Donet Tom dffe24e958 hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr ... generic_hugetlb_get_unmapped_area() was returning an address less than mmap_min_addr if the mmap argument addr, after alignment, was less than mmap_min_addr, causing mmap to fail. This is because current generic_hugetlb_get_unmapped_area() code does not take into account mmap_min_addr. This patch ensures that generic_hugetlb_get_unmapped_area() always returns an address that is greater than mmap_min_addr. Additionally, similar to generic_get_unmapped_area(), vm_end_gap() checks are included to maintain stack gap. How to reproduce ================ #include <stdio.h> #include <stdlib.h> #include <sys/mman.h> #include <unistd.h> #define HUGEPAGE_SIZE (16 * 1024 * 1024) int main() { void *addr = mmap((void *)-1, HUGEPAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0); if (addr == MAP_FAILED) { perror("mmap"); exit(EXIT_FAILURE); } snprintf((char *)addr, HUGEPAGE_SIZE, "Hello, Huge Pages!"); printf("%s\n", (char *)addr); if (munmap(addr, HUGEPAGE_SIZE) == -1) { perror("munmap"); exit(EXIT_FAILURE); } return 0; } Result without fix ================== # cat /proc/meminfo |grep -i HugePages_Free HugePages_Free: 20 # ./test mmap: Permission denied # Result with fix =============== # cat /proc/meminfo |grep -i HugePages_Free HugePages_Free: 20 # ./test Hello, Huge Pages! # Link: https://lkml.kernel.org/r/20240710051912.4681-1-donettom@linux.ibm.com Signed-off-by: Donet Tom <donettom@linux.ibm.com> Reported-by Pavithra Prakash <pavrampu@linux.vnet.ibm.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Cc: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>		2024-07-17 21:05:18 -07:00
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inode.c	hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr	2024-07-17 21:05:18 -07:00
Makefile	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00