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KASAN: slab-use-after-free Read in netdev_master_upper_dev_get_rcu

Status: closed as invalid on 2025/10/20 16:20
Subsystems: net
[Documentation on labels]
First crash: 186d, last: 186d

Sample crash report:
8021q: adding VLAN 0 to HW filter on device batadv0
==================================================================
BUG: KASAN: slab-use-after-free in netdev_master_upper_dev_get_rcu+0xd0/0xf0 net/core/dev.c:8429
Read of size 1 at addr ffff88806e7ca890 by task syz-executor/15369

CPU: 2 UID: 0 PID: 15369 Comm: syz-executor Not tainted 6.16.0-syzkaller-11852-g479058002c32 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xcd/0x630 mm/kasan/report.c:482
 kasan_report+0xe0/0x110 mm/kasan/report.c:595
 netdev_master_upper_dev_get_rcu+0xd0/0xf0 net/core/dev.c:8429
 rtnl_link_get_slave_info_data_size net/core/rtnetlink.c:705 [inline]
 rtnl_link_get_size net/core/rtnetlink.c:741 [inline]
 if_nlmsg_size+0x241/0xaf0 net/core/rtnetlink.c:1309
 rtmsg_ifinfo_build_skb+0x6d/0x280 net/core/rtnetlink.c:4392
 rtmsg_ifinfo_event net/core/rtnetlink.c:4434 [inline]
 rtmsg_ifinfo_event net/core/rtnetlink.c:4424 [inline]
 rtnetlink_event+0xf3/0x1f0 net/core/rtnetlink.c:7006
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 netif_set_mac_address+0x36f/0x4a0 net/core/dev.c:9781
 do_setlink.constprop.0+0x75f/0x4380 net/core/rtnetlink.c:3095
 rtnl_changelink net/core/rtnetlink.c:3761 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3920 [inline]
 rtnl_newlink+0x1446/0x2000 net/core/rtnetlink.c:4057
 rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6946
 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5a7/0x870 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg net/socket.c:729 [inline]
 __sys_sendto+0x4a3/0x520 net/socket.c:2228
 __do_compat_sys_socketcall net/compat.c:475 [inline]
 __se_compat_sys_socketcall net/compat.c:423 [inline]
 __ia32_compat_sys_socketcall+0x625/0x770 net/compat.c:423
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f16579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000ff8afe70 EFLAGS: 00000293 ORIG_RAX: 0000000000000066
RAX: ffffffffffffffda RBX: 000000000000000b RCX: 00000000ff8afe84
RDX: 0000000000000000 RSI: 00000000f7f04568 RDI: 00000000f73a4ff4
RBP: 00000000f7f04568 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 15369:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:405
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4365 [inline]
 __kmalloc_noprof+0x223/0x510 mm/slub.c:4377
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 tnode_alloc net/ipv4/fib_trie.c:327 [inline]
 tnode_new+0x25a/0x340 net/ipv4/fib_trie.c:380
 fib_insert_node net/ipv4/fib_trie.c:1125 [inline]
 fib_insert_alias+0x6ee/0xe30 net/ipv4/fib_trie.c:1159
 fib_table_insert+0xa0c/0x1c40 net/ipv4/fib_trie.c:1354
 fib_magic+0x4d4/0x5c0 net/ipv4/fib_frontend.c:1133
 fib_add_ifaddr+0x16d/0x580 net/ipv4/fib_frontend.c:1155
 fib_inetaddr_event+0x147/0x270 net/ipv4/fib_frontend.c:1469
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 blocking_notifier_call_chain kernel/notifier.c:380 [inline]
 blocking_notifier_call_chain+0x69/0xa0 kernel/notifier.c:368
 __inet_insert_ifa+0x925/0xcd0 net/ipv4/devinet.c:567
 inet_rtm_newaddr+0xd87/0x1540 net/ipv4/devinet.c:1002
 rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6946
 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5a7/0x870 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg net/socket.c:729 [inline]
 __sys_sendto+0x4a3/0x520 net/socket.c:2228
 __do_compat_sys_socketcall net/compat.c:475 [inline]
 __se_compat_sys_socketcall net/compat.c:423 [inline]
 __ia32_compat_sys_socketcall+0x625/0x770 net/compat.c:423
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Freed by task 23:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2417 [inline]
 slab_free mm/slub.c:4680 [inline]
 kfree+0x2b4/0x4d0 mm/slub.c:4879
 __node_free_rcu+0x6f/0x80 net/ipv4/fib_trie.c:310
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0x79c/0x1530 kernel/rcu/tree.c:2861
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579
 run_ksoftirqd kernel/softirq.c:968 [inline]
 run_ksoftirqd+0x3a/0x60 kernel/softirq.c:960
 smpboot_thread_fn+0x3f4/0xae0 kernel/smpboot.c:160
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:548
 __call_rcu_common.constprop.0+0xa5/0xa10 kernel/rcu/tree.c:3123
 tnode_free+0xb5/0x120 net/ipv4/fib_trie.c:491
 replace+0x149/0x4f0 net/ipv4/fib_trie.c:517
 inflate net/ipv4/fib_trie.c:619 [inline]
 resize+0x105a/0x22a0 net/ipv4/fib_trie.c:864
 trie_rebalance net/ipv4/fib_trie.c:1101 [inline]
 fib_insert_node net/ipv4/fib_trie.c:1145 [inline]
 fib_insert_alias+0x9b9/0xe30 net/ipv4/fib_trie.c:1159
 fib_table_insert+0xa0c/0x1c40 net/ipv4/fib_trie.c:1354
 fib_magic+0x4d4/0x5c0 net/ipv4/fib_frontend.c:1133
 fib_add_ifaddr+0x16d/0x580 net/ipv4/fib_frontend.c:1155
 fib_inetaddr_event+0x147/0x270 net/ipv4/fib_frontend.c:1469
 notifier_call_chain+0xbc/0x410 kernel/notifier.c:85
 blocking_notifier_call_chain kernel/notifier.c:380 [inline]
 blocking_notifier_call_chain+0x69/0xa0 kernel/notifier.c:368
 __inet_insert_ifa+0x925/0xcd0 net/ipv4/devinet.c:567
 inet_rtm_newaddr+0xd87/0x1540 net/ipv4/devinet.c:1002
 rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6946
 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5a7/0x870 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg net/socket.c:729 [inline]
 __sys_sendto+0x4a3/0x520 net/socket.c:2228
 __do_compat_sys_socketcall net/compat.c:475 [inline]
 __se_compat_sys_socketcall net/compat.c:423 [inline]
 __ia32_compat_sys_socketcall+0x625/0x770 net/compat.c:423
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

