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 <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Fri May 8 13:16:04 CEST 2015
From: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Date: Mon, 27 Apr 2015 14:40:37 -0700
Subject: bpf: fix 64-bit divide
From: Alexei Starovoitov <ast@xxxxxxxxxxxx>
[ 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.
Fixes: 89aa075832b0 ("net: sock: allow eBPF programs to be attached to sockets")
Reported-by: Michael Holzheu <holzheu@xxxxxxxxxxxxxxxxxx>
Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/bpf/core.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -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 ast@xxxxxxxxxxxx are
queue-4.0/bpf-fix-64-bit-divide.patch
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