Daniel Borkmann 1bfceb3750 bpf, arm64: remove prefetch insn in xadd mapping ...

commit 8968c67a82 upstream.

Prefetch-with-intent-to-write is currently part of the XADD mapping in
the AArch64 JIT and follows the kernel's implementation of atomic_add.
This may interfere with other threads executing the LDXR/STXR loop,
leading to potential starvation and fairness issues. Drop the optional
prefetch instruction.

Fixes: 85f68fe898 ("bpf, arm64: implement jiting of BPF_XADD")
Reported-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2019-05-22 07:37:38 +02:00

..

bpf_jit_comp.c

bpf, arm64: remove prefetch insn in xadd mapping

2019-05-22 07:37:38 +02:00

bpf_jit.h

bpf, arm64: remove prefetch insn in xadd mapping

2019-05-22 07:37:38 +02:00

Makefile

arm64: eBPF JIT compiler

2014-09-08 14:39:21 +01:00