syzbot

==================================================================
BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

read-write to 0xffff888237d1b854 of 4 bytes by interrupt on cpu 1:
 hrtimer_interrupt+0x70/0x460 kernel/time/hrtimer.c:1881
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1d0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
 should_watch kernel/kcsan/core.c:280 [inline]
 check_access kernel/kcsan/core.c:752 [inline]
 __tsan_read8+0x118/0x190 kernel/kcsan/core.c:1025
 wp_page_copy mm/memory.c:3786 [inline]
 do_wp_page+0x1532/0x2510 mm/memory.c:4180
 handle_pte_fault mm/memory.c:6289 [inline]
 __handle_mm_fault mm/memory.c:6411 [inline]
 handle_mm_fault+0x7b0/0x2c60 mm/memory.c:6580
 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:618

read to 0xffff888237d1b854 of 4 bytes by task 9475 on cpu 0:
 print_cpu+0x338/0x660 kernel/time/timer_list.c:133
 timer_list_show+0x107/0x170 kernel/time/timer_list.c:293
 seq_read_iter+0x31e/0x950 fs/seq_file.c:230
 proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
 copy_splice_read+0x442/0x660 fs/splice.c:363
 do_splice_read fs/splice.c:982 [inline]
 splice_direct_to_actor+0x26f/0x680 fs/splice.c:1086
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1230
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0x2db1/0x3000 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd8/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0009a115 -> 0x0009a118

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 9475 Comm: syz.4.2040 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================
netlink: 64 bytes leftover after parsing attributes in process `syz.4.2040'.
loop4: detected capacity change from 0 to 1024
EXT4-fs (loop4): stripe (65535) is not aligned with cluster size (4096), stripe is disabled
EXT4-fs error (device loop4): ext4_map_blocks:825: inode #3: block 1: comm syz.4.2040: lblock 1 mapped to illegal pblock 1 (length 1)
EXT4-fs error (device loop4): ext4_acquire_dquot:6986: comm syz.4.2040: Failed to acquire dquot type 0
EXT4-fs error (device loop4): ext4_free_blocks:6728: comm syz.4.2040: Freeing blocks not in datazone - block = 0, count = 4096
EXT4-fs error (device loop4): ext4_read_inode_bitmap:139: comm syz.4.2040: Invalid inode bitmap blk 0 in block_group 0
EXT4-fs error (device loop4) in ext4_free_inode:361: Corrupt filesystem
EXT4-fs (loop4): 1 orphan inode deleted
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.