| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.9 54/75] mm/swapfile: do not sleep with a spin lock held | Date | Thu, 10 Dec 2020 15:27:19 +0100 |
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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 @@ -2868,6 +2868,7 @@ 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; @@ -2896,7 +2897,7 @@ 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() @@ -2909,6 +2910,7 @@ 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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