================================================================== BUG: KASAN: slab-use-after-free in br_switchdev_fdb_populate net/bridge/br_switchdev.c:141 [inline] BUG: KASAN: slab-use-after-free in br_switchdev_fdb_notify+0x30b/0x3e0 net/bridge/br_switchdev.c:165 Read of size 8 at addr ffff888032b75008 by task kworker/1:5/5899 CPU: 1 UID: 0 PID: 5899 Comm: kworker/1:5 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_long br_fdb_cleanup Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 br_switchdev_fdb_populate net/bridge/br_switchdev.c:141 [inline] br_switchdev_fdb_notify+0x30b/0x3e0 net/bridge/br_switchdev.c:165 fdb_notify+0x89/0x160 net/bridge/br_fdb.c:186 fdb_delete+0xdcf/0x1060 net/bridge/br_fdb.c:324 br_fdb_cleanup+0x2aa/0x4d0 net/bridge/br_fdb.c:574 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 5830: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5748 kmalloc_noprof include/linux/slab.h:957 [inline] kzalloc_noprof include/linux/slab.h:1094 [inline] new_nbp+0x188/0x440 net/bridge/br_if.c:431 br_add_if+0x28e/0xec0 net/bridge/br_if.c:599 do_set_master+0x533/0x6d0 net/core/rtnetlink.c:2956 do_setlink+0xcf0/0x41c0 net/core/rtnetlink.c:3158 rtnl_changelink net/core/rtnetlink.c:3769 [inline] __rtnl_newlink net/core/rtnetlink.c:3928 [inline] rtnl_newlink+0x1619/0x1c80 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 __sys_sendto+0x3bd/0x520 net/socket.c:2244 __do_sys_sendto net/socket.c:2251 [inline] __se_sys_sendto net/socket.c:2247 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2247 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 50: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2523 [inline] slab_free mm/slub.c:6611 [inline] kfree+0x19a/0x6d0 mm/slub.c:6818 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x22b/0x480 lib/kobject.c:737 rcu_do_batch kernel/rcu/tree.c:2605 [inline] rcu_core+0xcab/0x1770 kernel/rcu/tree.c:2861 handle_softirqs+0x286/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_call_function_single arch/x86/kernel/smp.c:266 [inline] sysvec_call_function_single+0xa3/0xc0 arch/x86/kernel/smp.c:266 asm_sysvec_call_function_single+0x1a/0x20 arch/x86/include/asm/idtentry.h:704 Last potentially related work creation: kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559 __call_rcu_common kernel/rcu/tree.c:3123 [inline] call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3243 br_del_if+0x146/0x320 net/bridge/br_if.c:740 do_set_master+0x312/0x6d0 net/core/rtnetlink.c:2940 do_setlink+0xcf0/0x41c0 net/core/rtnetlink.c:3158 rtnl_group_changelink net/core/rtnetlink.c:3783 [inline] __rtnl_newlink net/core/rtnetlink.c:3937 [inline] rtnl_newlink+0x14ad/0x1c80 net/core/rtnetlink.c:4065 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6954 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x830 net/socket.c:2630 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The buggy address belongs to the object at ffff888032b75000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 8 bytes inside of freed 1024-byte region [ffff888032b75000, ffff888032b75400) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x32b70 head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: f5(slab) raw: 00fff00000000040 ffff88813ffa6dc0 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000040 ffff88813ffa6dc0 0000000000000000 dead000000000001 head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000 head: 00fff00000000003 ffffea0000cadc01 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 5864, tgid 5864 (kworker/u8:0), ts 92600462520, free_ts 92593667807 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850 prep_new_page mm/page_alloc.c:1858 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416 alloc_slab_page mm/slub.c:3039 [inline] allocate_slab+0x96/0x3a0 mm/slub.c:3212 new_slab mm/slub.c:3266 [inline] ___slab_alloc+0xe94/0x18a0 mm/slub.c:4636 __slab_alloc+0x65/0x100 mm/slub.c:4755 __slab_alloc_node mm/slub.c:4831 [inline] slab_alloc_node mm/slub.c:5253 [inline] __do_kmalloc_node mm/slub.c:5626 [inline] __kmalloc_noprof+0x471/0x7f0 mm/slub.c:5639 kmalloc_noprof include/linux/slab.h:961 [inline] load_elf_phdrs+0x13e/0x230 fs/binfmt_elf.c:540 load_elf_binary+0x959/0x2740 fs/binfmt_elf.c:969 search_binary_handler fs/exec.c:1670 [inline] exec_binprm fs/exec.c:1702 [inline] bprm_execve+0x99c/0x1450 fs/exec.c:1754 kernel_execve+0x8f0/0x9f0 fs/exec.c:1920 call_usermodehelper_exec_async+0x210/0x360 kernel/umh.c:109 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 page last free pid 5863 tgid 5863 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906 discard_slab mm/slub.c:3310 [inline] __put_partials+0x146/0x170 mm/slub.c:3857 put_cpu_partial+0x1f2/0x2e0 mm/slub.c:3932 __slab_free+0x2b9/0x390 mm/slub.c:5906 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4955 [inline] slab_alloc_node mm/slub.c:5265 [inline] __do_kmalloc_node mm/slub.c:5626 [inline] __kmalloc_noprof+0x3c3/0x7f0 mm/slub.c:5639 kmalloc_noprof include/linux/slab.h:961 [inline] tomoyo_realpath_from_path+0xe3/0x5d0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x213/0x4b0 security/tomoyo/file.c:822 security_inode_getattr+0x12f/0x330 security/security.c:2416 vfs_getattr fs/stat.c:259 [inline] vfs_fstat fs/stat.c:281 [inline] __do_sys_newfstat fs/stat.c:555 [inline] __se_sys_newfstat fs/stat.c:550 [inline] __x64_sys_newfstat+0xfc/0x200 fs/stat.c:550 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff888032b74f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888032b74f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888032b75000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888032b75080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888032b75100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================