From 320661b08dd6f1746d5c7ab4eb435ec64b97cd45 Mon Sep 17 00:00:00 2001 From: Tahsin Erdogan Date: Sat, 25 Feb 2017 13:00:19 -0800 Subject: percpu: acquire pcpu_lock when updating pcpu_nr_empty_pop_pages Update to pcpu_nr_empty_pop_pages in pcpu_alloc() is currently done without holding pcpu_lock. This can lead to bad updates to the variable. Add missing lock calls. Fixes: b539b87fed37 ("percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated") Signed-off-by: Tahsin Erdogan Signed-off-by: Tejun Heo Cc: stable@vger.kernel.org # v3.18+ --- mm/percpu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/percpu.c b/mm/percpu.c index 5696039b5c07..60a6488e9e6d 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1011,8 +1011,11 @@ area_found: mutex_unlock(&pcpu_alloc_mutex); } - if (chunk != pcpu_reserved_chunk) + if (chunk != pcpu_reserved_chunk) { + spin_lock_irqsave(&pcpu_lock, flags); pcpu_nr_empty_pop_pages -= occ_pages; + spin_unlock_irqrestore(&pcpu_lock, flags); + } if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW) pcpu_schedule_balance_work(); -- cgit v1.2.3 From 8a1df543de8ad879d3c80bdda4c67ac4f82e7ee0 Mon Sep 17 00:00:00 2001 From: Tahsin Erdogan Date: Sat, 25 Feb 2017 12:59:26 -0800 Subject: percpu: remove unused chunk_alloc parameter from pcpu_get_pages() pcpu_get_pages() doesn't use chunk_alloc parameter, remove it. Fixes: fbbb7f4e149f ("percpu: remove the usage of separate populated bitmap in percpu-vm") Signed-off-by: Tahsin Erdogan Signed-off-by: Tejun Heo --- mm/percpu-vm.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c index 538998a137d2..9ac639499bd1 100644 --- a/mm/percpu-vm.c +++ b/mm/percpu-vm.c @@ -21,7 +21,6 @@ static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk, /** * pcpu_get_pages - get temp pages array - * @chunk: chunk of interest * * Returns pointer to array of pointers to struct page which can be indexed * with pcpu_page_idx(). Note that there is only one array and accesses @@ -30,7 +29,7 @@ static struct page *pcpu_chunk_page(struct pcpu_chunk *chunk, * RETURNS: * Pointer to temp pages array on success. */ -static struct page **pcpu_get_pages(struct pcpu_chunk *chunk_alloc) +static struct page **pcpu_get_pages(void) { static struct page **pages; size_t pages_size = pcpu_nr_units * pcpu_unit_pages * sizeof(pages[0]); @@ -275,7 +274,7 @@ static int pcpu_populate_chunk(struct pcpu_chunk *chunk, { struct page **pages; - pages = pcpu_get_pages(chunk); + pages = pcpu_get_pages(); if (!pages) return -ENOMEM; @@ -313,7 +312,7 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, * successful population attempt so the temp pages array must * be available now. */ - pages = pcpu_get_pages(chunk); + pages = pcpu_get_pages(); BUG_ON(!pages); /* unmap and free */ -- cgit v1.2.3