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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-07 09:18:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-07 09:18:12 -0700
commit0968621917add2e0d60c8fbc4e24c670cb14319c (patch)
tree79fc122606717ebcf0bbc8b2a986f2a0999a9c61 /Documentation
parent573de2a6e844cb230c4483833f29b8344a6a17cc (diff)
parent0f46c78391e1348fe45af86a0cd52795726695af (diff)
Merge tag 'printk-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk
Pull printk updates from Petr Mladek: - Allow state reset of printk_once() calls. - Prevent crashes when dereferencing invalid pointers in vsprintf(). Only the first byte is checked for simplicity. - Make vsprintf warnings consistent and inlined. - Treewide conversion of obsolete %pf, %pF to %ps, %pF printf modifiers. - Some clean up of vsprintf and test_printf code. * tag 'printk-for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: lib/vsprintf: Make function pointer_string static vsprintf: Limit the length of inlined error messages vsprintf: Avoid confusion between invalid address and value vsprintf: Prevent crash when dereferencing invalid pointers vsprintf: Consolidate handling of unknown pointer specifiers vsprintf: Factor out %pO handler as kobject_string() vsprintf: Factor out %pV handler as va_format() vsprintf: Factor out %p[iI] handler as ip_addr_string() vsprintf: Do not check address of well-known strings vsprintf: Consistent %pK handling for kptr_restrict == 0 vsprintf: Shuffle restricted_pointer() printk: Tie printk_once / printk_deferred_once into .data.once for reset treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively lib/test_printf: Switch to bitmap_zalloc()
Diffstat (limited to 'Documentation')
-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
--------------