KCSAN: data-race in hrtimer_interrupt / print_cpu (5)

Status: moderation: reported on 2023/12/08 00:04
Subsystems: kernel
Labels: prio:low
[Documentation on labels]
Reported-by: syzbot+8f0e958900a14d08a51d@syzkaller.appspotmail.com
Fix commit: timer_list: Annotate print_cpu() diagnostic reads
Patched on: [ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce], missing on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb]
First crash: 1680d, last: 2d06h
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
fea8f7fa assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ KCSAN: data-race in hrtimer_interrupt / print_cpu (5) 2026/05/23 11:12 2026/05/23 11:12 2026/05/23 11:37 c69befb3

			
		
25881fb6 assessment-kcsan Benign: ✅ Confident: ✅ KCSAN: data-race in hrtimer_interrupt / print_cpu (5) 2026/01/15 05:54 2026/01/15 05:54 2026/01/15 06:17 a9d6a792

			
		
Discussions (1)
Title Replies (including bot) Last reply
[PATCH] timer_list: Annotate print_cpu() diagnostic reads 2 (2) 2026/07/07 21:32
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in hrtimer_interrupt / print_cpu (2) kernel 6 7 2115d 2230d 0/29 auto-closed as invalid on 2020/11/19 01:50
upstream KCSAN: data-race in hrtimer_interrupt / print_cpu (4) kernel 6 44 1721d 1938d 0/29 auto-closed as invalid on 2021/12/18 07:26
upstream KCSAN: data-race in hrtimer_interrupt / print_cpu (3) kernel 6 13 1986d 2057d 0/29 auto-closed as invalid on 2021/03/28 05:11
upstream KCSAN: data-race in hrtimer_interrupt / print_cpu kernel 6 18 2244d 2390d 0/29 closed as invalid on 2020/06/18 14:24

Sample crash report:
loop0: detected capacity change from 0 to 512
==================================================================
BUG: KCSAN: data-race in hrtimer_interrupt / print_cpu

read-write to 0xffff888237c1b758 of 4 bytes by interrupt on cpu 0:
 hrtimer_interrupt+0x5e/0x810 kernel/time/hrtimer.c:2193
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
 __sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1068
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
 sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1062
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
 __sanitizer_cov_trace_pc+0x5c/0x70 kernel/kcov.c:233
 class_preempt_destructor include/linux/preempt.h:468 [inline]
 __migrate_disable include/linux/sched.h:2485 [inline]
 migrate_disable include/linux/sched.h:2500 [inline]
 bpf_disable_instrumentation include/linux/bpf.h:2671 [inline]
 bpf_map_copy_value+0x101/0x500 kernel/bpf/syscall.c:318
 generic_map_lookup_batch+0x5f3/0x910 kernel/bpf/syscall.c:2170
 bpf_map_do_batch+0x1bb/0x380 kernel/bpf/syscall.c:5828
 __sys_bpf+0x955/0xc30 kernel/bpf/syscall.c:-1
 __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 0xffff888237c1b758 of 4 bytes by task 2542 on cpu 1:
 print_cpu+0x346/0x5d0 kernel/time/timer_list.c:131
 timer_list_show+0x107/0x170 kernel/time/timer_list.c:287
 seq_read_iter+0x5f6/0x8f0 fs/seq_file.c:273
 proc_reg_read_iter+0x110/0x180 fs/proc/inode.c:299
 copy_splice_read+0x47a/0x6b0 fs/splice.c:362
 do_splice_read fs/splice.c:980 [inline]
 splice_direct_to_actor+0x261/0x680 fs/splice.c:1084
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x119/0x1a0 fs/splice.c:1228
 do_sendfile+0x37d/0x640 fs/read_write.c:1371
 __do_sys_sendfile64 fs/read_write.c:1432 [inline]
 __se_sys_sendfile64 fs/read_write.c:1418 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1418
 x64_sys_call+0x2dc4/0x3020 arch/x86/include/generated/asm/syscalls_64.h:41
 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

value changed: 0x006543ee -> 0x006543f0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 2542 Comm: syz.0.7394 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
==================================================================

Crashes (318):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/29 17:55 upstream fc02acf6ac0c 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/07/15 20:07 upstream 58717b2a1365 a4ed0f4f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/06/29 21:01 upstream dc59e4fea9d8 6a0c72dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/06/10 13:38 upstream acb7500801e9 f79bac11 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/06/09 10:17 upstream 2d3090a8aeb5 656e94c6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/06/07 11:42 upstream 979c294509f9 cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/05/25 03:21 upstream 6a97c4d5262d c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/05/23 20:10 upstream eed108edc117 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/05/14 05:50 upstream e1914add2799 6ccb967e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/05/12 21:59 upstream c21b90f77687 a0949470 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/05/11 21:56 upstream 5d6919055dec d168f260 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/05/02 03:40 upstream 6fe0be6dc7fa 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/04/28 01:13 upstream 3b3bea6d4b9c ce741359 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/04/26 23:41 upstream 20b64cf8705a 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/04/24 03:10 upstream 45dcf5e28813 9cfb3ca7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/04/08 04:48 upstream 3036cd0d3328 2c961e87 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/03/27 18:04 upstream 46b513250491 74a13a23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/03/16 21:35 upstream 2d1373e4246d 0737c18f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/03/07 04:29 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/03/03 21:44 upstream af4e9ef3d784 4180d919 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/02/27 13:46 upstream 3f4a08e64442 a2f13f71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/02/25 15:17 upstream 7dff99b35460 94a9671e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/02/23 09:37 upstream 6de23f81a5e0 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/02/22 20:25 upstream 32a92f8c8932 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/01/25 11:09 upstream 5dbeeb268b63 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2026/01/17 20:15 upstream d3eeb99bbc99 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/12/24 17:51 upstream b927546677c8 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/12/19 22:22 upstream dd9b004b7ff3 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/12/09 11:45 upstream cfd4039213e7 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/12/04 21:36 upstream 559e608c4655 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/11/26 12:39 upstream 30f09200cc4a 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/11/17 01:16 upstream 7254a2b52279 f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/11/16 08:03 upstream f824272b6e3f f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/11/15 15:37 upstream 7a0892d2836e f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/11/14 22:19 upstream d4f8cccc6230 f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/11/09 11:18 upstream 7bb4d6512545 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/11/07 01:50 upstream c2c2ccfd4ba7 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/26 21:52 upstream dbfc6422a34d c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/24 20:33 upstream 6fab32bb6508 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/23 08:10 upstream 43e9ad0c55a3 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/22 15:22 upstream 552c50713f27 252fbbad .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/21 11:01 upstream 6548d364a3e8 9832ed61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/19 16:47 upstream d9043c79ba68 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/19 02:30 upstream 1c64efcb083c 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/18 18:00 upstream f406055cb18c 1c8c8cd8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/13 11:47 upstream 3a8660878839 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/12 03:02 upstream 67029a49db6c ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/10 17:34 upstream 5472d60c129f ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/09 09:08 upstream cd5a0afbdf80 7e2882b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/10/05 09:11 upstream d104e3d17f7b 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/09/24 22:16 upstream 4ea5af085908 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2025/09/23 14:37 upstream cec1e6e5d1ab 0ac7291c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2023/12/03 01:21 upstream 1b8af6552cb7 f819d6f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
2021/12/24 23:31 upstream b927dfc67d05 6caa12e4 .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in hrtimer_interrupt / print_cpu
* Struck through repros no longer work on HEAD.