Merge tag 'mm-hotfixes-stable-2024-08-07-18-32' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "Nine hotfixes. Five are cc:stable, the others either pertain to
  post-6.10 material or aren't considered necessary for earlier kernels.

  Five are MM and four are non-MM. No identifiable theme here - please
  see the individual changelogs"

* tag 'mm-hotfixes-stable-2024-08-07-18-32' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  padata: Fix possible divide-by-0 panic in padata_mt_helper()
  mailmap: update entry for David Heidelberg
  memcg: protect concurrent access to mem_cgroup_idr
  mm: shmem: fix incorrect aligned index when checking conflicts
  mm: shmem: avoid allocating huge pages larger than MAX_PAGECACHE_ORDER for shmem
  mm: list_lru: fix UAF for memory cgroup
  kcov: properly check for softirq context
  MAINTAINERS: Update LTP members and web
  selftests: mm: add s390 to ARCH check

Author: torvalds

.mailmap

@@ -166,6 +166,7 @@ Daniel Borkmann <[email protected]> <[email protected]>
 Daniel Borkmann <[email protected]> <[email protected]>
 David Brownell <[email protected]>
 David Collins <[email protected]> <[email protected]>
+David Heidelberg <[email protected]> <[email protected]>
 David Rheinsberg <[email protected]> <[email protected]>
 David Rheinsberg <[email protected]> <[email protected]>
 David Rheinsberg <[email protected]> <[email protected]>

MAINTAINERS

@@ -13324,14 +13324,16 @@ F:	Documentation/devicetree/bindings/i2c/i2c-mux-ltc4306.txt
 F:	drivers/i2c/muxes/i2c-mux-ltc4306.c
 
 LTP (Linux Test Project)
+M:	Andrea Cervesato <[email protected]>
 M:	Cyril Hrubis <[email protected]>
 M:	Jan Stancek <[email protected]>
 M:	Petr Vorel <[email protected]>
 M:	Li Wang <[email protected]>
 M:	Yang Xu <[email protected]>
+M:	Xiao Yang <[email protected]>
 L:	[email protected] (subscribers-only)
 S:	Maintained
-W:	http://linux-test-project.github.io/
+W:	https://linux-test-project.readthedocs.io/
 T:	git https://github.com/linux-test-project/ltp.git
 
 LTR390 AMBIENT/UV LIGHT SENSOR DRIVER

kernel/kcov.c

@@ -161,6 +161,15 @@ static void kcov_remote_area_put(struct kcov_remote_area *area,
 	kmsan_unpoison_memory(&area->list, sizeof(area->list));
 }
 
+/*
+ * Unlike in_serving_softirq(), this function returns false when called during
+ * a hardirq or an NMI that happened in the softirq context.
+ */
+static inline bool in_softirq_really(void)
+{
+	return in_serving_softirq() && !in_hardirq() && !in_nmi();
+}
+
 static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t)
 {
 	unsigned int mode;
@@ -170,7 +179,7 @@ static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_stru
 	 * so we ignore code executed in interrupts, unless we are in a remote
 	 * coverage collection section in a softirq.
 	 */
-	if (!in_task() && !(in_serving_softirq() && t->kcov_softirq))
+	if (!in_task() && !(in_softirq_really() && t->kcov_softirq))
 		return false;
 	mode = READ_ONCE(t->kcov_mode);
 	/*
@@ -849,7 +858,7 @@ void kcov_remote_start(u64 handle)
 
 	if (WARN_ON(!kcov_check_handle(handle, true, true, true)))
 		return;
-	if (!in_task() && !in_serving_softirq())
+	if (!in_task() && !in_softirq_really())
 		return;
 
 	local_lock_irqsave(&kcov_percpu_data.lock, flags);
@@ -991,7 +1000,7 @@ void kcov_remote_stop(void)
 	int sequence;
 	unsigned long flags;
 
-	if (!in_task() && !in_serving_softirq())
+	if (!in_task() && !in_softirq_really())
 		return;
 
 	local_lock_irqsave(&kcov_percpu_data.lock, flags);

kernel/padata.c

@@ -517,6 +517,13 @@ void __init padata_do_multithreaded(struct padata_mt_job *job)
 	ps.chunk_size = max(ps.chunk_size, job->min_chunk);
 	ps.chunk_size = roundup(ps.chunk_size, job->align);
 
+	/*
+	 * chunk_size can be 0 if the caller sets min_chunk to 0. So force it
+	 * to at least 1 to prevent divide-by-0 panic in padata_mt_helper().`
+	 */
+	if (!ps.chunk_size)
+		ps.chunk_size = 1U;
+
 	list_for_each_entry(pw, &works, pw_list)
 		if (job->numa_aware) {
 			int old_node = atomic_read(&last_used_nid);

mm/list_lru.c

@@ -85,6 +85,7 @@ list_lru_from_memcg_idx(struct list_lru *lru, int nid, int idx)
 }
 #endif /* CONFIG_MEMCG */
 
+/* The caller must ensure the memcg lifetime. */
 bool list_lru_add(struct list_lru *lru, struct list_head *item, int nid,
 		    struct mem_cgroup *memcg)
 {
@@ -109,14 +110,22 @@ EXPORT_SYMBOL_GPL(list_lru_add);
 
 bool list_lru_add_obj(struct list_lru *lru, struct list_head *item)
 {
+	bool ret;
 	int nid = page_to_nid(virt_to_page(item));
-	struct mem_cgroup *memcg = list_lru_memcg_aware(lru) ?
-		mem_cgroup_from_slab_obj(item) : NULL;
 
