syzbot

EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
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BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff868714c8 of 8 bytes by task 7597 on cpu 1:
 data_alloc+0x271/0x2b0 kernel/printk/printk_ringbuffer.c:1095
 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
 dev_vprintk_emit+0x242/0x2a0 drivers/base/core.c:4914
 dev_printk_emit+0x84/0xb0 drivers/base/core.c:4925
 __dev_printk+0xf3/0x110 drivers/base/core.c:4937
 _dev_info+0x9b/0xd0 drivers/base/core.c:4983
 attach_store+0x495/0x680 drivers/usb/usbip/vhci_sysfs.c:416
 dev_attr_store+0x4a/0x70 drivers/base/core.c:2437
 sysfs_kf_write+0xfe/0x120 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x1c1/0x2d0 fs/kernfs/file.c:334
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x4a0/0x8e0 fs/read_write.c:686
 ksys_write+0xda/0x1a0 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:746
 x64_sys_call+0x27fe/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:2
 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 0xffffffff868714c8 of 16 bytes by task 7579 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:482 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1874 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1922 [inline]
 _prb_read_valid+0x1bc/0x920 kernel/printk/printk_ringbuffer.c:2113
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2185
 printk_get_next_message+0xc8/0x510 kernel/printk/printk.c:3005
 console_emit_next_record kernel/printk/printk.c:3092 [inline]
 console_flush_all+0x290/0x730 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xa1/0x330 kernel/printk/printk.c:3325
 vprintk_emit+0x388/0x650 kernel/printk/printk.c:2450
 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_fill_super+0x2d05/0x34e0 fs/ext4/super.c:5739
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1692
 get_tree_bdev+0x1f/0x30 fs/super.c:1715
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5756
 vfs_get_tree+0x54/0x1d0 fs/super.c:1815
 do_new_mount+0x207/0x5e0 fs/namespace.c:3805
 path_mount+0x4a4/0xb20 fs/namespace.c:4120
 do_mount fs/namespace.c:4133 [inline]
 __do_sys_mount fs/namespace.c:4344 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4321
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4321
 x64_sys_call+0x2b4d/0x2ff0 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7579 Comm: ’ Tainted: G        W           6.16.0-syzkaller-11241-g186f3edfdd41 #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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