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authorLinus Torvalds <torvalds@linux-foundation.org>2023-04-18 17:40:09 -0400
committerAndrew Morton <akpm@linux-foundation.org>2023-04-21 14:52:05 -0700
commit6b008640db7355d8de6ac18f74cedd7ccc92684f (patch)
tree6484f0e40840df9ded67e1bceb828addf7959555 /fs/hugetlbfs
parentf724392415b3e1ae844d2766669c0d955fe9a17b (diff)
mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
Instead of having callers care about the mmap_min_addr logic for the lowest valid mapping address (and some of them getting it wrong), just move the logic into vm_unmapped_area() itself. One less thing for various architecture cases (and generic helpers) to worry about. We should really try to make much more of this be common code, but baby steps.. Without this, vm_unmapped_area() could return an address below mmap_min_addr (because some caller forgot about that). That then causes the mmap machinery to think it has found a workable address, but then later security_mmap_addr(addr) is unhappy about it and the mmap() returns with a nonsensical error (EPERM). The proper action is to either return ENOMEM (if the virtual address space is exhausted), or try to find another address (ie do a bottom-up search for free addresses after the top-down one failed). See commit 2afc745f3e30 ("mm: ensure get_unmapped_area() returns higher address than mmap_min_addr"), which fixed this for one call site (the generic arch_get_unmapped_area_topdown() fallback) but left other cases alone. Link: https://lkml.kernel.org/r/20230418214009.1142926-1-Liam.Howlett@oracle.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Liam Howlett <liam.howlett@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/hugetlbfs')
-rw-r--r--fs/hugetlbfs/inode.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 702d79639c0d..ecfdfb2529a3 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -208,7 +208,7 @@ hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr,
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.length = len;
- info.low_limit = max(PAGE_SIZE, mmap_min_addr);
+ info.low_limit = PAGE_SIZE;
info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base);
info.align_mask = PAGE_MASK & ~huge_page_mask(h);
info.align_offset = 0;