Patch "MIPS: Avoid BUG warning in arch_check_elf" has been added to the 4.9-stable tree

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

MIPS: Avoid BUG warning in arch_check_elf

to the 4.9-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:
mips-avoid-bug-warning-in-arch_check_elf.patch
and it can be found in the queue-4.9 subdirectory.

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

From: James Cowgill <[email protected]>
Date: Tue, 11 Apr 2017 13:51:07 +0100
Subject: MIPS: Avoid BUG warning in arch_check_elf

From: James Cowgill <[email protected]>

commit c46f59e90226fa5bfcc83650edebe84ae47d454b upstream.

arch_check_elf contains a usage of current_cpu_data that will call smp_processor_id() with preemption enabled and therefore triggers a "BUG: using smp_processor_id() in preemptible" warning when an fpxx executable is loaded.

As a follow-up to commit b244614a60ab ("MIPS: Avoid a BUG warning during prctl(PR_SET_FP_MODE, ...)"), apply the same fix to arch_check_elf by using raw_current_cpu_data instead. The rationale quoted from the previous commit:

"It is assumed throughout the kernel that if any CPU has an FPU, then all CPUs would have an FPU as well, so it is safe to perform the check with preemption enabled - change the code to use raw_ variant of the check to avoid the warning."

Patchwork: https://patchwork.linux-mips.org/patch/15951/

---
 arch/mips/kernel/elf.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -257,7 +257,7 @@ int arch_check_elf(void *_ehdr, bool has
 	else if ((prog_req.fr1 && prog_req.frdefault) ||
 		 (prog_req.single && !prog_req.frdefault))
 		/* Make sure 64-bit MIPS III/IV/64R1 will not pick FR1 */
-		state->overall_fp_mode = ((current_cpu_data.fpu_id & MIPS_FPIR_F64) &&
+		state->overall_fp_mode = ((raw_current_cpu_data.fpu_id & MIPS_FPIR_F64) &&
 					  cpu_has_mips_r2_r6) ?
 					  FP_FR1 : FP_FR0;
 	else if (prog_req.fr1)

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

queue-4.9/mips-avoid-bug-warning-in-arch_check_elf.patch