syzbot


KCSAN: data-race in __process_echoes / n_tty_write (11)

Status: moderation: reported on 2024/01/24 10:51
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+d0161f5342a1deb36840@syzkaller.appspotmail.com
First crash: 83d, last: 5d01h
Similar bugs (10)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __process_echoes / n_tty_write (9) serial 4 274d 320d 0/26 auto-obsoleted due to no activity on 2023/08/21 10:01
upstream KCSAN: data-race in __process_echoes / n_tty_write serial 3 1339d 1380d 0/26 auto-closed as invalid on 2020/09/20 17:41
upstream KCSAN: data-race in __process_echoes / n_tty_write (3) serial 7 1052d 1117d 0/26 auto-closed as invalid on 2021/07/04 10:36
upstream KCSAN: data-race in __process_echoes / n_tty_write (10) serial 10 128d 128d 0/26 auto-obsoleted due to no activity on 2024/01/14 04:02
upstream KCSAN: data-race in __process_echoes / n_tty_write (4) serial 1 1010d 1010d 0/26 auto-closed as invalid on 2021/08/15 21:06
upstream KCSAN: data-race in __process_echoes / n_tty_write (6) serial 41 561d 856d 0/26 auto-obsoleted due to no activity on 2022/11/07 20:53
upstream KCSAN: data-race in __process_echoes / n_tty_write (2) serial 4 1206d 1226d 0/26 auto-closed as invalid on 2021/01/30 23:25
upstream KCSAN: data-race in __process_echoes / n_tty_write (7) serial 2 505d 505d 0/26 auto-obsoleted due to no activity on 2023/01/13 20:09
upstream KCSAN: data-race in __process_echoes / n_tty_write (5) serial 1 929d 929d 0/26 auto-closed as invalid on 2021/11/04 02:47
upstream KCSAN: data-race in __process_echoes / n_tty_write (8) serial 3 368d 421d 0/26 auto-obsoleted due to no activity on 2023/05/19 15:46

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

write to 0xffffc90000f47280 of 8 bytes by task 49 on cpu 0:
 __process_echoes+0x688/0x6b0 drivers/tty/n_tty.c:746
 flush_echoes drivers/tty/n_tty.c:807 [inline]
 __receive_buf drivers/tty/n_tty.c:1632 [inline]
 n_tty_receive_buf_common+0x8e6/0xbd0 drivers/tty/n_tty.c:1729
 n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1775
 tty_ldisc_receive_buf+0x63/0x100 drivers/tty/tty_buffer.c:387
 tty_port_default_receive_buf+0x59/0x90 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:445 [inline]
 flush_to_ldisc+0x1ce/0x410 drivers/tty/tty_buffer.c:495
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 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 0xffffc90000f47280 of 8 bytes by task 2543 on cpu 1:
 process_echoes drivers/tty/n_tty.c:784 [inline]
 n_tty_write+0x172/0xb90 drivers/tty/n_tty.c:2365
 iterate_tty_write drivers/tty/tty_io.c:1021 [inline]
 file_tty_write+0x386/0x690 drivers/tty/tty_io.c:1096
 tty_write+0x28/0x30 drivers/tty/tty_io.c:1117
 do_iter_readv_writev+0x339/0x3e0
 vfs_writev+0x2e9/0x860 fs/read_write.c:971
 do_writev+0xf8/0x220 fs/read_write.c:1018
 __do_sys_writev fs/read_write.c:1091 [inline]
 __se_sys_writev fs/read_write.c:1088 [inline]
 __x64_sys_writev+0x45/0x50 fs/read_write.c:1088
 x64_sys_call+0x1eca/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:21
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000042fe -> 0x0000000000004306

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2543 Comm: syz-executor.2 Tainted: G        W          6.9.0-rc3-syzkaller-00073-ge8c39d0f57f3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/11 20:06 upstream e8c39d0f57f3 95ed9ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/03/24 20:16 upstream 70293240c5ce 0ea90952 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/03/19 09:17 upstream b3603fcb79b1 baa80228 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/03/18 23:56 upstream f6cef5f8c37f baa80228 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/03/05 00:33 upstream 90d35da658da 5fc53669 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/03/03 22:52 upstream 58c806d867bf 25905f5d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/02/24 13:27 upstream 603c04e27c3e 8d446f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/02/23 15:17 upstream ffd2cb6b718e 8d446f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/02/16 06:28 upstream 4f5e5092fdbf 578f7538 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/02/12 22:19 upstream 716f4aaa7b48 77b23aa1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/02/11 18:17 upstream 7521f258ea30 77b23aa1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/02/10 16:47 upstream 4a7bbe7519b6 77b23aa1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
2024/01/24 10:51 upstream 615d30064886 1e153dc8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __process_echoes / n_tty_write
* Struck through repros no longer work on HEAD.