From: Qian Cai <qcai@redhat.com> stable inclusion from linux-4.19.163 commit 2498ae24602cdd33666cc305e16773c73c2ec252 -------------------------------- 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> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: Cheng Jian <cj.chengjian@huawei.com> --- mm/swapfile.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 46e6b0c06f09..13171e764c56 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2930,6 +2930,7 @@ 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); @@ -2959,7 +2960,7 @@ static struct swap_info_struct *alloc_swap_info(void) 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() @@ -2972,6 +2973,7 @@ static struct swap_info_struct *alloc_swap_info(void) 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); -- 2.25.1