vsprintf: Fix %pK with kptr_restrict == 0

Although kptr_restrict is set to 0 and the kernel is booted with
no_hash_pointers parameter, the content of /proc/vmallocinfo is
lacking the real addresses.

  / # cat /proc/vmallocinfo
  0x(ptrval)-0x(ptrval)    8192 load_module+0xc0c/0x2c0c pages=1 vmalloc
  0x(ptrval)-0x(ptrval)   12288 start_kernel+0x4e0/0x690 pages=2 vmalloc
  0x(ptrval)-0x(ptrval)   12288 start_kernel+0x4e0/0x690 pages=2 vmalloc
  0x(ptrval)-0x(ptrval)    8192 _mpic_map_mmio.constprop.0+0x20/0x44 phys=0x80041000 ioremap
  0x(ptrval)-0x(ptrval)   12288 _mpic_map_mmio.constprop.0+0x20/0x44 phys=0x80041000 ioremap
    ...

According to the documentation for /proc/sys/kernel/, %pK is
equivalent to %p when kptr_restrict is set to 0.

Fixes: 5ead723a20e0 ("lib/vsprintf: no_hash_pointers prints all addresses as unhashed")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/107476128e59bff11a309b5bf7579a1753a41aca.1645087605.git.christophe.leroy@csgroup.eu

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 46bfadf..86e2b58 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3491,8 +3491,7 @@
                        difficult since unequal pointers can no longer be
                        compared.  However, if this command-line option is
                        specified, then all normal pointers will have their true
-                       value printed.  Pointers printed via %pK may still be
-                       hashed.  This option should only be specified when
+                       value printed. This option should only be specified when
                        debugging the kernel.  Please do not use on production
                        kernels.
 

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 53d6081..8fb4a21 100644 (file)
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -53,6 +53,10 @@
 #include <linux/string_helpers.h>
 #include "kstrtox.h"
 
+/* Disable pointer hashing if requested */
+bool no_hash_pointers __ro_after_init;
+EXPORT_SYMBOL_GPL(no_hash_pointers);
+
 static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base)
 {
        const char *cp;
@@ -848,6 +852,19 @@ static char *ptr_to_id(char *buf, char *end, const void *ptr,
        return pointer_string(buf, end, (const void *)hashval, spec);
 }
 
+static char *default_pointer(char *buf, char *end, const void *ptr,
+                            struct printf_spec spec)
+{
+       /*
+        * default is to _not_ leak addresses, so hash before printing,
+        * unless no_hash_pointers is specified on the command line.
+        */
+       if (unlikely(no_hash_pointers))
+               return pointer_string(buf, end, ptr, spec);
+
+       return ptr_to_id(buf, end, ptr, spec);
+}
+
 int kptr_restrict __read_mostly;
 
 static noinline_for_stack
@@ -857,7 +874,7 @@ char *restricted_pointer(char *buf, char *end, const void *ptr,
        switch (kptr_restrict) {
        case 0:
                /* Handle as %p, hash and do _not_ leak addresses. */
-               return ptr_to_id(buf, end, ptr, spec);
+               return default_pointer(buf, end, ptr, spec);
        case 1: {
                const struct cred *cred;
 
@@ -2233,10 +2250,6 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode,
        return widen_string(buf, buf - buf_start, end, spec);
 }
 
-/* Disable pointer hashing if requested */
-bool no_hash_pointers __ro_after_init;
-EXPORT_SYMBOL_GPL(no_hash_pointers);
-
 int __init no_hash_pointers_enable(char *str)
 {
        if (no_hash_pointers)
@@ -2465,7 +2478,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
        case 'e':
                /* %pe with a non-ERR_PTR gets treated as plain %p */
                if (!IS_ERR(ptr))
-                       break;
+                       return default_pointer(buf, end, ptr, spec);
                return err_ptr(buf, end, ptr, spec);
        case 'u':
        case 'k':
@@ -2475,16 +2488,9 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
                default:
                        return error_string(buf, end, "(einval)", spec);
                }
+       default:
+               return default_pointer(buf, end, ptr, spec);
        }
-
-       /*
-        * default is to _not_ leak addresses, so hash before printing,
-        * unless no_hash_pointers is specified on the command line.
-        */
-       if (unlikely(no_hash_pointers))
-               return pointer_string(buf, end, ptr, spec);
-       else
-               return ptr_to_id(buf, end, ptr, spec);
 }
 
 /*