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| author | Thomas Gleixner <tglx@linutronix.de> | 2016-05-06 20:48:16 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-05-07 10:06:55 +0200 |
| commit | 56402d63eefe22179f7311a51ff2094731420406 (patch) | |
| tree | 0466e2d9dc3205256269aff0bebf137669aa5f3f /arch | |
| parent | 07837831047fb72856d1f61a726a4094397facd8 (diff) | |
| download | linux-56402d63eefe22179f7311a51ff2094731420406.tar.bz2 | |
x86/topology: Handle CPUID bogosity gracefully
Joseph reported that a XEN guest dies with a division by 0 in the package
topology setup code. This happens if cpu_info.x86_max_cores is zero.
Handle that case and emit a warning. This does not fix the underlying XEN bug,
but makes the code more robust.
Reported-and-tested-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1605062046270.3540@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index a2065d3b3b39..0e4329ed91ef 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -332,6 +332,11 @@ static void __init smp_init_package_map(void) * primary cores. */ ncpus = boot_cpu_data.x86_max_cores; + if (!ncpus) { + pr_warn("x86_max_cores == zero !?!?"); + ncpus = 1; + } + __max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus); /* |