BUG: KCSAN: data-race in data_alloc / data_push_tail write to 0xffffffff88e514f0 of 8 bytes by task 11916 on cpu 1: data_alloc+0x1d5/0x2e0 kernel/printk/printk_ringbuffer.c:1088 prb_reserve+0x807/0xaf0 kernel/printk/printk_ringbuffer.c:1685 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2299 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2448 printk_stack_address arch/x86/kernel/dumpstack.c:70 [inline] show_trace_log_lvl+0x4e3/0x560 arch/x86/kernel/dumpstack.c:282 __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0xe8/0x140 lib/dump_stack.c:120 dump_stack+0x15/0x1b lib/dump_stack.c:129 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x265/0x280 lib/fault-inject.c:174 should_fail+0xb/0x20 lib/fault-inject.c:184 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:35 _inline_copy_from_user include/linux/uaccess.h:163 [inline] _copy_from_user+0x1c/0xb0 lib/usercopy.c:18 copy_from_user include/linux/uaccess.h:212 [inline] copy_msghdr_from_user net/socket.c:2560 [inline] recvmsg_copy_msghdr net/socket.c:2816 [inline] ___sys_recvmsg+0xaa/0x370 net/socket.c:2888 do_recvmmsg+0x1ef/0x540 net/socket.c:2987 __sys_recvmmsg net/socket.c:3061 [inline] __do_sys_recvmmsg net/socket.c:3084 [inline] __se_sys_recvmmsg net/socket.c:3077 [inline] __x64_sys_recvmmsg+0xe5/0x170 net/socket.c:3077 x64_sys_call+0x27aa/0x3000 arch/x86/include/generated/asm/syscalls_64.h:300 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 0xffffffff88e514f0 of 8 bytes by task 29 on cpu 0: data_make_reusable kernel/printk/printk_ringbuffer.c:591 [inline] data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:676 data_alloc+0xfb/0x2e0 kernel/printk/printk_ringbuffer.c:1061 prb_reserve+0x807/0xaf0 kernel/printk/printk_ringbuffer.c:1685 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2299 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2448 kauditd_printk_skb kernel/audit.c:583 [inline] kauditd_hold_skb+0x1b1/0x1c0 kernel/audit.c:618 kauditd_send_queue+0x273/0x2c0 kernel/audit.c:803 kauditd_thread+0x421/0x630 kernel/audit.c:927 kthread+0x489/0x510 kernel/kthread.c:463 ret_from_fork+0x122/0x1b0 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 value changed: 0x00000000ffffeeb8 -> 0x00000000fffffb65 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 29 Comm: kauditd Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 ================================================================== audit: type=1326 audit(1763737161.928:23623): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=11917 comm="syz.2.3216" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7faa0691f749 code=0x7ffc0000 audit: type=1326 audit(1763737161.928:23624): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=11917 comm="syz.2.3216" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7faa0691f749 code=0x7ffc0000 audit: type=1326 audit(1763737161.928:23625): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=11917 comm="syz.2.3216" exe="/root/syz-executor" sig=0 arch=c000003e syscall=321 compat=0 ip=0x7faa0691f749 code=0x7ffc0000 audit: type=1326 audit(1763737161.928:23626): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=11917 comm="syz.2.3216" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7faa0691f749 code=0x7ffc0000 audit: type=1326 audit(1763737161.928:23627): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=11917 comm="syz.2.3216" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7faa0691f749 code=0x7ffc0000 audit: type=1326 audit(1763737161.928:23628): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=11917 comm="syz.2.3216" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7faa0691f749 code=0x7ffc0000 audit: type=1326 audit(1763737161.928:23629): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=11917 comm="syz.2.3216" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7faa0691f749 code=0x7ffc0000 audit: type=1326 audit(1763737161.928:23630): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=11917 comm="syz.2.3216" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7faa0691f749 code=0x7ffc0000 audit: type=1326 audit(1763737161.928:23631): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=11917 comm="syz.2.3216" exe="/root/syz-executor" sig=0 arch=c000003e syscall=321 compat=0 ip=0x7faa0691f749 code=0x7ffc0000