------------[ cut here ]------------
!skb_shinfo(skb)->nr_frags
WARNING: net/kcm/kcmsock.c:631 at kcm_write_msgs+0x1452/0x1610 net/kcm/kcmsock.c:631, CPU#0: syz-executor/7521
Modules linked in:
CPU: 0 UID: 0 PID: 7521 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:kcm_write_msgs+0x1452/0x1610 net/kcm/kcmsock.c:631
Code: f8 f8 f8 c6 44 18 10 f8 eb 68 e8 99 f0 ef f6 e9 56 ed ff ff e8 8f f0 ef f6 45 31 e4 45 31 ed e9 46 ed ff ff e8 7f f0 ef f6 90 <0f> 0b 90 41 bc ea ff ff ff 48 bb 00 00 00 00 00 fc ff df eb a8 e8
RSP: 0018:ffffc90003a7f6e0 EFLAGS: 00010293
RAX: ffffffff8ad5ad51 RBX: 0000000000000180 RCX: ffff88805b430000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003a7f8b0 R08: ffffc90003a7f827 R09: 0000000000000000
R10: ffffc90003a7f7c0 R11: fffff5200074ff05 R12: dffffc0000000000
R13: ffff888036f7ec00 R14: ffff88802ad970c0 R15: 0000000000000000
FS:  00007fd3217216c0(0000) GS:ffff88812546a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020229000 CR3: 000000002b148000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 kcm_sendmsg+0x24bc/0x2b00 net/kcm/kcmsock.c:907
 sock_sendmsg_nosec+0x18f/0x1d0 net/socket.c:737
 __sock_sendmsg net/socket.c:752 [inline]
 sock_write_iter+0x302/0x410 net/socket.c:1210
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61d/0xb90 fs/read_write.c:688
 ksys_write+0x150/0x270 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd320a6e9b9
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 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd3217210b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd320babf80 RCX: 00007fd320a6e9b9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007fd320acf4bc R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fd320babf80 R15: 00007ffd01831018
 </TASK>