On Fri, 9 Feb 2018, Eric Biggers wrote:

This is a build fix for the 4.4 PTI backport. 4.4 kernels do not have commit be7635e7287e ("arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections") which went into 4.6. Consequently, the irqentry sections are only created when CONFIG_FUNCTION_GRAPH_TRACER is enabled, not also when CONFIG_KASAN is enabled. Therefore, fix the condition for trying to add a user mapping for this section.

This fixes the following build error:

arch/x86/mm/kaiser.c: In function ‘kaiser_init’:
arch/x86/mm/kaiser.c:367:33: error: ‘__irqentry_text_start’ undeclared (first use in this function)
  kaiser_add_user_map_ptrs_early(__irqentry_text_start,
[...]

Signed-off-by: Eric Biggers ebiggers@google.com

Yep, sorry about that, thanks Eric: Acked-by: Hugh Dickins hughd@google.com

---

arch/x86/mm/kaiser.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c index 2298434f7bdb..7a72e32e4806 100644 --- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -363,7 +363,7 @@ void __init kaiser_init(void) kaiser_add_user_map_ptrs_early(__entry_text_start, __entry_text_end, __PAGE_KERNEL_RX); -#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) +#ifdef CONFIG_FUNCTION_GRAPH_TRACER kaiser_add_user_map_ptrs_early(__irqentry_text_start, __irqentry_text_end, __PAGE_KERNEL_RX); -- 2.16.0.rc1.238.g530d649a79-goog

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

x86/kaiser: fix build error with KASAN && !FUNCTION_GRAPH_TRACER

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: x86-kaiser-fix-build-error-with-kasan-function_graph_tracer.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From ebiggers@google.com Tue Feb 13 16:43:57 2018

From: Eric Biggers ebiggers@google.com Date: Fri, 9 Feb 2018 15:21:31 -0800 Subject: x86/kaiser: fix build error with KASAN && !FUNCTION_GRAPH_TRACER To: stable@vger.kernel.org, Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Alexander Potapenko glider@google.com, Dave Hansen dave.hansen@linux.intel.com, Hugh Dickins hughd@google.com, x86@kernel.org, Eric Biggers ebiggers@google.com Message-ID: 20180209232131.60555-1-ebiggers@google.com

From: Eric Biggers ebiggers@google.com

This is a build fix for the 4.4 PTI backport. 4.4 kernels do not have commit be7635e7287e ("arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections") which went into 4.6. Consequently, the irqentry sections are only created when CONFIG_FUNCTION_GRAPH_TRACER is enabled, not also when CONFIG_KASAN is enabled. Therefore, fix the condition for trying to add a user mapping for this section.

This fixes the following build error:

arch/x86/mm/kaiser.c: In function ‘kaiser_init’: arch/x86/mm/kaiser.c:367:33: error: ‘__irqentry_text_start’ undeclared (first use in this function) kaiser_add_user_map_ptrs_early(__irqentry_text_start, [...]

Signed-off-by: Eric Biggers ebiggers@google.com Acked-by: Hugh Dickins hughd@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/mm/kaiser.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/mm/kaiser.c +++ b/arch/x86/mm/kaiser.c @@ -363,7 +363,7 @@ void __init kaiser_init(void) kaiser_add_user_map_ptrs_early(__entry_text_start, __entry_text_end, __PAGE_KERNEL_RX);

-#if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN) +#ifdef CONFIG_FUNCTION_GRAPH_TRACER kaiser_add_user_map_ptrs_early(__irqentry_text_start, __irqentry_text_end, __PAGE_KERNEL_RX);

Patches currently in stable-queue which might be from ebiggers@google.com are

queue-4.4/keys-encrypted-fix-buffer-overread-in-valid_master_desc.patch queue-4.4/x86-kaiser-fix-build-error-with-kasan-function_graph_tracer.patch