================================================================== BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline] BUG: KASAN: use-after-free in atomic_long_read include/linux/atomic/atomic-instrumented.h:1183 [inline] BUG: KASAN: use-after-free in __down_read_trylock kernel/locking/rwsem.c:1348 [inline] BUG: KASAN: use-after-free in down_read_trylock+0x9d/0x660 kernel/locking/rwsem.c:1624 Read of size 8 at addr ffff888123eea070 by task kworker/u4:16/6131 CPU: 0 PID: 6131 Comm: kworker/u4:16 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: writeback wb_workfn (flush-7:2) Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:88 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:427 [inline] kasan_report+0xf1/0x140 mm/kasan/report.c:444 check_region_inline mm/kasan/generic.c:-1 [inline] kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189 __kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31 instrument_atomic_read include/linux/instrumented.h:71 [inline] atomic_long_read include/linux/atomic/atomic-instrumented.h:1183 [inline] __down_read_trylock kernel/locking/rwsem.c:1348 [inline] down_read_trylock+0x9d/0x660 kernel/locking/rwsem.c:1624 trylock_super+0x1f/0xf0 fs/super.c:418 __writeback_inodes_wb+0x119/0x400 fs/fs-writeback.c:2002 wb_writeback+0x41f/0x9d0 fs/fs-writeback.c:2118 wb_check_start_all fs/fs-writeback.c:2244 [inline] wb_do_writeback fs/fs-writeback.c:2270 [inline] wb_workfn+0x858/0xf30 fs/fs-writeback.c:2304 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Allocated by task 58: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:433 [inline] ____kasan_kmalloc mm/kasan/common.c:512 [inline] __kasan_kmalloc+0xda/0x110 mm/kasan/common.c:521 kasan_kmalloc include/linux/kasan.h:227 [inline] __kmalloc_track_caller+0x13c/0x2c0 mm/slub.c:4959 kmalloc_reserve net/core/skbuff.c:357 [inline] __alloc_skb+0x21a/0x740 net/core/skbuff.c:428 alloc_skb include/linux/skbuff.h:1183 [inline] mld_newpack+0x142/0x9e0 net/ipv6/mcast.c:1745 add_grhead+0x5e/0x290 net/ipv6/mcast.c:1856 add_grec+0xd41/0x1100 net/ipv6/mcast.c:1994 mld_send_cr net/ipv6/mcast.c:2081 [inline] mld_ifc_work+0x1e1/0xbe0 net/ipv6/mcast.c:2658 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Freed by task 58: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4a/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x125/0x160 mm/kasan/common.c:365 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:373 kasan_slab_free include/linux/kasan.h:193 [inline] slab_free_hook mm/slub.c:1728 [inline] slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1754 slab_free mm/slub.c:3526 [inline] kfree+0xc4/0x270 mm/slub.c:4588 skb_free_head net/core/skbuff.c:656 [inline] skb_release_data+0x814/0xa10 net/core/skbuff.c:678 skb_release_all net/core/skbuff.c:743 [inline] __kfree_skb net/core/skbuff.c:757 [inline] kfree_skb_reason net/core/skbuff.c:778 [inline] kfree_skb+0xb9/0x2f0 net/core/skbuff.c:792 macsec_start_xmit+0x43f/0x2a60 drivers/net/macsec.c:3428 __netdev_start_xmit include/linux/netdevice.h:5064 [inline] netdev_start_xmit include/linux/netdevice.h:5078 [inline] xmit_one net/core/dev.c:3670 [inline] dev_hard_start_xmit+0x244/0x670 net/core/dev.c:3686 __dev_queue_xmit+0x180d/0x2df0 net/core/dev.c:4309 dev_queue_xmit+0x17/0x20 net/core/dev.c:4342 neigh_resolve_output+0x6cf/0x770 net/core/neighbour.c:1504 neigh_output include/net/neighbour.h:517 [inline] ip6_finish_output2+0x10b6/0x17a0 net/ipv6/ip6_output.c:130 __ip6_finish_output+0x61e/0x7d0 net/ipv6/ip6_output.c:201 ip6_finish_output+0x31/0x240 net/ipv6/ip6_output.c:211 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip6_output+0x1fa/0x410 net/ipv6/ip6_output.c:234 dst_output include/net/dst.h:453 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] mld_sendpack+0x6ab/0xbc0 net/ipv6/mcast.c:1825 mld_send_cr net/ipv6/mcast.c:2126 [inline] mld_ifc_work+0x80c/0xbe0 net/ipv6/mcast.c:2658 process_one_work+0x6be/0xba0 kernel/workqueue.c:2325 worker_thread+0xa59/0x1200 kernel/workqueue.c:2472 kthread+0x411/0x500 kernel/kthread.c:337 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 Last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 insert_work+0x51/0x310 kernel/workqueue.c:1373 __queue_work+0x8e5/0xc60 kernel/workqueue.c:1539 queue_work_on+0xde/0x150 kernel/workqueue.c:1566 queue_work include/linux/workqueue.h:510 [inline] schedule_work include/linux/workqueue.h:571 [inline] destroy_super_rcu+0xd1/0xe0 fs/super.c:172 rcu_do_batch+0x532/0xbe0 