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BUG: KASAN: use-after-free in get_disk_and_module block/genhd.c:1788 [inline]
BUG: KASAN: use-after-free in exact_lock+0x38/0xc0 block/genhd.c:677
Read of size 8 at addr ffff88810e20f450 by task udevd/409

CPU: 1 PID: 409 Comm: udevd Not tainted 5.10.117-syzkaller-986967-g0974b8411a58-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3c0 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report+0x1a4/0x1f0 mm/kasan/report.c:436
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
 get_disk_and_module block/genhd.c:1788 [inline]
 exact_lock+0x38/0xc0 block/genhd.c:677
 kobj_lookup+0x2a7/0x440 drivers/base/map.c:119
 get_gendisk+0xf6/0x3c0 block/genhd.c:1002
 bdev_get_gendisk fs/block_dev.c:1108 [inline]
 __blkdev_get+0x1a4/0x1360 fs/block_dev.c:1472
 blkdev_get fs/block_dev.c:1651 [inline]
 blkdev_open+0x21a/0x450 fs/block_dev.c:1768
 do_dentry_open+0x7a2/0x1090 fs/open.c:819
 vfs_open+0x73/0x80 fs/open.c:942
 do_open fs/namei.c:3327 [inline]
 path_openat+0x2638/0x2fd0 fs/namei.c:3444
 do_filp_open+0x200/0x440 fs/namei.c:3471
 do_sys_openat2+0x13b/0x470 fs/open.c:1211
 do_sys_open fs/open.c:1227 [inline]
 __do_sys_openat fs/open.c:1243 [inline]
 __se_sys_openat fs/open.c:1238 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1238
 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fbe00609697
Code: 25 00 00 41 00 3d 00 00 41 00 74 37 64 8b 04 25 18 00 00 00 85 c0 75 5b 44 89 e2 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 85 00 00 00 48 83 c4 68 5d 41 5c c3 0f 1f
RSP: 002b:00007ffd9b83f650 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000056422fc1fe30 RCX: 00007fbe00609697
RDX: 00000000000a0800 RSI: 000056422fc1ab00 RDI: 00000000ffffff9c
RBP: 000056422fc1ab00 R08: 00000000ffffffff R09: 00007ffd9b9e80b8
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800
R13: 000056422fbf8b00 R14: 0000000000000001 R15: 000056422fbea2c0

