bpf: fix 64-bit divide
authorAlexei Starovoitov <ast@plumgrid.com>
Mon, 27 Apr 2015 21:40:37 +0000 (14:40 -0700)
committerSasha Levin <sasha.levin@oracle.com>
Sun, 17 May 2015 23:12:32 +0000 (19:12 -0400)
commit2611e2418ca8be78f87cd8f727aa92f04fdcfd21
treeffd9ed751bbd3e4034c74cf98de13021a4fbaba9
parent7f1a6ae73b5c2d24b21d9a27928ceacef3a9a939
bpf: fix 64-bit divide

[ 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@linux.vnet.ibm.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
kernel/bpf/core.c