syzbot


KCSAN: data-race in rtc_dev_poll / rtc_pie_update_irq (4)

Status: moderation: reported on 2024/07/05 01:42
Subsystems: rtc
[Documentation on labels]
Reported-by: syzbot+89edf423b09b68ecc7a6@syzkaller.appspotmail.com
First crash: 14d, last: 14d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in rtc_dev_poll / rtc_pie_update_irq (2) rtc 1 918d 918d 0/27 auto-closed as invalid on 2022/02/16 06:16
upstream KCSAN: data-race in rtc_dev_poll / rtc_pie_update_irq rtc 1 1042d 1042d 0/27 auto-closed as invalid on 2021/10/16 01:04
upstream KCSAN: data-race in rtc_dev_poll / rtc_pie_update_irq (3) rtc 1 82d 82d 0/27 auto-obsoleted due to no activity on 2024/06/01 19:35

Sample crash report:
==================================================================
BUG: KCSAN: data-race in rtc_dev_poll / rtc_pie_update_irq

read-write to 0xffff888102b3eb88 of 8 bytes by interrupt on cpu 1:
 rtc_handle_legacy_irq drivers/rtc/interface.c:623 [inline]
 rtc_pie_update_irq+0x95/0xf0 drivers/rtc/interface.c:671
 __run_hrtimer kernel/time/hrtimer.c:1689 [inline]
 __hrtimer_run_queues+0x20d/0x5e0 kernel/time/hrtimer.c:1753
 hrtimer_interrupt+0x210/0x7b0 kernel/time/hrtimer.c:1815
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline]
 __sysvec_apic_timer_interrupt+0x5c/0x1a0 arch/x86/kernel/apic/apic.c:1049
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0x6e/0x80 arch/x86/kernel/apic/apic.c:1043
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
 check_kcov_mode kernel/kcov.c:175 [inline]
 __sanitizer_cov_trace_pc+0x37/0x70 kernel/kcov.c:207
 inet_twsk_purge+0x326/0x380 net/ipv4/inet_timewait_sock.c:276
 dccp_v4_exit_batch+0x15/0x20 net/dccp/ipv4.c:1047
 ops_exit_list net/core/net_namespace.c:178 [inline]
 cleanup_net+0x4cf/0x830 net/core/net_namespace.c:640
 process_one_work kernel/workqueue.c:3248 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3329
 worker_thread+0x526/0x720 kernel/workqueue.c:3409
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffff888102b3eb88 of 8 bytes by task 11945 on cpu 0:
 rtc_dev_poll+0x7c/0xb0 drivers/rtc/dev.c:198
 vfs_poll include/linux/poll.h:84 [inline]
 do_pollfd fs/select.c:873 [inline]
 do_poll fs/select.c:921 [inline]
 do_sys_poll+0x644/0xc10 fs/select.c:1016
 __do_sys_ppoll fs/select.c:1122 [inline]
 __se_sys_ppoll+0x1af/0x1f0 fs/select.c:1102
 __x64_sys_ppoll+0x67/0x80 fs/select.c:1102
 x64_sys_call+0xeaf/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:272
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x000000000000c5c0 -> 0x000000000000c6c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11945 Comm: syz.1.2230 Not tainted 6.10.0-rc6-syzkaller-00163-g661e504db04c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/07/05 01:41 upstream 661e504db04c 3f2748a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in rtc_dev_poll / rtc_pie_update_irq
* Struck through repros no longer work on HEAD.