linux-kernel - [syzbot] general protection fault in shm

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Date:   Sun, 13 Nov 2022 19:11:50 -0800
From:   syzbot <syzbot+83b4134621b7c326d950@...kaller.appspotmail.com>
To:     Liam.Howlett@...cle.com, akpm@...ux-foundation.org,
        alexander.mikhalitsyn@...tuozzo.com, linux-kernel@...r.kernel.org,
        manfred@...orfullife.com, mike.kravetz@...cle.com,
        syzkaller-bugs@...glegroups.com, willy@...radead.org
Subject: [syzbot] general protection fault in shm_close

Hello,

syzbot found the following issue on:

HEAD commit:    f8f60f322f06 Add linux-next specific files for 20221111
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15599bd5880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=85ba52c07cd97289
dashboard link: https://syzkaller.appspot.com/bug?extid=83b4134621b7c326d950
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15a05e71880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11de4db9880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6008df424195/disk-f8f60f32.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/394340525f66/vmlinux-f8f60f32.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b13604a3343a/bzImage-f8f60f32.xz

The issue was bisected to:

commit 6a892ddb84e542931554f4ee9a528190003b23a0
Author: Mike Kravetz <mike.kravetz@...cle.com>
Date:   Thu Nov 10 00:21:50 2022 +0000

    ipc/shm: call underlying open/close vm_ops

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14a0f199880000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=16a0f199880000
console output: https://syzkaller.appspot.com/x/log.txt?x=12a0f199880000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+83b4134621b7c326d950@...kaller.appspotmail.com
Fixes: 6a892ddb84e5 ("ipc/shm: call underlying open/close vm_ops")

general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 5247 Comm: syz-executor310 Not tainted 6.1.0-rc4-next-20221111-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0010:shm_close+0xbf/0x740 ipc/shm.c:378
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 1c 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5d 18 48 8d 7b 08 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 db 05 00 00 48 8b 5b 08 48 85 db 74 0a e8 99 7c
RSP: 0018:ffffc90003e0fba0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff83bf5016 RDI: 0000000000000008
RBP: ffff8880296a2d40 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000fffffff4 R11: 0000000000000000 R12: ffff8880263fb1c0
R13: ffffffff8c7a97a0 R14: 0000000000000008 R15: ffffc90003e0fca0
FS:  0000555555992300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fde9cc15348 CR3: 0000000025865000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 shm_mmap+0x1c2/0x230 ipc/shm.c:604
 call_mmap include/linux/fs.h:2164 [inline]
 mmap_region+0x6bf/0x1dc0 mm/mmap.c:2625
 do_mmap+0x825/0xf50 mm/mmap.c:1412
 do_shmat+0xe33/0x10c0 ipc/shm.c:1661
 __do_sys_shmat ipc/shm.c:1697 [inline]
 __se_sys_shmat ipc/shm.c:1692 [inline]
 __x64_sys_shmat+0xcc/0x160 ipc/shm.c:1692
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fde9cba2cf9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff3ed491f8 EFLAGS: 00000246 ORIG_RAX: 000000000000001e
RAX: ffffffffffffffda RBX: 000000000000cfd6 RCX: 00007fde9cba2cf9
RDX: ffffffffffffcfff RSI: 0000000020000000 RDI: 0000000000000008
RBP: 0000000000000000 R08: 00007fff3ed49398 R09: 00007fff3ed49398
R10: 00007fff3ed48c70 R11: 0000000000000246 R12: 00007fff3ed4920c
R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:shm_close+0xbf/0x740 ipc/shm.c:378
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 1c 06 00 00 48 b8 00 00 00 00 00 fc ff df 48 8b 5d 18 48 8d 7b 08 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 db 05 00 00 48 8b 5b 08 48 85 db 74 0a e8 99 7c
RSP: 0018:ffffc90003e0fba0 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff83bf5016 RDI: 0000000000000008
RBP: ffff8880296a2d40 R08: 0000000000000005 R09: 0000000000000000
R10: 00000000fffffff4 R11: 0000000000000000 R12: ffff8880263fb1c0
R13: ffffffff8c7a97a0 R14: 0000000000000008 R15: ffffc90003e0fca0
FS:  0000555555992300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff3ed491d8 CR3: 0000000025865000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 89 fa             	mov    %rdi,%rdx
   3:	48 c1 ea 03          	shr    $0x3,%rdx
   7:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   b:	0f 85 1c 06 00 00    	jne    0x62d
  11:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  18:	fc ff df
  1b:	48 8b 5d 18          	mov    0x18(%rbp),%rbx
  1f:	48 8d 7b 08          	lea    0x8(%rbx),%rdi
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 db 05 00 00    	jne    0x60f
  34:	48 8b 5b 08          	mov    0x8(%rbx),%rbx
  38:	48 85 db             	test   %rbx,%rbx
  3b:	74 0a                	je     0x47
  3d:	e8                   	.byte 0xe8
  3e:	99                   	cltd
  3f:	7c                   	.byte 0x7c


---
This report 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 issue. 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 issue, for details see:
https://goo.gl/tpsmEJ#testing-patches