livepatch: kernel: add TAINT_LIVEPATCH

sjenning · Jiri Kosina · commit c5f4546593e9 · 2014-12-22T15:40:48.000+01:00
This adds a new taint flag to indicate when the kernel or a kernel
module has been live patched.  This will provide a clean indication in
bug reports that live patching was used.

Additionally, if the crash occurs in a live patched function, the live
patch module will appear beside the patched function in the backtrace.

Signed-off-by: Seth Jennings &lt;sjenning@redhat.com&gt;
Acked-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Reviewed-by: Miroslav Benes &lt;mbenes@suse.cz&gt;
Reviewed-by: Petr Mladek &lt;pmladek@suse.cz&gt;
Reviewed-by: Masami Hiramatsu &lt;masami.hiramatsu.pt@hitachi.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.cz&gt;
diff --git a/Documentation/oops-tracing.txt b/Documentation/oops-tracing.txt
@@ -270,6 +270,8 @@ characters, each representing a particular tainted value.
 
  15: 'L' if a soft lockup has previously occurred on the system.
 
+ 16: 'K' if the kernel has been live patched.
+
 The primary reason for the 'Tainted: ' string is to tell kernel
 debuggers if this is a clean kernel or if anything unusual has
 occurred.  Tainting is permanent: even if an offending module is
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
@@ -843,6 +843,7 @@ can be ORed together:
 8192 - An unsigned module has been loaded in a kernel supporting module
        signature.
 16384 - A soft lockup has previously occurred on the system.
+32768 - The kernel has been live patched.
 
 ==============================================================
 
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
@@ -471,6 +471,7 @@ extern enum system_states {
 #define TAINT_OOT_MODULE		12
 #define TAINT_UNSIGNED_MODULE		13
 #define TAINT_SOFTLOCKUP		14
+#define TAINT_LIVEPATCH			15
 
 extern const char hex_asc[];
 #define hex_asc_lo(x)	hex_asc[((x) & 0x0f)]
diff --git a/kernel/panic.c b/kernel/panic.c
@@ -226,6 +226,7 @@ static const struct tnt tnts[] = {
 	{ TAINT_OOT_MODULE,		'O', ' ' },
 	{ TAINT_UNSIGNED_MODULE,	'E', ' ' },
 	{ TAINT_SOFTLOCKUP,		'L', ' ' },
+	{ TAINT_LIVEPATCH,		'K', ' ' },
 };
 
 /**
@@ -246,6 +247,7 @@ static const struct tnt tnts[] = {
  *  'O' - Out-of-tree module has been loaded.
  *  'E' - Unsigned module has been loaded.
  *  'L' - A soft lockup has previously occurred.
+ *  'K' - Kernel has been live patched.
  *
  *	The string is overwritten by the next call to print_tainted().
  */
