[syzbot] [net?] KASAN: slab-use-after-free Read in sock_def_readable (2)

[syzbot] [net?] KASAN: slab-use-after-free Read in sock_def_readable (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    6de23f81a5e0 Linux 7.0-rc1
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148d655a580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=3b4642149033fe7c
dashboard link: https://syzkaller.appspot.com/bug?extid=f50072212ab792c86925
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1085e55a580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12e6d9e6580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-6de23f81.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5258f38d5768/vmlinux-6de23f81.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a7730b97aa5a/bzImage-6de23f81.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f50072212ab792c86925@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in list_empty include/linux/list.h:381 [inline]
BUG: KASAN: slab-use-after-free in waitqueue_active include/linux/wait.h:127 [inline]
BUG: KASAN: slab-use-after-free in wq_has_sleeper include/linux/wait.h:161 [inline]
BUG: KASAN: slab-use-after-free in skwq_has_sleeper include/net/sock.h:2404 [inline]
BUG: KASAN: slab-use-after-free in sock_def_readable+0x1cb/0x580 net/core/sock.c:3610
Read of size 8 at addr ffff888047cb0c00 by task kworker/0:4/5308

CPU: 0 UID: 0 PID: 5308 Comm: kworker/0:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: mld mld_ifc_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 list_empty include/linux/list.h:381 [inline]
 waitqueue_active include/linux/wait.h:127 [inline]
 wq_has_sleeper include/linux/wait.h:161 [inline]
 skwq_has_sleeper include/net/sock.h:2404 [inline]
 sock_def_readable+0x1cb/0x580 net/core/sock.c:3610
 send_to_lecd+0x322/0x600 net/atm/lec.c:538
 lec_arp_resolve net/atm/lec.c:1787 [inline]
 lec_start_xmit+0xec0/0x2660 net/atm/lec.c:285
 __netdev_start_xmit include/linux/netdevice.h:5275 [inline]
 netdev_start_xmit include/linux/netdevice.h:5284 [inline]
 xmit_one net/core/dev.c:3871 [inline]
 dev_hard_start_xmit+0x2d8/0x870 net/core/dev.c:3887
 sch_direct_xmit+0x251/0x4c0 net/sched/sch_generic.c:347
 __dev_xmit_skb net/core/dev.c:4186 [inline]
 __dev_queue_xmit+0x1538/0x38a0 net/core/dev.c:4802
 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
 ip6_finish_output+0x25c/0x610 net/ipv6/ip6_output.c:219
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246
 NF_HOOK+0xa2/0x3a0 include/linux/netfilter.h:318
 mld_sendpack+0x8b4/0xe40 net/ipv6/mcast.c:1855
 mld_send_cr net/ipv6/mcast.c:2154 [inline]
 mld_ifc_work+0x835/0xe70 net/ipv6/mcast.c:2693
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
 kthread+0x388/0x470 kernel/kthread.c:467
 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>

Allocated by task 6850:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 kmem_cache_alloc_lru_noprof+0x2b8/0x640 mm/slub.c:4849
 sock_alloc_inode+0x28/0xc0 net/socket.c:322
 alloc_inode+0x6a/0x1b0 fs/inode.c:347
 new_inode_pseudo include/linux/fs.h:3003 [inline]
 sock_alloc net/socket.c:637 [inline]
 __sock_create+0x12d/0x9d0 net/socket.c:1569
 sock_create net/socket.c:1663 [inline]
 __sys_socket_create net/socket.c:1700 [inline]
 __sys_socket+0xd6/0x1b0 net/socket.c:1747
 __do_sys_socket net/socket.c:1761 [inline]
 __se_sys_socket net/socket.c:1759 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1759
 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

