Patch "bpf: fix 64-bit divide" has been added to the 4.0-stable tree

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

bpf: fix 64-bit divide

to the 4.0-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:

     bpf-fix-64-bit-divide.patch

and it can be found in the queue-4.0 subdirectory.

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

From: Alexei Starovoitov <[email protected]>
Date: Mon, 27 Apr 2015 14:40:37 -0700
Subject: bpf: fix 64-bit divide

From: Alexei Starovoitov <[email protected]>

[ Upstream commit 876a7ae65b86d8cec8efe7d15d050ac61116874e ]

ALU64_DIV instruction should be dividing 64-bit by 64-bit, whereas do_div() does 64-bit by 32-bit divide.
x64 and arm64 JITs correctly implement 64 by 64 unsigned divide. llvm BPF backend emits code assuming that ALU64_DIV does 64 by 64.

---
 kernel/bpf/core.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

@@ -357,8 +357,8 @@ select_insn:
 	ALU64_MOD_X:
 		if (unlikely(SRC == 0))
 			return 0;
-		tmp = DST;
-		DST = do_div(tmp, SRC);
+		div64_u64_rem(DST, SRC, &tmp);
+		DST = tmp;
 		CONT;
 	ALU_MOD_X:
 		if (unlikely(SRC == 0))

@@ -367,8 +367,8 @@ select_insn:
 		DST = do_div(tmp, (u32) SRC);
 		CONT;
 	ALU64_MOD_K:
-		tmp = DST;
-		DST = do_div(tmp, IMM);
+		div64_u64_rem(DST, IMM, &tmp);
+		DST = tmp;
 		CONT;
 	ALU_MOD_K:
 		tmp = (u32) DST;

@@ -377,7 +377,7 @@ select_insn:
 	ALU64_DIV_X:
 		if (unlikely(SRC == 0))
 			return 0;
-		do_div(DST, SRC);
+		DST = div64_u64(DST, SRC);
 		CONT;
 	ALU_DIV_X:
 		if (unlikely(SRC == 0))

@@ -387,7 +387,7 @@ select_insn:
 		DST = (u32) tmp;
 		CONT;
 	ALU64_DIV_K:
-		do_div(DST, IMM);
+		DST = div64_u64(DST, IMM);
 		CONT;
 	ALU_DIV_K:
 		tmp = (u32) DST;

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

queue-4.0/bpf-fix-64-bit-divide.patch