Subject: BUG: unable to handle kernel paging request in check_memory_region

From: syzbot <[email-masked]>
Date: Fri, 12 Jan 2018 14:58:02 -0800

Hello,

syzkaller hit the following crash on  
c92a9a461dff6140c539c61e457aa97df29517d6
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
C reproducer is attached
syzkaller reproducer is attached. See https://goo.gl/kgGztJ
for information about syzkaller reproducers

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]
It will help syzbot understand when the bug is fixed. See footer for  
details.
If you forward the report, please keep this part and the footer.

audit: type=1400 audit(1515790631.378:9): avc:  denied  { sys_chroot } for   
pid=3510 comm="syzkaller602893" capability=18   
scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023  
tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns  
permissive=1
BUG: unable to handle kernel paging request at ffffed004e875e33
IP: bytes_is_nonzero mm/kasan/kasan.c:166 [inline]
IP: memory_is_nonzero mm/kasan/kasan.c:184 [inline]
IP: memory_is_poisoned_n mm/kasan/kasan.c:210 [inline]
IP: memory_is_poisoned mm/kasan/kasan.c:241 [inline]
IP: check_memory_region_inline mm/kasan/kasan.c:257 [inline]
IP: check_memory_region+0x61/0x190 mm/kasan/kasan.c:267
PGD 21ffee067 P4D 21ffee067 PUD 21ffec067 PMD 0
Oops: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
    (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 3510 Comm: syzkaller602893 Not tainted 4.15.0-rc7+ #259
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:bytes_is_nonzero mm/kasan/kasan.c:166 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/kasan.c:184 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/kasan.c:210 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/kasan.c:241 [inline]
RIP: 0010:check_memory_region_inline mm/kasan/kasan.c:257 [inline]
RIP: 0010:check_memory_region+0x61/0x190 mm/kasan/kasan.c:267
RSP: 0018:ffff8801bfa77770 EFLAGS: 00010202
RAX: ffffed004e875e33 RBX: ffff8802743af19b RCX: ffffffff817deb1c
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8802743af198
RBP: ffff8801bfa77780 R08: 1ffff1004e875e33 R09: ffffed004e875e33
R10: 0000000000000001 R11: ffffed004e875e33 R12: ffffed004e875e34
R13: ffff8802743af198 R14: ffff8801bfc9f000 R15: ffff8801c135a680
FS:  0000000001a1d880(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffed004e875e33 CR3: 00000001bfe22003 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  memcpy+0x23/0x50 mm/kasan/kasan.c:302
  memcpy include/linux/string.h:344 [inline]
  map_lookup_elem+0x4dc/0xbd0 kernel/bpf/syscall.c:584
  SYSC_bpf kernel/bpf/syscall.c:1711 [inline]
  SyS_bpf+0x922/0x4400 kernel/bpf/syscall.c:1685
  entry_SYSCALL_64_fastpath+0x23/0x9a
RIP: 0033:0x440ac9
RSP: 002b:00000000007dff68 EFLAGS: 00000203 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 0000000000440ac9
RDX: 0000000000000018 RSI: 0000000020eed000 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000203 R12: 00000000004022a0
R13: 0000000000402330 R14: 0000000000000000 R15: 0000000000000000
Code: 89 f8 49 c1 e8 03 49 89 db 49 c1 eb 03 4d 01 cb 4d 01 c1 4d 8d 63 01  
4c 89 c8 4d 89 e2 4d 29 ca 49 83 fa 10 7f 3d 4d 85 d2 74 33 <41> 80 39 00  
75 21 48 b8 01 00 00 00 00 fc ff df 4d 01 d1 49 01
RIP: bytes_is_nonzero mm/kasan/kasan.c:166 [inline] RSP: ffff8801bfa77770
RIP: memory_is_nonzero mm/kasan/kasan.c:184 [inline] RSP: ffff8801bfa77770
RIP: memory_is_poisoned_n mm/kasan/kasan.c:210 [inline] RSP:  
ffff8801bfa77770
RIP: memory_is_poisoned mm/kasan/kasan.c:241 [inline] RSP: ffff8801bfa77770
RIP: check_memory_region_inline mm/kasan/kasan.c:257 [inline] RSP:  
ffff8801bfa77770
RIP: check_memory_region+0x61/0x190 mm/kasan/kasan.c:267 RSP:  
ffff8801bfa77770
CR2: ffffed004e875e33
---[ end trace 769bd3705f3abe78 ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to [email-masked].

syzbot will keep track of this bug report.
If you forgot to add the Reported-by tag, once the fix for this bug is  
merged
into any tree, please reply to this email with:
#syz fix: exact-commit-title
If you want to test a patch for this bug, please reply with:
#syz test: git://repo/address.git branch
and provide the patch inline or as an attachment.
To mark this as a duplicate of another syzbot report, please reply with:
#syz dup: exact-subject-of-another-report
If it's a one-off invalid bug report, please reply with:
#syz invalid
Note: if the crash happens again, it will cause creation of a new bug  
report.
Note: all commands must start from beginning of the line in the email body.