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BUG: KASAN: double-free or invalid-free in tomoyo_realpath_from_path+0x1de/0x7a0 security/tomoyo/realpath.c:319

CPU: 1 PID: 11697 Comm: syz-executor.3 Not tainted 5.2.0-rc1+ #2
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+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 kasan_report_invalid_free+0x65/0xa0 mm/kasan/report.c:279
 __kasan_slab_free+0x13a/0x150 mm/kasan/common.c:430
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3432 [inline]
 kfree+0xcf/0x220 mm/slab.c:3755
 tomoyo_realpath_from_path+0x1de/0x7a0 security/tomoyo/realpath.c:319
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x2a8/0x3f0 security/tomoyo/file.c:771
 tomoyo_file_open security/tomoyo/tomoyo.c:319 [inline]
 tomoyo_file_open+0xa9/0xd0 security/tomoyo/tomoyo.c:314
 security_file_open+0x71/0x300 security/security.c:1458
 do_dentry_open+0x373/0x1250 fs/open.c:765
 vfs_open+0xa0/0xd0 fs/open.c:887
 do_last fs/namei.c:3416 [inline]
 path_openat+0x10e9/0x46d0 fs/namei.c:3533
 do_filp_open+0x1a1/0x280 fs/namei.c:3563
 do_sys_open+0x3fe/0x5d0 fs/open.c:1070
 __do_sys_open fs/open.c:1088 [inline]
 __se_sys_open fs/open.c:1083 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1083
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4571f0
Code: 31 c0 e9 45 ff ff ff 0f 1f 00 80 3f 00 0f 84 f7 00 00 00 55 53 b9 02 00 00 00 be 00 08 09 00 89 c8 48 81 ec 98 00 00 00 0f 05 <48> 3d 00 f0 ff ff 48 89 c3 0f 87 e9 00 00 00 85 db 0f 88 2f 01 00
RSP: 002b:00007ffee56b06a0 EFLAGS: 00000206 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00000000000cb440 RCX: 00000000004571f0
RDX: 000000000000000c RSI: 0000000000090800 RDI: 00007ffee56b1880
RBP: 0000000000000002 R08: 0000000000000001 R09: 0000555557133940
R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffee56b1880
R13: 00007ffee56b1870 R14: 0000000000000000 R15: 00007ffee56b1880

Allocated by task 11696:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503
 __do_kmalloc mm/slab.c:3660 [inline]
 __kmalloc+0x15c/0x740 mm/slab.c:3669
 kmalloc include/linux/slab.h:552 [inline]
 tomoyo_realpath_from_path+0xcd/0x7a0 security/tomoyo/realpath.c:277
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x2a8/0x3f0 security/tomoyo/file.c:771
 tomoyo_file_open security/tomoyo/tomoyo.c:319 [inline]
 tomoyo_file_open+0xa9/0xd0 security/tomoyo/tomoyo.c:314
 security_file_open+0x71/0x300 security/security.c:1458
 do_dentry_open+0x373/0x1250 fs/open.c:765
 vfs_open+0xa0/0xd0 fs/open.c:887
 do_last fs/namei.c:3416 [inline]
 path_openat+0x10e9/0x46d0 fs/namei.c:3533
 do_filp_open+0x1a1/0x280 fs/namei.c:3563
 do_sys_open+0x3fe/0x5d0 fs/open.c:1070
 __do_sys_open fs/open.c:1088 [inline]
 __se_sys_open fs/open.c:1083 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1083
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 11696:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3432 [inline]
 kfree+0xcf/0x220 mm/slab.c:3755
 tomoyo_realpath_from_path+0x1de/0x7a0 security/tomoyo/realpath.c:319
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x2a8/0x3f0 security/tomoyo/file.c:771
 tomoyo_file_open security/tomoyo/tomoyo.c:319 [inline]
 tomoyo_file_open+0xa9/0xd0 security/tomoyo/tomoyo.c:314
 security_file_open+0x71/0x300 security/security.c:1458
 do_dentry_open+0x373/0x1250 fs/open.c:765
 vfs_open+0xa0/0xd0 fs/open.c:887
 do_last fs/namei.c:3416 [inline]
 path_openat+0x10e9/0x46d0 fs/namei.c:3533
 do_filp_open+0x1a1/0x280 fs/namei.c:3563
 do_sys_open+0x3fe/0x5d0 fs/open.c:1070
 __do_sys_open fs/open.c:1088 [inline]
 __se_sys_open fs/open.c:1083 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1083
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88808b756780
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1792 bytes inside of
 4096-byte region [ffff88808b756780, ffff88808b757780)
The buggy address belongs to the page:
page:ffffea00022dd580 refcount:1 mapcount:0 mapping:ffff8880aa400dc0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea0002924e08 ffffea00027a6588 ffff8880aa400dc0
raw: 0000000000000000 ffff88808b756780 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808b756d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808b756e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808b756e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                   ^
 ffff88808b756f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88808b756f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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