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BUG: KCSAN: data-race in console_flush_all / console_flush_all

write to 0xffffffff86e363c8 of 8 bytes by task 20067 on cpu 1:
 console_emit_next_record kernel/printk/printk.c:3144 [inline]
 console_flush_one_record kernel/printk/printk.c:3269 [inline]
 console_flush_all+0x38c/0x6c0 kernel/printk/printk.c:3343
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xa1/0x280 kernel/printk/printk.c:3413
 vprintk_emit+0x3e4/0x600 kernel/printk/printk.c:2479
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 __ext4_grp_locked_error+0x56d/0x7a0 fs/ext4/super.c:1067
 ext4_mb_generate_buddy+0x3a0/0x430 fs/ext4/mballoc.c:1314
 ext4_mb_init_cache+0x887/0xbd0 fs/ext4/mballoc.c:1499
 ext4_mb_init_group+0x42d/0x580 fs/ext4/mballoc.c:1657
 ext4_mb_load_buddy_gfp+0x8d0/0x930 fs/ext4/mballoc.c:1705
 ext4_mb_clear_bb fs/ext4/mballoc.c:6580 [inline]
 ext4_free_blocks+0x761/0x1430 fs/ext4/mballoc.c:6782
 ext4_remove_blocks fs/ext4/extents.c:2569 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2734 [inline]
 ext4_ext_remove_space+0x1875/0x2950 fs/ext4/extents.c:2979
 ext4_ext_truncate+0xc7/0x160 fs/ext4/extents.c:4566
 ext4_truncate+0x6ea/0xa10 fs/ext4/inode.c:4667
 ext4_process_orphan+0x110/0x1c0 fs/ext4/orphan.c:337
 ext4_orphan_cleanup+0x69c/0x9f0 fs/ext4/orphan.c:472
 __ext4_fill_super fs/ext4/super.c:5701 [inline]
 ext4_fill_super+0x3408/0x37c0 fs/ext4/super.c:5824
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1694
 get_tree_bdev+0x1f/0x30 fs/super.c:1717
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5856
 vfs_get_tree+0x57/0x1d0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x288/0x8d0 fs/namespace.c:3834
 path_mount+0x4d0/0xbc0 fs/namespace.c:4154
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4360
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4360
 x64_sys_call+0x2d61/0x3020 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86e363c8 of 8 bytes by task 20076 on cpu 0:
 console_flush_one_record kernel/printk/printk.c:3270 [inline]
 console_flush_all+0x548/0x6c0 kernel/printk/printk.c:3343
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xa1/0x280 kernel/printk/printk.c:3413
 vprintk_emit+0x3e4/0x600 kernel/printk/printk.c:2479
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 selinux_netlink_send+0x5d9/0x650 security/selinux/hooks.c:6279
 security_netlink_send+0x3c/0x70 security/security.c:4122
 netlink_sendmsg+0x4d5/0x6f0 net/netlink/af_netlink.c:1884
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 ____sys_sendmsg+0x563/0x5b0 net/socket.c:2698
 ___sys_sendmsg+0x195/0x1e0 net/socket.c:2752
 __sys_sendmsg net/socket.c:2784 [inline]
 __do_sys_sendmsg net/socket.c:2789 [inline]
 __se_sys_sendmsg net/socket.c:2787 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2787
 x64_sys_call+0x194c/0x3020 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000002923 -> 0x0000000000002924

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 20076 Comm: syz.1.4127 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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