Freed by task 6859:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2687 [inline]
 slab_free mm/slub.c:6124 [inline]
 kmem_cache_free+0x187/0x630 mm/slub.c:6254
 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
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 __call_rcu_common kernel/rcu/tree.c:3131 [inline]
 call_rcu+0xee/0x890 kernel/rcu/tree.c:3251
 destroy_inode fs/inode.c:402 [inline]
 evict+0x95b/0xb10 fs/inode.c:870
 __dentry_kill+0x1a2/0x5e0 fs/dcache.c:670
 finish_dput+0xc9/0x480 fs/dcache.c:879
 __fput+0x691/0xa70 fs/file_table.c:477
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888047cb0b80
 which belongs to the cache sock_inode_cache of size 1344
The buggy address is located 128 bytes inside of
 freed 1344-byte region [ffff888047cb0b80, ffff888047cb10c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x47cb0
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888038584a01
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff888030419c80 dead000000000100 dead000000000122
raw: 0000000000000000 00000008000b000b 00000000f5000000 ffff888038584a01
head: 04fff00000000040 ffff888030419c80 dead000000000100 dead000000000122
head: 0000000000000000 00000008000b000b 00000000f5000000 ffff888038584a01
head: 04fff00000000002 ffffea00011f2c01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Reclaimable, gfp_mask 0xd20d0(__GFP_RECLAIMABLE|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5295, tgid 5295 (syz-execprog), ts 87351971632, free_ts 76295178870
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3255 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3444
 new_slab mm/slub.c:3502 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7134
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x2b9/0x620 mm/slub.c:4578
 alloc_from_pcs mm/slub.c:4681 [inline]
 slab_alloc_node mm/slub.c:4815 [inline]
 kmem_cache_alloc_lru_noprof+0x37c/0x640 mm/slub.c:4849
 sock_alloc_inode+0x28/0xc0 net/socket.c:322
 alloc_inode+0x6a/0x1b0 fs/inode.c:347
 new_inode_pseudo include/linux/fs.h:3003 [inline]
 sock_alloc net/socket.c:637 [inline]
 __sock_create+0x12d/0x9d0 net/socket.c:1569
 mptcp_subflow_create_socket+0xfb/0x800 net/mptcp/subflow.c:1788
 __mptcp_socket_create net/mptcp/protocol.c:110 [inline]
 __mptcp_nmpc_sk+0x155/0x790 net/mptcp/protocol.c:142
 mptcp_setsockopt_v6 net/mptcp/sockopt.c:399 [inline]
 mptcp_setsockopt+0xe4a/0x36a0 net/mptcp/sockopt.c:922
 do_sock_setsockopt+0x270/0x400 net/socket.c:2322
 __sys_setsockopt net/socket.c:2347 [inline]
 __do_sys_setsockopt net/socket.c:2353 [inline]
 __se_sys_setsockopt net/socket.c:2350 [inline]
 __x64_sys_setsockopt+0x18a/0x210 net/socket.c:2350
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
page last free pid 5281 tgid 5281 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 __slab_free+0x263/0x2b0 mm/slub.c:5532
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4501 [inline]
 slab_alloc_node mm/slub.c:4830 [inline]
 __kmalloc_cache_noprof+0x2ba/0x660 mm/slub.c:5334
 kmalloc_noprof include/linux/slab.h:962 [inline]
 tomoyo_print_header security/tomoyo/audit.c:156 [inline]
 tomoyo_init_log+0x195/0x1fb0 security/tomoyo/audit.c:255
 tomoyo_supervisor+0x353/0x1570 security/tomoyo/common.c:2232
 tomoyo_audit_env_log security/tomoyo/environ.c:37 [inline]
 tomoyo_env_perm+0x151/0x1f0 security/tomoyo/environ.c:64
 tomoyo_environ security/tomoyo/domain.c:673 [inline]
 tomoyo_find_next_domain+0x15cb/0x1aa0 security/tomoyo/domain.c:889
 tomoyo_bprm_check_security+0x11b/0x180 security/tomoyo/tomoyo.c:102
 security_bprm_check+0x85/0x240 security/security.c:794
 search_binary_handler fs/exec.c:1654 [inline]
 exec_binprm fs/exec.c:1696 [inline]
 bprm_execve+0x896/0x1460 fs/exec.c:1748
 do_execveat_common+0x50d/0x690 fs/exec.c:1846
 __do_sys_execve fs/exec.c:1930 [inline]
 __se_sys_execve fs/exec.c:1924 [inline]
 __x64_sys_execve+0x97/0xc0 fs/exec.c:1924
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94

Memory state around the buggy address:
 ffff888047cb0b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888047cb0b80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888047cb0c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888047cb0c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888047cb0d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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

Re: [syzbot] [net?] KASAN: slab-use-after-free Read in sock_def_readable (2)

[Jiayuan Chen]

