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

write to 0xffffffff86ac32f8 of 88 bytes by task 13334 on cpu 0:
 prb_reserve+0x6e6/0xae0 kernel/printk/printk_ringbuffer.c:1690
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2302
 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2402
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2441
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2451
 seq_buf_do_printk+0x113/0x1a0 lib/seq_buf.c:126
 mem_cgroup_print_oom_meminfo+0x17d/0x260 mm/memcontrol.c:1599
 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:1682 [inline]
 mem_cgroup_oom mm/memcontrol.c:1705 [inline]
 try_charge_memcg+0x62e/0xa10 mm/memcontrol.c:2430
 try_charge mm/memcontrol.c:2530 [inline]
 charge_memcg mm/memcontrol.c:4728 [inline]
 __mem_cgroup_charge+0x65/0x150 mm/memcontrol.c:4745
 mem_cgroup_charge include/linux/memcontrol.h:663 [inline]
 filemap_add_folio+0x110/0x350 mm/filemap.c:959
 __filemap_get_folio_mpol+0x326/0x680 mm/filemap.c:2016
 __filemap_get_folio include/linux/pagemap.h:774 [inline]
 filemap_fault+0x473/0xbb0 mm/filemap.c:3559
 __do_fault+0xbc/0x200 mm/memory.c:5323
 do_read_fault mm/memory.c:5758 [inline]
 do_fault mm/memory.c:5892 [inline]
 do_pte_missing mm/memory.c:4404 [inline]
 handle_pte_fault mm/memory.c:6276 [inline]
 __handle_mm_fault mm/memory.c:6414 [inline]
 handle_mm_fault+0x11d7/0x3030 mm/memory.c:6583
 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 0xffffffff86ac32f8 of 8 bytes by task 2991 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:500 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1931 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1979 [inline]
 _prb_read_valid+0x1c4/0x950 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:1626
 do_syslog+0x52b/0x7f0 kernel/printk/printk.c:1761
 __do_sys_syslog kernel/printk/printk.c:1853 [inline]
 __se_sys_syslog kernel/printk/printk.c:1851 [inline]
 __x64_sys_syslog+0x41/0x50 kernel/printk/printk.c:1851
 x64_sys_call+0x27ce/0x3000 arch/x86/include/generated/asm/syscalls_64.h:104
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc0/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000027d1 -> 0x00000000000047d1

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2991 Comm: klogd Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================