Joseph Qi
2022-Oct-18 09:02 UTC
[Ocfs2-devel] [PATCH] ocfs2: possible memory leak in mlog_sys_init()
Hi, On 10/18/22 3:52 PM, Yang Yingliang wrote:> Inject fault while probing module, kset_register() may fail, > if it fails, but the refcount of kobject is not decreased to > 0, the name allocated in kobject_set_name() is leaked. Fix > this by calling kset_put(), so that name can be freed in > callback function kobject_cleanup(). > > unreferenced object 0xffff888100da9348 (size 8): > comm "modprobe", pid 257, jiffies 4294701096 (age 33.334s) > hex dump (first 8 bytes): > 6c 6f 67 6d 61 73 6b 00 logmask. > backtrace: > [<00000000306e441c>] __kmalloc_node_track_caller+0x44/0x1b0 > [<000000007c491a9e>] kstrdup+0x3a/0x70 > [<0000000015719a3b>] kstrdup_const+0x63/0x80 > [<0000000084e458ea>] kvasprintf_const+0x149/0x180 > [<0000000091302b42>] kobject_set_name_vargs+0x56/0x150 > [<000000005f48eeac>] kobject_set_name+0xab/0xe0 > > Fixes: 34980ca8faeb ("Drivers: clean up direct setting of the name of a kset") > Signed-off-by: Yang Yingliang <yangyingliang at huawei.com> > --- > fs/ocfs2/cluster/masklog.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/fs/ocfs2/cluster/masklog.c b/fs/ocfs2/cluster/masklog.c > index 563881ddbf00..7f9ba816d955 100644 > --- a/fs/ocfs2/cluster/masklog.c > +++ b/fs/ocfs2/cluster/masklog.c > @@ -156,6 +156,7 @@ static struct kset mlog_kset = { > int mlog_sys_init(struct kset *o2cb_kset) > { > int i = 0; > + int ret; > > while (mlog_attrs[i].attr.mode) { > mlog_default_attrs[i] = &mlog_attrs[i].attr; > @@ -165,7 +166,11 @@ int mlog_sys_init(struct kset *o2cb_kset) > > kobject_set_name(&mlog_kset.kobj, "logmask"); > mlog_kset.kobj.kset = o2cb_kset; > - return kset_register(&mlog_kset); > + ret = kset_register(&mlog_kset);If register fails, it will call unregister in o2cb_sys_init(), which will put kobject. Thanks, Joseph> + if (ret) > + kset_put(&mlog_kset); > + > + return ret; > } > > void mlog_sys_shutdown(void)
Yang Yingliang
2022-Oct-18 10:33 UTC
[Ocfs2-devel] [PATCH] ocfs2: possible memory leak in mlog_sys_init()
Hi, On 2022/10/18 17:02, Joseph Qi wrote:> Hi, > > On 10/18/22 3:52 PM, Yang Yingliang wrote: >> Inject fault while probing module, kset_register() may fail, >> if it fails, but the refcount of kobject is not decreased to >> 0, the name allocated in kobject_set_name() is leaked. Fix >> this by calling kset_put(), so that name can be freed in >> callback function kobject_cleanup(). >> >> unreferenced object 0xffff888100da9348 (size 8): >> comm "modprobe", pid 257, jiffies 4294701096 (age 33.334s) >> hex dump (first 8 bytes): >> 6c 6f 67 6d 61 73 6b 00 logmask. >> backtrace: >> [<00000000306e441c>] __kmalloc_node_track_caller+0x44/0x1b0 >> [<000000007c491a9e>] kstrdup+0x3a/0x70 >> [<0000000015719a3b>] kstrdup_const+0x63/0x80 >> [<0000000084e458ea>] kvasprintf_const+0x149/0x180 >> [<0000000091302b42>] kobject_set_name_vargs+0x56/0x150 >> [<000000005f48eeac>] kobject_set_name+0xab/0xe0 >> >> Fixes: 34980ca8faeb ("Drivers: clean up direct setting of the name of a kset") >> Signed-off-by: Yang Yingliang <yangyingliang at huawei.com> >> --- >> fs/ocfs2/cluster/masklog.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/fs/ocfs2/cluster/masklog.c b/fs/ocfs2/cluster/masklog.c >> index 563881ddbf00..7f9ba816d955 100644 >> --- a/fs/ocfs2/cluster/masklog.c >> +++ b/fs/ocfs2/cluster/masklog.c >> @@ -156,6 +156,7 @@ static struct kset mlog_kset = { >> int mlog_sys_init(struct kset *o2cb_kset) >> { >> int i = 0; >> + int ret; >> >> while (mlog_attrs[i].attr.mode) { >> mlog_default_attrs[i] = &mlog_attrs[i].attr; >> @@ -165,7 +166,11 @@ int mlog_sys_init(struct kset *o2cb_kset) >> >> kobject_set_name(&mlog_kset.kobj, "logmask"); >> mlog_kset.kobj.kset = o2cb_kset; >> - return kset_register(&mlog_kset); >> + ret = kset_register(&mlog_kset); > If register fails, it will call unregister in o2cb_sys_init(), which > will put kobject.They are different ksets, the kset unregistered in o2cb_sys_init() is 'o2cb_kset', the kset used to registered in mlog_sys_init() is 'mlog_kset', and they hold difference refcounts. Thanks, Yang> > Thanks, > Joseph > >> + if (ret) >> + kset_put(&mlog_kset); >> + >> + return ret; >> } >> >> void mlog_sys_shutdown(void) > .