1 files changed, 18 insertions, 5 deletions

diff --git a/fs/select.c b/fs/select.c
index b80e7eb0ac0d..f10a10317d54 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -22,6 +22,7 @@
 #include <linux/personality.h> /* for STICKY_TIMEOUTS */
 #include <linux/file.h>
 #include <linux/fs.h>
+#include <linux/rcupdate.h>
 
 #include <asm/uaccess.h>
 
@@ -132,11 +133,13 @@ static int max_select_fd(unsigned long n, fd_set_bits *fds)
         unsigned long *open_fds;
         unsigned long set;
         int max;
+        struct fdtable *fdt;
 
         /* handle last in-complete long-word first */
         set = ~(~0UL << (n & (__NFDBITS-1)));
         n /= __NFDBITS;
-        open_fds = current->files->open_fds->fds_bits+n;
+        fdt = files_fdtable(current->files);
+        open_fds = fdt->open_fds->fds_bits+n;
         max = 0;
         if (set) {
                 set &= BITS(fds, n);
@@ -183,9 +186,9 @@ int do_select(int n, fd_set_bits *fds, long *timeout)
         int retval, i;
         long __timeout = *timeout;
 
-        spin_lock(&current->files->file_lock);
+        rcu_read_lock();
         retval = max_select_fd(n, fds);
-        spin_unlock(&current->files->file_lock);
+        rcu_read_unlock();
 
         if (retval < 0)
                 return retval;
@@ -299,6 +302,7 @@ sys_select(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, s
         char *bits;
         long timeout;
         int ret, size, max_fdset;
+        struct fdtable *fdt;
 
         timeout = MAX_SCHEDULE_TIMEOUT;
         if (tvp) {
@@ -326,7 +330,10 @@ sys_select(int n, fd_set __user *inp, fd_set __user *outp, fd_set __user *exp, s
                 goto out_nofds;
 
         /* max_fdset can increase, so grab it once to avoid race */
-        max_fdset = current->files->max_fdset;
+        rcu_read_lock();
+        fdt = files_fdtable(current->files);
+        max_fdset = fdt->max_fdset;
+        rcu_read_unlock();
         if (n > max_fdset)
                 n = max_fdset;
 
@@ -464,9 +471,15 @@ asmlinkage long sys_poll(struct pollfd __user * ufds, unsigned int nfds, long ti
         unsigned int i;
         struct poll_list *head;
         struct poll_list *walk;
+        struct fdtable *fdt;
+        int max_fdset;
 
         /* Do a sanity check on nfds ... */
-        if (nfds > current->files->max_fdset && nfds > OPEN_MAX)
+        rcu_read_lock();
+        fdt = files_fdtable(current->files);
+        max_fdset = fdt->max_fdset;
+        rcu_read_unlock();
+        if (nfds > max_fdset && nfds > OPEN_MAX)
                 return -EINVAL;
 
         if (timeout) {