syzbot


KCSAN: data-race in n_tty_receive_char / n_tty_write (6)

Status: moderation: reported on 2023/12/07 10:05
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+b9fb1de8724719df2e7e@syzkaller.appspotmail.com
First crash: 203d, last: 8h51m
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in n_tty_receive_char / n_tty_write (4) serial 1 314d 314d 0/26 auto-obsoleted due to no activity on 2023/05/20 17:17
upstream KCSAN: data-race in n_tty_receive_char / n_tty_write (3) serial 5 372d 414d 0/26 auto-obsoleted due to no activity on 2023/03/30 21:01
upstream KCSAN: data-race in n_tty_receive_char / n_tty_write (2) serial 13 461d 602d 0/26 auto-obsoleted due to no activity on 2022/12/30 17:18
upstream KCSAN: data-race in n_tty_receive_char / n_tty_write serial 25 637d 901d 0/26 auto-closed as invalid on 2022/06/30 23:55
upstream KCSAN: data-race in n_tty_receive_char / n_tty_write (5) serial 3 239d 263d 0/26 auto-obsoleted due to no activity on 2023/08/03 17:30

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

write to 0xffffc9000cd31028 of 8 bytes by task 21855 on cpu 0:
 commit_echoes drivers/tty/n_tty.c:758 [inline]
 n_tty_receive_char+0x4be/0x670 drivers/tty/n_tty.c:1437
 n_tty_receive_buf_standard+0x4bd/0x2e20 drivers/tty/n_tty.c:1606
 __receive_buf drivers/tty/n_tty.c:1630 [inline]
 n_tty_receive_buf_common+0x7e5/0xbc0 drivers/tty/n_tty.c:1729
 n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1775
 tty_ldisc_receive_buf+0x60/0xe0 drivers/tty/tty_buffer.c:386
 tty_port_default_receive_buf+0x59/0x90 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:444 [inline]
 flush_to_ldisc+0x1ca/0x400 drivers/tty/tty_buffer.c:494
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x5b8/0xa40 kernel/workqueue.c:2706
 worker_thread+0x525/0x730 kernel/workqueue.c:2787
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

read to 0xffffc9000cd31028 of 8 bytes by task 14557 on cpu 1:
 process_echoes drivers/tty/n_tty.c:784 [inline]
 n_tty_write+0x161/0xb60 drivers/tty/n_tty.c:2365
 iterate_tty_write drivers/tty/tty_io.c:1021 [inline]
 file_tty_write+0x382/0x680 drivers/tty/tty_io.c:1096
 tty_write+0x28/0x30 drivers/tty/tty_io.c:1117
 do_iter_readv_writev+0x2b0/0x330
 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
 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+0x63/0x6b

value changed: 0x0000000000000006 -> 0x0000000000000013

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14557 Comm: syz-executor.4 Not tainted 6.8.0-rc5-syzkaller-00163-gffd2cb6b718e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================

Crashes (25):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/23 12:47 upstream ffd2cb6b718e 8d446f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2024/02/21 20:21 upstream 39133352cbed 345111b5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2024/02/02 02:25 upstream 5c24e4e9e708 d61103fc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2024/01/30 05:56 upstream 861c0981648f 991a98f4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2024/01/10 18:08 upstream ab27740f7665 04815ef1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2024/01/09 20:04 upstream 9f8413c4a66f 4807fb37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2024/01/05 19:02 upstream 1f874787ed9a 28c42cff .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2024/01/03 07:33 upstream 610a9b8f49fb fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/12/26 03:41 upstream fbafc3e621c3 fb427a07 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/12/22 09:31 upstream 9a6b294ab496 4f9530a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/12/19 02:28 upstream 2cf4f94d8e86 924661f4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/12/16 08:11 upstream 3bd7d7488169 3222d10c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/11/14 01:43 upstream 9bacdd8996c7 cb976f63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/11/09 08:37 upstream 6bc986ab839c 4862372a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/10/23 07:33 upstream 05d3ef8bba77 361b23dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/10/16 06:31 upstream fbe1bf1e5ff1 f757a323 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/10/12 16:07 upstream 401644852d0b 1b231e3c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/10/01 23:41 upstream e81a2dabc3f3 8e26a358 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/09/12 06:49 upstream 0bb80ecc33a8 59da8366 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/09/05 18:14 upstream 3f86ed6ec0b3 0b6286dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/08/25 16:17 upstream 4f9e7fabf864 03d9c195 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/08/14 15:46 upstream 2ccdd1b13c59 39990d51 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/08/07 11:54 upstream 52a93d39b17d 0ef3dfda .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/08/04 14:59 upstream c1a515d3c027 74621247 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
2023/08/04 01:04 upstream 7bafbd4027ae 74621247 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in n_tty_receive_char / n_tty_write
* Struck through repros no longer work on HEAD.