From a2a163f70bdf27fa3296c6d6c746adb3b48f3914 Mon Sep 17 00:00:00 2001 From: Qian Cai Date: Sat, 5 Dec 2020 22:14:55 -0800 Subject: [PATCH] mm/swapfile: do not sleep with a spin lock held 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 Signed-off-by: Andrew Morton Reviewed-by: Andrew Morton Cc: Hugh Dickins Cc: Link: https://lkml.kernel.org/r/20201202151549.10350-1-qcai@redhat.com Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/swapfile.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index ff83ffe7a910..7947633d3ced 100644 --- 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_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() @@ -2865,6 +2866,7 @@ 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);