#syz test

diff --git a/net/atm/lec.c b/net/atm/lec.c
index 7e6fc2bd40ac..7d99ba8ba3b4 100644
--- a/net/atm/lec.c
+++ b/net/atm/lec.c
@@ -139,6 +139,7 @@ static void lec_handle_bridge(struct sk_buff *skb, struct net_device *dev)
 	 */
 	buff = skb->data + skb->dev->hard_header_len;
 	if (*buff++ == 0x42 && *buff++ == 0x42 && *buff++ == 0x03) {
+		struct atm_vcc *vcc;
 		struct sock *sk;
 		struct sk_buff *skb2;
 		struct atmlec_msg *mesg;
@@ -154,10 +155,18 @@ static void lec_handle_bridge(struct sk_buff *skb, struct net_device *dev)
 					/* 0x01 is topology change */

 		priv = netdev_priv(dev);
-		atm_force_charge(priv->lecd, skb2->truesize);
-		sk = sk_atm(priv->lecd);
-		skb_queue_tail(&sk->sk_receive_queue, skb2);
-		sk->sk_data_ready(sk);
+
+		rcu_read_lock();
+		vcc = rcu_dereference(priv->lecd);
+		if (vcc) {
+			atm_force_charge(vcc, skb2->truesize);
+			sk = sk_atm(vcc);
+			skb_queue_tail(&sk->sk_receive_queue, skb2);
+			sk->sk_data_ready(sk);
+		} else {
+			dev_kfree_skb(skb2);
+		}
+		rcu_read_unlock();
 	}
 }
 #endif /* IS_ENABLED(CONFIG_BRIDGE) */
@@ -216,7 +225,7 @@ static netdev_tx_t lec_start_xmit(struct sk_buff *skb,
 	int is_rdesc;

 	pr_debug("called\n");
-	if (!priv->lecd) {
+	if (!rcu_access_pointer(priv->lecd)) {
 		pr_info("%s:No lecd attached\n", dev->name);
 		dev->stats.tx_errors++;
 		netif_stop_queue(dev);
@@ -440,6 +449,7 @@ static int lec_atm_send(struct atm_vcc *vcc, struct sk_buff *skb)
 		if (br_fdb_test_addr_hook(dev, mesg->content.proxy.mac_addr)) {
 			/* hit from bridge table, send LE_ARP_RESPONSE */
 			struct sk_buff *skb2;
+			struct atm_vcc *lecd;
 			struct sock *sk;

 			pr_debug("%s: entry found, responding to zeppelin\n",
@@ -449,10 +459,18 @@ static int lec_atm_send(struct atm_vcc *vcc, struct sk_buff *skb)
 				break;
 			skb2->len = sizeof(struct atmlec_msg);
 			skb_copy_to_linear_data(skb2, mesg, sizeof(*mesg));
-			atm_force_charge(priv->lecd, skb2->truesize);
-			sk = sk_atm(priv->lecd);
-			skb_queue_tail(&sk->sk_receive_queue, skb2);
-			sk->sk_data_ready(sk);
+
+			rcu_read_lock();
+			lecd = rcu_dereference(priv->lecd);
+			if (lecd) {
+				atm_force_charge(lecd, skb2->truesize);
+				sk = sk_atm(lecd);
+				skb_queue_tail(&sk->sk_receive_queue, skb2);
+				sk->sk_data_ready(sk);
+			} else {
+				dev_kfree_skb(skb2);
+			}
+			rcu_read_unlock();
 		}
 	}
 #endif /* IS_ENABLED(CONFIG_BRIDGE) */
@@ -472,7 +490,8 @@ static void lec_atm_close(struct atm_vcc *vcc)
 	struct net_device *dev = (struct net_device *)vcc->proto_data;
 	struct lec_priv *priv = netdev_priv(dev);

-	priv->lecd = NULL;
+	rcu_assign_pointer(priv->lecd, NULL);
+	synchronize_rcu();
 	/* Do something needful? */

 	netif_stop_queue(dev);
@@ -510,15 +529,25 @@ send_to_lecd(struct lec_priv *priv, atmlec_msg_type type,
 	     const unsigned char *mac_addr, const unsigned char *atm_addr,
 	     struct sk_buff *data)
 {
+	struct atm_vcc *vcc;
 	struct sock *sk;
 	struct sk_buff *skb;
 	struct atmlec_msg *mesg;

