1 files changed, 21 insertions, 21 deletions

diff --git a/fs/select.c b/fs/select.c
index d4d881d439dc..834f438296e2 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -77,19 +77,16 @@ u64 select_estimate_accuracy(struct timespec64 *tv)
 {
 	u64 ret;
 	struct timespec64 now;
+	u64 slack = current->timer_slack_ns;
 
-	/*
-	 * Realtime tasks get a slack of 0 for obvious reasons.
-	 */
-
-	if (rt_task(current))
+	if (slack == 0)
 		return 0;
 
 	ktime_get_ts64(&now);
 	now = timespec64_sub(*tv, now);
 	ret = __estimate_accuracy(&now);
-	if (ret < current->timer_slack_ns)
-		return current->timer_slack_ns;
+	if (ret < slack)
+		return slack;
 	return ret;
 }
 
@@ -532,10 +529,10 @@ static noinline_for_stack int do_select(int n, fd_set_bits *fds, struct timespec
 					continue;
 				mask = EPOLLNVAL;
 				f = fdget(i);
-				if (f.file) {
+				if (fd_file(f)) {
 					wait_key_set(wait, in, out, bit,
 						     busy_flag);
-					mask = vfs_poll(f.file, wait);
+					mask = vfs_poll(fd_file(f), wait);
 
 					fdput(f);
 				}
@@ -780,7 +777,9 @@ static inline int get_sigset_argpack(struct sigset_argpack *to,
 {
 	// the path is hot enough for overhead of copy_from_user() to matter
 	if (from) {
-		if (!user_read_access_begin(from, sizeof(*from)))
+		if (can_do_masked_user_access())
+			from = masked_user_access_begin(from);
+		else if (!user_read_access_begin(from, sizeof(*from)))
 			return -EFAULT;
 		unsafe_get_user(to->p, &from->p, Efault);
 		unsafe_get_user(to->size, &from->size, Efault);
@@ -788,7 +787,7 @@ static inline int get_sigset_argpack(struct sigset_argpack *to,
 	}
 	return 0;
 Efault:
-	user_access_end();
+	user_read_access_end();
 	return -EFAULT;
 }
 
@@ -839,8 +838,8 @@ SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
 
 struct poll_list {
 	struct poll_list *next;
-	int len;
-	struct pollfd entries[];
+	unsigned int len;
+	struct pollfd entries[] __counted_by(len);
 };
 
 #define POLLFD_PER_PAGE  ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
@@ -864,13 +863,13 @@ static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait,
 		goto out;
 	mask = EPOLLNVAL;
 	f = fdget(fd);
-	if (!f.file)
+	if (!fd_file(f))
 		goto out;
 
 	/* userland u16 ->events contains POLL... bitmap */
 	filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP;
 	pwait->_key = filter | busy_flag;
-	mask = vfs_poll(f.file, pwait);
+	mask = vfs_poll(fd_file(f), pwait);
 	if (mask & busy_flag)
 		*can_busy_poll = true;
 	mask &= filter;		/* Mask out unneeded events. */
@@ -975,14 +974,15 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
 		struct timespec64 *end_time)
 {
 	struct poll_wqueues table;
-	int err = -EFAULT, fdcount, len;
+	int err = -EFAULT, fdcount;
 	/* Allocate small arguments on the stack to save memory and be
 	   faster - use long to make sure the buffer is aligned properly
 	   on 64 bit archs to avoid unaligned access */
 	long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
 	struct poll_list *const head = (struct poll_list *)stack_pps;
  	struct poll_list *walk = head;
- 	unsigned long todo = nfds;
+	unsigned int todo = nfds;
+	unsigned int len;
 
 	if (nfds > rlimit(RLIMIT_NOFILE))
 		return -EINVAL;
@@ -998,9 +998,9 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
 					sizeof(struct pollfd) * walk->len))
 			goto out_fds;
 
-		todo -= walk->len;
-		if (!todo)
+		if (walk->len >= todo)
 			break;
+		todo -= walk->len;
 
 		len = min(todo, POLLFD_PER_PAGE);
 		walk = walk->next = kmalloc(struct_size(walk, entries, len),
@@ -1020,7 +1020,7 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
 
 	for (walk = head; walk; walk = walk->next) {
 		struct pollfd *fds = walk->entries;
-		int j;
+		unsigned int j;
 
 		for (j = walk->len; j; fds++, ufds++, j--)
 			unsafe_put_user(fds->revents, &ufds->revents, Efault);
@@ -1361,7 +1361,7 @@ static inline int get_compat_sigset_argpack(struct compat_sigset_argpack *to,
 	}
 	return 0;
 Efault:
-	user_access_end();
+	user_read_access_end();
 	return -EFAULT;
 }