================================================================== BUG: KASAN: slab-out-of-bounds in hlist_add_head include/linux/list.h:814 [inline] BUG: KASAN: slab-out-of-bounds in enqueue_timer+0xb7/0x300 kernel/time/timer.c:541 Write of size 8 at addr ffff8881d24971c8 by task kworker/0:0/5 CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.4.290-syzkaller-00002-g41adfeb3d639 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: rcu_gp process_srcu Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d8/0x241 lib/dump_stack.c:118 print_address_description+0x8c/0x600 mm/kasan/report.c:384 __kasan_report+0xf3/0x120 mm/kasan/report.c:516 kasan_report+0x30/0x60 mm/kasan/common.c:653 hlist_add_head include/linux/list.h:814 [inline] enqueue_timer+0xb7/0x300 kernel/time/timer.c:541 __internal_add_timer kernel/time/timer.c:554 [inline] internal_add_timer+0x240/0x430 kernel/time/timer.c:604 __mod_timer+0x6f1/0x13e0 kernel/time/timer.c:1065 call_timer_fn+0x36/0x390 kernel/time/timer.c:1448 expire_timers kernel/time/timer.c:1493 [inline] __run_timers+0x879/0xbe0 kernel/time/timer.c:1817 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1830 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x195/0x1c0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:539 [inline] smp_apic_timer_interrupt+0x11a/0x490 arch/x86/kernel/apic/apic.c:1161 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:834 RIP: 0010:_find_next_bit lib/find_bit.c:39 [inline] RIP: 0010:find_next_bit+0x4d/0x100 lib/find_bit.c:70 Code: 4d 39 f4 0f 83 c3 00 00 00 49 bd 00 00 00 00 00 fc ff df 4c 89 e0 48 c1 e8 06 49 8d 1c c7 48 89 d8 48 c1 e8 03 42 80 3c 28 00 <74> 08 48 89 df e8 09 9a 67 ff 48 8b 1b 44 89 e1 48 d3 eb 48 d3 e3 RSP: 0018:ffff8881f5da7bd8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff0c989af RBX: ffffffff864c4d78 RCX: ffff8881f5d64ec0 RDX: ffff8881f5d64ec0 RSI: 0000000000000008 RDI: 0000000000000002 RBP: ffff8881f6f4be80 R08: ffffffff822c9af3 R09: ffffed103ebb4f81 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000002 R13: dffffc0000000000 R14: 0000000000000008 R15: ffffffff864c4d78 srcu_readers_unlock_idx kernel/rcu/srcutree.c:272 [inline] srcu_readers_active_idx_check kernel/rcu/srcutree.c:288 [inline] try_check_zero+0x10c/0x360 kernel/rcu/srcutree.c:704 srcu_advance_state kernel/rcu/srcutree.c:1146 [inline] process_srcu+0x1ab/0xc40 kernel/rcu/srcutree.c:1241 process_one_work+0x765/0xd20 kernel/workqueue.c:2290 worker_thread+0xaef/0x1470 kernel/workqueue.c:2436 kthread+0x2da/0x360 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Allocated by task 685: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529 __kmalloc_node include/linux/slab.h:422 [inline] kmalloc_node include/linux/slab.h:599 [inline] kvmalloc_node+0x7e/0xf0 mm/util.c:596 kvmalloc include/linux/mm.h:761 [inline] kvmalloc_array include/linux/mm.h:779 [inline] __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:470 [inline] ptr_ring_init include/linux/ptr_ring.h:488 [inline] skb_array_init include/linux/skb_array.h:182 [inline] pfifo_fast_init+0x240/0x760 net/sched/sch_generic.c:784 qdisc_create_dflt+0x129/0x250 net/sched/sch_generic.c:944 mq_init+0x2c8/0x6b0 net/sched/sch_mq.c:90 qdisc_create_dflt+0x129/0x250 net/sched/sch_generic.c:944 attach_default_qdiscs net/sched/sch_generic.c:1113 [inline] dev_activate+0x11f/0xc00 net/sched/sch_generic.c:1154 __dev_open+0x302/0x420 net/core/dev.c:1335 __dev_change_flags+0x1db/0x6e0 net/core/dev.c:7958 dev_change_flags+0x87/0x190 