netlink: 28 bytes leftover after parsing attributes in process `syz.2.6677'. netlink: 28 bytes leftover after parsing attributes in process `syz.2.6677'. ================================================================== BUG: KASAN: slab-use-after-free in fib6_ifdown+0xa2/0x4c0 net/ipv6/route.c:4901 Read of size 8 at addr ffff88801dfdc8b0 by task syz.2.6677/30967 CPU: 0 UID: 0 PID: 30967 Comm: syz.2.6677 Not tainted 6.15.0-rc5-syzkaller-00277-g345030986df8 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xb4/0x290 mm/kasan/report.c:521 kasan_report+0x118/0x150 mm/kasan/report.c:634 fib6_ifdown+0xa2/0x4c0 net/ipv6/route.c:4901 fib6_clean_node+0x24a/0x590 net/ipv6/ip6_fib.c:2199 fib6_walk_continue+0x678/0x910 net/ipv6/ip6_fib.c:2124 fib6_walk+0x149/0x290 net/ipv6/ip6_fib.c:2172 fib6_clean_tree net/ipv6/ip6_fib.c:2252 [inline] __fib6_clean_all+0x234/0x380 net/ipv6/ip6_fib.c:2268 rt6_sync_down_dev net/ipv6/route.c:4951 [inline] rt6_disable_ip+0x120/0x720 net/ipv6/route.c:4956 addrconf_ifdown+0x15d/0x1880 net/ipv6/addrconf.c:3857 addrconf_notify+0x1bc/0x1010 net/ipv6/addrconf.c:-1 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline] call_netdevice_notifiers net/core/dev.c:2228 [inline] unregister_netdevice_many_notify+0x15d8/0x2330 net/core/dev.c:11970 unregister_netdevice_many net/core/dev.c:12034 [inline] unregister_netdevice_queue+0x33c/0x380 net/core/dev.c:11877 unregister_netdevice include/linux/netdevice.h:3374 [inline] hsr_dev_finalize+0x707/0x9f0 net/hsr/hsr_device.c:786 hsr_newlink+0x7d7/0x940 net/hsr/hsr_netlink.c:122 rtnl_newlink_create+0x305/0xaf0 net/core/rtnetlink.c:3833 __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0x16d6/0x1c70 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x219/0x490 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:727 ____sys_sendmsg+0x505/0x830 net/socket.c:2566 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620 __sys_sendmsg+0x164/0x220 net/socket.c:2652 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf705e539 Code: 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 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f504e55c EFLAGS: 00000206 ORIG_RAX: 0000000000000172 RAX: ffffffffffffffda RBX: 000000000000000f RCX: 00000000800000c0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 14974: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4358 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] binderfs_binder_device_create+0x17f/0xaf0 drivers/android/binderfs.c:147 binderfs_fill_super+0xa0e/0xe90 drivers/android/binderfs.c:730 vfs_get_super fs/super.c:1280 [inline] get_tree_nodev+0xb8/0x150 fs/super.c:1299 vfs_get_tree+0x8f/0x2b0 fs/super.c:1759 do_new_mount+0x24a/0xa40 fs/namespace.c:3881 do_mount fs/namespace.c:4221 [inline] __do_sys_mount fs/namespace.c:4432 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4409 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xb4/0x110 arch/x86/entry/syscall_32.c:306 do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Freed by task 15829: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2380 [inline] slab_free mm/slub.c:4642 [inline] kfree+0x193/0x440 mm/slub.c:4841 binder_free_proc drivers/android/binder.c:5248 [inline] binder_proc_dec_tmpref+0x228/0x4f0 drivers/android/binder.c:1565 binder_deferred_release drivers/android/binder.c:6292 [inline] binder_deferred_func+0x13a5/0x1520 drivers/android/binder.c:6319 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xadb/0x17a0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address belongs to the object at ffff88801dfdc800 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 176 bytes inside of freed 512-byte region [ffff88801dfdc800, ffff88801dfdca00) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1dfdc head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88801a041c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801a041c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000002 ffffea000077f701 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 Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5845, tgid 5845 (syz-executor), ts 90777696931, free_ts 90692475808 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1d8/0x230 mm/page_alloc.c:1718 prep_new_page mm/page_alloc.c:1726 [inline] get_page_from_freelist+0x21ce/0x22b0 mm/page_alloc.c:3688 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4970 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2450 [inline] allocate_slab+0x8a/0x3b0 mm/slub.c:2618 new_slab mm/slub.c:2672 [inline] ___slab_alloc+0xbfc/0x1480 mm/slub.c:3858 __slab_alloc mm/slub.c:3948 [inline] __slab_alloc_node mm/slub.c:4023 [inline] slab_alloc_node mm/slub.c:4184 [inline] __do_kmalloc_node mm/slub.c:4326 [inline] __kmalloc_noprof+0x305/0x4f0 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] fib6_info_alloc+0x30/0xf0 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x4b3/0x1360 net/ipv6/route.c:3802 addrconf_f6i_alloc+0x1c6/0x3f0 net/ipv6/route.c:4631 ipv6_add_addr+0x56e/0x1090 net/ipv6/addrconf.c:1121 inet6_addr_add+0x387/0xc00 net/ipv6/addrconf.c:3049 inet6_rtm_newaddr+0x93d/0xd20 net/ipv6/addrconf.c:5063 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x219/0x490 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339 page last free pid 36 tgid 36 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0xb0e/0xcd0 mm/page_alloc.c:2725 discard_slab mm/slub.c:2716 [inline] __put_partials+0x161/0x1c0 mm/slub.c:3185 put_cpu_partial+0x17c/0x250 mm/slub.c:3260 __slab_free+0x2f7/0x400 mm/slub.c:4512 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4147 [inline] slab_alloc_node mm/slub.c:4196 [inline] __do_kmalloc_node mm/slub.c:4326 [inline] __kmalloc_noprof+0x224/0x4f0 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] fib6_info_alloc+0x30/0xf0 net/ipv6/ip6_fib.c:155 ip6_route_info_create+0x4b3/0x1360 net/ipv6/route.c:3802 ip6_route_add+0x28/0x160 net/ipv6/route.c:3896 addrconf_add_mroute net/ipv6/addrconf.c:2551 [inline] addrconf_add_dev+0x24f/0x340 net/ipv6/addrconf.c:2569 addrconf_dev_config net/ipv6/addrconf.c:3477 [inline] addrconf_init_auto_addrs+0x5cf/0xb50 net/ipv6/addrconf.c:3571 addrconf_notify+0xacc/0x1010 net/ipv6/addrconf.c:3744 notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85 netif_state_change+0x284/0x3a0 net/core/dev.c:1530 Memory state around the buggy address: ffff88801dfdc780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88801dfdc800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88801dfdc880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801dfdc900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801dfdc980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- Code disassembly (best guess): 0: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 4: 10 07 adc %al,(%rdi) 6: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi a: 10 08 adc %cl,(%rax) c: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 20: 00 51 52 add %dl,0x52(%rcx) 23: 55 push %rbp 24: 89 e5 mov %esp,%ebp 26: 0f 34 sysenter 28: cd 80 int $0x80 * 2a: 5d pop %rbp <-- trapping instruction 2b: 5a pop %rdx 2c: 59 pop %rcx 2d: c3 ret 2e: 90 nop 2f: 90 nop 30: 90 nop 31: 90 nop 32: 90 nop 33: 90 nop 34: 90 nop 35: 90 nop 36: 90 nop 37: 90 nop 38: 90 nop 39: 90 nop 3a: 90 nop 3b: 90 nop 3c: 90 nop 3d: 90 nop 3e: 90 nop 3f: 90 nop