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BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:183 [inline]
BUG: KASAN: use-after-free in bpf_fd_array_map_lookup_elem+0x440/0x4c0 kernel/bpf/arraymap.c:374
Read of size 8 at addr ffff8801c6e944b8 by task syz-executor6/9219

CPU: 0 PID: 9219 Comm: syz-executor6 Not tainted 4.15.0-rc7+ #262
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
binder_alloc: binder_alloc_mmap_handler: 9225 20000000-20002000 already mapped failed -16
binder: BINDER_SET_CONTEXT_MGR already set
binder: 9225:9226 ioctl 40046207 0 returned -16
binder_alloc: 9225: binder_alloc_buf, no vma
binder: 9225:9227 transaction failed 29189/-3, size 80-16 line 2903
binder: 9225:9226 IncRefs 0 refcount change on invalid ref 2 ret -22
binder: release 9225:9226 transaction 24 out, still active
binder: send failed reply for transaction 24, target dead
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 __read_once_size include/linux/compiler.h:183 [inline]
 bpf_fd_array_map_lookup_elem+0x440/0x4c0 kernel/bpf/arraymap.c:374
 map_lookup_elem+0x6b5/0xbd0 kernel/bpf/syscall.c:577
 SYSC_bpf kernel/bpf/syscall.c:1711 [inline]
 SyS_bpf+0x922/0x4400 kernel/bpf/syscall.c:1685
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x452cf9
RSP: 002b:00007fa0f5b7fc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452cf9
RDX: 0000000000000018 RSI: 00000000206d1fe8 RDI: 0000000000000001
RBP: 00000000000005da R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f6d10
R13: 00000000ffffffff R14: 00007fa0f5b806d4 R15: 0000000000000000

Allocated by task 5965:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3610
 kmalloc include/linux/slab.h:499 [inline]
 kzalloc include/linux/slab.h:688 [inline]
 superblock_alloc_security security/selinux/hooks.c:391 [inline]
 selinux_sb_alloc_security+0x93/0x2e0 security/selinux/hooks.c:2647
 security_sb_alloc+0x6d/0xa0 security/security.c:357
 alloc_super fs/super.c:213 [inline]
 sget_userns+0x3a9/0xe40 fs/super.c:502
 sget+0xd2/0x120 fs/super.c:557
 mount_nodev+0x37/0x100 fs/super.c:1160
 ramfs_mount+0x2c/0x40 fs/ramfs/inode.c:253
 mount_fs+0x66/0x2d0 fs/super.c:1222
 vfs_kern_mount.part.26+0xc6/0x4a0 fs/namespace.c:1037
 vfs_kern_mount fs/namespace.c:2509 [inline]
 do_new_mount fs/namespace.c:2512 [inline]
 do_mount+0xea4/0x2bb0 fs/namespace.c:2842
 SYSC_mount fs/namespace.c:3058 [inline]
 SyS_mount+0xab/0x120 fs/namespace.c:3035
 entry_SYSCALL_64_fastpath+0x29/0xa0

Freed by task 4793:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3488 [inline]
 kfree+0xd6/0x260 mm/slab.c:3803
 superblock_free_security security/selinux/hooks.c:411 [inline]
 selinux_sb_free_security+0x42/0x50 security/selinux/hooks.c:2652
 security_sb_free+0x48/0x80 security/security.c:362
 __put_super.part.5+0x2a0/0x4b0 fs/super.c:273
 __put_super fs/super.c:268 [inline]
 put_super+0x53/0x70 fs/super.c:290
 deactivate_locked_super+0xb0/0xd0 fs/super.c:323
 deactivate_super+0x141/0x1b0 fs/super.c:343
 cleanup_mnt+0xb2/0x150 fs/namespace.c:1173
 __cleanup_mnt+0x16/0x20 fs/namespace.c:1180
 task_work_run+0x199/0x270 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x296/0x310 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x9e/0xa0

The buggy address belongs to the object at ffff8801c6e943c0
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 248 bytes inside of
 256-byte region [ffff8801c6e943c0, ffff8801c6e944c0)
The buggy address belongs to the page:
page:ffffea00071ba500 count:1 mapcount:0 mapping:ffff8801c6e94000 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801c6e94000 0000000000000000 000000010000000c
raw: ffffea00071beda0 ffffea0006f59820 ffff8801dac007c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801c6e94380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801c6e94400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801c6e94480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                                        ^
 ffff8801c6e94500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801c6e94580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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