syzbot


KCSAN: data-race in vcs_poll_data_get / vcs_poll_data_get

Status: moderation: reported on 2024/03/20 06:11
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+50d654bcd3a74a3dab85@syzkaller.appspotmail.com
First crash: 32d, last: 32d

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

write to 0xffff888124e74dc8 of 8 bytes by task 26279 on cpu 1:
 vcs_poll_data_get+0x15e/0x170 drivers/tty/vt/vc_screen.c:163
 vcs_poll+0x20/0xe0 drivers/tty/vt/vc_screen.c:714
 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
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff888124e74dc8 of 8 bytes by task 26278 on cpu 0:
 vcs_poll_data_get+0x1f/0x170 drivers/tty/vt/vc_screen.c:128
 vcs_poll+0x20/0xe0 drivers/tty/vt/vc_screen.c:714
 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
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0x0000000000000000 -> 0xffff88815b4bdf00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26278 Comm: syz-executor.1 Not tainted 6.8.0-syzkaller-11743-ga4145ce1e7bc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/20 06:10 upstream a4145ce1e7bc a485f239 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in vcs_poll_data_get / vcs_poll_data_get
* Struck through repros no longer work on HEAD.