[moderation] [kernel?] KCSAN: data-race in hrtimer_reprogram / print_cpu (8)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 98b1cc82c4af Linux 6.7-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=172380a4e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=8c1151391aefc0c3
dashboard link: https://syzkaller.appspot.com/bug?extid=a717c11dbd302d767fe5
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [linux-...@vger.kernel.org tg...@linutronix.de]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b63fb347c844/disk-98b1cc82.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a75961292759/vmlinux-98b1cc82.xz
kernel image: https://storage.googleapis.com/syzbot-assets/52ef29cc01f9/bzImage-98b1cc82.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a717c1...@syzkaller.appspotmail.com

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

write to 0xffff888237c1ede0 of 8 bytes by task 3072 on cpu 0:
__hrtimer_reprogram kernel/time/hrtimer.c:661 [inline]
hrtimer_reprogram+0x1a8/0x220 kernel/time/hrtimer.c:868
hrtimer_start_range_ns+0x4e3/0x660 kernel/time/hrtimer.c:1302
hrtimer_start_expires include/linux/hrtimer.h:432 [inline]
hrtimer_sleeper_start_expires kernel/time/hrtimer.c:1968 [inline]
do_nanosleep+0x85/0x2f0 kernel/time/hrtimer.c:2044
hrtimer_nanosleep kernel/time/hrtimer.c:2100 [inline]
__do_sys_nanosleep kernel/time/hrtimer.c:2135 [inline]
__se_sys_nanosleep+0x20b/0x2e0 kernel/time/hrtimer.c:2121
__x64_sys_nanosleep+0x31/0x40 kernel/time/hrtimer.c:2121
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888237c1ede0 of 8 bytes by task 21370 on cpu 1:
print_cpu+0x2fb/0x640 kernel/time/timer_list.c:133
timer_list_show+0x115/0x180 kernel/time/timer_list.c:291
seq_read_iter+0x612/0x8f0 fs/seq_file.c:272
proc_reg_read_iter+0x114/0x180 fs/proc/inode.c:302
call_read_iter include/linux/fs.h:2014 [inline]
copy_splice_read+0x26b/0x4b0 fs/splice.c:364
vfs_splice_read fs/splice.c:993 [inline]
splice_direct_to_actor+0x28c/0x690 fs/splice.c:1069
do_splice_direct+0x10d/0x190 fs/splice.c:1194
do_sendfile+0x3c4/0x980 fs/read_write.c:1254
__do_sys_sendfile64 fs/read_write.c:1322 [inline]
__se_sys_sendfile64 fs/read_write.c:1308 [inline]
__x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1308
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x000002adb4c1b79e -> 0x000002adb4b78b54

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 21370 Comm: syz-executor.3 Not tainted 6.7.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.