-	return list_lru_add(lru, item, nid, memcg);
+	if (list_lru_memcg_aware(lru)) {
+		rcu_read_lock();
+		ret = list_lru_add(lru, item, nid, mem_cgroup_from_slab_obj(item));
+		rcu_read_unlock();
+	} else {
+		ret = list_lru_add(lru, item, nid, NULL);
+	}
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(list_lru_add_obj);
 
+/* The caller must ensure the memcg lifetime. */
 bool list_lru_del(struct list_lru *lru, struct list_head *item, int nid,
 		    struct mem_cgroup *memcg)
 {
@@ -139,11 +148,18 @@ EXPORT_SYMBOL_GPL(list_lru_del);
 
 bool list_lru_del_obj(struct list_lru *lru, struct list_head *item)
 {
+	bool ret;
 	int nid = page_to_nid(virt_to_page(item));
-	struct mem_cgroup *memcg = list_lru_memcg_aware(lru) ?
-		mem_cgroup_from_slab_obj(item) : NULL;
 
-	return list_lru_del(lru, item, nid, memcg);
+	if (list_lru_memcg_aware(lru)) {
+		rcu_read_lock();
+		ret = list_lru_del(lru, item, nid, mem_cgroup_from_slab_obj(item));
+		rcu_read_unlock();
+	} else {
+		ret = list_lru_del(lru, item, nid, NULL);
+	}
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(list_lru_del_obj);
 

mm/memcontrol.c

@@ -3386,11 +3386,28 @@ static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
 
 #define MEM_CGROUP_ID_MAX	((1UL << MEM_CGROUP_ID_SHIFT) - 1)
 static DEFINE_IDR(mem_cgroup_idr);
+static DEFINE_SPINLOCK(memcg_idr_lock);
+
+static int mem_cgroup_alloc_id(void)
+{
+	int ret;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock(&memcg_idr_lock);
+	ret = idr_alloc(&mem_cgroup_idr, NULL, 1, MEM_CGROUP_ID_MAX + 1,
+			GFP_NOWAIT);
+	spin_unlock(&memcg_idr_lock);
+	idr_preload_end();
+	return ret;
+}
 
 static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
 {
 	if (memcg->id.id > 0) {
+		spin_lock(&memcg_idr_lock);
 		idr_remove(&mem_cgroup_idr, memcg->id.id);
+		spin_unlock(&memcg_idr_lock);
+
 		memcg->id.id = 0;
 	}
 }
@@ -3524,8 +3541,7 @@ static struct mem_cgroup *mem_cgroup_alloc(struct mem_cgroup *parent)
 	if (!memcg)
 		return ERR_PTR(error);
 
-	memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
-				 1, MEM_CGROUP_ID_MAX + 1, GFP_KERNEL);
+	memcg->id.id = mem_cgroup_alloc_id();
 	if (memcg->id.id < 0) {
 		error = memcg->id.id;
 		goto fail;
@@ -3667,7 +3683,9 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
 	 * publish it here at the end of onlining. This matches the
 	 * regular ID destruction during offlining.
 	 */
+	spin_lock(&memcg_idr_lock);
 	idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
+	spin_unlock(&memcg_idr_lock);
 
 	return 0;
 offline_kmem:

mm/shmem.c

@@ -1629,11 +1629,6 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
 	unsigned long mask = READ_ONCE(huge_shmem_orders_always);
 	unsigned long within_size_orders = READ_ONCE(huge_shmem_orders_within_size);
 	unsigned long vm_flags = vma->vm_flags;
-	/*
-	 * Check all the (large) orders below HPAGE_PMD_ORDER + 1 that
-	 * are enabled for this vma.
-	 */
-	unsigned long orders = BIT(PMD_ORDER + 1) - 1;
 	loff_t i_size;
 	int order;
 
@@ -1678,14 +1673,15 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
 	if (global_huge)
 		mask |= READ_ONCE(huge_shmem_orders_inherit);
 
-	return orders & mask;
+	return THP_ORDERS_ALL_FILE_DEFAULT & mask;
 }
 
 static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault *vmf,
 					   struct address_space *mapping, pgoff_t index,
 					   unsigned long orders)
 {
 	struct vm_area_struct *vma = vmf->vma;
+	pgoff_t aligned_index;
 	unsigned long pages;
 	int order;
 
@@ -1697,9 +1693,9 @@ static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault
 	order = highest_order(orders);
 	while (orders) {
 		pages = 1UL << order;
-		index = round_down(index, pages);
-		if (!xa_find(&mapping->i_pages, &index,
-			     index + pages - 1, XA_PRESENT))
+		aligned_index = round_down(index, pages);
+		if (!xa_find(&mapping->i_pages, &aligned_index,
+			     aligned_index + pages - 1, XA_PRESENT))
 			break;
 		order = next_order(&orders, order);
 	}

tools/testing/selftests/mm/Makefile

@@ -110,7 +110,7 @@ endif
 
 endif
 
-ifneq (,$(filter $(ARCH),arm64 ia64 mips64 parisc64 powerpc riscv64 s390x sparc64 x86_64))
+ifneq (,$(filter $(ARCH),arm64 ia64 mips64 parisc64 powerpc riscv64 s390x sparc64 x86_64 s390))
 TEST_GEN_FILES += va_high_addr_switch
 TEST_GEN_FILES += virtual_address_range
 TEST_GEN_FILES += write_to_hugetlbfs