46 lines
1.8 KiB
Diff
46 lines
1.8 KiB
Diff
|
https://github.com/rclone/rclone/pull/6311
|
||
|
|
From 67fd60275a6187c41c4944545c2145cd28bc330d Mon Sep 17 00:00:00 2001
|
||
|
|
From: r-ricci <ricci@disroot.org>
|
||
|
|
Date: Mon, 11 Jul 2022 18:34:06 +0100
|
||
|
|
Subject: [PATCH] union: fix panic due to misalignment of struct field in 32
|
||
|
|
bit architectures
|
||
|
|
|
||
|
|
`FS.cacheExpiry` is accessed through sync/atomic.
|
||
|
|
According to the documentation, "On ARM, 386, and 32-bit MIPS, it is
|
||
|
|
the caller's responsibility to arrange for 64-bit alignment of 64-bit
|
||
|
|
words accessed atomically. The first word in a variable or in an
|
||
|
|
allocated struct, array, or slice can be relied upon to be 64-bit
|
||
|
|
aligned."
|
||
|
|
Before commit 1d2fe0d8564bc679ece166c24b24e6fe7dc1455c this field was
|
||
|
|
aligned, but then a new field was added to the structure, causing the
|
||
|
|
test suite to panic on linux/386.
|
||
|
|
No other field is used with sync/atomic, so `cacheExpiry` can just be
|
||
|
|
placed at the beginning of the stuct to ensure it is always aligned.
|
||
|
|
---
|
||
|
|
backend/union/upstream/upstream.go | 5 ++++-
|
||
|
|
1 file changed, 4 insertions(+), 1 deletion(-)
|
||
|
|
|
||
|
|
diff --git a/backend/union/upstream/upstream.go b/backend/union/upstream/upstream.go
|
||
|
|
index 35b477f7930a..7b9f44fd2a39 100644
|
||
|
|
--- a/backend/union/upstream/upstream.go
|
||
|
|
+++ b/backend/union/upstream/upstream.go
|
||
|
|
@@ -24,6 +24,10 @@ var (
|
||
|
|
|
||
|
|
// Fs is a wrap of any fs and its configs
|
||
|
|
type Fs struct {
|
||
|
|
+ // In order to ensure memory alignment on 32-bit architectures
|
||
|
|
+ // when this field is accessed through sync/atomic functions,
|
||
|
|
+ // it must be the first entry in the struct
|
||
|
|
+ cacheExpiry int64 // usage cache expiry time
|
||
|
|
fs.Fs
|
||
|
|
RootFs fs.Fs
|
||
|
|
RootPath string
|
||
|
|
@@ -32,7 +36,6 @@ type Fs struct {
|
||
|
|
creatable bool
|
||
|
|
usage *fs.Usage // Cache the usage
|
||
|
|
cacheTime time.Duration // cache duration
|
||
|
|
- cacheExpiry int64 // usage cache expiry time
|
||
|
|
cacheMutex sync.RWMutex
|
||
|
|
cacheOnce sync.Once
|
||
|
|
cacheUpdate bool // if the cache is updating
|