github-mirror/rclone
github-mirror/rclone
2
0
Fork 0
mirror of https://github.com/rclone/rclone.git synced 2025-02-21 06:24:10 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

union: fix panic due to misalignment of struct field in 32 bit architectures

Browse Source 
`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.
This commit is contained in:
r-ricci 2022-07-11 18:34:06 +01:00 committed by GitHub
parent b310490fa5
commit 67fd60275a
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 4 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
backend/union/upstream/upstream.go
View File

@ -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