Re: Kernel Panic when accessing NFS share and locking files

From: Andrew Morton
Date: Wed May 14 2008 - 23:50:20 EST


On Wed, 14 May 2008 19:27:36 +0200 Michael Lang <Michael.Lang@xxxxxxxxxxxxx> wrote:

> Hi,
>
> we encountered a serious problem, when using Solaris NFS (Server)
> accessing it with a CentOS5.1/RHEL5.1 client.
> There are more occurrences of the problem, one i felt over when tried to
> recreate a different one was, that a unprivileged
> User is able to Kernel Panic a machine with a few lines of code. I
> tested it with the result that 3 threads requesting a lock
> on the same file already cause the kernel panic. Since this is my first
> kernel bug request, and it's at least for my understandig
> a security problem, i will provide the code for recreation to a closed
> group only. Please point me to the right group ...
>
> Call Trace:
> [<ffffffff80012323>] __fput+0x94/0x198
> [<ffffffff8002e2d2>] sys_fcntl+0x2d0/0x2dc
> [<ffffffff8005b28d>] tracesys+0xd5/0xe0
> Code: 0f 0b 68 8a de 28 80 c2 c7 07 48 89 c3 48 8b 03 48 85 c0 75
> RIP [<ffffffff80027073>] locks_remove_flock+0xe4/0x122
> RSP <ffff81000be87e48>

Which kernel version is being used?
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