diff options
| author | Chao Yu <yuchao0@huawei.com> | 2018-05-28 16:57:32 +0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2018-05-31 11:31:52 -0700 |
| commit | 250dbf515192811025c4f3ba764a985f9b95be8e (patch) | |
| tree | 387694a4b8840e81b04b601143333a6a7fdeaedf /fs/f2fs | |
| parent | aec2f729fca13661e9bc651839ae23bf8367195a (diff) | |
f2fs: fix to avoid race during access gc_thread pointer
Thread A Thread B
- f2fs_remount
- stop_gc_thread
- f2fs_sbi_store
sbi->gc_thread = NULL;
access sbi->gc_thread->gc_*
Previously, we allocate memory for sbi->gc_thread based on background
gc thread mount option, the memory can be released if we turn off
that mount option, but still there are several places access gc_thread
pointer without considering race condition, result in NULL point
dereference.
In order to fix this issue, use sb->s_umount to exclude those operations.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs')
| -rw-r--r-- | fs/f2fs/sysfs.c | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c index dd940d156af6..ac3ea6044936 100644 --- a/fs/f2fs/sysfs.c +++ b/fs/f2fs/sysfs.c @@ -165,7 +165,7 @@ static ssize_t f2fs_sbi_show(struct f2fs_attr *a, return snprintf(buf, PAGE_SIZE, "%u\n", *ui); } -static ssize_t f2fs_sbi_store(struct f2fs_attr *a, +static ssize_t __f2fs_sbi_store(struct f2fs_attr *a, struct f2fs_sb_info *sbi, const char *buf, size_t count) { @@ -278,6 +278,23 @@ out: return count; } +static ssize_t f2fs_sbi_store(struct f2fs_attr *a, + struct f2fs_sb_info *sbi, + const char *buf, size_t count) +{ + ssize_t ret; + bool gc_entry = (!strcmp(a->attr.name, "gc_urgent") || + a->struct_type == GC_THREAD); + + if (gc_entry) + down_read(&sbi->sb->s_umount); + ret = __f2fs_sbi_store(a, sbi, buf, count); + if (gc_entry) + up_read(&sbi->sb->s_umount); + + return ret; +} + static ssize_t f2fs_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { |