Merge linux-3.0.31 from korg into jellybean

Conflicts:
	arch/arm/mm/proc-v7.S
	drivers/base/core.c
	drivers/gpu/drm/i915/i915_gem_execbuffer.c
	drivers/gpu/drm/i915/intel_display.c
	drivers/gpu/drm/i915/intel_lvds.c
	drivers/gpu/drm/radeon/evergreen.c
	drivers/gpu/drm/radeon/r100.c
	drivers/gpu/drm/radeon/radeon_connectors.c
	drivers/gpu/drm/radeon/rs600.c
	drivers/usb/core/hub.c
	drivers/usb/host/xhci-pci.c
	drivers/usb/host/xhci.c
	drivers/usb/serial/qcserial.c
	fs/proc/base.c

Change-Id: Ia98b35db3f8c0bfd95817867d3acb85be8e5e772

1 files changed, 46 insertions, 37 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index 11cbe05..b2d51a7 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -59,6 +59,7 @@
 #include <linux/magic.h>
 #include <linux/pid.h>
 #include <linux/nsproxy.h>
+#include <linux/ptrace.h>
 
 #include <asm/futex.h>
 
@@ -314,17 +315,29 @@ again:
 #endif
 
 	lock_page(page_head);
+
+	/*
+	 * If page_head->mapping is NULL, then it cannot be a PageAnon
+	 * page; but it might be the ZERO_PAGE or in the gate area or
+	 * in a special mapping (all cases which we are happy to fail);
+	 * or it may have been a good file page when get_user_pages_fast
+	 * found it, but truncated or holepunched or subjected to
+	 * invalidate_complete_page2 before we got the page lock (also
+	 * cases which we are happy to fail).  And we hold a reference,
+	 * so refcount care in invalidate_complete_page's remove_mapping
+	 * prevents drop_caches from setting mapping to NULL beneath us.
+	 *
+	 * The case we do have to guard against is when memory pressure made
+	 * shmem_writepage move it from filecache to swapcache beneath us:
+	 * an unlikely race, but we do need to retry for page_head->mapping.
+	 */
 	if (!page_head->mapping) {
+		int shmem_swizzled = PageSwapCache(page_head);
 		unlock_page(page_head);
 		put_page(page_head);
-		/*
-		* ZERO_PAGE pages don't have a mapping. Avoid a busy loop
-		* trying to find one. RW mapping would have COW'd (and thus
-		* have a mapping) so this page is RO and won't ever change.
-		*/
-		if ((page_head == ZERO_PAGE(address)))
-			return -EFAULT;
-		goto again;
+		if (shmem_swizzled)
+			goto again;
+		return -EFAULT;
 	}
 
 	/*
@@ -2431,40 +2444,29 @@ SYSCALL_DEFINE3(get_robust_list, int, pid,
 {
 	struct robust_list_head __user *head;
 	unsigned long ret;
-	const struct cred *cred = current_cred(), *pcred;
+	struct task_struct *p;
 
 	if (!futex_cmpxchg_enabled)
 		return -ENOSYS;
 
+	rcu_read_lock();
+
+	ret = -ESRCH;
 	if (!pid)
-		head = current->robust_list;
+		p = current;
 	else {
-		struct task_struct *p;
-
-		ret = -ESRCH;
-		rcu_read_lock();
 		p = find_task_by_vpid(pid);
 		if (!p)
 			goto err_unlock;
-		ret = -EPERM;
-		pcred = __task_cred(p);
-		/* If victim is in different user_ns, then uids are not
-		   comparable, so we must have CAP_SYS_PTRACE */
-		if (cred->user->user_ns != pcred->user->user_ns) {
-			if (!ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
-				goto err_unlock;
-			goto ok;
-		}
-		/* If victim is in same user_ns, then uids are comparable */
-		if (cred->euid != pcred->euid &&
-		    cred->euid != pcred->uid &&
-		    !ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
-			goto err_unlock;
-ok:
-		head = p->robust_list;
-		rcu_read_unlock();
 	}
 
+	ret = -EPERM;
+	if (!ptrace_may_access(p, PTRACE_MODE_READ))
+		goto err_unlock;
+
+	head = p->robust_list;
+	rcu_read_unlock();
+
 	if (put_user(sizeof(*head), len_ptr))
 		return -EFAULT;
 	return put_user(head, head_ptr);
@@ -2629,6 +2631,16 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 	}
 
 	switch (cmd) {
+	case FUTEX_LOCK_PI:
+	case FUTEX_UNLOCK_PI:
+	case FUTEX_TRYLOCK_PI:
+	case FUTEX_WAIT_REQUEUE_PI:
+	case FUTEX_CMP_REQUEUE_PI:
+		if (!futex_cmpxchg_enabled)
+			return -ENOSYS;
+	}
+
+	switch (cmd) {
 	case FUTEX_WAIT:
 		val3 = FUTEX_BITSET_MATCH_ANY;
 	case FUTEX_WAIT_BITSET:
@@ -2649,16 +2661,13 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 		ret = futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
 		break;
 	case FUTEX_LOCK_PI:
-		if (futex_cmpxchg_enabled)
-			ret = futex_lock_pi(uaddr, flags, val, timeout, 0);
+		ret = futex_lock_pi(uaddr, flags, val, timeout, 0);
 		break;
 	case FUTEX_UNLOCK_PI:
-		if (futex_cmpxchg_enabled)
-			ret = futex_unlock_pi(uaddr, flags);
+		ret = futex_unlock_pi(uaddr, flags);
 		break;
 	case FUTEX_TRYLOCK_PI:
-		if (futex_cmpxchg_enabled)
-			ret = futex_lock_pi(uaddr, flags, 0, timeout, 1);
+		ret = futex_lock_pi(uaddr, flags, 0, timeout, 1);
 		break;
 	case FUTEX_WAIT_REQUEUE_PI:
 		val3 = FUTEX_BITSET_MATCH_ANY;