--- /dev/null
+From b663c6fd98c9cf586279db03cec3257c413efd00 Mon Sep 17 00:00:00 2001
+From: J. Bruce Fields <bfields@citi.umich.edu>
+Date: Fri, 14 Mar 2008 19:37:11 -0400
+Message-ID: <20080314233711.GN2119@fieldses.org>
+Subject: nfsd: fix oops on access from high-numbered ports
+
+This bug was always here, but before my commit 6fa02839bf9412e18e77
+("recheck for secure ports in fh_verify"), it could only be triggered by
+failure of a kmalloc(). After that commit it could be triggered by a
+client making a request from a non-reserved port for access to an export
+marked "secure". (Exports are "secure" by default.)
+
+The result is a struct svc_export with a reference count one too low,
+resulting in likely oopses next time the export is accessed.
+
+The reference counting here is not straightforward; a later patch will
+clean up fh_verify().
+
+Thanks to Lukas Hejtmanek for the bug report and followup.
+
+Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
+Cc: Lukas Hejtmanek <xhejtman@ics.muni.cz>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+Signed-off-by: Chris Wright <chrisw@sous-sol.org>
+---
+ fs/nfsd/nfsfh.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/fs/nfsd/nfsfh.c
++++ b/fs/nfsd/nfsfh.c
+@@ -231,6 +231,7 @@ fh_verify(struct svc_rqst *rqstp, struct
+ fhp->fh_dentry = dentry;
+ fhp->fh_export = exp;
+ nfsd_nr_verified++;
++ cache_get(&exp->h);
+ } else {
+ /*
+ * just rechecking permissions
+@@ -240,6 +241,7 @@ fh_verify(struct svc_rqst *rqstp, struct
+ dprintk("nfsd: fh_verify - just checking\n");
+ dentry = fhp->fh_dentry;
+ exp = fhp->fh_export;
++ cache_get(&exp->h);
+ /*
+ * Set user creds for this exportpoint; necessary even
+ * in the "just checking" case because this may be a
+@@ -251,8 +253,6 @@ fh_verify(struct svc_rqst *rqstp, struct
+ if (error)
+ goto out;
+ }
+- cache_get(&exp->h);
+-
+
+ error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type);
+ if (error)
--- /dev/null
+From 0e1f34833bd9170ccc93ab759e48e695917fa48f Mon Sep 17 00:00:00 2001
+From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
+Date: Mon, 10 Mar 2008 11:01:20 -0700
+Message-Id: <1205535434.6423.2.camel@lappy>
+Subject: sched: fix race in schedule()
+
+Fix a hard to trigger crash seen in the -rt kernel that also affects
+the vanilla scheduler.
+
+There is a race condition between schedule() and some dequeue/enqueue
+functions; rt_mutex_setprio(), __setscheduler() and sched_move_task().
+
+When scheduling to idle, idle_balance() is called to pull tasks from
+other busy processor. It might drop the rq lock. It means that those 3
+functions encounter on_rq=0 and running=1. The current task should be
+put when running.
+
+Here is a possible scenario:
+
+ CPU0 CPU1
+ | schedule()
+ | ->deactivate_task()
+ | ->idle_balance()
+ | -->load_balance_newidle()
+rt_mutex_setprio() |
+ | --->double_lock_balance()
+ *get lock *rel lock
+ * on_rq=0, ruuning=1 |
+ * sched_class is changed |
+ *rel lock *get lock
+ : |
+ :
+ ->put_prev_task_rt()
+ ->pick_next_task_fair()
+ => panic
+
+The current process of CPU1(P1) is scheduling. Deactivated P1, and the
+scheduler looks for another process on other CPU's runqueue because CPU1
+will be idle. idle_balance(), load_balance_newidle() and
+double_lock_balance() are called and double_lock_balance() could drop
+the rq lock. On the other hand, CPU0 is trying to boost the priority of
+P1. The result of boosting only P1's prio and sched_class are changed to
+RT. The sched entities of P1 and P1's group are never put. It makes
+cfs_rq invalid, because the cfs_rq has curr and no leaf, but
+pick_next_task_fair() is called, then the kernel panics.
+
+Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
+Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
+Signed-off-by: Ingo Molnar <mingo@elte.hu>
+[chrisw@sous-sol.org: backport to 2.6.24.3]
+Signed-off-by: Chris Wright <chrisw@sous-sol.org>
+---
+ kernel/sched.c | 36 ++++++++++++++++--------------------
+ 1 file changed, 16 insertions(+), 20 deletions(-)
+
+--- a/kernel/sched.c
++++ b/kernel/sched.c
+@@ -4028,11 +4028,10 @@ void rt_mutex_setprio(struct task_struct
+ oldprio = p->prio;
+ on_rq = p->se.on_rq;
+ running = task_current(rq, p);
+- if (on_rq) {
++ if (on_rq)
+ dequeue_task(rq, p, 0);
+- if (running)
+- p->sched_class->put_prev_task(rq, p);
+- }
++ if (running)
++ p->sched_class->put_prev_task(rq, p);
+
+ if (rt_prio(prio))
+ p->sched_class = &rt_sched_class;
+@@ -4041,9 +4040,9 @@ void rt_mutex_setprio(struct task_struct
+
+ p->prio = prio;
+
++ if (running)
++ p->sched_class->set_curr_task(rq);
+ if (on_rq) {
+- if (running)
+- p->sched_class->set_curr_task(rq);
+ enqueue_task(rq, p, 0);
+ /*
+ * Reschedule if we are currently running on this runqueue and
+@@ -4339,18 +4338,17 @@ recheck:
+ update_rq_clock(rq);
+ on_rq = p->se.on_rq;
+ running = task_current(rq, p);
+- if (on_rq) {
++ if (on_rq)
+ deactivate_task(rq, p, 0);
+- if (running)
+- p->sched_class->put_prev_task(rq, p);
+- }
++ if (running)
++ p->sched_class->put_prev_task(rq, p);
+
+ oldprio = p->prio;
+ __setscheduler(rq, p, policy, param->sched_priority);
+
++ if (running)
++ p->sched_class->set_curr_task(rq);
+ if (on_rq) {
+- if (running)
+- p->sched_class->set_curr_task(rq);
+ activate_task(rq, p, 0);
+ /*
+ * Reschedule if we are currently running on this runqueue and
+@@ -7110,19 +7108,17 @@ void sched_move_task(struct task_struct
+ running = task_current(rq, tsk);
+ on_rq = tsk->se.on_rq;
+
+- if (on_rq) {
++ if (on_rq)
+ dequeue_task(rq, tsk, 0);
+- if (unlikely(running))
+- tsk->sched_class->put_prev_task(rq, tsk);
+- }
++ if (unlikely(running))
++ tsk->sched_class->put_prev_task(rq, tsk);
+
+ set_task_cfs_rq(tsk, task_cpu(tsk));
+
+- if (on_rq) {
+- if (unlikely(running))
+- tsk->sched_class->set_curr_task(rq);
++ if (unlikely(running))
++ tsk->sched_class->set_curr_task(rq);
++ if (on_rq)
+ enqueue_task(rq, tsk, 0);
+- }
+
+ done:
+ task_rq_unlock(rq, &flags);
projects / thirdparty / kernel / stable-queue.git / commitdiff
