==================================================================
BUG: KASAN: slab-out-of-bounds in qrtr_endpoint_post+0xeeb/0x1010 net/qrtr/qrtr.c:462
Read of size 2 at addr ffff8880a848f3c8 by task syz-executor063/6829

CPU: 0 PID: 6829 Comm: syz-executor063 Not tainted 5.8.0-rc2-next-20200626-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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 qrtr_endpoint_post+0xeeb/0x1010 net/qrtr/qrtr.c:462
 qrtr_tun_write_iter+0xf5/0x180 net/qrtr/tun.c:92
 call_write_iter include/linux/fs.h:1877 [inline]
 do_iter_readv_writev+0x567/0x780 fs/read_write.c:694
 do_iter_write+0x188/0x5f0 fs/read_write.c:999
 vfs_writev+0x1aa/0x2e0 fs/read_write.c:1072
 do_pwritev fs/read_write.c:1169 [inline]
 __do_sys_pwritev fs/read_write.c:1216 [inline]
 __se_sys_pwritev fs/read_write.c:1211 [inline]
 __x64_sys_pwritev+0x231/0x310 fs/read_write.c:1211
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4401d9
Code: Bad RIP value.
RSP: 002b:00007fffece3f658 EFLAGS: 00000246 ORIG_RAX: 0000000000000128
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401d9
RDX: 0000000000000001 RSI: 0000000020000440 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a60
R13: 0000000000401af0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6829:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:494
 __do_kmalloc mm/slab.c:3649 [inline]
 __kmalloc+0x18f/0x4d0 mm/slab.c:3658
 kmalloc include/linux/slab.h:559 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 qrtr_tun_write_iter+0x8a/0x180 net/qrtr/tun.c:83
 call_write_iter include/linux/fs.h:1877 [inline]
 do_iter_readv_writev+0x567/0x780 fs/read_write.c:694
 do_iter_write+0x188/0x5f0 fs/read_write.c:999
 vfs_writev+0x1aa/0x2e0 fs/read_write.c:1072
 do_pwritev fs/read_write.c:1169 [inline]
 __do_sys_pwritev fs/read_write.c:1216 [inline]
 __se_sys_pwritev fs/read_write.c:1211 [inline]
 __x64_sys_pwritev+0x231/0x310 fs/read_write.c:1211
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 6757:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf2/0x130 mm/kasan/common.c:455
 __cache_free mm/slab.c:3412 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3750
 security_cred_free+0xc3/0x130 security/security.c:1610
 put_cred_rcu+0x122/0x4a0 kernel/cred.c:114
 __put_cred+0x1de/0x250 kernel/cred.c:148
 put_cred include/linux/cred.h:287 [inline]
 put_cred include/linux/cred.h:280 [inline]
 revert_creds+0x1a8/0x1f0 kernel/cred.c:598
 do_faccessat+0x2ca/0x820 fs/open.c:464
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880a848f3c0
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 32-byte region [ffff8880a848f3c0, ffff8880a848f3e0)
The buggy address belongs to the page:
page:ffffea0002a123c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a848ffc1
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00029c2448 ffffea00027dc308 ffff8880aa000100
raw: ffff8880a848ffc1 ffff8880a848f000 0000000100000021 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a848f280: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a848f300: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8880a848f380: 06 fc fc fc fc fc fc fc 04 fc fc fc fc fc fc fc
                                              ^
 ffff8880a848f400: 05 fc fc fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a848f480: fb fb fb fb fc fc fc fc 07 fc fc fc fc fc fc fc
==================================================================