Re: [PATCH v3] ARM64: Dynamically allocate cpumasks and increase supported CPUs to 512
From: Christoph Lameter (Ampere) <hidden>
Date: 2024-03-14 17:01:07
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On Thu, 14 Mar 2024, Russell King (Oracle) wrote:
quoted
It is really surprising that this didn't blow up for anyone else so far... This means that the $subject patch is fine.Wow. I guess we've been lucky with that allocation hitting memory containing zeros. Well done at tracking it down!
It would have blown up with slub_debug because that includes poisoning the contents of all allocations via the slab allocator. Why did that not occur? We should have seen a backtrace with data in registers etc showing poisoning values for an unitialized object. Note that this was indeed triggered by OFFSTACK because (z)alloc_cpumask_var() only generates a kmalloc allocation if that option is set. The config option was never set before my patch was applied on ARM64. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel