The quilt patch titled Subject: percpu: fix data race with pcpu_nr_empty_pop_pages has been removed from the -mm tree. Its filename was percpu-fix-data-race-with-pcpu_nr_empty_pop_pages.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Dennis Zhou <dennis@xxxxxxxxxx> Subject: percpu: fix data race with pcpu_nr_empty_pop_pages Date: Mon, 7 Oct 2024 17:19:42 -0700 Fixes the data race by moving the read to be behind the pcpu_lock. This is okay because the code (initially) above it will not increase the empty populated page count because it is populating backing pages that already have allocations served out of them. Link: https://lkml.kernel.org/r/20241008001942.8114-1-dennis@xxxxxxxxxx Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> Closes: https://lore.kernel.org/oe-lkp/202407191651.f24e499d-oliver.sang@xxxxxxxxx Signed-off-by: Dennis Zhou <dennis@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/percpu.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/mm/percpu.c~percpu-fix-data-race-with-pcpu_nr_empty_pop_pages +++ a/mm/percpu.c @@ -1864,6 +1864,10 @@ restart: area_found: pcpu_stats_area_alloc(chunk, size); + + if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW) + pcpu_schedule_balance_work(); + spin_unlock_irqrestore(&pcpu_lock, flags); /* populate if not all pages are already there */ @@ -1891,9 +1895,6 @@ area_found: mutex_unlock(&pcpu_alloc_mutex); } - if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW) - pcpu_schedule_balance_work(); - /* clear the areas and return address relative to base address */ for_each_possible_cpu(cpu) memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size); _ Patches currently in -mm which might be from dennis@xxxxxxxxxx are