Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] Integer overflow in `memory_block_aligned_range` when `range->end == U64_MAX` incorrectly truncates valid memory ranges. --
--- Patch [1]: [PATCH v7 01/10] mm/memory: add memory_block_aligned_range() helper --- commit 1d936debbb2e5198011a220a96cf6a3dc9882748 Author: Gregory Price <[email protected]> mm/memory: add memory_block_aligned_range() helper This commit introduces memory_block_aligned_range() in <linux/memory.h> to align ranges to memory block boundaries for memory hotplug operations. It also updates the dax/kmem driver to use this new generic helper. > diff --git a/include/linux/memory.h b/include/linux/memory.h > index 463dc02f6cff0..1783299073e47 100644 > --- a/include/linux/memory.h > +++ b/include/linux/memory.h [ ... ] > @@ -100,6 +101,32 @@ int arch_get_memory_phys_device(unsigned long start_pfn); > unsigned long memory_block_size_bytes(void); > int set_memory_block_size_order(unsigned int order); > > +/** > + * memory_block_aligned_range - align a physical address range to memory > blocks > + * @range: the input range to align > + * > + * Aligns the start address up and the end address down to memory block > + * boundaries. This is required for memory hotplug operations which must > + * operate on memory-block aligned ranges. > + * > + * Returns the aligned range. Callers should check that the returned > + * range is valid (aligned.start < aligned.end) before using it. > + */ > +static inline struct range memory_block_aligned_range(const struct range > *range) > +{ > + struct range aligned; > + > + aligned.start = ALIGN(range->start, memory_block_size_bytes()); > + aligned.end = ALIGN_DOWN(range->end + 1, memory_block_size_bytes()); > + /* No whole block fits (e.g. range below the first boundary): empty. */ > + if (aligned.end <= aligned.start) > + aligned.start = aligned.end; [Severity: Medium] Does this overflow if range->end is U64_MAX? If range->end is U64_MAX, range->end + 1 will wrap around to 0. This makes ALIGN_DOWN(0, ...) return 0. Since aligned.end is now 0, the condition aligned.end <= aligned.start evaluates to true. This would incorrectly report a valid range spanning to the end of the 64-bit address space as an empty range. Is there a way to handle the U64_MAX upper bound safely to avoid truncating the range? > + else > + aligned.end -= 1; > + > + return aligned; > +} > + > struct memory_notify { > unsigned long start_pfn; > unsigned long nr_pages; -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=1
