[syzbot] [hams?] general protection fault in rose_transmit_link (4)

[syzbot <syzbot+d00f90e0af54102fb271@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    6f3b6e91f720 Merge tag 'io_uring-6.18-20251016' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1714fdcd980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f3e7b5a3627a90dd
dashboard link: https://syzkaller.appspot.com/bug?extid=d00f90e0af54102fb271
compiler:       gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12483de2580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=148d5c58580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-6f3b6e91.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9a3a64b415ae/vmlinux-6f3b6e91.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1a864a92eaa0/bzImage-6f3b6e91.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d00f90e0af54102fb271@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
CPU: 1 UID: 0 PID: 6092 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:rose_transmit_link+0x32/0x5f0 net/rose/rose_link.c:266
Code: 41 55 41 54 55 48 89 fd 53 48 89 f3 48 83 ec 08 e8 23 80 69 f7 48 8d 7b 36 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 d8 04 00 00
RSP: 0018:ffffc90003f67a00 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8a545988
RDX: 0000000000000006 RSI: ffffffff8a53b88d RDI: 0000000000000036
RBP: ffff88803bc14780 R08: 0000000000000005 R09: 000000000000001f
R10: 0000000000000013 R11: 0000000000000000 R12: ffff888028c2e000
R13: 0000000000000010 R14: 0000000000000013 R15: ffff88805181e41a
FS:  00007ff7e01a96c0(0000) GS:ffff8880d6ad6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562fe4bbada8 CR3: 000000003ceb8000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 rose_write_internal+0x2f6/0x1850 net/rose/rose_subr.c:198
 rose_release+0x1f1/0x740 net/rose/af_rose.c:671
 __sock_release+0xb3/0x270 net/socket.c:662
 sock_close+0x1c/0x30 net/socket.c:1455
 __fput+0x402/0xb70 fs/file_table.c:468
 task_work_run+0x150/0x240 kernel/task_work.c:227
 get_signal+0x1d0/0x26d0 kernel/signal.c:2807
 arch_do_signal_or_restart+0x8f/0x7c0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff7df38efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ff7e01a9038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: 0000000000000000 RBX: 00007ff7df5e5fa0 RCX: 00007ff7df38efc9
RDX: 0000000000000040 RSI: 0000200000000140 RDI: 0000000000000005
RBP: 00007ff7df411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff7df5e6038 R14: 00007ff7df5e5fa0 R15: 00007ffc5e3517f8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:rose_transmit_link+0x32/0x5f0 net/rose/rose_link.c:266
Code: 41 55 41 54 55 48 89 fd 53 48 89 f3 48 83 ec 08 e8 23 80 69 f7 48 8d 7b 36 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 d8 04 00 00
RSP: 0018:ffffc90003f67a00 EFLAGS: 00010207
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff8a545988
RDX: 0000000000000006 RSI: ffffffff8a53b88d RDI: 0000000000000036
RBP: ffff88803bc14780 R08: 0000000000000005 R09: 000000000000001f
R10: 0000000000000013 R11: 0000000000000000 R12: ffff888028c2e000
R13: 0000000000000010 R14: 0000000000000013 R15: ffff88805181e41a
FS:  00007ff7e01a96c0(0000) GS:ffff8880d6ad6000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000562fe4bbada8 CR3: 000000003ceb8000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	41 55                	push   %r13
   2:	41 54                	push   %r12
   4:	55                   	push   %rbp
   5:	48 89 fd             	mov    %rdi,%rbp
   8:	53                   	push   %rbx
   9:	48 89 f3             	mov    %rsi,%rbx
   c:	48 83 ec 08          	sub    $0x8,%rsp
  10:	e8 23 80 69 f7       	call   0xf7698038
  15:	48 8d 7b 36          	lea    0x36(%rbx),%rdi
  19:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  20:	fc ff df
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	0f b6 04 02          	movzbl (%rdx,%rax,1),%eax <-- trapping instruction
  2e:	48 89 fa             	mov    %rdi,%rdx
  31:	83 e2 07             	and    $0x7,%edx
  34:	38 d0                	cmp    %dl,%al
  36:	7f 08                	jg     0x40
  38:	84 c0                	test   %al,%al
  3a:	0f 85 d8 04 00 00    	jne    0x518


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