syzbot


KCSAN: data-race in print_cpu / tick_nohz_stop_idle (3)

Status: moderation: reported on 2024/04/21 02:19
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+8f03f7153a596ac6fb8b@syzkaller.appspotmail.com
First crash: 37d, last: 29d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in print_cpu / tick_nohz_stop_idle (2) kernel 2 283d 289d 0/26 auto-obsoleted due to no activity on 2023/09/22 19:10
upstream KCSAN: data-race in print_cpu / tick_nohz_stop_idle kernel 1 386d 386d 0/26 auto-obsoleted due to no activity on 2023/06/11 20:07

Sample crash report:
==================================================================
BUG: KCSAN: data-race in print_cpu / tick_nohz_stop_idle

read-write to 0xffff888237d204b8 of 8 bytes by interrupt on cpu 1:
 tick_sched_flag_clear kernel/time/tick-sched.c:201 [inline]
 tick_nohz_stop_idle+0xd0/0x110 kernel/time/tick-sched.c:741
 tick_nohz_irq_enter kernel/time/tick-sched.c:1541 [inline]
 tick_irq_enter+0xa2/0x150 kernel/time/tick-sched.c:1567
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x66/0x80 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
 arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
 acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112
 acpi_idle_do_entry+0x1d/0x30 drivers/acpi/processor_idle.c:573
 acpi_idle_enter+0x96/0xb0 drivers/acpi/processor_idle.c:707
 cpuidle_enter_state+0xcf/0x270 drivers/cpuidle/cpuidle.c:267
 cpuidle_enter+0x40/0x70 drivers/cpuidle/cpuidle.c:388
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:236 [inline]
 do_idle+0x195/0x230 kernel/sched/idle.c:332
 cpu_startup_entry+0x25/0x30 kernel/sched/idle.c:430
 start_secondary+0x94/0xa0 arch/x86/kernel/smpboot.c:313
 common_startup_64+0x12c/0x137

read to 0xffff888237d204b8 of 8 bytes by task 14197 on cpu 0:
 print_cpu+0x44e/0x670 kernel/time/timer_list.c:158
 timer_list_show+0x115/0x180 kernel/time/timer_list.c:295
 seq_read_iter+0x65b/0x940 fs/seq_file.c:272
 proc_reg_read_iter+0x11e/0x190 fs/proc/inode.c:299
 call_read_iter include/linux/fs.h:2104 [inline]
 copy_splice_read+0x3a4/0x5d0 fs/splice.c:365
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x26c/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3b9/0x970 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0x2c67/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000000003d -> 0x0000000000000038

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14197 Comm: syz-executor.3 Tainted: G        W          6.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/29 13:34 upstream e67572cd2204 27e33c58 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in print_cpu / tick_nohz_stop_idle
2024/04/23 08:50 upstream 71b1543c83d6 21339d7b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in print_cpu / tick_nohz_stop_idle
2024/04/21 02:19 upstream 977b1ef51866 af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in print_cpu / tick_nohz_stop_idle
* Struck through repros no longer work on HEAD.