================================================================== BUG: KASAN: slab-out-of-bounds in strlen+0x57/0x70 lib/string.c:402 Read of size 1 at addr ffff88802fda3758 by task syz.2.2298/13549 CPU: 1 UID: 0 PID: 13549 Comm: syz.2.2298 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_address_description+0x55/0x1e0 mm/kasan/report.c:378 print_report+0x58/0x70 mm/kasan/report.c:482 kasan_report+0x117/0x150 mm/kasan/report.c:595 strlen+0x57/0x70 lib/string.c:402 __fortify_strlen include/linux/fortify-string.h:218 [inline] str_to_user+0x20/0x90 drivers/input/evdev.c:769 evdev_do_ioctl drivers/input/evdev.c:-1 [inline] evdev_ioctl_handler+0x1164/0x1f60 drivers/input/evdev.c:1270 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd237d9e019 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:00007fd238bf2028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fd238026090 RCX: 00007fd237d9e019 RDX: 0000200000000040 RSI: 0000000080404506 RDI: 0000000000000005 RBP: 00007fd237e3500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd238026128 R14: 00007fd238026090 R15: 00007fd23814fa48 Allocated by task 11955: kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x32d/0x660 mm/slub.c:5489 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] br_vlan_add+0x22d/0x1060 net/bridge/br_vlan.c:795 __vlan_add+0x46b/0x29e0 net/bridge/br_vlan.c:297 nbp_vlan_add+0x27c/0xb20 net/bridge/br_vlan.c:1348 br_vlan_info+0x100/0x470 net/bridge/br_netlink.c:711 br_process_vlan_info+0x61f/0x8b0 net/bridge/br_netlink.c:774 br_afspec+0x3a5/0x600 net/bridge/br_netlink.c:842 br_setlink+0x34f/0x830 net/bridge/br_netlink.c:1159 rtnl_bridge_setlink+0x5b6/0x7e0 net/core/rtnetlink.c:5651 rtnetlink_rcv_msg+0x7b9/0xc00 net/core/rtnetlink.c:7085 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmmsg+0x273/0x4d0 net/socket.c:2827 __do_sys_sendmmsg net/socket.c:2854 [inline] __se_sys_sendmmsg net/socket.c:2851 [inline] __x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2851 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff88802fda3000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 832 bytes to the right of allocated 1048-byte region [ffff88802fda3000, ffff88802fda3418) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2fda0 head: order:3 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 ffff88801b002000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88801b002000 dead000000000100 dead000000000122 head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000 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 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5649, tgid 5649 (syz-executor), ts 82561046137, free_ts 57555710775 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1859 prep_new_page mm/page_alloc.c:1867 [inline] get_page_from_freelist+0x21fa/0x2270 mm/page_alloc.c:3946 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5304 alloc_slab_page mm/slub.c:3266 [inline] allocate_slab+0x79/0x5e0 mm/slub.c:3380 new_slab mm/slub.c:3426 [inline] refill_objects+0x2d5/0x350 mm/slub.c:7310 refill_sheaf mm/slub.c:2804 [inline] __pcs_replace_empty_main+0x2bf/0x6b0 mm/slub.c:4675 alloc_from_pcs mm/slub.c:4773 [inline] slab_alloc_node mm/slub.c:4905 [inline] __kmalloc_cache_noprof+0x3a7/0x660 mm/slub.c:5485 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] batadv_hardif_add_interface net/batman-adv/hard-interface.c:878 [inline] batadv_hard_if_event+0x282a/0x3520 net/batman-adv/hard-interface.c:1087 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline] call_netdevice_notifiers net/core/dev.c:2302 [inline] register_netdevice+0x18a4/0x1eb0 net/core/dev.c:11484 veth_newlink+0x49f/0xb70 drivers/net/veth.c:1863 rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3913 __rtnl_newlink net/core/rtnetlink.c:4044 [inline] rtnl_newlink+0x167f/0x1bd0 net/core/rtnetlink.c:4159 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7076 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 page last free pid 5421 tgid 5421 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0xc1e/0xd10 mm/page_alloc.c:2950 __slab_free+0x274/0x2c0 mm/slub.c:5741 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 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:4584 [inline] slab_alloc_node mm/slub.c:4917 [inline] kmem_cache_alloc_noprof+0x2a0/0x5f0 mm/slub.c:4931 alloc_filename fs/namei.c:147 [inline] do_getname+0x2e/0x250 fs/namei.c:187 getname include/linux/fs.h:2537 [inline] class_filename_constructor include/linux/fs.h:2564 [inline] __do_sys_chroot fs/open.c:593 [inline] __se_sys_chroot+0x8d/0x3f0 fs/open.c:588 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802fda3600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802fda3680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88802fda3700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff88802fda3780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88802fda3800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================