KASAN: use-after-free Read in loop_control

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
android-54	KASAN: use-after-free Read in loop_control_ioctl				1	689d	689d	0/2	auto-obsoleted due to no activity on 2023/05/04 06:54
==================================================================
BUG: KASAN: use-after-free in mutex_can_spin_on_owner kernel/locking/mutex.c:617 [inline]
BUG: KASAN: use-after-free in mutex_optimistic_spin kernel/locking/mutex.c:661 [inline]
BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:973 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0xcd7/0x1060 kernel/locking/mutex.c:1114
Read of size 4 at addr ffff8881e1005eb8 by task syz-executor.2/24985

CPU: 1 PID: 24985 Comm: syz-executor.2 Not tainted 5.4.254-syzkaller-00004-g8e02ba97da24 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d8/0x241 lib/dump_stack.c:118
 print_address_description+0x8c/0x600 mm/kasan/report.c:384
 __kasan_report+0xf3/0x120 mm/kasan/report.c:516
 kasan_report+0x30/0x60 mm/kasan/common.c:653
 mutex_can_spin_on_owner kernel/locking/mutex.c:617 [inline]
 mutex_optimistic_spin kernel/locking/mutex.c:661 [inline]
 __mutex_lock_common kernel/locking/mutex.c:973 [inline]
 __mutex_lock+0xcd7/0x1060 kernel/locking/mutex.c:1114
 mutex_lock_killable+0xd8/0x110 kernel/locking/mutex.c:1348
 loop_control_ioctl+0x95/0x620 drivers/block/loop.c:2265
 do_vfs_ioctl+0x742/0x1720 fs/ioctl.c:47
 ksys_ioctl fs/ioctl.c:742 [inline]
 __do_sys_ioctl fs/ioctl.c:749 [inline]
 __se_sys_ioctl fs/ioctl.c:747 [inline]
 __x64_sys_ioctl+0xd4/0x110 fs/ioctl.c:747
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Allocated by task 24903:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 __kasan_kmalloc+0x171/0x210 mm/kasan/common.c:529
 slab_post_alloc_hook mm/slab.h:584 [inline]
 slab_alloc_node mm/slub.c:2829 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0xd9/0x250 mm/slub.c:2842
 kmem_cache_alloc_node include/linux/slab.h:427 [inline]
 alloc_task_struct_node kernel/fork.c:171 [inline]
 dup_task_struct+0x4f/0x600 kernel/fork.c:874
 copy_process+0x56d/0x3230 kernel/fork.c:1881
 _do_fork+0x197/0x900 kernel/fork.c:2391
 __do_sys_clone3 kernel/fork.c:2680 [inline]
 __se_sys_clone3 kernel/fork.c:2667 [inline]
 __x64_sys_clone3+0x2da/0x300 kernel/fork.c:2667
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1

Freed by task 10:
 save_stack mm/kasan/common.c:70 [inline]
 set_track mm/kasan/common.c:78 [inline]
 kasan_set_free_info mm/kasan/common.c:345 [inline]
 __kasan_slab_free+0x1b5/0x270 mm/kasan/common.c:487
 slab_free_hook mm/slub.c:1455 [inline]
 slab_free_freelist_hook mm/slub.c:1494 [inline]
 slab_free mm/slub.c:3080 [inline]
 kmem_cache_free+0x10b/0x2c0 mm/slub.c:3096
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch+0x492/0xa00 kernel/rcu/tree.c:2167
 rcu_core+0x4c8/0xcb0 kernel/rcu/tree.c:2387
 __do_softirq+0x23b/0x6b7 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881e1005e80
 which belongs to the cache task_struct of size 3904
The buggy address is located 56 bytes inside of
 3904-byte region [ffff8881e1005e80, ffff8881e1006dc0)
The buggy address belongs to the page:
page:ffffea0007840000 refcount:1 mapcount:0 mapping:ffff8881f5cf9b80 index:0xffff8881e1003f00 compound_mapcount: 0
flags: 0x8000000000010200(slab|head)
raw: 8000000000010200 ffffea0006884408 ffffea0006b11208 ffff8881f5cf9b80
raw: ffff8881e1003f00 0000000000080003 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)
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2165 [inline]
 prep_new_page+0x18f/0x370 mm/page_alloc.c:2171
 get_page_from_freelist+0x2d13/0x2d90 mm/page_alloc.c:3794
 __alloc_pages_nodemask+0x393/0x840 mm/page_alloc.c:4891
 alloc_slab_page+0x39/0x3c0 mm/slub.c:343
 allocate_slab mm/slub.c:1683 [inline]
 new_slab+0x97/0x440 mm/slub.c:1749
 new_slab_objects mm/slub.c:2505 [inline]
 ___slab_alloc+0x2fe/0x490 mm/slub.c:2667
 __slab_alloc+0x62/0xa0 mm/slub.c:2707
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2837 [inline]
 kmem_cache_alloc+0x109/0x250 mm/slub.c:2842
 kmem_cache_alloc_node include/linux/slab.h:427 [inline]
 alloc_task_struct_node kernel/fork.c:171 [inline]
 dup_task_struct+0x4f/0x600 kernel/fork.c:874
 copy_process+0x56d/0x3230 kernel/fork.c:1881
 _do_fork+0x197/0x900 kernel/fork.c:2391
 __ia32_sys_vfork+0xbf/0x110 kernel/fork.c:2508
 do_syscall_64+0xca/0x1c0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x5c/0xc1
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881e1005d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e1005e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881e1005e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff8881e1005f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881e1005f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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