Re: [syzbot] [net?] [bpf?] KASAN: slab-use-after-free Read in __sk_msg_recvmsg

[syzbot <syzbot+431f9a9e3f5227fbb904@syzkaller.appspotmail.com>]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in inet_sock_destruct

------------[ cut here ]------------
sk->sk_forward_alloc
WARNING: net/ipv4/af_inet.c:162 at inet_sock_destruct+0x62d/0x740 net/ipv4/af_inet.c:162, CPU#1: ksoftirqd/1/23
Modules linked in:
CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:inet_sock_destruct+0x62d/0x740 net/ipv4/af_inet.c:162
Code: 0f 0b 90 e9 58 fe ff ff e8 50 dd 9e f7 90 0f 0b 90 e9 8b fe ff ff e8 42 dd 9e f7 90 0f 0b 90 e9 b1 fe ff ff e8 34 dd 9e f7 90 <0f> 0b 90 e9 d7 fe ff ff 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c 95 fc
RSP: 0018:ffffc900001d7ae8 EFLAGS: 00010246
RAX: ffffffff8a26d13c RBX: dffffc0000000000 RCX: ffff88801daf8000
RDX: 0000000000000100 RSI: 0000000000000090 RDI: 0000000000000000
RBP: 0000000000000090 R08: ffff88801bffcf27 R09: 1ffff110037ff9e4
R10: dffffc0000000000 R11: ffffed10037ff9e5 R12: ffff88801bffcc80
R13: dffffc0000000000 R14: ffff88801bffcf0c R15: ffffffff8fca6c00
FS:  0000000000000000(0000) GS:ffff888125557000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdb873e9f00 CR3: 000000000e54c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __sk_destruct+0x85/0x880 net/core/sock.c:2350
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
 handle_softirqs+0x22a/0x870 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1063
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


Tested on:

commit:         a77fb1ac Octeontx2-af: add WQ_PERCPU to alloc_workqueu..
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git main
console output: https://syzkaller.appspot.com/x/log.txt?x=137ed5da580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=71d49d824b43a0d9
dashboard link: https://syzkaller.appspot.com/bug?extid=431f9a9e3f5227fbb904
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=143bf0f2580000