net/core/dev.c:8029 dev_ifsioc+0x104/0xa60 net/core/dev_ioctl.c:226 dev_ioctl+0x505/0xb40 net/core/dev_ioctl.c:483 sock_do_ioctl+0x295/0x3a0 net/socket.c:1081 sock_ioctl+0x4a4/0x760 net/socket.c:1198 do_vfs_ioctl+0x742/0x1720 fs/ioctl.c:47 ksys_ioctl fs/ioctl.c:742 [inline] __do_sys_ioctl fs/ioctl.c:749 [inline] __se_sys_ioctl fs/ioctl.c:747 [inline] __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 Freed by task 684: save_stack mm/kasan/common.c:70 [inline] set_track mm/kasan/common.c:78 [inline] kasan_set_free_info mm/kasan/common.c:345 [inline] __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487 slab_free_hook mm/slub.c:1455 [inline] slab_free_freelist_hook mm/slub.c:1494 [inline] slab_free mm/slub.c:3080 [inline] kfree+0x123/0x370 mm/slub.c:4071 ptr_ring_cleanup include/linux/ptr_ring.h:670 [inline] pfifo_fast_destroy+0x82/0xd0 net/sched/sch_generic.c:810 qdisc_destroy+0xd2/0x490 net/sched/sch_generic.c:1008 qdisc_put net/sched/sch_generic.c:1035 [inline] shutdown_scheduler_queue net/sched/sch_generic.c:1372 [inline] netdev_for_each_tx_queue include/linux/netdevice.h:2194 [inline] dev_shutdown+0x18a/0x540 net/sched/sch_generic.c:1378 rollback_registered_many+0x87d/0x1330 net/core/dev.c:8643 rollback_registered net/core/dev.c:8692 [inline] unregister_netdevice_queue+0x333/0x500 net/core/dev.c:9786 unregister_netdevice include/linux/netdevice.h:2726 [inline] __tun_detach+0x8de/0x1390 drivers/net/tun.c:747 tun_detach drivers/net/tun.c:763 [inline] tun_chr_close+0x8f/0x130 drivers/net/tun.c:3563 __fput+0x262/0x680 fs/file_table.c:281 task_work_run+0x140/0x170 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x190/0x1a0 arch/x86/entry/common.c:163 prepare_exit_to_usermode+0x199/0x200 arch/x86/entry/common.c:194 entry_SYSCALL_64_after_hwframe+0x5c/0xc1 The buggy address belongs to the object at ffff8881d2494000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 4552 bytes to the right of 8192-byte region [ffff8881d2494000, ffff8881d2496000) The buggy address belongs to the page: page:ffffea0007492400 refcount:1 mapcount:0 mapping:ffff8881f5c0c500 index:0x0 compound_mapcount: 0 flags: 0x8000000000010200(slab|head) raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c0c500 raw: 0000000000000000 0000000000020002 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) set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook mm/page_alloc.c:2165 [inline] prep_new_page+0x18f/0x370 mm/page_alloc.c:2171 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4893 alloc_slab_page+0x39/0x3c0 mm/slub.c:343 allocate_slab mm/slub.c:1683 [inline] new_slab+0x97/0x440 mm/slub.c:1749 new_slab_objects mm/slub.c:2505 [inline] ___slab_alloc+0x2fe/0x490 mm/slub.c:2667 __slab_alloc+0x62/0xa0 mm/slub.c:2707 slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2837 [inline] __kmalloc+0x19b/0x2e0 mm/slub.c:3909 __kmalloc_node include/linux/slab.h:422 [inline] kmalloc_node include/linux/slab.h:599 [inline] kvmalloc_node+0x7e/0xf0 mm/util.c:596 kvmalloc include/linux/mm.h:761 [inline] kvmalloc_array include/linux/mm.h:779 [inline] __ptr_ring_init_queue_alloc include/linux/ptr_ring.h:470 [inline] ptr_ring_init include/linux/ptr_ring.h:488 [inline] skb_array_init include/linux/skb_array.h:182 [inline] pfifo_fast_init+0x109/0x760 net/sched/sch_generic.c:784 qdisc_create_dflt+0x129/0x250 net/sched/sch_generic.c:944 mq_init+0x2c8/0x6b0 net/sched/sch_mq.c:90 qdisc_create_dflt+0x129/0x250 net/sched/sch_generic.c:944 attach_default_qdiscs net/sched/sch_generic.c:1113 [inline] dev_activate+0x11f/0xc00 net/sched/sch_generic.c:1154 __dev_open+0x302/0x420 net/core/dev.c:1335 __dev_change_flags+0x1db/0x6e0 net/core/dev.c:7958 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1176 [inline] free_pcp_prepare mm/page_alloc.c:1233 [inline] free_unref_page_prepare+0x297/0x380 mm/page_alloc.c:3085 free_unref_page mm/page_alloc.c:3134 [inline] free_the_page mm/page_alloc.c:4953 [inline] __free_pages+0xaf/0x140 mm/page_alloc.c:4961 __vunmap+0x75b/0x890 mm/vmalloc.c:2260 bpf_map_free_deferred+0xa8/0x100 kernel/bpf/syscall.c:311 process_one_work+0x765/0xd20 kernel/workqueue.c:2290 worker_thread+0xaef/0x1470 kernel/workqueue.c:2436 kthread+0x2da/0x360 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Memory state around the buggy address: ffff8881d2497080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881d2497100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881d2497180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff8881d2497200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8881d2497280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor instruction fetch in kernel mode #PF: error_code(0x0010) - not-present page PGD 0 P4D 0 Oops: 0010 [#1] PREEMPT SMP KASAN CPU: 0 PID: 10 Comm: ksoftirqd/0 Tainted: G B 5.4.290-syzkaller-00002-g41adfeb3d639 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f5dd7b58 EFLAGS: 00010206 RAX: ffffffff8154e8ca RBX: 0000000000000100 RCX: ffff8881f5dc0000 RDX: 0000000080000100 RSI: 0000000000000000 RDI: ffff8881d24971c0 RBP: ffff8881f5dd7d08 R08: ffffffff8154e50e R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffff9ae0 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d24971c0 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000005e0e000 CR4: 00000000003406b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: call_timer_fn+0x36/0x390 kernel/time/timer.c:1448 expire_timers kernel/time/timer.c:1493 [inline] __run_timers+0x879/0xbe0 kernel/time/timer.c:1817 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1830 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292 run_ksoftirqd+0x1f/0x30 kernel/softirq.c:603 smpboot_thread_fn+0x545/0x930 kernel/smpboot.c:165 kthread+0x2da/0x360 kernel/kthread.c:288 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:354 Modules linked in: CR2: 0000000000000000 ---[ end trace d7538c26642aedb4 ]--- RIP: 0010:0x0 Code: Bad RIP value. RSP: 0018:ffff8881f5dd7b58 EFLAGS: 00010206 RAX: ffffffff8154e8ca RBX: 0000000000000100 RCX: ffff8881f5dc0000 RDX: 0000000080000100 RSI: 0000000000000000 RDI: ffff8881d24971c0 RBP: ffff8881f5dd7d08 R08: ffffffff8154e50e R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffff9ae0 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881d24971c0 FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 0000000005e0e000 CR4: 00000000003406b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 ---------------- Code disassembly (best guess): 0: 4d 39 f4 cmp %r14,%r12 3: 0f 83 c3 00 00 00 jae 0xcc 9: 49 bd 00 00 00 00 00 movabs $0xdffffc0000000000,%r13 10: fc ff df 13: 4c 89 e0 mov %r12,%rax 16: 48 c1 e8 06 shr $0x6,%rax 1a: 49 8d 1c c7 lea (%r15,%rax,8),%rbx 1e: 48 89 d8 mov %rbx,%rax 21: 48 c1 e8 03 shr $0x3,%rax 25: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) * 2a: 74 08 je 0x34 <-- trapping instruction 2c: 48 89 df mov %rbx,%rdi 2f: e8 09 9a 67 ff call 0xff679a3d 34: 48 8b 1b mov (%rbx),%rbx 37: 44 89 e1 mov %r12d,%ecx 3a: 48 d3 eb shr %cl,%rbx 3d: 48 d3 e3 shl %cl,%rbx