Re: [syzbot] [net?] [s390?] general protection fault in smc_diag_dump_proto

[syzbot <syzbot+f69bfae0a4eb29976e44@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
general protection fault in smc_diag_dump_proto

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 6159 Comm: syz.0.21 Not tainted 6.10.0-syzkaller-09703-gd7e78951a8b8-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:smc_diag_msg_common_fill net/smc/smc_diag.c:44 [inline]
RIP: 0010:__smc_diag_dump net/smc/smc_diag.c:89 [inline]
RIP: 0010:smc_diag_dump_proto+0x709/0x3270 net/smc/smc_diag.c:217
Code: 08 48 89 df e8 f8 0d 9d f6 48 8b 44 24 28 4c 8d 68 14 48 8b 1b 48 83 c3 0e 48 89 d8 48 c1 e8 03 49 bf 00 00 00 00 00 fc ff df <42> 0f b6 04 38 84 c0 0f 85 46 1b 00 00 0f b7 1b 66 c1 c3 08 4c 89
RSP: 0018:ffffc9000358eb00 EFLAGS: 00010203
RAX: 0000000000000001 RBX: 000000000000000e RCX: ffff888069659e00
RDX: 0000000000000000 RSI: 0000000080000001 RDI: 0000000000000000
RBP: ffffc9000358ef90 R08: ffffffff8990c562 R09: 1ffff1100eef084b
R10: dffffc0000000000 R11: ffffed100eef084c R12: 1ffff1100eef08e0
R13: ffff8880777f0014 R14: ffff888077784200 R15: dffffc0000000000
FS:  00007fddae9ea6c0(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fddae9e9fa8 CR3: 00000000736f2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 smc_diag_dump+0x59/0xa0 net/smc/smc_diag.c:236
 netlink_dump+0x647/0xd80 net/netlink/af_netlink.c:2325
 __netlink_dump_start+0x59f/0x780 net/netlink/af_netlink.c:2440
 netlink_dump_start include/linux/netlink.h:339 [inline]
 smc_diag_handler_dump+0x1ab/0x250 net/smc/smc_diag.c:251
 sock_diag_rcv_msg+0x3dc/0x5f0
 netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0x7f0/0x990 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x221/0x270 net/socket.c:745
 sock_sendmsg+0x134/0x200 net/socket.c:768
 splice_to_socket+0xa13/0x10b0 fs/splice.c:889
 do_splice_from fs/splice.c:941 [inline]
 do_splice+0xd77/0x1900 fs/splice.c:1354
 __do_splice fs/splice.c:1436 [inline]
 __do_sys_splice fs/splice.c:1652 [inline]
 __se_sys_splice+0x331/0x4a0 fs/splice.c:1634
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fddadb75f19
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:00007fddae9ea048 EFLAGS: 00000246 ORIG_RAX: 0000000000000113
RAX: ffffffffffffffda RBX: 00007fddadd06038 RCX: 00007fddadb75f19
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fddadbe4e68 R08: 0000000080000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007fddadd06038 R15: 00007ffc243501f8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:smc_diag_msg_common_fill net/smc/smc_diag.c:44 [inline]
RIP: 0010:__smc_diag_dump net/smc/smc_diag.c:89 [inline]
RIP: 0010:smc_diag_dump_proto+0x709/0x3270 net/smc/smc_diag.c:217
Code: 08 48 89 df e8 f8 0d 9d f6 48 8b 44 24 28 4c 8d 68 14 48 8b 1b 48 83 c3 0e 48 89 d8 48 c1 e8 03 49 bf 00 00 00 00 00 fc ff df <42> 0f b6 04 38 84 c0 0f 85 46 1b 00 00 0f b7 1b 66 c1 c3 08 4c 89
RSP: 0018:ffffc9000358eb00 EFLAGS: 00010203
RAX: 0000000000000001 RBX: 000000000000000e RCX: ffff888069659e00
RDX: 0000000000000000 RSI: 0000000080000001 RDI: 0000000000000000
RBP: ffffc9000358ef90 R08: ffffffff8990c562 R09: 1ffff1100eef084b
R10: dffffc0000000000 R11: ffffed100eef084c R12: 1ffff1100eef08e0
R13: ffff8880777f0014 R14: ffff888077784200 R15: dffffc0000000000
FS:  00007fddae9ea6c0(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fddae9e9fa8 CR3: 00000000736f2000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	08 48 89             	or     %cl,-0x77(%rax)
   3:	df e8                	fucomip %st(0),%st
   5:	f8                   	clc
   6:	0d 9d f6 48 8b       	or     $0x8b48f69d,%eax
   b:	44 24 28             	rex.R and $0x28,%al
   e:	4c 8d 68 14          	lea    0x14(%rax),%r13
  12:	48 8b 1b             	mov    (%rbx),%rbx
  15:	48 83 c3 0e          	add    $0xe,%rbx
  19:	48 89 d8             	mov    %rbx,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	49 bf 00 00 00 00 00 	movabs $0xdffffc0000000000,%r15
  27:	fc ff df
* 2a:	42 0f b6 04 38       	movzbl (%rax,%r15,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 46 1b 00 00    	jne    0x1b7d
  37:	0f b7 1b             	movzwl (%rbx),%ebx
  3a:	66 c1 c3 08          	rol    $0x8,%bx
  3e:	4c                   	rex.WR
  3f:	89                   	.byte 0x89


Tested on:

commit:         d7e78951 Merge tag 'net-6.11-rc0' of git://git.kernel...
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=137931c5980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a6f4e2cb79bdcd45
dashboard link: https://syzkaller.appspot.com/bug?extid=f69bfae0a4eb29976e44
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1363c96d980000