KASAN: slab-use-after-free Write in pn_bind

Status: upstream: reported on 2026/08/01 00:13
Subsystems: usb
Labels: prio:normal
[Documentation on labels]
Reported-by: syzbot+098999e05b6b877c01b3@syzkaller.appspotmail.com
First crash: 5d12h, last: 9h33m
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
bcd07fa8 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: slab-use-after-free Write in pn_bind 2026/07/29 00:00 2026/07/29 00:00 2026/07/29 00:49 7be3c40b 

			
				
	

	
	



			

		

	

	
	

		

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			[syzbot] [usb?] KASAN: slab-use-after-free Write in pn_bind
			0 (1)
			2026/08/01 00:13
		

	
	




			
			
		

	

	
	

		

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			linux-6.6
			
				KASAN: slab-use-after-free Write in pn_bind
			
			22
			
			
			
			2
			2d11h
			
				
					3d03h
				
			
			
			
			
				0/2
			
			
				
					
						upstream: reported on 2026/07/29 22:52
					
				
			
			
		

	
		

			linux-6.1
			
				KASAN: use-after-free Write in pn_bind
			
			22
			
			
			
			2
			3d04h
			
				
					4d19h
				
			
			
			
			
				0/3
			
			
				
					
						upstream: reported on 2026/07/28 06:20
					
				
			
			
		

	
	





			
			
			
			
		

	

	

	
	
Sample crash report:

	
==================================================================
BUG: KASAN: slab-use-after-free in gphonet_set_gadget drivers/usb/gadget/function/f_phonet.c:720 [inline]
BUG: KASAN: slab-use-after-free in pn_bind+0x550/0x5b0 drivers/usb/gadget/function/f_phonet.c:510
Write of size 8 at addr ffff88803497c800 by task syz.6.1008/8979

CPU: 0 UID: 0 PID: 8979 Comm: syz.6.1008 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x13d/0x4b0 mm/kasan/report.c:482
 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
 gphonet_set_gadget drivers/usb/gadget/function/f_phonet.c:720 [inline]
 pn_bind+0x550/0x5b0 drivers/usb/gadget/function/f_phonet.c:510
 usb_add_function+0x219/0x890 drivers/usb/gadget/composite.c:333
 configfs_composite_bind+0xd83/0x1960 drivers/usb/gadget/configfs.c:1802
 gadget_bind_driver+0x28c/0xbf0 drivers/usb/gadget/udc/core.c:1662
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __driver_attach+0x21f/0x5b0 drivers/base/dd.c:1292
 bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:383
 bus_add_driver+0x305/0x5b0 drivers/base/bus.c:763
 driver_register+0x1e2/0x360 drivers/base/driver.c:174
 usb_gadget_register_driver_owner+0x132/0x210 drivers/usb/gadget/udc/core.c:1752
 gadget_dev_desc_UDC_store+0x1b0/0x2e0 drivers/usb/gadget/configfs.c:300
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4af359e019
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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4af449d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4af3825fa0 RCX: 00007f4af359e019
RDX: 000000000000000b RSI: 00002000000003c0 RDI: 0000000000000003
RBP: 00007f4af363500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4af3826038 R14: 00007f4af3825fa0 R15: 00007ffec50b6008
 </TASK>

