Messages in this thread | | | Subject | Re: [PATCH] ocfs2: possible memory leak in mlog_sys_init() | From | Yang Yingliang <> | Date | Tue, 18 Oct 2022 18:33:29 +0800 |
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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@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) > .
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