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Subject[patch 1/1]pat: fix type check error on chk_conflict function
 On chk_conflict() function, if new->type does not match entry->type
and type is not NULL, this does not go through conflict path. This
patch fix this bug.

Signed-off-by: bibo.mao@gmail.com

----------------------------------------------------------------------
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 12cac5e..0632308 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -183,28 +183,29 @@ static unsigned long pat_x_mtrr_type(u64 start,
u64 end, unsigned long req_type)
static int chk_conflict(struct memtype *new, struct memtype *entry,
unsigned long *type)
{
- if (new->type != entry->type) {
- if (type) {
- new->type = entry->type;
- *type = entry->type;
- } else
- goto conflict;
- }
+ int err = -EBUSY;
+
+ if (new->type != entry->type)
+ goto conflict;

/* check overlaps with more than one entry in the list */
list_for_each_entry_continue(entry, &memtype_list, nd) {
if (new->end <= entry->start)
break;
- else if (new->type != entry->type)
+ else if (new->type != entry->type) {
+ err = -EINVAL;
goto conflict;
+ }
}
return 0;

conflict:
+ if (type)
+ *type = entry->type;
printk(KERN_INFO "%s:%d conflicting memory types "
"%Lx-%Lx %s<->%s\n", current->comm, current->pid, new->start,
new->end, cattr_name(new->type), cattr_name(entry->type));
- return -EBUSY;
+ return err;
}

static struct memtype *cached_entry;
@@ -278,9 +279,6 @@ int reserve_memtype(u64 start, u64 end, unsigned
long req_type,
new->end = end;
new->type = actual_type;

- if (new_type)
- *new_type = actual_type;
-
spin_lock(&memtype_lock);

if (cached_entry && start >= cached_start)
@@ -326,6 +324,9 @@ int reserve_memtype(u64 start, u64 end, unsigned
long req_type,

spin_unlock(&memtype_lock);

+ if (new_type)
+ *new_type = actual_type;
+
dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
start, end, cattr_name(new->type), cattr_name(req_type),
new_type ? cattr_name(*new_type) : "-");
@@ -474,15 +475,22 @@ void map_devmem(unsigned long pfn, unsigned long
size, pgprot_t vma_prot)
u64 addr = (u64)pfn << PAGE_SHIFT;
unsigned long flags;
unsigned long want_flags = (pgprot_val(vma_prot) & _PAGE_CACHE_MASK);
+ int err;

- reserve_memtype(addr, addr + size, want_flags, &flags);
- if (flags != want_flags) {
+ err = reserve_memtype(addr, addr + size, want_flags, &flags);
+ if (err == -EBUSY) {
printk(KERN_INFO
"%s:%d /dev/mem expected mapping type %s for %Lx-%Lx, got %s\n",
current->comm, current->pid,
cattr_name(want_flags),
addr, (unsigned long long)(addr + size),
cattr_name(flags));
+ } else if (err == -EINVAL) {
+ printk(KERN_INFO
+ "%s:%d /dev/mem has both mapping type %s and %s for %Lx-%Lx \n",
+ current->comm, current->pid,
+ cattr_name(want_flags), cattr_name(flags),
+ addr, (unsigned long long)(addr + size));
}
}

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