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BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic64_dec_if_positive include/asm-generic/atomic-instrumented.h:1176 [inline]
BUG: KASAN: use-after-free in atomic_long_dec_if_positive include/asm-generic/atomic-long.h:515 [inline]
BUG: KASAN: use-after-free in dec_ucount+0x54/0x130 kernel/ucount.c:245
Write of size 8 at addr ffff88801f0a2240 by task kworker/u4:0/9

CPU: 1 PID: 9 Comm: kworker/u4:0 Not tainted 5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:96
 print_address_description.constprop.0.cold+0x6c/0x309 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:436
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 atomic64_dec_if_positive include/asm-generic/atomic-instrumented.h:1176 [inline]
 atomic_long_dec_if_positive include/asm-generic/atomic-long.h:515 [inline]
 dec_ucount+0x54/0x130 kernel/ucount.c:245
 dec_net_namespaces net/core/net_namespace.c:394 [inline]
 cleanup_net+0x6f3/0xb10 net/core/net_namespace.c:611
 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276
 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422
 kthread+0x3e5/0x4d0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Allocated by task 8491:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc mm/kasan/common.c:513 [inline]
 ____kasan_kmalloc mm/kasan/common.c:472 [inline]
 __kasan_kmalloc+0x9b/0xd0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:591 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 alloc_ucounts+0x23d/0x5b0 kernel/ucount.c:169
 set_cred_ucounts+0x171/0x3a0 kernel/cred.c:684
 copy_creds+0x853/0xb20 kernel/cred.c:375
 copy_process+0x1413/0x74c0 kernel/fork.c:1992
 kernel_clone+0xe7/0xab0 kernel/fork.c:2509
 __do_sys_clone+0xc8/0x110 kernel/fork.c:2626
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Freed by task 9:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360
 ____kasan_slab_free mm/kasan/common.c:366 [inline]
 ____kasan_slab_free mm/kasan/common.c:328 [inline]
 __kasan_slab_free+0xfb/0x130 mm/kasan/common.c:374
 kasan_slab_free include/linux/kasan.h:229 [inline]
 slab_free_hook mm/slub.c:1639 [inline]
 slab_free_freelist_hook+0xdf/0x240 mm/slub.c:1664
 slab_free mm/slub.c:3224 [inline]
 kfree+0xeb/0x670 mm/slub.c:4268
 put_ucounts kernel/ucount.c:200 [inline]
 put_ucounts+0x117/0x150 kernel/ucount.c:192
 put_cred_rcu+0x27a/0x520 kernel/cred.c:124
 rcu_do_batch kernel/rcu/tree.c:2558 [inline]
 rcu_core+0x7ab/0x1380 kernel/rcu/tree.c:2793
 __do_softirq+0x29b/0x9bd kernel/softirq.c:558

Last potentially related work creation:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:348
 insert_work+0x48/0x370 kernel/workqueue.c:1332
 __queue_work+0x5c1/0xed0 kernel/workqueue.c:1498
 queue_work_on+0xee/0x110 kernel/workqueue.c:1525
 queue_work include/linux/workqueue.h:507 [inline]
 call_usermodehelper_exec+0x1f0/0x4c0 kernel/umh.c:435
 kobject_uevent_env+0xf8f/0x1650 lib/kobject_uevent.c:618
 device_add+0xb71/0x2100 drivers/base/core.c:3305
 device_create_groups_vargs+0x203/0x280 drivers/base/core.c:3983
 device_create+0xdf/0x120 drivers/base/core.c:4025
 bdi_register_va.part.0+0x9c/0x800 mm/backing-dev.c:871
 bdi_register_va mm/backing-dev.c:906 [inline]
 bdi_register+0x12a/0x140 mm/backing-dev.c:903
 __device_add_disk+0x6fb/0xd10 block/genhd.c:521
 add_disk include/linux/genhd.h:217 [inline]
 nbd_dev_add+0x712/0x900 drivers/block/nbd.c:1709