-	if (!priv || !priv->lecd)
+	if (!priv)
+		return -1;
+
+	rcu_read_lock();
+	vcc = rcu_dereference(priv->lecd);
+	if (!vcc) {
+		rcu_read_unlock();
 		return -1;
+	}
 	skb = alloc_skb(sizeof(struct atmlec_msg), GFP_ATOMIC);
-	if (!skb)
+	if (!skb) {
+		rcu_read_unlock();
 		return -1;
+	}
 	skb->len = sizeof(struct atmlec_msg);
 	mesg = (struct atmlec_msg *)skb->data;
 	memset(mesg, 0, sizeof(struct atmlec_msg));
@@ -532,18 +561,19 @@ send_to_lecd(struct lec_priv *priv, atmlec_msg_type type,
 	if (atm_addr)
 		memcpy(&mesg->content.normal.atm_addr, atm_addr, ATM_ESA_LEN);

-	atm_force_charge(priv->lecd, skb->truesize);
-	sk = sk_atm(priv->lecd);
+	atm_force_charge(vcc, skb->truesize);
+	sk = sk_atm(vcc);
 	skb_queue_tail(&sk->sk_receive_queue, skb);
 	sk->sk_data_ready(sk);

 	if (data != NULL) {
 		pr_debug("about to send %d bytes of data\n", data->len);
-		atm_force_charge(priv->lecd, data->truesize);
+		atm_force_charge(vcc, data->truesize);
 		skb_queue_tail(&sk->sk_receive_queue, data);
 		sk->sk_data_ready(sk);
 	}

+	rcu_read_unlock();
 	return 0;
 }

@@ -618,7 +648,8 @@ static void lec_push(struct atm_vcc *vcc, struct sk_buff *skb)

 		atm_return(vcc, skb->truesize);
 		if (*(__be16 *) skb->data == htons(priv->lecid) ||
-		    !priv->lecd || !(dev->flags & IFF_UP)) {
+		    !rcu_access_pointer(priv->lecd) ||
+		    !(dev->flags & IFF_UP)) {
 			/*
 			 * Probably looping back, or if lecd is missing,
 			 * lecd has gone down
@@ -753,12 +784,12 @@ static int lecd_attach(struct atm_vcc *vcc, int arg)
 		priv = netdev_priv(dev_lec[i]);
 	} else {
 		priv = netdev_priv(dev_lec[i]);
-		if (priv->lecd)
+		if (rcu_access_pointer(priv->lecd))
 			return -EADDRINUSE;
 	}
 	lec_arp_init(priv);
 	priv->itfnum = i;	/* LANE2 addition */
-	priv->lecd = vcc;
+	rcu_assign_pointer(priv->lecd, vcc);
 	vcc->dev = &lecatm_dev;
 	vcc_insert_socket(sk_atm(vcc));

diff --git a/net/atm/lec.h b/net/atm/lec.h
index be0e2667bd8c..ec85709bf818 100644
--- a/net/atm/lec.h
+++ b/net/atm/lec.h
@@ -91,7 +91,7 @@ struct lec_priv {
 						 */
 	spinlock_t lec_arp_lock;
 	struct atm_vcc *mcast_vcc;		/* Default Multicast Send VCC */
-	struct atm_vcc *lecd;
+	struct atm_vcc __rcu *lecd;
 	struct delayed_work lec_arp_work;	/* C10 */
 	unsigned int maximum_unknown_frame_count;
 						/*

Re: [syzbot] [net?] KASAN: slab-use-after-free Read in sock_def_readable (2)

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to copy syz-execprog to VM: failed to run ["scp" "-P" "48817" "-F" "/dev/null" "-o" "UserKnownHostsFile=/dev/null" "-o" "IdentitiesOnly=yes" "-o" "BatchMode=yes" "-o" "StrictHostKeyChecking=no" "-o" "ConnectTimeout=10" "/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/bin/linux_amd64/syz-execprog" "root@localhost:/syz-execprog"]: exit status 255



syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build3224921581=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.26.0'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 7c9658af8505
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=7c9658af8505abccd5bf5890cc8a8e6d9826eaa0 -X github.com/google/syzkaller/prog.gitRevisionDate=20260223-092328"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=7c9658af8505abccd5bf5890cc8a8e6d9826eaa0 -X github.com/google/syzkaller/prog.gitRevisionDate=20260223-092328"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=7c9658af8505abccd5bf5890cc8a8e6d9826eaa0 -X github.com/google/syzkaller/prog.gitRevisionDate=20260223-092328"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"7c9658af8505abccd5bf5890cc8a8e6d9826eaa0\"
/usr/bin/ld: /tmp/cc2JgryH.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null



Tested on:

commit:         1f318b96 Linux 7.0-rc3
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=c5c49ee0942d1cdb
dashboard link: https://syzkaller.appspot.com/bug?extid=f50072212ab792c86925
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=1528375a580000