[moderation] [fs?] KCSAN: data-race in do_select / pollwake (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7475e51b8796 Merge tag 'net-6.7-rc2' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16c0923f680000
kernel config: https://syzkaller.appspot.com/x/.config?x=a91f789b98394377
dashboard link: https://syzkaller.appspot.com/bug?extid=98a4e3481a6349deaf03
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [bra...@kernel.org linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bbddf75380f9/disk-7475e51b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/48dc989cfad1/vmlinux-7475e51b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1245c85c200f/bzImage-7475e51b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+98a4e3...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in do_select / pollwake

read to 0xffffc9000b0b7a70 of 4 bytes by task 29874 on cpu 1:
poll_schedule_timeout fs/select.c:243 [inline]
do_select+0xea9/0xf90 fs/select.c:607
core_sys_select+0x361/0x520 fs/select.c:681
kern_select fs/select.c:722 [inline]
__do_sys_select fs/select.c:729 [inline]
__se_sys_select+0x1c7/0x200 fs/select.c:726
__x64_sys_select+0x67/0x80 fs/select.c:726
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

write to 0xffffc9000b0b7a70 of 4 bytes by task 29897 on cpu 0:
__pollwake fs/select.c:198 [inline]
pollwake+0xbe/0x110 fs/select.c:218
__wake_up_common kernel/sched/wait.c:89 [inline]
__wake_up_common_lock kernel/sched/wait.c:106 [inline]
__wake_up+0x64/0xa0 kernel/sched/wait.c:127
n_tty_set_termios+0x82b/0x840 drivers/tty/n_tty.c:1870
tty_set_termios+0x843/0x8a0 drivers/tty/tty_ioctl.c:352
set_termios+0x355/0x4c0 drivers/tty/tty_ioctl.c:520
tty_mode_ioctl+0x3e1/0x590
n_tty_ioctl_helper+0x8d/0x240 drivers/tty/tty_ioctl.c:986
n_tty_ioctl+0xfd/0x200 drivers/tty/n_tty.c:2511
tty_ioctl+0x875/0xbc0 drivers/tty/tty_io.c:2789
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xcf/0x140 fs/ioctl.c:857
__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
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: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29897 Comm: syz-executor.0 Not tainted 6.7.0-rc1-syzkaller-00125-g7475e51b8796 #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