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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 ffff8881009a0460 by task syz-executor/11213

CPU: 0 PID: 11213 Comm: syz-executor 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_openat fs/open.c:1249 [inline]
 __se_sys_openat fs/open.c:1244 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1244
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fcadc335a51
Code: 75 57 89 f0 25 00 00 41 00 3d 00 00 41 00 74 49 80 3d fa 1a 1f 00 00 74 6d 89 da 48 89 ee bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 93 00 00 00 48 8b 54 24 28 64 48 2b 14 25
RSP: 002b:00007ffcf3b03cb0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fcadc335a51
RDX: 0000000000000002 RSI: 00007ffcf3b03dc0 RDI: 00000000ffffff9c
RBP: 00007ffcf3b03dc0 R08: 000000000000000a R09: 00007ffcf3b03a77
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000040
R13: 00000000000927c0 R14: 00000000000a3e1f R15: 00007ffcf3b03dc0

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 12664:
 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
 disk_release+0x242/0x2a0 block/genhd.c:1568
 device_release+0x95/0x1c0
 kobject_cleanup lib/kobject.c:713 [inline]
 kobject_release lib/kobject.c:744 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x178/0x260 lib/kobject.c:761
 put_disk+0x23/0x30 block/genhd.c:1815
 loop_remove+0x93/0xb0 drivers/block/loop.c:2213
 loop_control_ioctl+0x564/0x620 drivers/block/loop.c:2309
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0x114/0x190 fs/ioctl.c:739
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:739
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff8881009a0000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1120 bytes inside of
 2048-byte region [ffff8881009a0000, ffff8881009a0800)
The buggy address belongs to the page:
page:ffffea0004026800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1009a0
head:ffffea0004026800 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 1950660453, 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]
 bdi_alloc+0x4e/0x110 mm/backing-dev.c:746
 blk_alloc_queue+0x112/0x640 block/blk-core.c:535
 brd_alloc+0x100/0x400 drivers/block/brd.c:383
 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
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881009a0300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881009a0380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881009a0400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff8881009a0480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881009a0500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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