From 639118d1571f70b1157b4bb5ac574b0ab0f38099 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Sat, 27 Aug 2022 19:20:43 +0800 Subject: mm: kill is_memblock_offlined() Directly check state of struct memory_block, no need a single function. Link: https://lkml.kernel.org/r/20220827112043.187028-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: David Hildenbrand Reviewed-by: Oscar Salvador Reviewed-by: Anshuman Khandual Signed-off-by: Andrew Morton --- mm/memory_hotplug.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'mm/memory_hotplug.c') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index fad6d1f2262a..dc727aee4ad3 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1969,11 +1969,10 @@ failed_removal: static int check_memblock_offlined_cb(struct memory_block *mem, void *arg) { - int ret = !is_memblock_offlined(mem); int *nid = arg; *nid = mem->nid; - if (unlikely(ret)) { + if (unlikely(mem->state != MEM_OFFLINE)) { phys_addr_t beginpa, endpa; beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)); -- cgit v1.2.3 From b4a0215e11dcfe23a48c65c6d6c82c0c2c551a48 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Sat, 27 Aug 2022 19:19:59 +0800 Subject: mm: fix null-ptr-deref in kswapd_is_running() kswapd_run/stop() will set pgdat->kswapd to NULL, which could race with kswapd_is_running() in kcompactd(), kswapd_run/stop() kcompactd() kswapd_is_running() pgdat->kswapd // error or nomal ptr verify pgdat->kswapd // load non-NULL pgdat->kswapd pgdat->kswapd = NULL task_is_running(pgdat->kswapd) // Null pointer derefence KASAN reports the null-ptr-deref shown below, vmscan: Failed to start kswapd on node 0 ... BUG: KASAN: null-ptr-deref in kcompactd+0x440/0x504 Read of size 8 at addr 0000000000000024 by task kcompactd0/37 CPU: 0 PID: 37 Comm: kcompactd0 Kdump: loaded Tainted: G OE 5.10.60 #1 Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 Call trace: dump_backtrace+0x0/0x394 show_stack+0x34/0x4c dump_stack+0x158/0x1e4 __kasan_report+0x138/0x140 kasan_report+0x44/0xdc __asan_load8+0x94/0xd0 kcompactd+0x440/0x504 kthread+0x1a4/0x1f0 ret_from_fork+0x10/0x18 At present kswapd/kcompactd_run() and kswapd/kcompactd_stop() are protected by mem_hotplug_begin/done(), but without kcompactd(). There is no need to involve memory hotplug lock in kcompactd(), so let's add a new mutex to protect pgdat->kswapd accesses. Also, because the kcompactd task will check the state of kswapd task, it's better to call kcompactd_stop() before kswapd_stop() to reduce lock conflicts. [akpm@linux-foundation.org: add comments] Link: https://lkml.kernel.org/r/20220827111959.186838-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/memory_hotplug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/memory_hotplug.c') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index dc727aee4ad3..9ae1f98548b1 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1940,8 +1940,8 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages, node_states_clear_node(node, &arg); if (arg.status_change_nid >= 0) { - kswapd_stop(node); kcompactd_stop(node); + kswapd_stop(node); } writeback_set_ratelimit(); -- cgit v1.2.3 From ee0913c4719610204315a0d8a35122c6233249e0 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Wed, 7 Sep 2022 14:08:44 +0800 Subject: mm: add pageblock_aligned() macro Add pageblock_aligned() and use it to simplify code. Link: https://lkml.kernel.org/r/20220907060844.126891-3-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Acked-by: Mike Rapoport Cc: David Hildenbrand Cc: Oscar Salvador Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/memory_hotplug.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'mm/memory_hotplug.c') diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 9ae1f98548b1..fd40f7e9f176 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1085,8 +1085,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, * of the physical memory space for vmemmaps. That space is pageblock * aligned. */ - if (WARN_ON_ONCE(!nr_pages || - !IS_ALIGNED(pfn, pageblock_nr_pages) || + if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) || !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION))) return -EINVAL; @@ -1806,8 +1805,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages, * of the physical memory space for vmemmaps. That space is pageblock * aligned. */ - if (WARN_ON_ONCE(!nr_pages || - !IS_ALIGNED(start_pfn, pageblock_nr_pages) || + if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) || !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))) return -EINVAL; -- cgit v1.2.3