Locking bug in 3.0.25, IPv6.

Locking bug in 3.0.25, IPv6.

[Ben Greear]

Has anyone seen this in 3.0.25?  My kernel has some other patches
applied, but we did not see this before 3.0.24.

BUG: sleeping function called from invalid context at /home/greearb/git/linux-3.0.dev.y/mm/memory.c:3904

================================================
[ BUG: lock held when returning to user space! ]
------------------------------------------------
ip/6696 is leaving the kernel with locks still held!
1 lock held by ip/6696:
  #0:  (rcu_read_lock){.+.+..}, at: [<ffffffffa03051c4>] rcu_read_lock+0x0/0x35 [ipv6]
in_atomic(): 0, irqs_disabled(): 0, pid: 6694, name: ip
INFO: lockdep is turned off.
Pid: 6694, comm: ip Tainted: G         C  3.0.25+ #1
Call Trace:
  [<ffffffff8103e479>] __might_sleep+0x111/0x115
  [<ffffffff810c98bf>] might_fault+0x2f/0x9e
  [<ffffffff8138698e>] ? copy_from_user+0x2a/0x2c
  [<ffffffff810c98de>] ? might_fault+0x4e/0x9e
  [<ffffffff8137cc90>] move_addr_to_user+0x21/0x8e
  [<ffffffff8137ce7c>] __sys_recvmsg+0x17f/0x21e
  [<ffffffff810634a8>] ? up_read+0x1e/0x36
  [<ffffffff810fc06e>] ? fcheck_files+0xb7/0xee
  [<ffffffff810fc191>] ? fget_light+0x35/0xac
  [<ffffffff810d0023>] ? remove_vma+0x7a/0x82
  [<ffffffff8137d620>] sys_recvmsg+0x3d/0x5b
  [<ffffffff8144f092>] system_call_fastpath+0x16/0x1b

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

Re: Locking bug in 3.0.25, IPv6.

[Ben Greear]

On 03/26/2012 09:51 AM, Ben Greear wrote:
> Has anyone seen this in 3.0.25? My kernel has some other patches
> applied, but we did not see this before 3.0.24.
>
> BUG: sleeping function called from invalid context at /home/greearb/git/linux-3.0.dev.y/mm/memory.c:3904

Just FYI:  This happens in un-modified kernels...seems to have been introduced
(or made more visible) somewhere between 3.0.19 and 3.0.23.

I'm bisecting it now...

Thanks,
Ben

>
> ================================================
> [ BUG: lock held when returning to user space! ]
> ------------------------------------------------
> ip/6696 is leaving the kernel with locks still held!
> 1 lock held by ip/6696:
> #0: (rcu_read_lock){.+.+..}, at: [<ffffffffa03051c4>] rcu_read_lock+0x0/0x35 [ipv6]
> in_atomic(): 0, irqs_disabled(): 0, pid: 6694, name: ip
> INFO: lockdep is turned off.
> Pid: 6694, comm: ip Tainted: G C 3.0.25+ #1
> Call Trace:
> [<ffffffff8103e479>] __might_sleep+0x111/0x115
> [<ffffffff810c98bf>] might_fault+0x2f/0x9e
> [<ffffffff8138698e>] ? copy_from_user+0x2a/0x2c
> [<ffffffff810c98de>] ? might_fault+0x4e/0x9e
> [<ffffffff8137cc90>] move_addr_to_user+0x21/0x8e
> [<ffffffff8137ce7c>] __sys_recvmsg+0x17f/0x21e
> [<ffffffff810634a8>] ? up_read+0x1e/0x36
> [<ffffffff810fc06e>] ? fcheck_files+0xb7/0xee
> [<ffffffff810fc191>] ? fget_light+0x35/0xac
> [<ffffffff810d0023>] ? remove_vma+0x7a/0x82
> [<ffffffff8137d620>] sys_recvmsg+0x3d/0x5b
> [<ffffffff8144f092>] system_call_fastpath+0x16/0x1b
>


-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com