================================================================== 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+0x91/0x660 kernel/locking/rwsem.c:1624 Read of size 8 at addr ffff888129768070 by task kworker/u4:5/2915 CPU: 1 PID: 2915 Comm: kworker/u4:5 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Workqueue: writeback wb_workfn (flush-7:3) Call Trace: __dump_stack+0x21/0x30 lib/dump_stack.c:88 dump_stack_lvl+0xee/0x150 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+0x280/0x290 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+0x91/0x660 kernel/locking/rwsem.c:1624 trylock_super+0x1f/0xf0 fs/super.c:418 __writeback_inodes_wb+0x119/0x400 fs/fs-writeback.c:1992 wb_writeback+0x403/0x980 fs/fs-writeback.c:2108 wb_check_old_data_flush fs/fs-writeback.c:2212 [inline] wb_do_writeback fs/fs-writeback.c:2265 [inline] wb_workfn+0x9ae/0xe20 fs/fs-writeback.c:2294 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 12089: 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+0x13a/0x9d0 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:2120 [inline] mld_ifc_work+0x75d/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 12089: 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 ip6_mc_input+0x235/0x2a0 net/ipv6/ip6_input.c:572 dst_input include/net/dst.h:463 [inline] ip6_rcv_finish+0x18d/0x360 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:305 [inline] ipv6_rcv+0xe9/0x210 net/ipv6/ip6_input.c:300 __netif_receive_skb_one_core net/core/dev.c:5533 [inline] __netif_receive_skb+0xc8/0x280 net/core/dev.c:5647 process_backlog+0x368/0x600 net/core/dev.c:6524 __napi_poll+0xbe/0x590 net/core/dev.c:7083 napi_poll net/core/dev.c:7150 [inline] net_rx_action+0x371/0x8e0 net/core/dev.c:7240 handle_softirqs+0x250/0x560 kernel/softirq.c:583 __do_softirq+0xb/0xd kernel/softirq.c:621 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+0xd2/0x140 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+0x51d/0xba0 kernel/rcu/tree.c:2523 rcu_core+0x5e4/0xf80 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+0x105/0xfe0 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+0x446/0x500 fs/namespace.c:1139 __cleanup_mnt+0x19/0x20 fs/namespace.c:1146 task_work_run+0x127/0x190 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0xa7e/0x27a0 kernel/exit.c:889 do_group_exit+0x141/0x310 kernel/exit.c:1003 __do_sys_exit_group kernel/exit.c:1014 [inline] __se_sys_exit_group kernel/exit.c:1012 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1012 x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 The buggy address belongs to the object at ffff888129768000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 112 bytes inside of 2048-byte region [ffff888129768000, ffff888129768800) The buggy address belongs to the page: page:ffffea0004a5da00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x129768 head:ffffea0004a5da00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100043200 raw: 0000000000000000 0000000000080008 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 285, ts 27637522341, free_ts 0 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+0x2cc5/0x2d50 mm/page_alloc.c:4485 __alloc_pages+0x18f/0x440 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+0x16a/0x2c0 mm/slub.c:4432 kmalloc include/linux/slab.h:621 [inline] kzalloc include/linux/slab.h:747 [inline] __register_sysctl_table+0xeb/0x1250 fs/proc/proc_sysctl.c:1326 register_net_sysctl+0x238/0x250 net/sysctl_net.c:169 __devinet_sysctl_register+0x2c4/0x390 net/ipv4/devinet.c:2604 devinet_sysctl_register+0x169/0x1e0 net/ipv4/devinet.c:2644 inetdev_init+0x2b9/0x500 net/ipv4/devinet.c:284 inetdev_event+0x1f8/0x10a0 net/ipv4/devinet.c:1544 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:2057 [inline] call_netdevice_notifiers_extack net/core/dev.c:2069 [inline] call_netdevice_notifiers+0x111/0x190 net/core/dev.c:2083 page_owner free stack trace missing Memory state around the buggy address: ffff888129767f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888129767f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888129768000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888129768080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888129768100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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