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BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff86c7a1e8 of 8 bytes by task 16205 on cpu 0:
 data_alloc+0x310/0x390 kernel/printk/printk_ringbuffer.c:1129
 prb_reserve+0x8d7/0xae0 kernel/printk/printk_ringbuffer.c:1724
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354
 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 seq_buf_do_printk+0x113/0x1a0 lib/seq_buf.c:126
 mem_cgroup_print_oom_meminfo+0x17d/0x260 mm/memcontrol.c:1617
 dump_header+0xa2/0x240 mm/oom_kill.c:469
 oom_kill_process+0x295/0x350 mm/oom_kill.c:1047
 out_of_memory+0x97d/0xb80 mm/oom_kill.c:1185
 mem_cgroup_out_of_memory mm/memcontrol.c:1695 [inline]
 mem_cgroup_oom mm/memcontrol.c:1718 [inline]
 try_charge_memcg+0x62e/0xa10 mm/memcontrol.c:2456
 try_charge mm/memcontrol.c:2556 [inline]
 charge_memcg mm/memcontrol.c:4744 [inline]
 mem_cgroup_swapin_charge_folio+0x103/0x1f0 mm/memcontrol.c:4830
 __swap_cache_prepare_and_add+0x386/0x530 mm/swap_state.c:517
 swap_cache_alloc_folio+0xa2/0x120 mm/swap_state.c:575
 swap_cluster_readahead+0x36b/0x3d0 mm/swap_state.c:768
 swapin_readahead+0xde/0x840 mm/swap_state.c:924
 do_swap_page+0x30d/0x2220 mm/memory.c:4802
 handle_pte_fault mm/memory.c:6320 [inline]
 __handle_mm_fault mm/memory.c:6455 [inline]
 handle_mm_fault+0xb40/0x3020 mm/memory.c:6624
 do_user_addr_fault+0x62f/0x1050 arch/x86/mm/fault.c:1334
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

read to 0xffffffff86c7a1e8 of 16 bytes by task 2990 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:496 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1931 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1979 [inline]
 _prb_read_valid+0x1bc/0x950 kernel/printk/printk_ringbuffer.c:2170
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2242
 syslog_print+0x258/0x560 kernel/printk/printk.c:1628
 do_syslog+0x52b/0x7f0 kernel/printk/printk.c:1763
 __do_sys_syslog kernel/printk/printk.c:1855 [inline]
 __se_sys_syslog kernel/printk/printk.c:1853 [inline]
 __x64_sys_syslog+0x41/0x50 kernel/printk/printk.c:1853
 x64_sys_call+0x2b9e/0x3020 arch/x86/include/generated/asm/syscalls_64.h:104
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 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: 2990 Comm: klogd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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