From: David Hildenbrand <[email protected]> commit e84fe99b68ce353c37ceeecc95dce9696c976556 upstream.
Without CONFIG_PREEMPT, it can happen that we get soft lockups detected, e.g., while booting up. watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0-next-20200331+ #4 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: __pageblock_pfn_to_page+0x134/0x1c0 Call Trace: set_zone_contiguous+0x56/0x70 page_alloc_init_late+0x166/0x176 kernel_init_freeable+0xfa/0x255 kernel_init+0xa/0x106 ret_from_fork+0x35/0x40 The issue becomes visible when having a lot of memory (e.g., 4TB) assigned to a single NUMA node - a system that can easily be created using QEMU. Inside VMs on a hypervisor with quite some memory overcommit, this is fairly easy to trigger. Signed-off-by: David Hildenbrand <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Reviewed-by: Pavel Tatashin <[email protected]> Reviewed-by: Pankaj Gupta <[email protected]> Reviewed-by: Baoquan He <[email protected]> Reviewed-by: Shile Zhang <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Kirill Tkhai <[email protected]> Cc: Shile Zhang <[email protected]> Cc: Pavel Tatashin <[email protected]> Cc: Daniel Jordan <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Alexander Duyck <[email protected]> Cc: Baoquan He <[email protected]> Cc: Oscar Salvador <[email protected]> Cc: <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/page_alloc.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1555,6 +1555,7 @@ void set_zone_contiguous(struct zone *zo if (!__pageblock_pfn_to_page(block_start_pfn, block_end_pfn, zone)) return; + cond_resched(); } /* We confirm that there is no hole */
