mm/swapfile: do not sleep with a spin lock held (b11a76b3) · Commits · 戴 / test

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

mm/swapfile.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -2867,6 +2867,7 @@ 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;

		@@ -2895,7 +2896,7 @@ 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()
		@@ -2908,6 +2909,7 @@ 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);

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