Patch "ARM: net: bpf: clarify tail_call index" has been added to the 4.14-stable tree

Patch "ARM: net: bpf: clarify tail_call index" has been added to the 4.14-stable tree

[gregkh]

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

    ARM: net: bpf: clarify tail_call index

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:
     arm-net-bpf-clarify-tail_call-index.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 <stable@vger.kernel.org> know about it.


>From 091f02483df7b56615b524491f404e574c5e0668 Mon Sep 17 00:00:00 2001
From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Sat, 13 Jan 2018 12:11:26 +0000
Subject: ARM: net: bpf: clarify tail_call index

From: Russell King <rmk+kernel@armlinux.org.uk>

commit 091f02483df7b56615b524491f404e574c5e0668 upstream.

As per 90caccdd8cc0 ("bpf: fix bpf_tail_call() x64 JIT"), the index used
for array lookup is defined to be 32-bit wide. Update a misleading
comment that suggests it is 64-bit wide.

Fixes: 39c13c204bb1 ("arm: eBPF JIT compiler")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm/net/bpf_jit_32.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -1016,7 +1016,7 @@ static int emit_bpf_tail_call(struct jit
 	emit_a32_mov_i(tmp[1], off, false, ctx);
 	emit(ARM_LDR_I(tmp2[1], ARM_SP, STACK_VAR(r2[1])), ctx);
 	emit(ARM_LDR_R(tmp[1], tmp2[1], tmp[1]), ctx);
-	/* index (64 bit) */
+	/* index is 32-bit for arrays */
 	emit(ARM_LDR_I(tmp2[1], ARM_SP, STACK_VAR(r3[1])), ctx);
 	/* index >= array->map.max_entries */
 	emit(ARM_CMP_R(tmp2[1], tmp[1]), ctx);


Patches currently in stable-queue which might be from rmk+kernel@armlinux.org.uk are

queue-4.14/arm-net-bpf-fix-stack-alignment.patch
queue-4.14/arm-net-bpf-fix-ldx-instructions.patch
queue-4.14/arm-net-bpf-fix-register-saving.patch
queue-4.14/arm-net-bpf-move-stack-documentation.patch
queue-4.14/arm-net-bpf-correct-stack-layout-documentation.patch
queue-4.14/arm-net-bpf-clarify-tail_call-index.patch
queue-4.14/arm-net-bpf-avoid-bx-instruction-on-non-thumb-capable-cpus.patch
queue-4.14/arm-net-bpf-fix-tail-call-jumps.patch