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KCSAN: data-race in n_tty_receive_char / n_tty_write (8)

Status: auto-obsoleted due to no activity on 2024/11/22 07:31
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+42a0b6a4eb0bccdfaf51@syzkaller.appspotmail.com
First crash: 48d, last: 48d
Similar bugs (7)
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 600d 600d 0/28 auto-obsoleted due to no activity on 2023/05/20 17:17
upstream KCSAN: data-race in n_tty_receive_char / n_tty_write (6) serial 28 231d 364d 0/28 auto-obsoleted due to no activity on 2024/05/23 04:54
upstream KCSAN: data-race in n_tty_receive_char / n_tty_write (3) serial 5 658d 700d 0/28 auto-obsoleted due to no activity on 2023/03/30 21:01
upstream KCSAN: data-race in n_tty_receive_char / n_tty_write (7) serial 6 91d 186d 0/28 auto-obsoleted due to no activity on 2024/10/10 09:15
upstream KCSAN: data-race in n_tty_receive_char / n_tty_write (2) serial 13 747d 888d 0/28 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 923d 1187d 0/28 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 525d 549d 0/28 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 0xffffc9001a983028 of 8 bytes by task 1272 on cpu 1:
 commit_echoes drivers/tty/n_tty.c:758 [inline]
 n_tty_receive_char+0x4c4/0x680 drivers/tty/n_tty.c:1437
 n_tty_receive_buf_standard+0x4bd/0x2e30 drivers/tty/n_tty.c:1606
 __receive_buf drivers/tty/n_tty.c:1640 [inline]
 n_tty_receive_buf_common+0x83a/0xbe0 drivers/tty/n_tty.c:1739
 n_tty_receive_buf2+0x33/0x40 drivers/tty/n_tty.c:1785
 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:3229 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3310
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3391
 kthread+0x1d1/0x210 kernel/kthread.c:389
 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 0xffffc9001a983028 of 8 bytes by task 14554 on cpu 0:
 process_echoes drivers/tty/n_tty.c:784 [inline]
 n_tty_write+0x15c/0xb80 drivers/tty/n_tty.c:2375
 iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
 file_tty_write+0x37a/0x680 drivers/tty/tty_io.c:1090
 tty_write+0x28/0x30 drivers/tty/tty_io.c:1111
 new_sync_write fs/read_write.c:590 [inline]
 vfs_write+0x76a/0x910 fs/read_write.c:683
 ksys_write+0xeb/0x1b0 fs/read_write.c:736
 __do_sys_write fs/read_write.c:748 [inline]
 __se_sys_write fs/read_write.c:745 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:745
 x64_sys_call+0x27dd/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000007 -> 0x0000000000000008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 14554 Comm: syz.0.2495 Not tainted 6.12.0-rc3-syzkaller-00183-g6efbea77b390 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/10/18 07:31 upstream 6efbea77b390 666f77ed .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.