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BUG: KASAN: use-after-free in get_disk_and_module block/genhd.c:1787 [inline]
BUG: KASAN: use-after-free in exact_lock+0x38/0xd0 block/genhd.c:677
Read of size 8 at addr ffff8881009a9460 by task syz.0.6617/25345

CPU: 1 PID: 25345 Comm: syz.0.6617 Tainted: G        W         5.10.234-syzkaller-00023-g3f5f2283d684 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:435 [inline]
 kasan_report+0x179/0x1c0 mm/kasan/report.c:452
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
 get_disk_and_module block/genhd.c:1787 [inline]
 exact_lock+0x38/0xd0 block/genhd.c:677
 kobj_lookup+0x294/0x430 drivers/base/map.c:119
 get_gendisk+0xf7/0x3d0 block/genhd.c:1001
 bdev_get_gendisk fs/block_dev.c:1110 [inline]
 __blkdev_get+0x18c/0x12f0 fs/block_dev.c:1474
 blkdev_get fs/block_dev.c:1653 [inline]
 blkdev_open+0x241/0x480 fs/block_dev.c:1770
 do_dentry_open+0x7c1/0x10d0 fs/open.c:819
 vfs_open+0x73/0x80 fs/open.c:942
 do_open fs/namei.c:3391 [inline]
 path_openat+0x2660/0x3000 fs/namei.c:3509
 do_filp_open+0x21c/0x460 fs/namei.c:3536
 do_sys_openat2+0x13f/0x710 fs/open.c:1217
 do_sys_open fs/open.c:1233 [inline]
 __do_sys_creat fs/open.c:1309 [inline]
 __se_sys_creat fs/open.c:1303 [inline]
 __x64_sys_creat+0x11f/0x160 fs/open.c:1303
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fa554a00169
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:00007fa55306a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00007fa554c18fa0 RCX: 00007fa554a00169
RDX: 0000000000000000 RSI: 0000000000000010 RDI: 0000400000000100
RBP: 00007fa554a812a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fa554c18fa0 R15: 00007ffe00510c58

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:430 [inline]
 ____kasan_kmalloc+0xdb/0x110 mm/kasan/common.c:509
 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:518
 kasan_kmalloc include/linux/kasan.h:254 [inline]
 kmem_cache_alloc_trace+0x18a/0x2e0 mm/slub.c:2974
 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+0x76/0x570 block/genhd.c:1727
 loop_add+0x32d/0x750 drivers/block/loop.c:2158
 loop_init+0x225/0x263 drivers/block/loop.c:2403
 do_one_initcall+0x189/0x620 init/main.c:1197
 do_initcall_level+0x186/0x304 init/main.c:1270
 do_initcalls+0x4e/0x8e init/main.c:1286
 do_basic_setup+0x88/0x91 init/main.c:1306
 kernel_init_freeable+0x2be/0x3f5 init/main.c:1510
 kernel_init+0x11/0x280 init/main.c:1397
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Freed by task 12:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:45
 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0x121/0x160 mm/kasan/common.c:362
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370
 kasan_slab_free include/linux/kasan.h:220 [inline]
 slab_free_hook mm/slub.c:1595 [inline]
 slab_free_freelist_hook+0xc0/0x190 mm/slub.c:1621
 slab_free mm/slub.c:3203 [inline]
 kfree+0xc3/0x270 mm/slub.c:4191
 skb_free_head net/core/skbuff.c:606 [inline]
 skb_release_data+0x5c6/0x6f0 net/core/skbuff.c:626
 skb_release_all net/core/skbuff.c:680 [inline]
 __kfree_skb net/core/skbuff.c:694 [inline]
 kfree_skb+0xb9/0x320 net/core/skbuff.c:713
 ip6_mc_input+0x233/0x2a0 net/ipv6/ip6_input.c:574
 dst_input include/net/dst.h:443 [inline]
 ip6_rcv_finish+0x185/0x350 net/ipv6/ip6_input.c:80
 NF_HOOK include/linux/netfilter.h:299 [inline]
 ipv6_rcv+0xee/0x270 net/ipv6/ip6_input.c:301
 __netif_receive_skb_one_core net/core/dev.c:5401 [inline]
 __netif_receive_skb+0x1c6/0x530 net/core/dev.c:5515
 process_backlog+0x31c/0x650 net/core/dev.c:6422
 napi_poll net/core/dev.c:6873 [inline]
 net_rx_action+0x516/0x10d0 net/core/dev.c:6943
 __do_softirq+0x268/0x5bb kernel/softirq.c:309

The buggy address belongs to the object at ffff8881009a9000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1120 bytes inside of
 2048-byte region [ffff8881009a9000, ffff8881009a9800)
The buggy address belongs to the page:
page:ffffea0004026a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1009a8
head:ffffea0004026a00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 2022694676, free_ts 0
 set_page_owner include/linux/page_owner.h:35 [inline]
 post_alloc_hook mm/page_alloc.c:2456 [inline]
 prep_new_page+0x166/0x180 mm/page_alloc.c:2462
 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254
 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5348
 allocate_slab mm/slub.c:1808 [inline]
 new_slab+0x80/0x400 mm/slub.c:1869
 new_slab_objects mm/slub.c:2627 [inline]
 ___slab_alloc+0x302/0x4b0 mm/slub.c:2791
 __slab_alloc+0x63/0xa0 mm/slub.c:2831
 slab_alloc_node mm/slub.c:2913 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc_trace+0x1bd/0x2e0 mm/slub.c:2972
 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+0x76/0x570 block/genhd.c:1727
 brd_alloc+0x146/0x400 drivers/block/brd.c:394
 brd_init+0x125/0x474 drivers/block/brd.c:517
 do_one_initcall+0x189/0x620 init/main.c:1197
 do_initcall_level+0x186/0x304 init/main.c:1270
 do_initcalls+0x4e/0x8e init/main.c:1286
 do_basic_setup+0x88/0x91 init/main.c:1306
 kernel_init_freeable+0x2be/0x3f5 init/main.c:1510
 kernel_init+0x11/0x280 init/main.c:1397
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881009a9300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881009a9380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881009a9400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff8881009a9480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881009a9500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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