Allocated by task 7252:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kvmalloc_node_noprof+0x34f/0x970 mm/slub.c:6905
 alloc_netdev_mqs+0xd7/0x15c0 net/core/dev.c:12054
 gphonet_setup_default+0x37/0x80 drivers/usb/gadget/function/f_phonet.c:706
 phonet_alloc_inst+0x83/0x130 drivers/usb/gadget/function/f_phonet.c:640
 try_get_usb_function_instance+0x136/0x1f0 drivers/usb/gadget/functions.c:28
 usb_get_function_instance+0x16/0x70 drivers/usb/gadget/functions.c:44
 function_make+0x18c/0x3f0 drivers/usb/gadget/configfs.c:626
 configfs_mkdir+0x51e/0xb70 fs/configfs/dir.c:1360
 vfs_mkdir+0x361/0x850 fs/namei.c:5276
 filename_mkdirat+0x48b/0x5e0 fs/namei.c:5309
 __do_sys_mkdirat fs/namei.c:5330 [inline]
 __se_sys_mkdirat fs/namei.c:5327 [inline]
 __x64_sys_mkdirat+0x89/0xc0 fs/namei.c:5327
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 8834:
 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
 kasan_save_track+0x14/0x30 mm/kasan/common.c:78
 kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x22b/0x6c0 mm/slub.c:6692
 free_netdev+0x6a0/0x8c0 net/core/dev.c:12240
 gphonet_register_netdev drivers/usb/gadget/function/f_phonet.c:729 [inline]
 pn_bind+0x3a7/0x5b0 drivers/usb/gadget/function/f_phonet.c:511
 usb_add_function+0x219/0x890 drivers/usb/gadget/composite.c:333
 configfs_composite_bind+0xd83/0x1960 drivers/usb/gadget/configfs.c:1802
 gadget_bind_driver+0x28c/0xbf0 drivers/usb/gadget/udc/core.c:1662
 call_driver_probe drivers/base/dd.c:628 [inline]
 really_probe+0x241/0xa60 drivers/base/dd.c:706
 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
 __driver_attach+0x21f/0x5b0 drivers/base/dd.c:1292
 bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:383
 bus_add_driver+0x305/0x5b0 drivers/base/bus.c:763
 driver_register+0x1e2/0x360 drivers/base/driver.c:174
 usb_gadget_register_driver_owner+0x132/0x210 drivers/usb/gadget/udc/core.c:1752
 gadget_dev_desc_UDC_store+0x1b0/0x2e0 drivers/usb/gadget/configfs.c:300
 flush_write_buffer fs/configfs/file.c:207 [inline]
 configfs_write_iter+0x302/0x4e0 fs/configfs/file.c:229
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x6ac/0x1050 fs/read_write.c:687
 ksys_write+0x12a/0x250 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88803497c000
 which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 2048 bytes inside of
 freed 4096-byte region [ffff88803497c000, ffff88803497d000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88803497a000 pfn:0x34978
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888035c79401
flags: 0xfff00000000240(workingset|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000240 ffff88813fe2b500 ffffea00014a4210 ffffea000149ca10
raw: ffff88803497a000 0000000800040002 00000000f5000000 ffff888035c79401
head: 00fff00000000240 ffff88813fe2b500 ffffea00014a4210 ffffea000149ca10
head: ffff88803497a000 0000000800040002 00000000f5000000 ffff888035c79401
head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5633, tgid 5633 (syz-executor), ts 98963027252, free_ts 59025545859
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
 prep_new_page mm/page_alloc.c:1867 [inline]
 get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
 alloc_slab_page mm/slub.c:3266 [inline]
 allocate_slab mm/slub.c:3380 [inline]
 new_slab+0xa2/0x640 mm/slub.c:3426
 refill_objects+0xe3/0x410 mm/slub.c:7310
 refill_sheaf mm/slub.c:2804 [inline]
 __pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
 alloc_from_pcs mm/slub.c:4773 [inline]
 slab_alloc_node mm/slub.c:4905 [inline]
 __kmalloc_cache_noprof+0x479/0x6c0 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 _kzalloc_noprof include/linux/slab.h:1309 [inline]
 snmp6_alloc_dev net/ipv6/addrconf.c:362 [inline]
 ipv6_add_dev+0x670/0x1520 net/ipv6/addrconf.c:413
 addrconf_notify+0x5db/0x1ba0 net/ipv6/addrconf.c:3685
 notifier_call_chain+0x99/0x3f0 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x110 net/core/dev.c:2250
 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline]
 call_netdevice_notifiers net/core/dev.c:2302 [inline]
 register_netdevice+0x1998/0x25a0 net/core/dev.c:11484
 veth_newlink+0x44a/0xa00 drivers/net/veth.c:1892
 rtnl_newlink_create net/core/rtnetlink.c:3913 [inline]
 __rtnl_newlink net/core/rtnetlink.c:4044 [inline]
 rtnl_newlink+0x1499/0x2380 net/core/rtnetlink.c:4159
 rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:7076
 netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556
page last free pid 5283 tgid 5283 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4584 [inline]
 slab_alloc_node mm/slub.c:4917 [inline]
 kmem_cache_alloc_node_noprof+0x27d/0x6b0 mm/slub.c:4989
 __alloc_skb+0x140/0x710 net/core/skbuff.c:704
 alloc_skb include/linux/skbuff.h:1384 [inline]
 alloc_skb_with_frags+0xdd/0x760 net/core/skbuff.c:6775
 sock_alloc_send_pskb+0x801/0x980 net/core/sock.c:3013
 unix_dgram_sendmsg+0x3c7/0x1810 net/unix/af_unix.c:2137
 unix_seqpacket_sendmsg+0x12a/0x1d0 net/unix/af_unix.c:2538
 sock_sendmsg_nosec net/socket.c:775 [inline]
 __sock_sendmsg net/socket.c:790 [inline]
 sock_write_iter+0x53a/0x5b0 net/socket.c:1241
 do_iter_readv_writev+0x6f7/0x930 fs/read_write.c:828
 vfs_writev+0x360/0xdd0 fs/read_write.c:1058
 do_writev+0x28a/0x340 fs/read_write.c:1104
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88803497c700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803497c780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88803497c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88803497c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88803497c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================



	

	



	Crashes (11):
		
		

			Time
			Kernel
			Commit
			Syzkaller
			Config
			Log
			Report
			Syz repro
			C repro
			VM info
			Assets (help?)
			Manager
			Title
		

		
		
		
		

			2026/08/01 06:22
			upstream
			0131b508c0e2
			7664cf44
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-kasan-badwrites-root
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/07/29 01:09
			upstream
			3b5f4b83c4ab
			19622d9d
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-kasan-gce-root
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/07/29 01:08
			upstream
			3b5f4b83c4ab
			19622d9d
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-kasan-gce-root
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/07/28 22:17
			upstream
			62cc90241548
			19622d9d
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-kasan-gce-smack-root
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/07/28 16:44
			upstream
			62cc90241548
			19622d9d
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-kasan-gce-root
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/07/28 01:42
			upstream
			f5098b6bae76
			4cb2b096
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-kasan-gce-smack-root
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/07/27 23:35
			upstream
			f5098b6bae76
			4cb2b096
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-kasan-badwrites-root
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/07/27 23:34
			upstream
			f5098b6bae76
			4cb2b096
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-kasan-badwrites-root
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/07/27 13:21
			upstream
			f5098b6bae76
			aae9036b
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci2-upstream-fs
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/08/01 16:26
			git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
			e2d5e23967d0
			e611ffe1
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-gce-arm64
			KASAN: slab-use-after-free Write in pn_bind
		

		
		

			2026/08/01 16:26
			git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
			e2d5e23967d0
			e611ffe1
			.config
			console log
			report
			
			
			info
			
				[disk image]
			
				[vmlinux]
			
				[kernel image]
			
			ci-upstream-gce-arm64
			KASAN: slab-use-after-free Write in pn_bind
		

		
		


* Struck through repros no longer work on HEAD.