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Subject: Re: [apparmor_mmap_file] WARNING: bad unlock balance detected!
To: Fengguang Wu <fengguang.wu@intel.com>,
        linux-security-module@vger.kernel.org
Cc: LKML <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Al Viro <viro@zeniv.linux.org.uk>, Eric Paris <eparis@redhat.com>
References: <20171107013821.2b34a6i6uez37stu@wfg-t540p.sh.intel.com>
From: John Johansen <john.johansen@canonical.com>
Organization: Canonical
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Date: Wed, 8 Nov 2017 07:54:53 -0800
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On 11/06/2017 05:38 PM, Fengguang Wu wrote:
> Hi,
> 
> Here is a warning in 4.14-rc8 -- it's not necessarily a new bug.
> 
sigh, yep its older than 4.14 but I have haven't finished bisecting it yet

thanks

> Please press Enter to activate this console.
> [   45.117766] e1000: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
> [   45.122174] 8021q: adding VLAN 0 to HW filter on device eth0
> [   45.247159] [   45.247451] =====================================
> [   45.248021] WARNING: bad unlock balance detected!
> [   45.248608] 4.14.0-rc8 #158 Not tainted
> [   45.249087] -------------------------------------
> [   45.249672] fw3/1183 is trying to release lock (rcu_preempt_state) at:
> [   45.250443] [<c10e4348>] rcu_read_unlock_special+0x5f8/0x620
> [   45.251136] but there are no more locks to release!
> [   45.251752] [   45.251752] other info that might help us debug this:
> [   45.252561] 1 lock held by fw3/1183:
> [   45.253019]  #0:  (rcu_read_lock){....}, at: [<c16e24c0>] aa_file_perm+0x0/0x460
> [   45.253925] [   45.253925] stack backtrace:
> [   45.254526] CPU: 0 PID: 1183 Comm: fw3 Not tainted 4.14.0-rc8 #158
> [   45.255275] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> [   45.256266] Call Trace:
> [   45.256628]  dump_stack+0x16/0x1c
> [   45.257082]  print_unlock_imbalance_bug+0xb9/0xd0
> [   45.257676]  ? rcu_read_unlock_special+0x5f8/0x620
> [   45.258259]  ? rcu_read_unlock_special+0x5f8/0x620
> [   45.258871]  lock_release+0x1cc/0x490
> [   45.259347]  ? rcu_read_unlock_special+0x5f8/0x620
> [   45.259969]  ? _raw_spin_unlock_irqrestore+0x86/0xd0
> [   45.260581]  rt_mutex_unlock+0x1e/0xb0
> [   45.261054]  rcu_read_unlock_special+0x5f8/0x620
> [   45.261643]  __rcu_read_unlock+0xa7/0xb0
> [   45.262152]  aa_file_perm+0x5a/0x460
> [   45.262633]  ? pvclock_clocksource_read+0xd5/0x230
> [   45.263203]  ? pvclock_clocksource_read+0xd5/0x230
> [   45.263797]  common_file_perm+0x81/0x240
> [   45.264308]  ? kvm_sched_clock_read+0x9/0x20
> [   45.264843]  common_mmap+0x93/0xd0
> [   45.265283]  ? apparmor_file_mprotect+0x30/0x30
> [   45.265867]  apparmor_mmap_file+0x12/0x20
> [   45.266388]  security_mmap_file+0xaf/0x170
> [   45.266903]  vm_mmap_pgoff+0x35/0x100
> [   45.267381]  ? __fget+0x1c3/0x1d0
> [   45.267831]  SyS_mmap_pgoff+0x16d/0x370
> [   45.268318]  do_int80_syscall_32+0x95/0x290
> [   45.268840]  entry_INT80_32+0x2f/0x2f
> [   45.269313] EIP: 0xb7f7c2d4
> [   45.269713] EFLAGS: 00000202 CPU: 0
> [   45.270169] EAX: ffffffda EBX: b7f63000 ECX: 000002ad EDX: 00000003
> [   45.270901] ESI: 00000012 EDI: 00000003 EBP: 00000004 ESP: bff29f24
> [   45.271637]  DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 007b
> [   45.351763] 8021q: adding VLAN 0 to HW filter on device eth0
> LKP: HOSTNAME vm-lkp-nhm-dp1-openwrt-ia32-6, MAC , kernel 4.14.0-rc8 158, serial console /dev/ttyS0
> [   47.390581] e1000: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX
> 
> Thanks,
> Fengguang