syzbot


general protection fault in n_tty_receive_buf_common (4)

Status: premoderation: reported on 2026/07/03 11:01
Reported-by: syzbot+152a17154b94a1e2f981@syzkaller.appspotmail.com
First crash: 6d16h, last: 6d16h
Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KMSAN: uninit-value in n_tty_receive_buf_common (2) serial 7 C 591 1086d 1667d 0/29 auto-obsoleted due to no activity on 2023/09/27 16:27
android-6-1 general protection fault in n_tty_receive_buf_common (3) 2 2 129d 207d 0/2 auto-obsoleted due to no activity on 2026/05/31 21:53
linux-6.1 general protection fault in n_tty_receive_buf_common 2 1 614d 614d 0/3 auto-obsoleted due to no activity on 2025/02/10 03:23
upstream general protection fault in n_tty_receive_buf_common (2) serial 2 21 266d 714d 0/29 auto-obsoleted due to no activity on 2026/01/24 04:46
android-6-1 general protection fault in n_tty_receive_buf_common 2 1 868d 868d 0/2 auto-obsoleted due to no activity on 2024/05/22 15:27
upstream general protection fault in n_tty_receive_buf_common serial 2 48 2794d 3177d 0/29 closed as dup on 2018/07/17 10:20
android-6-1 general protection fault in n_tty_receive_buf_common (2) 2 4 647d 718d 0/2 auto-obsoleted due to no activity on 2024/12/29 18:01

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc000000044c: 0000 [#1] PREEMPT SMP KASAN
KASAN: probably user-memory-access in range [0x0000000000002260-0x0000000000002267]
CPU: 1 PID: 43 Comm: kworker/u4:2 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: events_unbound flush_to_ldisc
RIP: 0010:n_tty_receive_buf_common+0x176/0x1340 drivers/tty/n_tty.c:1700
Code: 89 85 c8 fe ff ff 48 89 8d 40 ff ff ff 48 c1 e9 03 48 89 8d 08 ff ff ff 4c 89 75 b8 48 89 9d 58 ff ff ff 48 8b 85 b8 fe ff ff <42> 80 3c 28 00 74 0c 48 8b bd c0 fe ff ff e8 07 1a f7 fe 4d 8b be
RSP: 0018:ffffc900002cfa78 EFLAGS: 00010203

RAX: 000000000000044c RBX: ffff8881197559f8 RCX: 000000000000000b
RDX: 000000000000005d RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900002cfbd8 R08: ffff8881197558ff R09: 1ffff110232eab1f
R10: dffffc0000000000 R11: ffffed10232eab20 R12: ffff88811379882a
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff110232eab2c
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f55a1ccd170 CR3: 000000010990c000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 n_tty_receive_buf2+0x31/0x40 drivers/tty/n_tty.c:1767
 tty_ldisc_receive_buf+0xb5/0x180 drivers/tty/tty_buffer.c:457
 tty_port_default_receive_buf+0x6d/0xa0 drivers/tty/tty_port.c:39
 receive_buf drivers/tty/tty_buffer.c:515 [inline]
 flush_to_ldisc+0x2e1/0x820 drivers/tty/tty_buffer.c:565
 process_one_work+0x717/0xc30 kernel/workqueue.c:2302
 worker_thread+0xa4d/0x11d0 kernel/workqueue.c:2449
 kthread+0x281/0x320 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:n_tty_receive_buf_common+0x176/0x1340 drivers/tty/n_tty.c:1700
Code: 89 85 c8 fe ff ff 48 89 8d 40 ff ff ff 48 c1 e9 03 48 89 8d 08 ff ff ff 4c 89 75 b8 48 89 9d 58 ff ff ff 48 8b 85 b8 fe ff ff <42> 80 3c 28 00 74 0c 48 8b bd c0 fe ff ff e8 07 1a f7 fe 4d 8b be
RSP: 0018:ffffc900002cfa78 EFLAGS: 00010203
RAX: 000000000000044c RBX: ffff8881197559f8 RCX: 000000000000000b
RDX: 000000000000005d RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900002cfbd8 R08: ffff8881197558ff R09: 1ffff110232eab1f
R10: dffffc0000000000 R11: ffffed10232eab20 R12: ffff88811379882a
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff110232eab2c
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055bcf60fdc68 CR3: 0000000131f7b000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	89 85 c8 fe ff ff    	mov    %eax,-0x138(%rbp)
   6:	48 89 8d 40 ff ff ff 	mov    %rcx,-0xc0(%rbp)
   d:	48 c1 e9 03          	shr    $0x3,%rcx
  11:	48 89 8d 08 ff ff ff 	mov    %rcx,-0xf8(%rbp)
  18:	4c 89 75 b8          	mov    %r14,-0x48(%rbp)
  1c:	48 89 9d 58 ff ff ff 	mov    %rbx,-0xa8(%rbp)
  23:	48 8b 85 b8 fe ff ff 	mov    -0x148(%rbp),%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 0c                	je     0x3d
  31:	48 8b bd c0 fe ff ff 	mov    -0x140(%rbp),%rdi
  38:	e8 07 1a f7 fe       	call   0xfef71a44
  3d:	4d                   	rex.WRB
  3e:	8b                   	.byte 0x8b
  3f:	be                   	.byte 0xbe

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/03 11:00 android14-6.1 cf4093a4ac64 58bf2096 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in n_tty_receive_buf_common
* Struck through repros no longer work on HEAD.