================================================================== BUG: KASAN: slab-use-after-free in fib6_add_rt2node net/ipv6/ip6_fib.c:1102 [inline] BUG: KASAN: slab-use-after-free in fib6_add+0x3ced/0x4b60 net/ipv6/ip6_fib.c:1488 Read of size 4 at addr ffff88804f774090 by task syz.5.2065/11622 CPU: 3 UID: 0 PID: 11622 Comm: syz.5.2065 Not tainted 6.15.0-rc4-syzkaller-00147-gebd297a2affa #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: __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:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 fib6_add_rt2node net/ipv6/ip6_fib.c:1102 [inline] fib6_add+0x3ced/0x4b60 net/ipv6/ip6_fib.c:1488 __ip6_ins_rt net/ipv6/route.c:1351 [inline] ip6_route_add+0x8d/0x1c0 net/ipv6/route.c:3900 addrconf_add_mroute+0x1dd/0x350 net/ipv6/addrconf.c:2551 addrconf_add_dev+0x14e/0x1c0 net/ipv6/addrconf.c:2569 addrconf_dev_config net/ipv6/addrconf.c:3480 [inline] addrconf_init_auto_addrs+0x380/0x820 net/ipv6/addrconf.c:3568 addrconf_notify+0xe93/0x19e0 net/ipv6/addrconf.c:3741 notifier_call_chain+0xb9/0x410 kernel/notifier.c:85 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2176 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline] call_netdevice_notifiers net/core/dev.c:2228 [inline] __dev_notify_flags+0x12c/0x2e0 net/core/dev.c:9405 netif_change_flags+0x108/0x160 net/core/dev.c:9434 dev_change_flags+0xba/0x250 net/core/dev_api.c:68 dev_ifsioc+0x148f/0x1ee0 net/core/dev_ioctl.c:565 dev_ioctl+0x223/0x1060 net/core/dev_ioctl.c:821 sock_do_ioctl+0x19d/0x280 net/socket.c:1204 compat_sock_ioctl_trans net/socket.c:3481 [inline] compat_sock_ioctl+0x301/0x730 net/socket.c:3507 __do_compat_sys_ioctl fs/ioctl.c:1004 [inline] __se_compat_sys_ioctl fs/ioctl.c:947 [inline] __ia32_compat_sys_ioctl+0x24c/0x360 fs/ioctl.c:947 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x73/0x120 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: 0023:0xf710e579 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:00000000f50dd55c EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000008914 RDX: 0000000080002280 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 5352: 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:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] kernfs_fop_open+0x244/0xda0 fs/kernfs/file.c:623 do_dentry_open+0x741/0x1c10 fs/open.c:956 vfs_open+0x82/0x3f0 fs/open.c:1086 do_open fs/namei.c:3880 [inline] path_openat+0x1e5e/0x2d40 fs/namei.c:4039 do_filp_open+0x20b/0x470 fs/namei.c:4066 do_sys_openat2+0x11b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_openat fs/open.c:1460 [inline] __se_sys_openat fs/open.c:1455 [inline] __x64_sys_openat+0x174/0x210 fs/open.c:1455 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 5352: 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:247 [inline] __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2398 [inline] slab_free mm/slub.c:4656 [inline] kfree+0x2b6/0x4d0 mm/slub.c:4855 kernfs_fop_release+0x12c/0x1e0 fs/kernfs/file.c:768 __fput+0x3ff/0xb70 fs/file_table.c:465 fput_close_sync+0x118/0x260 fs/file_table.c:570 __do_sys_close fs/open.c:1581 [inline] __se_sys_close fs/open.c:1566 [inline] __x64_sys_close+0x8b/0x120 fs/open.c:1566 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x230 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88804f774000 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 144 bytes inside of freed 512-byte region [ffff88804f774000, ffff88804f774200) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4f774 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 04fff00000000040 ffff88801b442c80 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 04fff00000000040 ffff88801b442c80 dead000000000100 dead000000000122 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 04fff00000000002 ffffea00013ddd01 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 5942, tgid 5942 (syz-executor), ts 46379795258, free_ts 46302032095 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718 prep_new_page mm/page_alloc.c:1726 [inline] get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301 alloc_slab_page mm/slub.c:2468 [inline] allocate_slab mm/slub.c:2632 [inline] new_slab+0x244/0x340 mm/slub.c:2686 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3872 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3962 __slab_alloc_node mm/slub.c:4037 [inline] slab_alloc_node mm/slub.c:4198 [inline] __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4367 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] device_private_init drivers/base/core.c:3537 [inline] device_add+0xccc/0x1a70 drivers/base/core.c:3588 netdev_register_kobject+0x182/0x3a0 net/core/net-sysfs.c:2336 register_netdevice+0x13dc/0x2270 net/core/dev.c:11009 veth_newlink+0x30f/0xa00 drivers/net/veth.c:1818 rtnl_newlink_create net/core/rtnetlink.c:3833 [inline] __rtnl_newlink net/core/rtnetlink.c:3950 [inline] rtnl_newlink+0xc42/0x2000 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x16a/0x440 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339 page last free pid 5949 tgid 5949 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4161 [inline] slab_alloc_node mm/slub.c:4210 [inline] kmem_cache_alloc_node_noprof+0x1d5/0x3b0 mm/slub.c:4262 __alloc_skb+0x2b2/0x380 net/core/skbuff.c:658 alloc_skb include/linux/skbuff.h:1340 [inline] nlmsg_new include/net/netlink.h:1019 [inline] netlink_ack+0x15d/0xb80 net/netlink/af_netlink.c:2471 netlink_rcv_skb+0x347/0x440 net/netlink/af_netlink.c:2540 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] __sys_sendto+0x495/0x510 net/socket.c:2180 __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+0x73/0x120 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 Memory state around the buggy address: ffff88804f773f80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc ffff88804f774000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88804f774080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88804f774100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88804f774180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== ---------------- 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