Patch "x86/dumpstack: Indicate in Oops whether PTI is configured and enabled" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

x86/dumpstack: Indicate in Oops whether PTI is configured and enabled

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Vlastimil Babka <[email protected]>
Date: Tue, 19 Dec 2017 22:33:46 +0100
Subject: x86/dumpstack: Indicate in Oops whether PTI is configured and enabled

From: Vlastimil Babka <[email protected]>

commit 5f26d76c3fd67c48806415ef8b1116c97beff8ba upstream.

CONFIG_PAGE_TABLE_ISOLATION is relatively new and intrusive feature that may still have some corner cases which could take some time to manifest and be fixed. It would be useful to have Oops messages indicate whether it was enabled for building the kernel, and whether it was disabled during boot.

Example of fully enabled:

	Oops: 0001 [#1] SMP PTI

Example of enabled during build, but disabled during boot:

	Oops: 0001 [#1] SMP NOPTI

We can decide to remove this after the feature has been tested in the field long enough.

[ tglx: Made it use boot_cpu_has() as requested by Borislav ]

---
 arch/x86/kernel/dumpstack.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

@@ -297,11 +297,13 @@ int __die(const char *str, struct pt_reg
 	unsigned long sp;
 #endif
 	printk(KERN_DEFAULT
-	       "%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter,
+	       "%s: %04lx [#%d]%s%s%s%s%s\n", str, err & 0xffff, ++die_counter,
 	       IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT"         : "",
 	       IS_ENABLED(CONFIG_SMP)     ? " SMP"             : "",
 	       debug_pagealloc_enabled()  ? " DEBUG_PAGEALLOC" : "",
-	       IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : "");
+	       IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : "",
+	       IS_ENABLED(CONFIG_PAGE_TABLE_ISOLATION) ?
+	       (boot_cpu_has(X86_FEATURE_PTI) ? " PTI" : " NOPTI") : "");
 
 	if (notify_die(DIE_OOPS, str, regs, err,
 			current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/x86-dumpstack-indicate-in-oops-whether-pti-is-configured-and-enabled.patch