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charset=us-ascii Content-Disposition: inline In-Reply-To: <20260915071329.15125-1-orgads@gmail.com> X-Rspam-User: X-Stat-Signature: 8eky79ynzd1ch6y11espucnbstzs5hii X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 6E6CAA0005 X-HE-Tag: 1790416311-344218 X-HE-Meta: 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 s4mbeUaw 3HfPAGvEwDdMbhOKHSZBPdPxDALTeLILVBJ+jWSGZjmr+6QUsZRZbR/P5t3S+Quc+xhU1LSqjY5xAgh7nE41a9dWDACDO61tBpvZ0BdYDxi9SKlEj6xLItot9ew== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 15, 2026 at 07:13:24AM +0000, Orgad Shaneh wrote: > Since hugetlb mappings were made to go through the architecture's > arch_get_unmapped_area{,_topdown}(), every architecture that implements > those has to align hugetlb files itself. The generic implementation and > loongarch do it with huge_page_mask_align(); MIPS was left out. > > A non-MAP_FIXED mmap() of a hugetlbfs file therefore returns an address > that is only SHMLBA aligned, and the kernel then installs 2 MB PMDs for > a VMA that starts in the middle of a PMD. The consequences on an > Octeon (CN63XX) board running a process that links libhugetlbfs with > HUGETLB_ELFMAP=R and HUGETLB_MORECORE=yes, all within a minute of > start: the neighbouring 4 KB page table is clobbered, the TLB ends up > with overlapping entries ("Caught Machine Check exception - caused by > multiple matching entries in the TLB"), process exit trips > BUG_ON(start & ~huge_page_mask(h)) in __unmap_hugepage_range(), and > freed pages leak into unrelated kernel structures (oopses in the irq > maple tree, in pte_offset_map, ...). > > Do what loongarch does in commit 3109d5ff484b ("LoongArch: Set hugetlb > mmap base address aligned with pmd size"): when the file is a hugetlb > file, use its page mask as the search alignment instead of the cache > colour mask. > > Fixes: 7bd3f1e1a9ae ("mm: make hugetlb mappings go through mm_get_unmapped_area_vmflags") > Cc: stable@vger.kernel.org # 6.13+ > Assisted-by: Claude:claude-opus-5 > Signed-off-by: Orgad Shaneh > --- > diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c > --- a/arch/mips/mm/mmap.c > +++ b/arch/mips/mm/mmap.c > @@ -9,6 +9,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -72,8 +73,11 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp, > } > > info.length = len; > - info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0; > info.align_offset = pgoff << PAGE_SHIFT; > + if (filp && is_file_hugepages(filp)) > + info.align_mask = huge_page_mask_align(filp); > + else > + info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0; > > if (dir == DOWN) { > info.flags = VM_UNMAPPED_AREA_TOPDOWN; > -- > 2.47.0 applied to mips-next Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]