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KCSAN: data-race in commit_echoes / echo_char (2)

Status: closed as invalid on 2020/06/18 14:24
Subsystems: serial
[Documentation on labels]
First crash: 1568d, last: 1380d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in commit_echoes / echo_char serial 1 1603d 1603d 0/26 closed as invalid on 2019/11/19 14:04

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

write to 0xffffc90003a85018 of 8 bytes by task 17035 on cpu 0:
 add_echo_byte drivers/tty/n_tty.c:845 [inline]
 echo_char+0x148/0x1b0 drivers/tty/n_tty.c:948
 n_tty_receive_char_fast drivers/tty/n_tty.c:1448 [inline]
 n_tty_receive_buf_fast drivers/tty/n_tty.c:1609 [inline]
 __receive_buf drivers/tty/n_tty.c:1644 [inline]
 n_tty_receive_buf_common+0x16d4/0x1a40 drivers/tty/n_tty.c:1742
 n_tty_receive_buf+0x36/0x50 drivers/tty/n_tty.c:1771
 tiocsti drivers/tty/tty_io.c:2196 [inline]
 tty_ioctl+0xaf4/0xd80 drivers/tty/tty_io.c:2572
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x101/0x150 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x47/0x60 fs/ioctl.c:770
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffc90003a85018 of 8 bytes by task 3498 on cpu 1:
 commit_echoes+0x51/0x160 drivers/tty/n_tty.c:779
 n_tty_receive_char_fast drivers/tty/n_tty.c:1449 [inline]
 n_tty_receive_buf_fast drivers/tty/n_tty.c:1609 [inline]
 __receive_buf drivers/tty/n_tty.c:1644 [inline]
 n_tty_receive_buf_common+0x16dc/0x1a40 drivers/tty/n_tty.c:1742
 n_tty_receive_buf2+0x39/0x50 drivers/tty/n_tty.c:1777
 tty_ldisc_receive_buf+0x69/0xe0 drivers/tty/tty_buffer.c:461
 tty_port_default_receive_buf+0x82/0xd0 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x1dd/0x260 drivers/tty/tty_buffer.c:533
 process_one_work+0x424/0x930 kernel/workqueue.c:2268
 worker_thread+0x9a/0x7e0 kernel/workqueue.c:2414
 kthread+0x203/0x230 kernel/kthread.c:268
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3498 Comm: kworker/u4:4 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound flush_to_ldisc
==================================================================

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/17 19:17 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 b6c46f43 .config console log report ci2-upstream-kcsan-gce
2020/04/17 10:41 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 18397578 .config console log report ci2-upstream-kcsan-gce
2020/03/07 12:09 https://github.com/google/ktsan.git kcsan 941e0d917bbf 2e9971bb .config console log report ci2-upstream-kcsan-gce
2020/01/12 13:53 https://github.com/google/ktsan.git kcsan 245a43005292 31290a45 .config console log report ci2-upstream-kcsan-gce
2020/01/06 20:01 https://github.com/google/ktsan.git kcsan 245a43005292 53430d97 .config console log report ci2-upstream-kcsan-gce
2019/12/12 20:18 https://github.com/google/ktsan.git kcsan ef798c30ba4e 08003f64 .config console log report ci2-upstream-kcsan-gce
2019/12/12 06:14 https://github.com/google/ktsan.git kcsan ef798c30ba4e d973f528 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.