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BUG: KCSAN: data-race in _prb_read_valid / prb_reserve_in_last

write to 0xffffffff86e70f88 of 8 bytes by interrupt on cpu 1:
 data_realloc kernel/printk/printk_ringbuffer.c:1227 [inline]
 prb_reserve_in_last+0x975/0xa90 kernel/printk/printk_ringbuffer.c:1494
 vprintk_store+0x45b/0x910 kernel/printk/printk.c:2328
 vprintk_emit+0x1a4/0x580 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
 print_daily_error_info+0x24a/0x300 fs/ext4/super.c:3765
 call_timer_fn+0x36/0x250 kernel/time/timer.c:1749
 expire_timers kernel/time/timer.c:1800 [inline]
 __run_timers kernel/time/timer.c:2375 [inline]
 __run_timer_base+0x40c/0x5f0 kernel/time/timer.c:2387
 run_timer_base kernel/time/timer.c:2396 [inline]
 run_timer_softirq+0x31/0x70 kernel/time/timer.c:2406
 handle_softirqs+0x109/0x310 kernel/softirq.c:669
 __do_softirq kernel/softirq.c:703 [inline]
 invoke_softirq kernel/softirq.c:542 [inline]
 __irq_exit_rcu+0x40/0xf0 kernel/softirq.c:786
 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
 context_switch kernel/sched/core.c:5586 [inline]
 __schedule+0x7a9/0xd40 kernel/sched/core.c:7382
 preempt_schedule_irq+0x2c/0x50 kernel/sched/core.c:7662
 irqentry_exit_cond_resched kernel/entry/common.c:145 [inline]
 irqentry_exit_to_kernel_mode_preempt+0x63/0x80 include/linux/irq-entry-common.h:453
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:543 [inline]
 irqentry_exit+0x7d/0x610 kernel/entry/common.c:154
 sysvec_apic_timer_interrupt+0x44/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 check_kcov_mode kernel/kcov.c:179 [inline]
 write_comp_data kernel/kcov.c:252 [inline]
 __sanitizer_cov_trace_const_cmp4+0x4c/0xb0 kernel/kcov.c:328
 ext4_fc_disabled fs/ext4/fast_commit.c:227 [inline]
 ext4_fc_eligible fs/ext4/fast_commit.c:233 [inline]
 ext4_fc_track_inode+0x98/0x1f0 fs/ext4/fast_commit.c:587
 ext4_mark_iloc_dirty+0xab/0xe30 fs/ext4/inode.c:7404
 ext4_orphan_del+0x6da/0x710 fs/ext4/orphan.c:302
 ext4_truncate+0x62f/0xa50 fs/ext4/inode.c:5535
 ext4_process_orphan+0x10b/0x1c0 fs/ext4/orphan.c:338
 ext4_orphan_cleanup+0x753/0xab0 fs/ext4/orphan.c:473
 __ext4_fill_super fs/ext4/super.c:5769 [inline]
 ext4_fill_super+0x340a/0x37d0 fs/ext4/super.c:5899
 get_tree_bdev_flags+0x297/0x300 fs/super.c:1821
 get_tree_bdev+0x1f/0x30 fs/super.c:1844
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5931
 vfs_get_tree+0x57/0x1d0 fs/super.c:1881
 fc_mount fs/namespace.c:1282 [inline]
 do_new_mount_fc fs/namespace.c:3910 [inline]
 do_new_mount+0x288/0x730 fs/namespace.c:3986
 path_mount+0x4ad/0xba0 fs/namespace.c:4337
 do_mount fs/namespace.c:4350 [inline]
 __do_sys_mount fs/namespace.c:4565 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4542
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4542
 x64_sys_call+0xc3b/0x2550 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86e70f80 of 16 bytes by task 2968 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:495 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1930 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1978 [inline]
 _prb_read_valid+0x193/0x8f0 kernel/printk/printk_ringbuffer.c:2168
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2240
 syslog_print+0x15f/0x550 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+0x1d36/0x2550 arch/x86/include/generated/asm/syscalls_64.h:104
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2968 Comm: klogd Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026
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