syzbot

EXT4-fs (sda1): re-mounted 5941fea2-f5fa-4b4e-b5ef-9af118b27b95. Quota mode: none.
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BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff86f0bdd8 of 8 bytes by task 25065 on cpu 1:
 data_alloc+0x216/0x2c0 kernel/printk/printk_ringbuffer.c:1074
 prb_reserve+0x893/0xbc0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2230
 vprintk_emit+0xd0/0x430 kernel/printk/printk.c:2286
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2316
 vprintk+0x83/0x90 kernel/printk/printk_safe.c:50
 _printk+0x7a/0xa0 kernel/printk/printk.c:2326
 selinux_add_opt+0x22b/0x280 security/selinux/hooks.c:993
 selinux_sb_eat_lsm_opts+0x6c1/0x770 security/selinux/hooks.c:2555
 security_sb_eat_lsm_opts+0x3e/0x70 security/security.c:1261
 shmem_parse_options+0x28/0x160 mm/shmem.c:3580
 parse_monolithic_mount_data+0x42/0x50 fs/fs_context.c:667
 do_new_mount+0x1d3/0x650 fs/namespace.c:3035
 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 0xffffffff86f0bdd8 of 8 bytes by task 25064 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:2230
 vprintk_emit+0xd0/0x430 kernel/printk/printk.c:2286
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2316
 vprintk+0x83/0x90 kernel/printk/printk_safe.c:50
 _printk+0x7a/0xa0 kernel/printk/printk.c:2326
 __ext4_msg+0x18a/0x1a0 fs/ext4/super.c:937
 ext4_reconfigure+0x946/0x1720 fs/ext4/super.c:6646
 reconfigure_super+0x2a1/0x540 fs/super.c:956
 do_remount fs/namespace.c:2701 [inline]
 path_mount+0xa2a/0xb40 fs/namespace.c:3361
 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: 0x0000000100000284 -> 0x00000001000011c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 25064 Comm: syz-executor.0 Tainted: G        W          6.3.0-syzkaller-04626-g0cfd8703e7da #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
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