Message-ID: <000000000000683a810594d634a2@google.com>
Date:   Sun, 13 Oct 2019 20:10:06 -0700
From:   syzbot <syzbot+3370fc9fb190f98c5c72@...kaller.appspotmail.com>
To:     akpm@...ux-foundation.org, chenjianhong2@...wei.com,
        jannh@...gle.com, khlebnikov@...dex-team.ru,
        kirill.shutemov@...ux.intel.com, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, mhocko@...e.com, mike.kravetz@...cle.com,
        richardw.yang@...ux.intel.com, riel@...riel.com,
        sfr@...b.auug.org.au, steve.capper@....com,
        syzkaller-bugs@...glegroups.com, tiny.windzz@...il.com,
        vbabka@...e.cz, walken@...gle.com, willy@...radead.org,
        yang.shi@...ux.alibaba.com
Subject: kernel BUG at include/linux/rmap.h:LINE!

Hello,

syzbot found the following crash on:

HEAD commit:    442630f6 Add linux-next specific files for 20191008
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=11450d93600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=af1bfeef713eefdd
dashboard link: https://syzkaller.appspot.com/bug?extid=3370fc9fb190f98c5c72
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13132d57600000

The bug was bisected to:

commit 480706f51e2c3a450d2f7fc10f5af215c9d249df
Author: Wei Yang <richardw.yang@...ux.intel.com>
Date:   Mon Oct 7 20:25:37 2019 +0000

     mm/rmap.c: reuse mergeable anon_vma as parent when forking

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=107ea520e00000
final crash:    https://syzkaller.appspot.com/x/report.txt?x=127ea520e00000
console output: https://syzkaller.appspot.com/x/log.txt?x=147ea520e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3370fc9fb190f98c5c72@...kaller.appspotmail.com
Fixes: 480706f51e2c ("mm/rmap.c: reuse mergeable anon_vma as parent when  
forking")

prot 25 anon_vma ffff88809a9c4b40 vm_ops 0000000000000000
pgoff 20000 file 0000000000000000 private_data 0000000000000000
flags: 0x8100077(read|write|exec|mayread|maywrite|mayexec|account|softdirty)
------------[ cut here ]------------
kernel BUG at include/linux/rmap.h:159!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 8601 Comm: syz-executor.0 Not tainted 5.4.0-rc2-next-20191008 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:anon_vma_merge include/linux/rmap.h:159 [inline]
RIP: 0010:__vma_adjust+0x151c/0x1cc0 mm/mmap.c:921
Code: 4c 89 ee 4c 89 f7 e8 b3 01 d2 ff 4d 39 ee 0f 82 1b fe ff ff 45 31 ed  
e9 1b fe ff ff e8 7d 00 d2 ff 48 8b 7d c8 e8 76 62 fc ff <0f> 0b e8 6d 00  
d2 ff 48 8b 85 68 ff ff ff 80 38 00 0f 85 20 07 00
RSP: 0018:ffff8880a0e9f9c0 EFLAGS: 00010286
RAX: 0000000000000147 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815cb676 RDI: ffffed10141d3f12
RBP: ffff8880a0e9fa88 R08: 0000000000000147 R09: ffffed1015d06161
R10: ffffed1015d06160 R11: ffff8880ae830b07 R12: ffff888095f28e10
R13: ffff88808c0f7f18 R14: 0000000000000000 R15: 0000000000000001
FS:  0000000000c57940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020d06000 CR3: 0000000090f89000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  vma_merge+0xb8a/0xe60 mm/mmap.c:1169
  mmap_region+0x3e0/0x1760 mm/mmap.c:1741
  do_mmap+0x853/0x1190 mm/mmap.c:1552
  do_mmap_pgoff include/linux/mm.h:2361 [inline]
  vm_mmap_pgoff+0x1c5/0x230 mm/util.c:510
  ksys_mmap_pgoff+0xf7/0x630 mm/mmap.c:1604
  __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
  __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline]
  __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91
  do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459a59
Code: fd 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffcc91b5068 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000459a59
RDX: ffffffffefffffff RSI: 0000000000004000 RDI: 0000000020196000
RBP: 000000000075bf20 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008032 R11: 0000000000000246 R12: 0000000000c57914
R13: 00000000004c6176 R14: 00000000004db118 R15: 00000000ffffffff
Modules linked in:
---[ end trace aa2e499bc1c6fb5e ]---
RIP: 0010:anon_vma_merge include/linux/rmap.h:159 [inline]
RIP: 0010:__vma_adjust+0x151c/0x1cc0 mm/mmap.c:921
Code: 4c 89 ee 4c 89 f7 e8 b3 01 d2 ff 4d 39 ee 0f 82 1b fe ff ff 45 31 ed  
e9 1b fe ff ff e8 7d 00 d2 ff 48 8b 7d c8 e8 76 62 fc ff <0f> 0b e8 6d 00  
d2 ff 48 8b 85 68 ff ff ff 80 38 00 0f 85 20 07 00
RSP: 0018:ffff8880a0e9f9c0 EFLAGS: 00010286
RAX: 0000000000000147 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815cb676 RDI: ffffed10141d3f12
RBP: ffff8880a0e9fa88 R08: 0000000000000147 R09: ffffed1015d06161
R10: ffffed1015d06160 R11: ffff8880ae830b07 R12: ffff888095f28e10
R13: ffff88808c0f7f18 R14: 0000000000000000 R15: 0000000000000001
FS:  0000000000c57940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020d06000 CR3: 0000000090f89000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@...glegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

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