 nbd_init+0x250/0x271 drivers/block/nbd.c:2369
 do_one_initcall+0x103/0x650 init/main.c:1246
 do_initcall_level init/main.c:1319 [inline]
 do_initcalls init/main.c:1335 [inline]
 do_basic_setup init/main.c:1355 [inline]
 kernel_init_freeable+0x6b8/0x741 init/main.c:1557
 kernel_init+0x1a/0x1d0 init/main.c:1449
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff88801f0a2200
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 64 bytes inside of
 192-byte region [ffff88801f0a2200, ffff88801f0a22c0)
The buggy address belongs to the page:
page:ffffea00007c2880 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1f0a2
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 ffffea000096ed80 0000000800000002 ffff888011041a00
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x12c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY), pid 1, ts 8680961201, free_ts 8668449911
 prep_new_page mm/page_alloc.c:2445 [inline]
 get_page_from_freelist+0xa72/0x2f80 mm/page_alloc.c:4178
 __alloc_pages+0x1b2/0x500 mm/page_alloc.c:5386
 __alloc_pages_node include/linux/gfp.h:570 [inline]
 alloc_slab_page mm/slub.c:1704 [inline]
 allocate_slab+0x96/0x4c0 mm/slub.c:1842
 new_slab mm/slub.c:1905 [inline]
 new_slab_objects mm/slub.c:2651 [inline]
 ___slab_alloc+0x4ba/0x820 mm/slub.c:2814
 __slab_alloc.constprop.0+0xa7/0xf0 mm/slub.c:2854
 slab_alloc_node mm/slub.c:2936 [inline]
 __kmalloc_node+0x2df/0x380 mm/slub.c:4154
 kmalloc_array_node include/linux/slab.h:684 [inline]
 kcalloc_node include/linux/slab.h:689 [inline]
 sbitmap_init_node+0x1c3/0x6f0 lib/sbitmap.c:114
 blk_mq_alloc_hctx block/blk-mq.c:2791 [inline]
 blk_mq_alloc_and_init_hctx block/blk-mq.c:3175 [inline]
 blk_mq_realloc_hw_ctxs+0xc64/0x1570 block/blk-mq.c:3227
 blk_mq_init_allocated_queue+0x320/0x1400 block/blk-mq.c:3288
 blk_mq_init_queue_data block/blk-mq.c:3122 [inline]
 __blk_mq_alloc_disk+0x86/0x190 block/blk-mq.c:3142
 nbd_dev_add+0x27c/0x900 drivers/block/nbd.c:1679
 nbd_init+0x250/0x271 drivers/block/nbd.c:2369
 do_one_initcall+0x103/0x650 init/main.c:1246
 do_initcall_level init/main.c:1319 [inline]
 do_initcalls init/main.c:1335 [inline]
 do_basic_setup init/main.c:1355 [inline]
 kernel_init_freeable+0x6b8/0x741 init/main.c:1557
 kernel_init+0x1a/0x1d0 init/main.c:1449
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1355 [inline]
 free_pcp_prepare+0x2c5/0x780 mm/page_alloc.c:1406
 free_unref_page_prepare mm/page_alloc.c:3341 [inline]
 free_unref_page_list+0x1a1/0x1050 mm/page_alloc.c:3457
 release_pages+0x856/0x20a0 mm/swap.c:972
 tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:242 [inline]
 tlb_flush_mmu mm/mmu_gather.c:249 [inline]
 tlb_finish_mmu+0x165/0x8c0 mm/mmu_gather.c:340
 exit_mmap+0x1ea/0x620 mm/mmap.c:3204
 __mmput+0x122/0x470 kernel/fork.c:1101
 mmput+0x58/0x60 kernel/fork.c:1122
 free_bprm+0x65/0x2e0 fs/exec.c:1482
 kernel_execve+0x380/0x460 fs/exec.c:1979
 call_usermodehelper_exec_async+0x2e3/0x580 kernel/umh.c:112
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Memory state around the buggy address:
 ffff88801f0a2100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88801f0a2180: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801f0a2200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff88801f0a2280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88801f0a2300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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