Re: mmap() on cdrom files fails since 2.6.9-rc2-bk2

[Ingo Molnar <mingo@elte.hu>]

* Jean Delvare <khali@linux-fr.org> wrote:

> > Capture the strace output.
> 
> Here it is (using 2.6.9-rc2-mm4):

> old_mmap(NULL, 42, PROT_READ, MAP_SHARED, 3, 0) = -1 EPERM (Operation not permitted)

could you try the patch below? mmap() done from !pt_gnu_stack binaries
on noexec mounted filesystems indeed could fail due to the extra
PROT_EXEC bit.

	Ingo

Signed-off-by: Ingo Molnar <mingo@elte.hu>

--- linux/mm/mmap.c.orig
+++ linux/mm/mmap.c
@@ -773,13 +773,6 @@ unsigned long do_mmap_pgoff(struct file 
 	int accountable = 1;
 	unsigned long charged = 0;
 
-	/*
-	 * Does the application expect PROT_READ to imply PROT_EXEC:
-	 */
-	if (unlikely((prot & PROT_READ) &&
-			(current->personality & READ_IMPLIES_EXEC)))
-		prot |= PROT_EXEC;
-
 	if (file) {
 		if (is_file_hugepages(file))
 			accountable = 0;
@@ -791,6 +784,15 @@ unsigned long do_mmap_pgoff(struct file 
 		    (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))
 			return -EPERM;
 	}
+	/*
+	 * Does the application expect PROT_READ to imply PROT_EXEC?
+	 *
+	 * (the exception is when the underlying filesystem is noexec
+	 *  mounted, in which case we dont add PROT_EXEC.)
+	 */
+	if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
+		if (!(file && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC)))
+			prot |= PROT_EXEC;
 
 	if (!len)
 		return addr;