The buggy address belongs to the object at ffff88806e7ca880
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 16 bytes inside of
 freed 64-byte region [ffff88806e7ca880, ffff88806e7ca8c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6e7ca
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000000 ffff88801b8428c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 6084, tgid 6083 (syz.2.12), ts 49278053441, free_ts 49175348445
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1c0/0x230 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x132b/0x38e0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x261/0x23f0 mm/page_alloc.c:5148
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2487 [inline]
 allocate_slab mm/slub.c:2655 [inline]
 new_slab+0x247/0x330 mm/slub.c:2709
 ___slab_alloc+0xcf2/0x1740 mm/slub.c:3891
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3981
 __slab_alloc_node mm/slub.c:4056 [inline]
 slab_alloc_node mm/slub.c:4217 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4391
 kmalloc_noprof include/linux/slab.h:905 [inline]
 ip_setup_cork+0x63b/0xa30 net/ipv4/ip_output.c:1307
 ip_append_data net/ipv4/ip_output.c:1364 [inline]
 ip_append_data+0x163/0x1a0 net/ipv4/ip_output.c:1350
 icmp_push_reply+0xa8/0x440 net/ipv4/icmp.c:375
 __icmp_send+0xcdf/0x1960 net/ipv4/icmp.c:783
 icmp_send include/net/icmp.h:43 [inline]
 ip_protocol_deliver_rcu+0x41c/0x4c0 net/ipv4/ip_input.c:216
 ip_local_deliver_finish+0x3f2/0x720 net/ipv4/ip_input.c:239
 NF_HOOK include/linux/netfilter.h:318 [inline]
 NF_HOOK include/linux/netfilter.h:312 [inline]
 ip_local_deliver+0x18e/0x1f0 net/ipv4/ip_input.c:260
 dst_input include/net/dst.h:471 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:454 [inline]
 NF_HOOK include/linux/netfilter.h:318 [inline]
 NF_HOOK include/linux/netfilter.h:312 [inline]
 ip_rcv+0x2e0/0x600 net/ipv4/ip_input.c:574
page last free pid 0 tgid 0 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1395 [inline]
 __free_frozen_pages+0x7d5/0x10f0 mm/page_alloc.c:2895
 pagetable_free include/linux/mm.h:2898 [inline]
 pagetable_dtor_free include/linux/mm.h:2996 [inline]
 __tlb_remove_table include/asm-generic/tlb.h:220 [inline]
 __tlb_remove_table_free mm/mmu_gather.c:227 [inline]
 tlb_remove_table_rcu+0x116/0x1a0 mm/mmu_gather.c:290
 rcu_do_batch kernel/rcu/tree.c:2605 [inline]
 rcu_core+0x79c/0x1530 kernel/rcu/tree.c:2861
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Memory state around the buggy address:
 ffff88806e7ca780: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff88806e7ca800: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff88806e7ca880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                         ^
 ffff88806e7ca900: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff88806e7ca980: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	10 06                	adc    %al,(%rsi)
   2:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
   6:	10 07                	adc    %al,(%rdi)
   8:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
   c:	10 08                	adc    %cl,(%rax)
   e:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1e:	00 51 52             	add    %dl,0x52(%rcx)
  21:	55                   	push   %rbp
  22:	89 e5                	mov    %esp,%ebp
  24:	0f 34                	sysenter
  26:	cd 80                	int    $0x80
* 28:	5d                   	pop    %rbp <-- trapping instruction
  29:	5a                   	pop    %rdx
  2a:	59                   	pop    %rcx
  2b:	c3                   	ret
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	90                   	nop
  2f:	90                   	nop
  30:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  37:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/06 14:05 upstream 479058002c32 4bd24a3e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 KASAN: slab-use-after-free Read in netdev_master_upper_dev_get_rcu
* Struck through repros no longer work on HEAD.