/super.c:1510
 do_new_mount+0x200/0x650 fs/namespace.c:3039
 path_mount+0x498/0xb40 fs/namespace.c:3369
 do_mount fs/namespace.c:3382 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3568
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffffff86f3aff0 of 8 bytes by task 3934 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:590 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:675
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1046
 prb_reserve+0x893/0xbc0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2232
 vprintk_emit+0xd0/0x430 kernel/printk/printk.c:2288
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x83/0x90 kernel/printk/printk_safe.c:50
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 __ext4_msg+0x18a/0x1a0 fs/ext4/super.c:937
 ext4_check_feature_compatibility+0x58c/0x610
 __ext4_fill_super fs/ext4/super.c:5269 [inline]
 ext4_fill_super+0x2157/0x38d0 fs/ext4/super.c:5672
 get_tree_bdev+0x2a8/0x3a0 fs/super.c:1303
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5703
 vfs_get_tree+0x51/0x190 fs/super.c:1510
 do_new_mount+0x200/0x650 fs/namespace.c:3039
 path_mount+0x498/0xb40 fs/namespace.c:3369
 do_mount fs/namespace.c:3382 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3568
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000001000043ef -> 0x0000000100232065

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3934 Comm: syz-executor.4 Not tainted 6.3.0-syzkaller-13390-g2e1e1337881b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
==================================================================