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BUG: KASAN: use-after-free in smk_destroy_label_list security/smack/smackfs.c:1975 [inline]
BUG: KASAN: use-after-free in smk_write_relabel_self+0x2f6/0x480 security/smack/smackfs.c:2748
Read of size 8 at addr ffff8880981738c0 by task syz-executor.1/12495

CPU: 0 PID: 12495 Comm: syz-executor.1 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1e9/0x30e lib/dump_stack.c:118
 print_address_description+0x66/0x5a0 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 smk_destroy_label_list security/smack/smackfs.c:1975 [inline]
 smk_write_relabel_self+0x2f6/0x480 security/smack/smackfs.c:2748
 __vfs_write+0x9c/0x6e0 fs/read_write.c:495
 __kernel_write+0x120/0x350 fs/read_write.c:516
 write_pipe_buf+0xf9/0x150 fs/splice.c:799
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x351/0x8b0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 default_file_splice_write fs/splice.c:811 [inline]
 do_splice_from fs/splice.c:847 [inline]
 direct_splice_actor+0x1eb/0x2a0 fs/splice.c:1016
 splice_direct_to_actor+0x4a2/0xb60 fs/splice.c:971
 do_splice_direct+0x201/0x340 fs/splice.c:1059
 do_sendfile+0x809/0xfe0 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1582 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0x164/0x1a0 fs/read_write.c:1568
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca69
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f5d87c51c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00000000004fc580 RCX: 000000000045ca69
RDX: 0000000000000000 RSI: 0000000000000006 RDI: 0000000000000007
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000100000064 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008dc R14: 00000000004cba56 R15: 00007f5d87c526d4

Allocated by task 12510:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x103/0x140 mm/kasan/common.c:494
 kmem_cache_alloc_trace+0x234/0x300 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 smk_parse_label_list+0xff/0x280 security/smack/smackfs.c:1955
 smk_write_relabel_self+0x190/0x480 security/smack/smackfs.c:2744
 __vfs_write+0x9c/0x6e0 fs/read_write.c:495
 __kernel_write+0x120/0x350 fs/read_write.c:516
 write_pipe_buf+0xf9/0x150 fs/splice.c:799
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x351/0x8b0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 default_file_splice_write fs/splice.c:811 [inline]
 do_splice_from fs/splice.c:847 [inline]
 direct_splice_actor+0x1eb/0x2a0 fs/splice.c:1016
 splice_direct_to_actor+0x4a2/0xb60 fs/splice.c:971
 do_splice_direct+0x201/0x340 fs/splice.c:1059
 do_sendfile+0x809/0xfe0 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1582 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0x164/0x1a0 fs/read_write.c:1568
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 12502:
 save_stack mm/kasan/common.c:48 [inline]
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0x114/0x170 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x10a/0x220 mm/slab.c:3757
 smk_destroy_label_list security/smack/smackfs.c:1976 [inline]
 smk_write_relabel_self+0x302/0x480 security/smack/smackfs.c:2748
 __vfs_write+0x9c/0x6e0 fs/read_write.c:495
 __kernel_write+0x120/0x350 fs/read_write.c:516
 write_pipe_buf+0xf9/0x150 fs/splice.c:799
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x351/0x8b0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 default_file_splice_write fs/splice.c:811 [inline]
 do_splice_from fs/splice.c:847 [inline]
 direct_splice_actor+0x1eb/0x2a0 fs/splice.c:1016
 splice_direct_to_actor+0x4a2/0xb60 fs/splice.c:971
 do_splice_direct+0x201/0x340 fs/splice.c:1059
 do_sendfile+0x809/0xfe0 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1582 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0x164/0x1a0 fs/read_write.c:1568
 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

The buggy address belongs to the object at ffff8880981738c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8880981738c0, ffff8880981738e0)
The buggy address belongs to the page:
page:ffffea0002605cc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888098173fc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00029be9c8 ffffea00024e3288 ffff8880aa4001c0
raw: ffff888098173fc1 ffff888098173000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888098173780: 00 00 00 fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888098173800: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff888098173880: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                                           ^
 ffff888098173900: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888098173980: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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