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-rw-r--r--Documentation/clearing-warn-once.txt2
-rw-r--r--Documentation/core-api/printk-formats.rst8
2 files changed, 9 insertions, 1 deletions
diff --git a/Documentation/clearing-warn-once.txt b/Documentation/clearing-warn-once.txt
index 5b1f5d547be1..c68598b31428 100644
--- a/Documentation/clearing-warn-once.txt
+++ b/Documentation/clearing-warn-once.txt
@@ -1,5 +1,5 @@
-WARN_ONCE / WARN_ON_ONCE only print a warning once.
+WARN_ONCE / WARN_ON_ONCE / printk_once only emit a message once.
echo 1 > /sys/kernel/debug/clear_warn_once
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index c37ec7cd9c06..75d2bbe9813f 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -58,6 +58,14 @@ A raw pointer value may be printed with %p which will hash the address
before printing. The kernel also supports extended specifiers for printing
pointers of different types.
+Some of the extended specifiers print the data on the given address instead
+of printing the address itself. In this case, the following error messages
+might be printed instead of the unreachable information::
+
+ (null) data on plain NULL address
+ (efault) data on invalid address
+ (einval) invalid data on a valid address
+
Plain Pointers
--------------