Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
From:   Wei Chen <harperchen1110@gmail.com>
Date:   Sun, 30 Oct 2022 18:13:44 +0800
Message-ID: <CAO4mrfcW2NzeigGk26DbuZBs_br86krAMW5Xos_=BuAUBr5OAg@mail.gmail.com>
Subject: BUG: unable to handle kernel NULL pointer dereference in tipc_conn_close
To:     jmaloy@redhat.com, ying.xue@windriver.com, davem@davemloft.net,
        kuba@kernel.org
Cc:     netdev@vger.kernel.org, tipc-discussion@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Dear Linux Developer,

Recently when using our tool to fuzz kernel, the following crash was triggered:

HEAD commit: 64570fbc14f8 Linux 5.15-rc5
git tree: upstream
compiler: gcc 8.0.1
console output:
https://drive.google.com/file/d/1nDvjcSyhzWncMlR35k1P1dC8rswJ_Zin/view?usp=share_link
kernel config: https://drive.google.com/file/d/1uDOeEYgJDcLiSOrx9W8v2bqZ6uOA_55t/view?usp=share_link

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: Wei Chen <harperchen1110@gmail.com>

BUG: kernel NULL pointer dereference, address: 0000000000000018
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP
CPU: 1 PID: 7336 Comm: kworker/u4:4 Not tainted 5.15.0-rc5 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:tipc_conn_close+0x12/0x100
Code: 02 01 e8 52 74 20 00 e9 c6 fd ff ff 66 90 66 2e 0f 1f 84 00 00
00 00 00 41 55 41 54 55 53 48 89 fb e8 82 4f c2 fc 48 8b 43 08 <4c> 8b
68 18 4d 8d a5 b0 03 00 00 4c 89 e7 e8 fb 36 44 00 f0 48 0f
RSP: 0018:ffffc90005137d60 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88805a9eea00 RCX: ffff88810b035280
RDX: 0000000000000000 RSI: ffff88810b035280 RDI: 0000000000000002
RBP: ffffc90005137db0 R08: ffffffff847b23de R09: 0000000000000001
R10: 0000000000000005 R11: 0000000000000000 R12: ffff88810bdeed40
R13: 000000000000027b R14: ffff88805a9eea00 R15: ffff88810ebc2058
FS:  0000000000000000(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000018 CR3: 000000010b0e2000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tipc_topsrv_exit_net+0x139/0x320
 ops_exit_list.isra.9+0x49/0x80
 cleanup_net+0x31a/0x540
 process_one_work+0x3fa/0x9f0
 worker_thread+0x42/0x5c0
 kthread+0x1a6/0x1e0
 ret_from_fork+0x1f/0x30
Modules linked in:
CR2: 0000000000000018
---[ end trace 1524bb8c4ed3c3b4 ]---
RIP: 0010:tipc_conn_close+0x12/0x100
Code: 02 01 e8 52 74 20 00 e9 c6 fd ff ff 66 90 66 2e 0f 1f 84 00 00
00 00 00 41 55 41 54 55 53 48 89 fb e8 82 4f c2 fc 48 8b 43 08 <4c> 8b
68 18 4d 8d a5 b0 03 00 00 4c 89 e7 e8 fb 36 44 00 f0 48 0f
RSP: 0018:ffffc90005137d60 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88805a9eea00 RCX: ffff88810b035280
RDX: 0000000000000000 RSI: ffff88810b035280 RDI: 0000000000000002
RBP: ffffc90005137db0 R08: ffffffff847b23de R09: 0000000000000001
R10: 0000000000000005 R11: 0000000000000000 R12: ffff88810bdeed40
R13: 000000000000027b R14: ffff88805a9eea00 R15: ffff88810ebc2058
FS:  0000000000000000(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000018 CR3: 000000010b0e2000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0: 02 01                add    (%rcx),%al
   2: e8 52 74 20 00        callq  0x207459
   7: e9 c6 fd ff ff        jmpq   0xfffffdd2
   c: 66 90                xchg   %ax,%ax
   e: 66 2e 0f 1f 84 00 00 nopw   %cs:0x0(%rax,%rax,1)
  15: 00 00 00
  18: 41 55                push   %r13
  1a: 41 54                push   %r12
  1c: 55                    push   %rbp
  1d: 53                    push   %rbx
  1e: 48 89 fb              mov    %rdi,%rbx
  21: e8 82 4f c2 fc        callq  0xfcc24fa8
  26: 48 8b 43 08          mov    0x8(%rbx),%rax
* 2a: 4c 8b 68 18          mov    0x18(%rax),%r13 <-- trapping instruction
  2e: 4d 8d a5 b0 03 00 00 lea    0x3b0(%r13),%r12
  35: 4c 89 e7              mov    %r12,%rdi
  38: e8 fb 36 44 00        callq  0x443738
  3d: f0                    lock
  3e: 48                    rex.W
  3f: 0f                    .byte 0xf

Best,
Wei