[syzbot] [net?] general protection fault in generic_hwtstamp_ioctl_lower (2)

[syzbot <syzbot+86a8ab09a0f655f1ff19@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    69e858e0b8b2 Merge tag 'uml-for-linus-6.14-rc1' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13324b24580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=98d83cc1742b7377
dashboard link: https://syzkaller.appspot.com/bug?extid=86a8ab09a0f655f1ff19
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17324b24580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=161595f8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3d07b0558b0e/disk-69e858e0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e5e2250eb3b1/vmlinux-69e858e0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3e676d17effc/bzImage-69e858e0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+86a8ab09a0f655f1ff19@syzkaller.appspotmail.com

netdevsim netdevsim0 netdevsim1: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim2: set [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim3: set [1, 0] type 2 family 0 port 6081 - 0
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 0 UID: 0 PID: 5827 Comm: syz-executor976 Not tainted 6.13.0-syzkaller-09760-g69e858e0b8b2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:generic_hwtstamp_ioctl_lower+0x125/0x420 net/core/dev_ioctl.c:456
Code: fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 b7 02 00 00 48 ba 00 00 00 00 00 fc ff df 4d 8b 75 10 49 8d 7e 10 48 89 f8 48 c1 e8 03 <0f> b6 0c 10 49 8d 46 27 48 89 c6 83 e0 07 48 c1 ee 03 0f b6 14 16
RSP: 0018:ffffc90003e4f250 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffff88807c788000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff893547b8 RDI: 0000000000000010
RBP: ffffc90003e4f338 R08: 0000000000000007 R09: 0000000000000003
R10: ffffc90003e4f2ab R11: 0000000000000001 R12: 1ffff920007c9e4e
R13: ffffc90003e4f410 R14: 0000000000000000 R15: 1ffff920007c9e9b
FS:  0000555562e35380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000180 CR3: 0000000078b1a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 generic_hwtstamp_get_lower net/core/dev_ioctl.c:480 [inline]
 generic_hwtstamp_get_lower+0xe8/0x130 net/core/dev_ioctl.c:468
 dev_get_hwtstamp_phylib+0x181/0x610 net/core/dev_ioctl.c:291
 tsconfig_prepare_data+0x15f/0x650 net/ethtool/tsconfig.c:51
 ethnl_default_doit+0x31a/0xbd0 net/ethtool/netlink.c:493
 genl_family_rcv_msg_doit+0x202/0x2f0 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x565/0x800 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x165/0x410 net/netlink/af_netlink.c:2543
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
 netlink_unicast+0x53c/0x7f0 net/netlink/af_netlink.c:1348
 netlink_sendmsg+0x8b8/0xd70 net/netlink/af_netlink.c:1892
 sock_sendmsg_nosec net/socket.c:713 [inline]
 __sock_sendmsg net/socket.c:728 [inline]
 ____sys_sendmsg+0x9ae/0xb40 net/socket.c:2568
 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2622
 __sys_sendmsg+0x16e/0x220 net/socket.c:2654
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f098155c919
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffca30ea5f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f09815aa4ad RCX: 00007f098155c919
RDX: 0000000000000000 RSI: 0000000020000280 RDI: 0000000000000003
RBP: 00007f09815aa47d R08: 0000000000000000 R09: 0000555500000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f09815aa3e5
R13: 0000000000000001 R14: 00007ffca30ea640 R15: 0000000000000003
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:generic_hwtstamp_ioctl_lower+0x125/0x420 net/core/dev_ioctl.c:456
Code: fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 b7 02 00 00 48 ba 00 00 00 00 00 fc ff df 4d 8b 75 10 49 8d 7e 10 48 89 f8 48 c1 e8 03 <0f> b6 0c 10 49 8d 46 27 48 89 c6 83 e0 07 48 c1 ee 03 0f b6 14 16
RSP: 0018:ffffc90003e4f250 EFLAGS: 00010202
RAX: 0000000000000002 RBX: ffff88807c788000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff893547b8 RDI: 0000000000000010
RBP: ffffc90003e4f338 R08: 0000000000000007 R09: 0000000000000003
R10: ffffc90003e4f2ab R11: 0000000000000001 R12: 1ffff920007c9e4e
R13: ffffc90003e4f410 R14: 0000000000000000 R15: 1ffff920007c9e9b
FS:  0000555562e35380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000180 CR3: 0000000078b1a000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 3 bytes skipped:
   0:	48 c1 ea 03          	shr    $0x3,%rdx
   4:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   8:	0f 85 b7 02 00 00    	jne    0x2c5
   e:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  15:	fc ff df
  18:	4d 8b 75 10          	mov    0x10(%r13),%r14
  1c:	49 8d 7e 10          	lea    0x10(%r14),%rdi
  20:	48 89 f8             	mov    %rdi,%rax
  23:	48 c1 e8 03          	shr    $0x3,%rax
* 27:	0f b6 0c 10          	movzbl (%rax,%rdx,1),%ecx <-- trapping instruction
  2b:	49 8d 46 27          	lea    0x27(%r14),%rax
  2f:	48 89 c6             	mov    %rax,%rsi
  32:	83 e0 07             	and    $0x7,%eax
  35:	48 c1 ee 03          	shr    $0x3,%rsi
  39:	0f b6 14 16          	movzbl (%rsi,%rdx,1),%edx


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup