From: Qian Cai <[email protected]>

commit b11a76b37a5aa7b07c3e3eeeaae20b25475bddd3 upstream.

We can't call kvfree() with a spin lock held, so defer it.  Fixes a
might_sleep() runtime warning.

Fixes: 873d7bcfd066 ("mm/swapfile.c: use kvzalloc for swap_info_struct 
allocation")
Signed-off-by: Qian Cai <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 mm/swapfile.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2824,6 +2824,7 @@ late_initcall(max_swapfiles_check);
 static struct swap_info_struct *alloc_swap_info(void)
 {
        struct swap_info_struct *p;
+       struct swap_info_struct *defer = NULL;
        unsigned int type;
        int i;
 
@@ -2852,7 +2853,7 @@ static struct swap_info_struct *alloc_sw
                smp_wmb();
                WRITE_ONCE(nr_swapfiles, nr_swapfiles + 1);
        } else {
-               kvfree(p);
+               defer = p;
                p = swap_info[type];
                /*
                 * Do not memset this entry: a racing procfs swap_next()
@@ -2865,6 +2866,7 @@ static struct swap_info_struct *alloc_sw
                plist_node_init(&p->avail_lists[i], 0);
        p->flags = SWP_USED;
        spin_unlock(&swap_lock);
+       kvfree(defer);
        spin_lock_init(&p->lock);
        spin_lock_init(&p->cont_lock);
 


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