==================================================================
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:791 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:824 [inline]
BUG: KASAN: use-after-free in expire_timers kernel/time/timer.c:1482 [inline]
BUG: KASAN: use-after-free in __run_timers+0x7be/0xbe0 kernel/time/timer.c:1817
Write of size 8 at addr ffff8881de9131c8 by task syz.1.1526/5757

CPU: 1 PID: 5757 Comm: syz.1.1526 Not tainted 5.4.290-syzkaller-00017-g6b07fcd94a6a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 <IRQ>
 __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_del include/linux/list.h:791 [inline]
 detach_timer kernel/time/timer.c:824 [inline]
 expire_timers kernel/time/timer.c:1482 [inline]
 __run_timers+0x7be/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
 </IRQ>
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:166 [inline]
RIP: 0010:unwind_next_frame+0x2a5/0x1ea0 arch/x86/kernel/unwind_orc.c:438
Code: f8 48 8d 1c 85 58 dd b7 86 48 89 d8 48 c1 e8 03 49 bd 00 00 00 00 00 fc ff df 42 0f b6 04 28 84 c0 0f 85 53 18 00 00 44 8b 33 <44> 89 f8 ff c0 48 8d 1c 85 58 dd b7 86 48 89 d8 48 c1 e8 03 42 0f
RSP: 0018:ffff8881e3bc6e20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffffff86c55d58 RCX: ffffffff84573f00
RDX: 0000000000038021 RSI: 0000000000000040 RDI: ffffffff812fbdbc
RBP: ffff8881e3bc7110 R08: ffffffff8153c592 R09: ffff8881e3bc7170
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff8460008f
R13: dffffc0000000000 R14: 000000000009efbb R15: 0000000000036000
 arch_stack_walk+0x111/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1c0 kernel/stacktrace.c:123
 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
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842
 kmem_cache_zalloc include/linux/slab.h:680 [inline]
 __kernfs_new_node+0xdb/0x6e0 fs/kernfs/dir.c:639
 kernfs_new_node+0x130/0x230 fs/kernfs/dir.c:717
 __kernfs_create_file+0x45/0x260 fs/kernfs/file.c:1001
 sysfs_add_file_mode_ns+0x292/0x340 fs/sysfs/file.c:306
 create_files fs/sysfs/group.c:63 [inline]
 internal_create_group+0x573/0xf00 fs/sysfs/group.c:148
 internal_create_groups fs/sysfs/group.c:188 [inline]
 sysfs_create_groups+0x52/0x110 fs/sysfs/group.c:214
 device_add_groups drivers/base/core.c:2007 [inline]
 device_add_attrs+0x87/0x370 drivers/base/core.c:2155
 device_add+0x4f4/0xbb0 drivers/base/core.c:2862
 netdev_register_kobject+0x176/0x310 net/core/net-sysfs.c:1854
 register_netdevice+0xbc5/0x12a0 net/core/dev.c:9209
 ppp_unit_register drivers/net/ppp/ppp_generic.c:1020 [inline]
 ppp_dev_configure+0x7f7/0xab0 drivers/net/ppp/ppp_generic.c:1076
 ppp_create_interface drivers/net/ppp/ppp_generic.c:3090 [inline]
 ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:864 [inline]
 ppp_ioctl+0x672/0x15d0 drivers/net/ppp/ppp_generic.c:617
 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
RIP: 0033:0x7f16d0f23169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f16cf58d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f16d113bfa0 RCX: 00007f16d0f23169
RDX: 000000110c230000 RSI: 00000000c004743e RDI: 000000000000000a
RBP: 00007f16d0fa42a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f16d113bfa0 R15: 00007fffb92605a8

Allocated by task 5668:
 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
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 __kmalloc_track_caller+0x100/0x2b0 mm/slub.c:4449
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0xb4/0x4d0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1080 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1178 [inline]
 netlink_sendmsg+0x797/0xcf0 net/netlink/af_netlink.c:1875
 sock_sendmsg_nosec net/socket.c:638 [inline]
