diff options
| -rw-r--r-- | kernel/Makefile | 4 | ||||
| -rw-r--r-- | kernel/futex.c | 45 | ||||
| -rw-r--r-- | mm/page_alloc.c | 4 | ||||
| -rw-r--r-- | mm/slub.c | 10 |
4 files changed, 36 insertions, 27 deletions
diff --git a/kernel/Makefile b/kernel/Makefile index da750010a6fc..780c8dcf4516 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -69,8 +69,8 @@ obj-$(CONFIG_IKCONFIG) += configs.o obj-$(CONFIG_RESOURCE_COUNTERS) += res_counter.o obj-$(CONFIG_STOP_MACHINE) += stop_machine.o obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o -obj-$(CONFIG_AUDIT) += audit.o auditfilter.o -obj-$(CONFIG_AUDITSYSCALL) += auditsc.o audit_watch.o +obj-$(CONFIG_AUDIT) += audit.o auditfilter.o audit_watch.o +obj-$(CONFIG_AUDITSYSCALL) += auditsc.o obj-$(CONFIG_GCOV_KERNEL) += gcov/ obj-$(CONFIG_AUDIT_TREE) += audit_tree.o obj-$(CONFIG_KPROBES) += kprobes.o diff --git a/kernel/futex.c b/kernel/futex.c index 80b5ce716596..1c337112335c 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -284,6 +284,25 @@ void put_futex_key(int fshared, union futex_key *key) drop_futex_key_refs(key); } +/* + * fault_in_user_writeable - fault in user address and verify RW access + * @uaddr: pointer to faulting user space address + * + * Slow path to fixup the fault we just took in the atomic write + * access to @uaddr. + * + * We have no generic implementation of a non destructive write to the + * user address. We know that we faulted in the atomic pagefault + * disabled section so we can as well avoid the #PF overhead by + * calling get_user_pages() right away. + */ +static int fault_in_user_writeable(u32 __user *uaddr) +{ + int ret = get_user_pages(current, current->mm, (unsigned long)uaddr, + sizeof(*uaddr), 1, 0, NULL, NULL); + return ret < 0 ? ret : 0; +} + /** * futex_top_waiter() - Return the highest priority waiter on a futex * @hb: the hash bucket the futex_q's reside in @@ -896,7 +915,6 @@ retry: retry_private: op_ret = futex_atomic_op_inuser(op, uaddr2); if (unlikely(op_ret < 0)) { - u32 dummy; double_unlock_hb(hb1, hb2); @@ -914,7 +932,7 @@ retry_private: goto out_put_keys; } - ret = get_user(dummy, uaddr2); + ret = fault_in_user_writeable(uaddr2); if (ret) goto out_put_keys; @@ -1204,7 +1222,7 @@ retry_private: double_unlock_hb(hb1, hb2); put_futex_key(fshared, &key2); put_futex_key(fshared, &key1); - ret = get_user(curval2, uaddr2); + ret = fault_in_user_writeable(uaddr2); if (!ret) goto retry; goto out; @@ -1482,7 +1500,7 @@ retry: handle_fault: spin_unlock(q->lock_ptr); - ret = get_user(uval, uaddr); + ret = fault_in_user_writeable(uaddr); spin_lock(q->lock_ptr); @@ -1807,7 +1825,6 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared, { struct hrtimer_sleeper timeout, *to = NULL; struct futex_hash_bucket *hb; - u32 uval; struct futex_q q; int res, ret; @@ -1909,16 +1926,9 @@ out: return ret != -EINTR ? ret : -ERESTARTNOINTR; uaddr_faulted: - /* - * We have to r/w *(int __user *)uaddr, and we have to modify it - * atomically. Therefore, if we continue to fault after get_user() - * below, we need to handle the fault ourselves, while still holding - * the mmap_sem. This can occur if the uaddr is under contention as - * we have to drop the mmap_sem in order to call get_user(). - */ queue_unlock(&q, hb); - ret = get_user(uval, uaddr); + ret = fault_in_user_writeable(uaddr); if (ret) goto out_put_key; @@ -2013,17 +2023,10 @@ out: return ret; pi_faulted: - /* - * We have to r/w *(int __user *)uaddr, and we have to modify it - * atomically. Therefore, if we continue to fault after get_user() - * below, we need to handle the fault ourselves, while still holding - * the mmap_sem. This can occur if the uaddr is under contention as - * we have to drop the mmap_sem in order to call get_user(). - */ spin_unlock(&hb->lock); put_futex_key(fshared, &key); - ret = get_user(uval, uaddr); + ret = fault_in_user_writeable(uaddr); if (!ret) goto retry; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index aecc9cdfdfce..5d714f8fb303 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1153,10 +1153,10 @@ again: * properly detect and handle allocation failures. * * We most definitely don't want callers attempting to - * allocate greater than single-page units with + * allocate greater than order-1 page units with * __GFP_NOFAIL. */ - WARN_ON_ONCE(order > 0); + WARN_ON_ONCE(order > 1); } spin_lock_irqsave(&zone->lock, flags); page = __rmqueue(zone, order, migratetype); diff --git a/mm/slub.c b/mm/slub.c index ce62b770e2fc..819f056b39c6 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1085,11 +1085,17 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) { struct page *page; struct kmem_cache_order_objects oo = s->oo; + gfp_t alloc_gfp; flags |= s->allocflags; - page = alloc_slab_page(flags | __GFP_NOWARN | __GFP_NORETRY, node, - oo); + /* + * Let the initial higher-order allocation fail under memory pressure + * so we fall-back to the minimum order allocation. + */ + alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL; + + page = alloc_slab_page(alloc_gfp, node, oo); if (unlikely(!page)) { oo = s->min; /* |