==================================================================
BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff86877580 of 8 bytes by task 13034 on cpu 0:
 data_alloc+0x274/0x2e0 kernel/printk/printk_ringbuffer.c:1101
 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
 __oom_kill_process+0x45e/0x8d0 mm/oom_kill.c:960
 oom_kill_process+0xf6/0x400 mm/oom_kill.c:1057
 out_of_memory+0x979/0xb80 mm/oom_kill.c:1184
 mem_cgroup_out_of_memory mm/memcontrol.c:1650 [inline]
 mem_cgroup_oom mm/memcontrol.c:1673 [inline]
 try_charge_memcg+0x5e6/0x9e0 mm/memcontrol.c:2397
 try_charge mm/memcontrol.c:2497 [inline]
 charge_memcg+0x51/0xc0 mm/memcontrol.c:4700
 mem_cgroup_swapin_charge_folio+0xcc/0x150 mm/memcontrol.c:4786
 __read_swap_cache_async+0x17b/0x2d0 mm/swap_state.c:481
 swap_cluster_readahead+0x362/0x3c0 mm/swap_state.c:669
 swapin_readahead+0xde/0x6f0 mm/swap_state.c:813
 do_swap_page+0x2ae/0x2370 mm/memory.c:4713
 handle_pte_fault mm/memory.c:6180 [inline]
 __handle_mm_fault mm/memory.c:6318 [inline]
 handle_mm_fault+0x9a5/0x2be0 mm/memory.c:6487
 do_user_addr_fault+0x630/0x1080 arch/x86/mm/fault.c:1336
 handle_page_fault arch/x86/mm/fault.c:1476 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

read to 0xffffffff86877580 of 16 bytes by task 2991 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:479 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1892 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1940 [inline]
 _prb_read_valid+0x1bc/0x920 kernel/printk/printk_ringbuffer.c:2131
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2203
 syslog_print+0x23a/0x540 kernel/printk/printk.c:1623
 do_syslog+0x52b/0x7e0 kernel/printk/printk.c:1758
 __do_sys_syslog kernel/printk/printk.c:1850 [inline]
 __se_sys_syslog kernel/printk/printk.c:1848 [inline]
 __x64_sys_syslog+0x41/0x50 kernel/printk/printk.c:1848
 x64_sys_call+0x2f45/0x3000 arch/x86/include/generated/asm/syscalls_64.h:104
 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: 1 UID: 0 PID: 2991 Comm: klogd Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
==================================================================