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: 42d, last: 11d
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: 321 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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 d7 17 f7 fe 4d 8b be
RSP: 0018:ffffc9000dcbfa78 EFLAGS: 00010203
RAX: 000000000000044c RBX: ffff888115a351f8 RCX: 000000000000000b
RDX: 000000000000005d RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000dcbfbd8 R08: ffff888115a350ff R09: 1ffff11022b46a1f
R10: dffffc0000000000 R11: ffffed1022b46a20 R12: ffff888115ae0020
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff11022b46a2c
FS: 0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000f000 CR3: 000000010ff66000 CR4: 00000000003526a0
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 d7 17 f7 fe 4d 8b be
RSP: 0018:ffffc9000dcbfa78 EFLAGS: 00010203
RAX: 000000000000044c RBX: ffff888115a351f8 RCX: 000000000000000b
RDX: 000000000000005d RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000dcbfbd8 R08: ffff888115a350ff R09: 1ffff11022b46a1f
R10: dffffc0000000000 R11: ffffed1022b46a20 R12: ffff888115ae0020
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff11022b46a2c
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f933bdef2f8 CR3: 000000000700f000 CR4: 00000000003526b0
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 d7 17 f7 fe call 0xfef71814
3d: 4d rex.WRB
3e: 8b .byte 0x8b
3f: be .byte 0xbe
Struck through repros no longer work on HEAD.