 __sock_sendmsg net/socket.c:650 [inline]
 __sys_sendto+0x4f3/0x6c0 net/socket.c:1961
 __do_sys_sendto net/socket.c:1973 [inline]
 __se_sys_sendto net/socket.c:1969 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:1969
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 5668:
 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
 skb_release_all net/core/skbuff.c:675 [inline]
 __kfree_skb net/core/skbuff.c:689 [inline]
 consume_skb+0xa5/0x2a0 net/core/skbuff.c:849
 netlink_unicast_kernel net/netlink/af_netlink.c:1307 [inline]
 netlink_unicast+0x93e/0xb20 net/netlink/af_netlink.c:1332
 netlink_sendmsg+0xa18/0xcf0 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:638 [inline]
 __sock_sendmsg net/socket.c:650 [inline]
 __sys_sendto+0x4f3/0x6c0 net/socket.c:1961
 __do_sys_sendto net/socket.c:1973 [inline]
 __se_sys_sendto net/socket.c:1969 [inline]
 __x64_sys_sendto+0xda/0xf0 net/socket.c:1969
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

The buggy address belongs to the object at ffff8881de913000
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 456 bytes inside of
 512-byte region [ffff8881de913000, ffff8881de913200)
The buggy address belongs to the page:
page:ffffea00077a4400 refcount:1 mapcount:0 mapping:ffff8881f5c02500 index:0x0 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff8881f5c02500
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, 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 include/linux/slab.h:561 [inline]
 kzalloc include/linux/slab.h:690 [inline]
 fib6_info_alloc+0x2c/0xd0 net/ipv6/ip6_fib.c:154
 ip6_route_info_create+0x459/0x1420 net/ipv6/route.c:3666
 addrconf_f6i_alloc+0x215/0x4c0 net/ipv6/route.c:4453
 ipv6_add_addr+0x44e/0xd40 net/ipv6/addrconf.c:1114
 add_addr+0x18c/0x470 net/ipv6/addrconf.c:3139
 addrconf_notify+0x9b4/0xe50 net/ipv6/addrconf.c:3656
 notifier_call_chain kernel/notifier.c:98 [inline]
 __raw_notifier_call_chain kernel/notifier.c:399 [inline]
 raw_notifier_call_chain+0x95/0x110 kernel/notifier.c:406
 __dev_notify_flags+0x26e/0x510 net/core/dev.c:1670
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
 pcpu_free_pages mm/percpu-vm.c:64 [inline]
 pcpu_depopulate_chunk mm/percpu-vm.c:328 [inline]
 pcpu_balance_workfn+0x940/0x1450 mm/percpu.c:1865
 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:
 ffff8881de913080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881de913100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881de913180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff8881de913200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881de913280: 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 1e68ac067 P4D 1e68ac067 PUD 0 
Oops: 0010 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5757 Comm: syz.1.1526 Tainted: G    B             5.4.290-syzkaller-00017-g6b07fcd94a6a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6f09d18 EFLAGS: 00010202
RAX: ffffffff8154e8ca RBX: 0000000000000101 RCX: ffff8881e3686e40
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881de9131c0
RBP: ffff8881f6f09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffca80
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881de9131c0
FS:  00007f16cf58d6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001e1cba000 CR4: 00000000003406a0
DR0: 0000000000000000 DR1: 0000400000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 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
 </IRQ>
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:166 [inline]
RIP: 0010:unwind_next_frame+0x2a5/0x1ea0 arch/x86/kernel/unwind_orc.c:438
Code: f8 48 8d 1c 85 58 dd b7 86 48 89 d8 48 c1 e8 03 49 bd 00 00 00 00 00 fc ff df 42 0f b6 04 28 84 c0 0f 85 53 18 00 00 44 8b 33 <44> 89 f8 ff c0 48 8d 1c 85 58 dd b7 86 48 89 d8 48 c1 e8 03 42 0f
