==================================================================
BUG: KASAN: slab-use-after-free in kvm_gmem_release+0x155/0x380
Write of size 8 at addr ffff888028938908 by task syz.2.8319/31908

CPU: 0 UID: 0 PID: 31908 Comm: syz.2.8319 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 kvm_gmem_release+0x155/0x380
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb7cb18ebe9
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:00007fffa02d2d98 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00000000000e2aa1 RCX: 00007fb7cb18ebe9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fb7cb3c7da0 R08: 0000000000000001 R09: 0000000aa02d308f
R10: 0000001b31220000 R11: 0000000000000246 R12: 00007fb7cb3c5fac
R13: 00007fb7cb3c5fa0 R14: ffffffffffffffff R15: 00007fffa02d2eb0
 </TASK>

Allocated by task 31909:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x230/0x3d0
 kvm_set_memory_region+0x747/0xb90
 kvm_vm_ioctl_set_memory_region+0x6f/0xd0
 kvm_vm_ioctl+0x957/0xc60
 __se_sys_ioctl+0xf9/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 31909:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5b/0x80
 kfree+0x18e/0x440
 kvm_set_memslot+0xf77/0x1310
 kvm_set_memory_region+0x966/0xb90
 kvm_vm_ioctl_set_memory_region+0x6f/0xd0
 kvm_vm_ioctl+0x957/0xc60
 __se_sys_ioctl+0xf9/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888028938800
 which belongs to the cache kmalloc-cg-512 of size 512
The buggy address is located 264 bytes inside of
 freed 512-byte region [ffff888028938800, ffff888028938a00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28938
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888031bd1d01
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a44b140 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080100010 00000000f5000000 ffff888031bd1d01
head: 00fff00000000040 ffff88801a44b140 dead000000000122 0000000000000000
head: 0000000000000000 0000000080100010 00000000f5000000 ffff888031bd1d01
head: 00fff00000000002 ffffea0000a24e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 31904, tgid 31903 (syz.0.8318), ts 928613526545, free_ts 67553771800
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x8a/0x370
 ___slab_alloc+0xbeb/0x1410
 __kmalloc_cache_noprof+0x296/0x3d0
 kvm_set_memory_region+0x747/0xb90
 kvm_vm_ioctl_set_memory_region+0x6f/0xd0
 kvm_vm_ioctl+0x957/0xc60
 __se_sys_ioctl+0xf9/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5906 tgid 5906 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 __slab_free+0x303/0x3c0
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 getname_flags+0xb8/0x540
 vfs_fstatat+0x43/0x170
 __x64_sys_newfstatat+0x116/0x190
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888028938800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028938880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888028938900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888028938980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028938a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
