Re: [syzbot] general protection fault in sanity_check_pinned_pages

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 8/21/22 01:34, Andrew Morton wrote:

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: 3608 Comm: syz-executor314 Not tainted 6.0.0-rc1-next-20220817-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
RIP: 0010:_compound_head include/linux/page-flags.h:253 [inline]
RIP: 0010:sanity_check_pinned_pages+0x25e/0xec0 mm/gup.c:52

Thanks.  Another GUP explosion.

OK, so what's happening here is that rds_cmsg_rdma_args() called
pin_user_pages_fast(), and after either finishing the RDS send
operation, *or* perhaps after failing early due to an error, it then
calls unpin_user_pages_dirty_lock(), which crashes due to a NULL page*
in the pages** array.

commit 4d1225cd5560 ("mm/gup.c: simplify and fix
check_and_migrate_movable_pages() return codes") gets involved in the
code that NULLs out pages during migration in gup.c, so it is under some
suspicion here.

A bisection would be very nice to have, but meanwhile I'll look at the
other gup crash that arrived in my inbox at the same time as this one.

thanks,
--
John Hubbard
NVIDIA


Code: a2 06 00 00 e8 f3 8a c9 ff 4c 89 f0 48 c1 e8 03 80 3c 18 00 0f 85 8e 0a 00 00 4d 8b 26 49 8d 44 24 08 48 89 04 24 48 c1 e8 03 <80> 3c 18 00 0f 85 8b 0a 00 00 49 8b 6c 24 08 31 ff 49 89 ef 41 83
RSP: 0018:ffffc900039df6d0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff88802763bb00 RSI: ffffffff81b28a5d RDI: 0000000000000007
RBP: 000000000000034e R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: ffffc900039df7c8 R15: 0000000000000000
FS:  00007fc2d0fe9700(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001600 CR3: 0000000076052000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
  <TASK>
  unpin_user_pages_dirty_lock mm/gup.c:311 [inline]
  unpin_user_pages_dirty_lock+0x4a/0x4c0 mm/gup.c:299
  rds_rdma_free_op+0x28d/0x3c0 net/rds/rdma.c:501
  rds_cmsg_rdma_args+0x32c/0x1540 net/rds/rdma.c:797
  rds_cmsg_send net/rds/send.c:1005 [inline]
  rds_sendmsg+0x1c5c/0x3040 net/rds/send.c:1316
  sock_sendmsg_nosec net/socket.c:714 [inline]
  sock_sendmsg+0xcf/0x120 net/socket.c:734
  ____sys_sendmsg+0x6eb/0x810 net/socket.c:2482
  ___sys_sendmsg+0x110/0x1b0 net/socket.c:2536
  __sys_sendmsg+0xf3/0x1c0 net/socket.c:2565
  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: 0033:0x7fc2d1036e39
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fc2d0fe9308 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fc2d10bf408 RCX: 00007fc2d1036e39
RDX: 0000000000000000 RSI: 0000000020001600 RDI: 0000000000000004
RBP: 00007fc2d10bf400 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc2d10bf40c
R13: 00007fc2d108d004 R14: 632e79726f6d656d R15: 0000000000022000
  </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:_compound_head include/linux/page-flags.h:253 [inline]
RIP: 0010:sanity_check_pinned_pages+0x25e/0xec0 mm/gup.c:52
Code: a2 06 00 00 e8 f3 8a c9 ff 4c 89 f0 48 c1 e8 03 80 3c 18 00 0f 85 8e 0a 00 00 4d 8b 26 49 8d 44 24 08 48 89 04 24 48 c1 e8 03 <80> 3c 18 00 0f 85 8b 0a 00 00 49 8b 6c 24 08 31 ff 49 89 ef 41 83
RSP: 0018:ffffc900039df6d0 EFLAGS: 00010202
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff88802763bb00 RSI: ffffffff81b28a5d RDI: 0000000000000007
RBP: 000000000000034e R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000001 R14: ffffc900039df7c8 R15: 0000000000000000
FS:  00007fc2d0fe9700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000002034d000 CR3: 0000000076052000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
    0:	a2 06 00 00 e8 f3 8a 	movabs %al,0xffc98af3e8000006
    7:	c9 ff
    9:	4c 89 f0             	mov    %r14,%rax
    c:	48 c1 e8 03          	shr    $0x3,%rax
   10:	80 3c 18 00          	cmpb   $0x0,(%rax,%rbx,1)
   14:	0f 85 8e 0a 00 00    	jne    0xaa8
   1a:	4d 8b 26             	mov    (%r14),%r12
   1d:	49 8d 44 24 08       	lea    0x8(%r12),%rax
   22:	48 89 04 24          	mov    %rax,(%rsp)
   26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 18 00          	cmpb   $0x0,(%rax,%rbx,1) <-- trapping instruction
   2e:	0f 85 8b 0a 00 00    	jne    0xabf
   34:	49 8b 6c 24 08       	mov    0x8(%r12),%rbp
   39:	31 ff                	xor    %edi,%edi
   3b:	49 89 ef             	mov    %rbp,%r15
   3e:	41                   	rex.B
   3f:	83                   	.byte 0x83


---
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@xxxxxxxxxxxxxxxx.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches





[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux