Ashish Samant
2018-Jun-21 23:57 UTC
[Ocfs2-devel] [PATCH] ocfs2: Fix locking for res->tracking and dlm->tracking_list
In dlm_init_lockres() and dlm_unregister_domain() we access and modify res->tracking and dlm->tracking_list without holding dlm->track_lock. This can cause list corruptions and can end up in kernel panic. Fix this by locking res->tracking and dlm->tracking_list with dlm->track_lock at all places. Signed-off-by: Ashish Samant <ashish.samant at oracle.com> --- fs/ocfs2/dlm/dlmdomain.c | 2 ++ fs/ocfs2/dlm/dlmmaster.c | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c index 2acd58b..cfb1edd 100644 --- a/fs/ocfs2/dlm/dlmdomain.c +++ b/fs/ocfs2/dlm/dlmdomain.c @@ -723,6 +723,7 @@ void dlm_unregister_domain(struct dlm_ctxt *dlm) mlog(0, "%s: more migration to do\n", dlm->name); } + spin_lock(&dlm->track_lock); /* This list should be empty. If not, print remaining lockres */ if (!list_empty(&dlm->tracking_list)) { mlog(ML_ERROR, "Following lockres' are still on the " @@ -730,6 +731,7 @@ void dlm_unregister_domain(struct dlm_ctxt *dlm) list_for_each_entry(res, &dlm->tracking_list, tracking) dlm_print_one_lock_resource(res); } + spin_unlock(&dlm->track_lock); dlm_mark_domain_leaving(dlm); dlm_leave_domain(dlm); diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index aaca094..826f056 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -584,9 +584,9 @@ static void dlm_init_lockres(struct dlm_ctxt *dlm, res->last_used = 0; - spin_lock(&dlm->spinlock); + spin_lock(&dlm->track_lock); list_add_tail(&res->tracking, &dlm->tracking_list); - spin_unlock(&dlm->spinlock); + spin_unlock(&dlm->track_lock); memset(res->lvb, 0, DLM_LVB_LEN); memset(res->refmap, 0, sizeof(res->refmap)); -- 1.9.1
piaojun
2018-Jun-22 00:34 UTC
[Ocfs2-devel] [PATCH] ocfs2: Fix locking for res->tracking and dlm->tracking_list
Hi Ashish, I think we should get 'res->spinlock' before getting 'dlm->track_lock' such as in __dlm_do_purge_lockres(). But your patch reverse the locking sequence as we will get 'res->spinlock' in dlm_print_one_lock_resource() which may cause 'ABBA' deadlock. thanks, Jun On 2018/6/22 7:57, Ashish Samant wrote:> In dlm_init_lockres() and dlm_unregister_domain() we access and modify > res->tracking and dlm->tracking_list without holding dlm->track_lock. > This can cause list corruptions and can end up in kernel panic. > > Fix this by locking res->tracking and dlm->tracking_list with > dlm->track_lock at all places. > > Signed-off-by: Ashish Samant <ashish.samant at oracle.com> > --- > fs/ocfs2/dlm/dlmdomain.c | 2 ++ > fs/ocfs2/dlm/dlmmaster.c | 4 ++-- > 2 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c > index 2acd58b..cfb1edd 100644 > --- a/fs/ocfs2/dlm/dlmdomain.c > +++ b/fs/ocfs2/dlm/dlmdomain.c > @@ -723,6 +723,7 @@ void dlm_unregister_domain(struct dlm_ctxt *dlm) > mlog(0, "%s: more migration to do\n", dlm->name); > } > > + spin_lock(&dlm->track_lock); > /* This list should be empty. If not, print remaining lockres */ > if (!list_empty(&dlm->tracking_list)) { > mlog(ML_ERROR, "Following lockres' are still on the " > @@ -730,6 +731,7 @@ void dlm_unregister_domain(struct dlm_ctxt *dlm) > list_for_each_entry(res, &dlm->tracking_list, tracking) > dlm_print_one_lock_resource(res); > } > + spin_unlock(&dlm->track_lock); > > dlm_mark_domain_leaving(dlm); > dlm_leave_domain(dlm); > diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c > index aaca094..826f056 100644 > --- a/fs/ocfs2/dlm/dlmmaster.c > +++ b/fs/ocfs2/dlm/dlmmaster.c > @@ -584,9 +584,9 @@ static void dlm_init_lockres(struct dlm_ctxt *dlm, > > res->last_used = 0; > > - spin_lock(&dlm->spinlock); > + spin_lock(&dlm->track_lock); > list_add_tail(&res->tracking, &dlm->tracking_list); > - spin_unlock(&dlm->spinlock); > + spin_unlock(&dlm->track_lock); > > memset(res->lvb, 0, DLM_LVB_LEN); > memset(res->refmap, 0, sizeof(res->refmap)); >
Joseph Qi
2018-Jun-22 08:32 UTC
[Ocfs2-devel] [PATCH] ocfs2: Fix locking for res->tracking and dlm->tracking_list
On 18/6/22 07:57, Ashish Samant wrote:> In dlm_init_lockres() and dlm_unregister_domain() we access and modify > res->tracking and dlm->tracking_list without holding dlm->track_lock. > This can cause list corruptions and can end up in kernel panic. > > Fix this by locking res->tracking and dlm->tracking_list with > dlm->track_lock at all places. > > Signed-off-by: Ashish Samant <ashish.samant at oracle.com> > --- > fs/ocfs2/dlm/dlmdomain.c | 2 ++ > fs/ocfs2/dlm/dlmmaster.c | 4 ++-- > 2 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c > index 2acd58b..cfb1edd 100644 > --- a/fs/ocfs2/dlm/dlmdomain.c > +++ b/fs/ocfs2/dlm/dlmdomain.c > @@ -723,6 +723,7 @@ void dlm_unregister_domain(struct dlm_ctxt *dlm) > mlog(0, "%s: more migration to do\n", dlm->name); > } > > + spin_lock(&dlm->track_lock); > /* This list should be empty. If not, print remaining lockres */ > if (!list_empty(&dlm->tracking_list)) { > mlog(ML_ERROR, "Following lockres' are still on the " > @@ -730,6 +731,7 @@ void dlm_unregister_domain(struct dlm_ctxt *dlm) > list_for_each_entry(res, &dlm->tracking_list, tracking) > dlm_print_one_lock_resource(res); > } > + spin_unlock(&dlm->track_lock); >The locking order should be res->spinlock > dlm->track_lock. Since here just want to print error message for issue tracking, I'm wandering if we can copy tracking list to local first. Thanks, Joseph> dlm_mark_domain_leaving(dlm); > dlm_leave_domain(dlm); > diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c > index aaca094..826f056 100644 > --- a/fs/ocfs2/dlm/dlmmaster.c > +++ b/fs/ocfs2/dlm/dlmmaster.c > @@ -584,9 +584,9 @@ static void dlm_init_lockres(struct dlm_ctxt *dlm, > > res->last_used = 0; > > - spin_lock(&dlm->spinlock); > + spin_lock(&dlm->track_lock); > list_add_tail(&res->tracking, &dlm->tracking_list); > - spin_unlock(&dlm->spinlock); > + spin_unlock(&dlm->track_lock); > > memset(res->lvb, 0, DLM_LVB_LEN); > memset(res->refmap, 0, sizeof(res->refmap)); >