[PATCH] don't do exit_io_context() until we know we won't be doing any IO

testcase:

mount /dev/sdb10 /mnt
touch /mnt/tmp/b
umount /mnt
mount /dev/sdb10 /mnt
rm /mnt/tmp/b </mnt/tmp/b
umount /mnt

and watch blkdev_ioc line in /proc/slabinfo.  Vanilla kernel leaks.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 5 insertions, 2 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 531aadca5530..d1e8d500a7e1 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -807,8 +807,6 @@ fastcall NORET_TYPE void do_exit(long code)
                 panic("Attempted to kill the idle task!");
         if (unlikely(tsk->pid == 1))
                 panic("Attempted to kill init!");
-        if (tsk->io_context)
-                exit_io_context();
 
         if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
                 current->ptrace_message = code;
@@ -822,6 +820,8 @@ fastcall NORET_TYPE void do_exit(long code)
         if (unlikely(tsk->flags & PF_EXITING)) {
                 printk(KERN_ALERT
                         "Fixing recursive fault but reboot is needed!\n");
+                if (tsk->io_context)
+                        exit_io_context();
                 set_current_state(TASK_UNINTERRUPTIBLE);
                 schedule();
         }
@@ -881,6 +881,9 @@ fastcall NORET_TYPE void do_exit(long code)
          */
         mutex_debug_check_no_locks_held(tsk);
 
+        if (tsk->io_context)
+                exit_io_context();
+
         /* PF_DEAD causes final put_task_struct after we schedule. */
         preempt_disable();
         BUG_ON(tsk->flags & PF_DEAD);