syzbot

syz.6.8821[30352] is installing a program with bpf_probe_write_user helper that may corrupt user memory!
syz.6.8821[30352] is installing a program with bpf_probe_write_user helper that may corrupt user memory!
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BUG: KCSAN: data-race in data_push_tail / number

write to 0xffffffff88bc4090 of 1 bytes by task 29 on cpu 1:
 number+0x8b5/0xa90 lib/vsprintf.c:564
 vsnprintf+0xa44/0xe30 lib/vsprintf.c:2869
 vscnprintf+0x42/0x90 lib/vsprintf.c:2909
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2197
 vprintk_store+0x570/0x810 kernel/printk/printk.c:2311
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2383
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2422
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:68
 _printk+0x7a/0xa0 kernel/printk/printk.c:2432
 kauditd_printk_skb kernel/audit.c:546 [inline]
 kauditd_hold_skb+0x1a3/0x1b0 kernel/audit.c:581
 kauditd_send_queue+0x288/0x2e0 kernel/audit.c:766
 kauditd_thread+0x42a/0x650 kernel/audit.c:890
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffffffff88bc4090 of 8 bytes by task 30352 on cpu 0:
 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:2301
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2383
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2422
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:68
 _printk+0x7a/0xa0 kernel/printk/printk.c:2432
 bpf_get_probe_write_proto+0x8b/0x90 kernel/trace/bpf_trace.c:365
 bpf_tracing_func_proto+0x596/0x790 kernel/trace/bpf_trace.c:1466
 raw_tp_prog_func_proto+0x65/0xc0 kernel/trace/bpf_trace.c:1938
 do_misc_fixups kernel/bpf/verifier.c:21227 [inline]
 bpf_check+0x76a1/0xcbf0 kernel/bpf/verifier.c:22457
 bpf_prog_load+0xed4/0x1070 kernel/bpf/syscall.c:2846
 __sys_bpf+0x463/0x7a0 kernel/bpf/syscall.c:5653
 __do_sys_bpf kernel/bpf/syscall.c:5760 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5758 [inline]
 __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5758
 x64_sys_call+0x2914/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000100001e22 -> 0x3428746964756120

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 30352 Comm: syz.6.8821 Not tainted 6.12.0-syzkaller-00971-g158f238aa69d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
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