mm: madvise(): correct return code (75927af8) · Commits · e / devices / android_kernel_fairphone_FP5

The posix_madvise() function succeeds (and does nothing) when called with parameters (NULL, 0, -1); according to LSB tests, it should fail with EINVAL because -1 is not a valid flag. When called with a valid address and size, it correctly fails. So perform an initial check for valid flags first. Reported-by:

Jiri Dluhos <jdluhos@novell.com> Signed-off-by:

Nick Piggin <npiggin@suse.de> Reviewed-and-Tested-by:

WANG Cong <xiyou.wangcong@gmail.com> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/madvise.c

+22 −1

Original line number	Diff line number	Diff line
		@@ -238,12 +238,30 @@ madvise_vma(struct vm_area_struct vma, struct vm_area_struct *prev,
		break;

		default:
		error = -EINVAL;
		BUG();
		break;
		}
		return error;
		}

		static int
		madvise_behavior_valid(int behavior)
		{
		switch (behavior) {
		case MADV_DOFORK:
		case MADV_DONTFORK:
		case MADV_NORMAL:
		case MADV_SEQUENTIAL:
		case MADV_RANDOM:
		case MADV_REMOVE:
		case MADV_WILLNEED:
		case MADV_DONTNEED:
		return 1;

		default:
		return 0;
		}
		}
		/*
		* The madvise(2) system call.
		*
		@@ -289,6 +307,9 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
		int write;
		size_t len;

		if (!madvise_behavior_valid(behavior))
		return error;

		write = madvise_need_mmap_write(behavior);
		if (write)
		down_write(&current->mm->mmap_sem);