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BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff86c79e40 of 8 bytes by interrupt on cpu 1:
 data_alloc+0x2fc/0x380 kernel/printk/printk_ringbuffer.c:1129
 prb_reserve+0x8e3/0xaf0 kernel/printk/printk_ringbuffer.c:1727
 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
 __ext4_msg+0x1aa/0x1c0 fs/ext4/super.c:1001
 print_daily_error_info+0x7a/0x300 fs/ext4/super.c:3697
 call_timer_fn+0x3b/0x240 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x40c/0x5f0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0x31/0x70 kernel/time/timer.c:2405
 handle_softirqs+0xb9/0x280 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x42/0xd0 kernel/softirq.c:735
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x74/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 __mod_memcg_state+0x0/0x280 include/linux/rcupdate.h:-1
 mod_memcg_state mm/memcontrol.c:880 [inline]
 account_kmem_nmi_safe mm/memcontrol.c:3057 [inline]
 obj_cgroup_charge_pages mm/memcontrol.c:3101 [inline]
 __obj_cgroup_charge+0x219/0x230 mm/memcontrol.c:3478
 __memcg_slab_post_alloc_hook+0x492/0x860 mm/memcontrol.c:3607
 memcg_slab_post_alloc_hook mm/slub.c:2475 [inline]
 slab_post_alloc_hook mm/slub.c:4631 [inline]
 slab_alloc_node mm/slub.c:4945 [inline]
 __kmalloc_cache_noprof+0x1f9/0x3d0 mm/slub.c:5511
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1290 [inline]
 push_stack+0x49/0x1d0 kernel/bpf/verifier.c:1754
 check_cond_jmp_op kernel/bpf/verifier.c:16068 [inline]
 do_check_insn+0xa6aa/0xf4b0 kernel/bpf/verifier.c:17297
 do_check kernel/bpf/verifier.c:17446 [inline]
 do_check_common+0x267c/0x2d30 kernel/bpf/verifier.c:18477
 do_check_main+0x3c/0xd0 kernel/bpf/verifier.c:18565
 bpf_check+0x2e05/0x3180 kernel/bpf/verifier.c:19868
 bpf_prog_load+0xfaf/0x1100 kernel/bpf/syscall.c:3197
 __sys_bpf+0xbae/0xc30 kernel/bpf/syscall.c:6418
 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6534 [inline]
 __x64_sys_bpf+0x69/0x80 kernel/bpf/syscall.c:6534
 x64_sys_call+0x10cb/0x3020 arch/x86/include/generated/asm/syscalls_64.h:322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86c79e40 of 16 bytes by task 2970 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:496 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1934 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1982 [inline]
 _prb_read_valid+0x183/0x930 kernel/printk/printk_ringbuffer.c:2173
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2245
 syslog_print+0x199/0x560 kernel/printk/printk.c:1612
 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+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2970 Comm: klogd Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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