From: Qian Cai qcai@redhat.com
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 qcai@redhat.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Reviewed-by: Andrew Morton akpm@linux-foundation.org Cc: Hugh Dickins hughd@google.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20201202151549.10350-1-qcai@redhat.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- mm/swapfile.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2825,6 +2825,7 @@ 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; int size = sizeof(*p) + nr_node_ids * sizeof(struct plist_node); @@ -2854,7 +2855,7 @@ 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() @@ -2867,6 +2868,7 @@ 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);