Bug 200017

Created attachment 276443 [details]
Found this bug with modified syzkaller

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BUG: KASAN: slab-out-of-bounds in predicate_parse kernel/trace/trace_events_filter.c:557 [inline]
BUG: KASAN: slab-out-of-bounds in process_preds+0x140a/0x16b0 kernel/trace/trace_events_filter.c:1509
Write of size 4 at addr ffff8800695b3a10 by task syz-executor1/26773

CPU: 0 PID: 26773 Comm: syz-executor1 Not tainted 4.17.0 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
Call Trace:

Allocated by task 2813:
(stack is not available)

Freed by task 2813:
(stack is not available)

The buggy address belongs to the object at ffff8800695b39c0
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 16 bytes to the right of
 64-byte region [ffff8800695b39c0, ffff8800695b3a00)
The buggy address belongs to the page:
page:ffffea0001a56cc0 count:1 mapcount:0 mapping:ffff88006d0018c0 index:0x0
flags: 0x100000000000100(slab)
raw: 0100000000000100 ffffea0001a626c0 0000000c0000000c ffff88006d0018c0
raw: 0000000000000000 00000000802a002a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8800695b3900: 00 00 00 00 00 00 00 00 fc fc fc fc fb fb fb fb
 ffff8800695b3980: fb fb fb fb fc fc fc fc 00 00 00 00 00 00 00 fc
>ffff8800695b3a00: fc fc fc fc 00 00 00 00 00 00 fc fc fc fc fc fc
                         ^
 ffff8800695b3a80: fb fb fb fb fb fb fb fb fc fc fc fc fb fb fb fb
 ffff8800695b3b00: fb fb fb fb fc fc fc fc fb fb fb fb fb fb fb fb
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