Messages in this thread |  | | Date | Fri, 15 Aug 2008 13:38:42 +0200 | | From | Ingo Molnar <> | | Subject | Re: [PATCH] msr: Fix NULL pointer deref due to msr_open on nonexistent CPUs |
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* Darrick J. Wong <djwong@us.ibm.com> wrote:
> msr_open tests for someone trying to open a device for a nonexistent CPU. > However, the function always returns 0, not ret like it should, hence userspace > can BUG the kernel trivially. This bug was introduced by the cdev lock_kernel > pushdown patch last May. > > The BUG can be reproduced with these commands: > > # mknod fubar c 202 8 <-- pick a number less than NR_CPUS that is not > the number of an online CPU > # cat fubar
applied to tip/x86/urgent - thanks Darrick.
Ingo
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