syzbot

==================================================================
BUG: KASAN: use-after-free in cpu_map_generic_redirect+0x1c7/0x650 kernel/bpf/cpumap.c:788
Read of size 8 at addr ffff88801e3ee218 by task syz.9.3616/19380

CPU: 1 PID: 19380 Comm: syz.9.3616 Tainted: G        W          6.1.120-syzkaller-00773-g52f863f820fd #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:427
 kasan_report+0x136/0x160 mm/kasan/report.c:531
 cpu_map_generic_redirect+0x1c7/0x650 kernel/bpf/cpumap.c:788
 xdp_do_generic_redirect_map net/core/filter.c:4419 [inline]
 xdp_do_generic_redirect+0x401/0x850 net/core/filter.c:4466
 do_xdp_generic+0x50b/0x6d0 net/core/dev.c:4955
 tun_get_user+0x261e/0x42d0 drivers/net/tun.c:1920
 tun_chr_write_iter+0x10c/0x1f0 drivers/net/tun.c:2044
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x857/0xbc0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9e071847cf
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007f9e08001000 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f9e07375fa0 RCX: 00007f9e071847cf
RDX: 0000000000000d86 RSI: 0000000020002340 RDI: 00000000000000c8
RBP: 00007f9e07201a20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000d86 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f9e07375fa0 R15: 00007ffc9924c7e8
 </TASK>

Allocated by task 16519:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x97/0xb0 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:563 [inline]
 kmalloc_array include/linux/slab.h:614 [inline]
 kcalloc include/linux/slab.h:646 [inline]
 kvm_arch_vcpu_create+0x35b/0x920 arch/x86/kvm/x86.c:11973
 kvm_vm_ioctl_create_vcpu+0x30c/0x8e0 virt/kvm/kvm_main.c:3951
 kvm_vm_ioctl+0x60b/0xb60 virt/kvm/kvm_main.c:4723
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Last potentially related work creation:
 kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xb0/0xc0 mm/kasan/generic.c:486
 insert_work+0x54/0x3d0 kernel/workqueue.c:1361
 __queue_work+0xb4b/0xf90 kernel/workqueue.c:1520
 queue_work_on+0x14b/0x250 kernel/workqueue.c:1548
 cpu_map_free+0xd7/0x1b0 kernel/bpf/cpumap.c:641
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Second to last potentially related work creation:
 kasan_save_stack+0x3b/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xb0/0xc0 mm/kasan/generic.c:486
 call_rcu+0x163/0xa10 kernel/rcu/tree.c:2845
 __cpu_map_entry_replace+0x74/0x170 kernel/bpf/cpumap.c:556
 cpu_map_free+0xd7/0x1b0 kernel/bpf/cpumap.c:641
 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292
 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439
 kthread+0x28d/0x320 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff88801e3ee200
 which belongs to the cache kmalloc-cg-256 of size 256
The buggy address is located 24 bytes inside of
 256-byte region [ffff88801e3ee200, ffff88801e3ee300)

The buggy address belongs to the physical page:
page:ffffea000078fb80 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801e3ef000 pfn:0x1e3ee
head:ffffea000078fb80 order:1 compound_mapcount:0 compound_pincount:0
memcg:ffff8880567c5301
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0000779000 dead000000000003 ffff888017c42c80
raw: ffff88801e3ef000 0000000080100006 00000001ffffffff ffff8880567c5301
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4259, tgid 4259 (syz-executor), ts 76895155629, free_ts 76873107901
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4328
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5605
 alloc_slab_page+0x6a/0x150 mm/slub.c:1794
 allocate_slab mm/slub.c:1939 [inline]
 new_slab+0x84/0x2d0 mm/slub.c:1992
 ___slab_alloc+0xc20/0x1270 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 __kmem_cache_alloc_node+0x19f/0x260 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:935 [inline]
 __kmalloc+0xa1/0x230 mm/slab_common.c:949
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 __register_sysctl_table+0xdc/0x11e0 fs/proc/proc_sysctl.c:1341
 smc_sysctl_net_init+0x10b/0x310 net/smc/smc_sysctl.c:90
 smc_net_init+0x12/0x40 net/smc/af_smc.c:3367
 ops_init+0x35d/0x610 net/core/net_namespace.c:138
 setup_net+0x4b5/0xb90 net/core/net_namespace.c:335
 copy_net_ns+0x392/0x5d0 net/core/net_namespace.c:481
 create_new_namespaces+0x425/0x7a0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11e/0x170 kernel/nsproxy.c:226
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x12a6/0x15b0 mm/page_alloc.c:3384
 free_unref_page+0x33/0x3e0 mm/page_alloc.c:3479
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x156/0x170 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook+0x52/0x3a0 mm/slab.h:737
 slab_alloc_node mm/slub.c:3398 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0x10c/0x2d0 mm/slub.c:3422
 skb_clone+0x1e5/0x360 net/core/skbuff.c:1660
 do_one_broadcast net/netlink/af_netlink.c:1440 [inline]
 netlink_broadcast+0x674/0x10b0 net/netlink/af_netlink.c:1506
 netlink_sendmsg+0x8f3/0xd60 net/netlink/af_netlink.c:1857
 sock_sendmsg_nosec net/socket.c:718 [inline]
 __sock_sendmsg net/socket.c:730 [inline]
 ____sys_sendmsg+0x5a5/0x8f0 net/socket.c:2519
 ___sys_sendmsg net/socket.c:2573 [inline]
 __sys_sendmsg+0x2a9/0x390 net/socket.c:2602
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88801e3ee100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801e3ee180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801e3ee200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88801e3ee280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801e3ee300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================