x86/cpu_entry_area: Prevent wraparound in setup_cpu_entry_area_ptes() on 32bit

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commit f6c4fd506c upstream.

The loop which populates the CPU entry area PMDs can wrap around on 32bit
machines when the number of CPUs is small.

It worked wonderful for NR_CPUS=64 for whatever reason and the moron who
wrote that code did not bother to test it with !SMP.

Check for the wraparound to fix it.

Fixes: 92a0f81d89 ("x86/cpu_entry_area: Move it out of the fixmap")
Reported-by: kernel test robot <fengguang.wu@intel.com>
Signed-off-by: Thomas "Feels stupid" Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Thomas Gleixner 2017-12-23 19:45:11 +01:00 • committed by Greg Kroah-Hartman

parent 763f7eaf60

commit 752d01704a

1 changed files with 2 additions and 1 deletions

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arch/x86/mm/cpu_entry_area.c

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