Allocated by task 422:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:428 [inline]
 ____kasan_kmalloc+0xdc/0x110 mm/kasan/common.c:507
 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:516
 kasan_kmalloc include/linux/kasan.h:269 [inline]
 kmem_cache_alloc_trace+0x1dd/0x330 mm/slub.c:2983
 kmem_cache_alloc_node_trace include/linux/slab.h:440 [inline]
 kmalloc_node include/linux/slab.h:570 [inline]
 kzalloc_node include/linux/slab.h:675 [inline]
 __alloc_disk_node+0x75/0x330 block/genhd.c:1728
 loop_add+0x372/0x870 drivers/block/loop.c:2133
 loop_control_ioctl+0x564/0x740 drivers/block/loop.c:2299
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0x115/0x190 fs/ioctl.c:739
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739
 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 422:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4c/0x80 mm/kasan/common.c:46
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:357
 ____kasan_slab_free+0x121/0x160 mm/kasan/common.c:360
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:368
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:1604 [inline]
 slab_free_freelist_hook+0xcc/0x1a0 mm/slub.c:1630
 slab_free mm/slub.c:3212 [inline]
 kfree+0xc3/0x290 mm/slub.c:4200
 disk_release+0x240/0x2a0 block/genhd.c:1569
 device_release+0x9c/0x1d0 drivers/base/core.c:2114
 kobject_cleanup lib/kobject.c:705 [inline]
 kobject_release lib/kobject.c:736 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x163/0x240 lib/kobject.c:753
 put_disk+0x23/0x30 block/genhd.c:1816
 loop_add+0x61d/0x870 drivers/block/loop.c:2178
 loop_control_ioctl+0x564/0x740 drivers/block/loop.c:2299
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0x115/0x190 fs/ioctl.c:739
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739
 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88810e20f000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1104 bytes inside of
 2048-byte region [ffff88810e20f000, ffff88810e20f800)
The buggy address belongs to the page:
page:ffffea0004388200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e208
head:ffffea0004388200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 dead000000000100 dead000000000122 ffff888100042d80
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 0x1d2a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 19, ts 42366525015, free_ts 42020874765
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2385 [inline]
 prep_new_page mm/page_alloc.c:2391 [inline]
 get_page_from_freelist+0x745/0x760 mm/page_alloc.c:4067
 __alloc_pages_nodemask+0x3b6/0x890 mm/page_alloc.c:5117
 alloc_slab_page mm/slub.c:1815 [inline]
 allocate_slab+0x78/0x540 mm/slub.c:1817
 new_slab mm/slub.c:1878 [inline]
 new_slab_objects mm/slub.c:2637 [inline]
 ___slab_alloc+0x131/0x2e0 mm/slub.c:2800
 __slab_alloc+0x63/0xa0 mm/slub.c:2840
 slab_alloc_node mm/slub.c:2922 [inline]
 slab_alloc mm/slub.c:2964 [inline]
 __kmalloc_track_caller+0x23e/0x350 mm/slub.c:4545
 __kmalloc_reserve net/core/skbuff.c:143 [inline]
 __alloc_skb+0xbe/0x580 net/core/skbuff.c:211
 alloc_skb include/linux/skbuff.h:1101 [inline]
 alloc_skb_with_frags+0xac/0x5a0 net/core/skbuff.c:5887
 sock_alloc_send_pskb+0x848/0x970 net/core/sock.c:2347
 sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2364
 mld_newpack+0x1b4/0x9c0 net/ipv6/mcast.c:1604
 add_grhead net/ipv6/mcast.c:1707 [inline]
 add_grec+0xf55/0x13d0 net/ipv6/mcast.c:1838
 mld_send_initial_cr+0x1f8/0x2c0 net/ipv6/mcast.c:2088
 ipv6_mc_dad_complete+0x70/0x3b0 net/ipv6/mcast.c:2100
 addrconf_dad_completed+0x66c/0xdd0 net/ipv6/addrconf.c:4221
 addrconf_dad_work+0xd72/0x15d0 net/ipv6/addrconf.c:4006
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1331 [inline]
 __free_pages_ok+0x7f8/0x830 mm/page_alloc.c:1611
 free_the_page mm/page_alloc.c:5178 [inline]
 __free_pages+0x2d2/0x4c0 mm/page_alloc.c:5184
 __free_slab+0xd3/0x190 mm/slub.c:1903
 free_slab mm/slub.c:1918 [inline]
 discard_slab mm/slub.c:1924 [inline]
 unfreeze_partials+0x17d/0x1b0 mm/slub.c:2418
 put_cpu_partial+0xc8/0x190 mm/slub.c:2454
 __slab_free+0x2d8/0x3a0 mm/slub.c:3104
 do_slab_free mm/slub.c:3200 [inline]
 ___cache_free+0x11f/0x140 mm/slub.c:3219
 qlink_free+0x38/0x40 mm/kasan/quarantine.c:146
 qlist_free_all+0x4c/0xc0 mm/kasan/quarantine.c:165
 kasan_quarantine_reduce+0x15a/0x170 mm/kasan/quarantine.c:272
 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:438
 kasan_slab_alloc include/linux/kasan.h:259 [inline]
 slab_post_alloc_hook mm/slab.h:583 [inline]
 slab_alloc_node mm/slub.c:2956 [inline]
 slab_alloc mm/slub.c:2964 [inline]
 kmem_cache_alloc+0x16c/0x300 mm/slub.c:2969
 getname_flags+0xba/0x510 fs/namei.c:141
 user_path_at_empty+0x2d/0x50 fs/namei.c:2726
 user_path_at include/linux/namei.h:59 [inline]
 ksys_umount fs/namespace.c:1761 [inline]
 __do_sys_umount fs/namespace.c:1769 [inline]
 __se_sys_umount fs/namespace.c:1767 [inline]
 __x64_sys_umount+0xf0/0x170 fs/namespace.c:1767
 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:46

Memory state around the buggy address:
 ffff88810e20f300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810e20f380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810e20f400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                 ^
 ffff88810e20f480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810e20f500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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