syzbot

[EXT4 FS bs=1024, gc=1, bpg=131072, ipg=32, mo=a840e11d, mo2=0002]
System zones: 0-1, 2-3, 4-36, 98-101, 102-102
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 ro without journal. Quota mode: writeback.
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BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff883b9b80 of 1 bytes by task 4177 on cpu 0:
 string_nocheck lib/vsprintf.c:650 [inline]
 string+0x16c/0x210 lib/vsprintf.c:728
 vsnprintf+0xa09/0xe30 lib/vsprintf.c:2824
 vscnprintf+0x42/0x90 lib/vsprintf.c:2930
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2165
 vprintk_store+0x570/0x810 kernel/printk/printk.c:2279
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2329
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2363
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2373
 __ext4_error_file+0x322/0x420 fs/ext4/super.c:902
 __ext4_check_dir_entry+0x436/0x500 fs/ext4/dir.c:111
 ext4_readdir+0xb77/0x1ad0 fs/ext4/dir.c:258
 iterate_dir+0x12c/0x310 fs/readdir.c:110
 __do_sys_getdents64 fs/readdir.c:409 [inline]
 __se_sys_getdents64+0x88/0x1a0 fs/readdir.c:394
 __x64_sys_getdents64+0x43/0x50 fs/readdir.c:394
 x64_sys_call+0x2997/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff883b9b80 of 8 bytes by task 8156 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2269
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2329
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2363
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2373
 __ext4_msg+0x18e/0x1a0 fs/ext4/super.c:1006
 ext4_fill_super+0x1a1e/0x39d0 fs/ext4/super.c:5714
 get_tree_bdev+0x253/0x2e0 fs/super.c:1614
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5731
 vfs_get_tree+0x56/0x1d0 fs/super.c:1779
 do_new_mount+0x227/0x690 fs/namespace.c:3352
 path_mount+0x49b/0xb30 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3875
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3875
 x64_sys_call+0x2591/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000ffffe21d -> 0x726964747365742d

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8156 Comm: syz-executor.0 Not tainted 6.9.0-rc5-syzkaller-00031-g71b1543c83d6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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