kernel/rcu/tree.c:2523 rcu_core+0x5ee/0xf80 kernel/rcu/tree.c:2763 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2776 handle_softirqs+0x250/0x560 kernel/softirq.c:583 __do_softirq kernel/softirq.c:621 [inline] invoke_softirq kernel/softirq.c:443 [inline] __irq_exit_rcu+0x52/0xf0 kernel/softirq.c:670 irq_exit_rcu+0x9/0x10 kernel/softirq.c:682 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:676 Second to last potentially related work creation: kasan_save_stack+0x3a/0x60 mm/kasan/common.c:38 __kasan_record_aux_stack+0xd2/0x100 mm/kasan/generic.c:348 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:358 __call_rcu_common kernel/rcu/tree.c:3011 [inline] call_rcu+0x10b/0xf80 kernel/rcu/tree.c:3129 __put_super+0x26b/0x2d0 fs/super.c:299 put_super fs/super.c:313 [inline] deactivate_locked_super+0xd4/0x100 fs/super.c:346 deactivate_super+0xaf/0xe0 fs/super.c:366 cleanup_mnt+0x45b/0x510 fs/namespace.c:1148 __cleanup_mnt+0x19/0x20 fs/namespace.c:1155 task_work_run+0x127/0x190 kernel/task_work.c:188 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop+0xd0/0xe0 kernel/entry/common.c:181 exit_to_user_mode_prepare+0x87/0xd0 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x1a/0x30 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff888123eea000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 112 bytes inside of 2048-byte region [ffff888123eea000, ffff888123eea800) The buggy address belongs to the page: page:ffffea00048fba00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888123eec000 pfn:0x123ee8 head:ffffea00048fba00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 ffffea000412f608 ffffea00048ab808 ffff888100043200 raw: ffff888123eec000 0000000000080006 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 821, ts 41457430616, free_ts 35282542271 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611 get_page_from_freelist+0x2d3a/0x2dc0 mm/page_alloc.c:4485 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5808 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1937 [inline] new_slab+0xa1/0x4d0 mm/slub.c:2000 ___slab_alloc+0x381/0x810 mm/slub.c:3033 __slab_alloc+0x49/0x90 mm/slub.c:3120 slab_alloc_node mm/slub.c:3211 [inline] slab_alloc mm/slub.c:3255 [inline] __kmalloc_track_caller+0x169/0x2c0 mm/slub.c:4954 kmemdup+0x26/0x60 mm/util.c:132 neigh_sysctl_register+0xbe/0xa90 net/core/neighbour.c:3652 addrconf_sysctl_register+0xb3/0x1a0 net/ipv6/addrconf.c:7207 ipv6_add_dev+0xc03/0x1150 net/ipv6/addrconf.c:456 addrconf_notify+0x582/0xde0 net/ipv6/addrconf.c:3600 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0x90/0x100 kernel/notifier.c:391 call_netdevice_notifiers_info net/core/dev.c:2070 [inline] call_netdevice_notifiers_extack net/core/dev.c:2082 [inline] call_netdevice_notifiers+0x119/0x190 net/core/dev.c:2096 register_netdevice+0x10e5/0x1460 net/core/dev.c:10449 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1472 [inline] free_pcp_prepare mm/page_alloc.c:1544 [inline] free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534 free_unref_page+0xae/0x540 mm/page_alloc.c:3616 free_the_page mm/page_alloc.c:805 [inline] __free_pages+0x6c/0x100 mm/page_alloc.c:5884 free_pages+0x82/0x90 mm/page_alloc.c:5895 kasan_depopulate_vmalloc_pte+0x6b/0x90 mm/kasan/shadow.c:354 apply_to_pte_range mm/memory.c:2643 [inline] apply_to_pmd_range mm/memory.c:2687 [inline] apply_to_pud_range mm/memory.c:2723 [inline] apply_to_p4d_range mm/memory.c:2759 [inline] __apply_to_page_range+0x8cd/0xc70 mm/memory.c:2795 apply_to_existing_page_range+0x38/0x50 mm/memory.c:2828 kasan_release_vmalloc+0x97/0xb0 mm/kasan/shadow.c:464 __purge_vmap_area_lazy+0xa93/0x18a0 mm/vmalloc.c:1723 _vm_unmap_aliases+0x2fd/0x380 mm/vmalloc.c:2126 vm_remove_mappings mm/vmalloc.c:2619 [inline] __vunmap+0x690/0xa00 mm/vmalloc.c:2650 __vfree mm/vmalloc.c:2709 [inline] vfree+0x8b/0xc0 mm/vmalloc.c:2740 module_memfree+0x17/0x30 kernel/module.c:2150 bpf_jit_free_exec+0x15/0x20 kernel/bpf/core.c:871 bpf_jit_binary_free kernel/bpf/core.c:918 [inline] bpf_jit_free+0x98/0x240 kernel/bpf/core.c:931 bpf_prog_free_deferred+0x5c7/0x6d0 kernel/bpf/core.c:2315 Memory state around the buggy address: ffff888123ee9f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888123ee9f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888123eea000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888123eea080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888123eea100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================