RSP: 0018:ffff8881e3bc6e20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffffffff86c55d58 RCX: ffffffff84573f00
RDX: 0000000000038021 RSI: 0000000000000040 RDI: ffffffff812fbdbc
RBP: ffff8881e3bc7110 R08: ffffffff8153c592 R09: ffff8881e3bc7170
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff8460008f
R13: dffffc0000000000 R14: 000000000009efbb R15: 0000000000036000
 arch_stack_walk+0x111/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1c0 kernel/stacktrace.c:123
 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
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842
 kmem_cache_zalloc include/linux/slab.h:680 [inline]
 __kernfs_new_node+0xdb/0x6e0 fs/kernfs/dir.c:639
 kernfs_new_node+0x130/0x230 fs/kernfs/dir.c:717
 __kernfs_create_file+0x45/0x260 fs/kernfs/file.c:1001
 sysfs_add_file_mode_ns+0x292/0x340 fs/sysfs/file.c:306
 create_files fs/sysfs/group.c:63 [inline]
 internal_create_group+0x573/0xf00 fs/sysfs/group.c:148
 internal_create_groups fs/sysfs/group.c:188 [inline]
 sysfs_create_groups+0x52/0x110 fs/sysfs/group.c:214
 device_add_groups drivers/base/core.c:2007 [inline]
 device_add_attrs+0x87/0x370 drivers/base/core.c:2155
 device_add+0x4f4/0xbb0 drivers/base/core.c:2862
 netdev_register_kobject+0x176/0x310 net/core/net-sysfs.c:1854
 register_netdevice+0xbc5/0x12a0 net/core/dev.c:9209
 ppp_unit_register drivers/net/ppp/ppp_generic.c:1020 [inline]
 ppp_dev_configure+0x7f7/0xab0 drivers/net/ppp/ppp_generic.c:1076
 ppp_create_interface drivers/net/ppp/ppp_generic.c:3090 [inline]
 ppp_unattached_ioctl drivers/net/ppp/ppp_generic.c:864 [inline]
 ppp_ioctl+0x672/0x15d0 drivers/net/ppp/ppp_generic.c:617
 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
RIP: 0033:0x7f16d0f23169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f16cf58d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f16d113bfa0 RCX: 00007f16d0f23169
RDX: 000000110c230000 RSI: 00000000c004743e RDI: 000000000000000a
RBP: 00007f16d0fa42a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f16d113bfa0 R15: 00007fffb92605a8
Modules linked in:
CR2: 0000000000000000
---[ end trace 6130834ff9b54eae ]---
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0018:ffff8881f6f09d18 EFLAGS: 00010202
RAX: ffffffff8154e8ca RBX: 0000000000000101 RCX: ffff8881e3686e40
RDX: 0000000000000101 RSI: 0000000000000000 RDI: ffff8881de9131c0
RBP: ffff8881f6f09ec8 R08: ffffffff8154e50e R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 00000000ffffca80
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8881de9131c0
FS:  00007f16cf58d6c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000001e1cba000 CR4: 00000000003406a0
DR0: 0000000000000000 DR1: 0000400000000300 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
----------------
Code disassembly (best guess):
   0:	f8                   	clc
   1:	48 8d 1c 85 58 dd b7 	lea    -0x794822a8(,%rax,4),%rbx
   8:	86
   9:	48 89 d8             	mov    %rbx,%rax
   c:	48 c1 e8 03          	shr    $0x3,%rax
  10:	49 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%r13
  17:	fc ff df
  1a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax
  1f:	84 c0                	test   %al,%al
  21:	0f 85 53 18 00 00    	jne    0x187a
  27:	44 8b 33             	mov    (%rbx),%r14d
* 2a:	44 89 f8             	mov    %r15d,%eax <-- trapping instruction
  2d:	ff c0                	inc    %eax
  2f:	48 8d 1c 85 58 dd b7 	lea    -0x794822a8(,%rax,4),%rbx
  36:	86
  37:	48 89 d8             	mov    %rbx,%rax
  3a:	48 c1 e8 03          	shr    $0x3,%rax
  3e:	42                   	rex.X
  3f:	0f                   	.byte 0xf