Merge tag 'mm-hotfixes-stable-2026-01-15-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:

 - kerneldoc fixes from Bagas Sanjaya

 - DAMON fixes from SeongJae

 - mremap VMA-related fixes from Lorenzo

 - various singletons - please see the changelogs for details

* tag 'mm-hotfixes-stable-2026-01-15-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (30 commits)
  drivers/dax: add some missing kerneldoc comment fields for struct dev_dax
  mm: numa,memblock: include <asm/numa.h> for 'numa_nodes_parsed'
  mailmap: add entry for Daniel Thompson
  tools/testing/selftests: fix gup_longterm for unknown fs
  mm/page_alloc: prevent pcp corruption with SMP=n
  iommu/sva: include mmu_notifier.h header
  mm: kmsan: fix poisoning of high-order non-compound pages
  tools/testing/selftests: add forked (un)/faulted VMA merge tests
  mm/vma: enforce VMA fork limit on unfaulted,faulted mremap merge too
  tools/testing/selftests: add tests for !tgt, src mremap() merges
  mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge
  mm/zswap: fix error pointer free in zswap_cpu_comp_prepare()
  mm/damon/sysfs-scheme: cleanup access_pattern subdirs on scheme dir setup failure
  mm/damon/sysfs-scheme: cleanup quotas subdirs on scheme dir setup failure
  mm/damon/sysfs: cleanup attrs subdirs on context dir setup failure
  mm/damon/sysfs: cleanup intervals subdirs on attrs dir setup failure
  mm/damon/core: remove call_control in inactive contexts
  powerpc/watchdog: add support for hardlockup_sys_info sysctl
  mips: fix HIGHMEM initialization
  mm/hugetlb: ignore hugepage kernel args if hugepages are unsupported
  ...

Author: torvalds

.mailmap

@@ -207,6 +207,7 @@ Daniel Borkmann <daniel@iogearbox.net> <daniel.borkmann@tik.ee.ethz.ch>
 Daniel Borkmann <daniel@iogearbox.net> <dborkmann@redhat.com>
 Daniel Borkmann <daniel@iogearbox.net> <dborkman@redhat.com>
 Daniel Borkmann <daniel@iogearbox.net> <dxchgb@gmail.com>
+Daniel Thompson <danielt@kernel.org> <daniel.thompson@linaro.org>
 Danilo Krummrich <dakr@kernel.org> <dakr@redhat.com>
 David Brownell <david-b@pacbell.net>
 David Collins <quic_collinsd@quicinc.com> <collinsd@codeaurora.org>
@@ -794,6 +795,7 @@ Sven Eckelmann <sven@narfation.org> <sven.eckelmann@open-mesh.com>
 Sven Eckelmann <sven@narfation.org> <sven.eckelmann@openmesh.com>
 Sven Eckelmann <sven@narfation.org> <sven@open-mesh.com>
 Sven Peter <sven@kernel.org> <sven@svenpeter.dev>
+Szymon Wilczek <swilczek.lx@gmail.com> <szymonwilczek@gmx.com>
 Takashi YOSHII <takashi.yoshii.zj@renesas.com>
 Tamizh Chelvam Raja <quic_tamizhr@quicinc.com> <tamizhr@codeaurora.org>
 Taniya Das <quic_tdas@quicinc.com> <tdas@codeaurora.org>

Documentation/admin-guide/kernel-parameters.txt

@@ -2917,6 +2917,41 @@ Kernel parameters
 			for Movable pages.  "nn[KMGTPE]", "nn%", and "mirror"
 			are exclusive, so you cannot specify multiple forms.
 
+	kfence.burst=	[MM,KFENCE] The number of additional successive
+			allocations to be attempted through KFENCE for each
+			sample interval.
+			Format: <unsigned integer>
+			Default: 0
+
+	kfence.check_on_panic=
+			[MM,KFENCE] Whether to check all KFENCE-managed objects'
+			canaries on panic.
+			Format: <bool>
+			Default: false
+
+	kfence.deferrable=
+			[MM,KFENCE] Whether to use a deferrable timer to trigger
+			allocations. This avoids forcing CPU wake-ups if the
+			system is idle, at the risk of a less predictable
+			sample interval.
+			Format: <bool>
+			Default: CONFIG_KFENCE_DEFERRABLE
+
+	kfence.sample_interval=
+			[MM,KFENCE] KFENCE's sample interval in milliseconds.
+			Format: <unsigned integer>
+			 0 - Disable KFENCE.
+			>0 - Enabled KFENCE with given sample interval.
+			Default: CONFIG_KFENCE_SAMPLE_INTERVAL
+
+	kfence.skip_covered_thresh=
+			[MM,KFENCE] If pool utilization reaches this threshold
+			(pool usage%), KFENCE limits currently covered
+			allocations of the same source from further filling
+			up the pool.
+			Format: <unsigned integer>
+			Default: 75
+
 	kgdbdbgp=	[KGDB,HW,EARLY] kgdb over EHCI usb debug port.
 			Format: <Controller#>[,poll interval]
 			The controller # is the number of the ehci usb debug

arch/mips/mm/init.c

@@ -425,6 +425,28 @@ void __init paging_init(void)
 static struct kcore_list kcore_kseg0;
 #endif
 
+static inline void __init highmem_init(void)
+{
+#ifdef CONFIG_HIGHMEM
+	unsigned long tmp;
+
+	/*
+	 * If CPU cannot support HIGHMEM discard the memory above highstart_pfn
+	 */
+	if (cpu_has_dc_aliases) {
+		memblock_remove(PFN_PHYS(highstart_pfn), -1);
+		return;
+	}
+
+	for (tmp = highstart_pfn; tmp < highend_pfn; tmp++) {
+		struct page *page = pfn_to_page(tmp);
+
+		if (!memblock_is_memory(PFN_PHYS(tmp)))
+			SetPageReserved(page);
+	}
+#endif
+}
+
 void __init arch_mm_preinit(void)
 {
 	/*
@@ -435,6 +457,7 @@ void __init arch_mm_preinit(void)
 
 	maar_init();
 	setup_zero_pages();	/* Setup zeroed pages.  */
+	highmem_init();
 
 #ifdef CONFIG_64BIT
 	if ((unsigned long) &_text > (unsigned long) CKSEG0)

arch/powerpc/kernel/watchdog.c

@@ -26,6 +26,7 @@
 #include <linux/delay.h>
 #include <linux/processor.h>
 #include <linux/smp.h>
+#include <linux/sys_info.h>
 
 #include <asm/interrupt.h>
 #include <asm/paca.h>
@@ -235,7 +236,11 @@ static void watchdog_smp_panic(int cpu)
 	pr_emerg("CPU %d TB:%lld, last SMP heartbeat TB:%lld (%lldms ago)\n",
 		 cpu, tb, last_reset, tb_to_ns(tb - last_reset) / 1000000);
 
-	if (!sysctl_hardlockup_all_cpu_backtrace) {
+	if (sysctl_hardlockup_all_cpu_backtrace ||
+	    (hardlockup_si_mask & SYS_INFO_ALL_BT)) {
+		trigger_allbutcpu_cpu_backtrace(cpu);
+		cpumask_clear(&wd_smp_cpus_ipi);
+	} else {
 		/*
 		 * Try to trigger the stuck CPUs, unless we are going to
 		 * get a backtrace on all of them anyway.
@@ -244,11 +249,9 @@ static void watchdog_smp_panic(int cpu)
 			smp_send_nmi_ipi(c, wd_lockup_ipi, 1000000);
 			__cpumask_clear_cpu(c, &wd_smp_cpus_ipi);
 		}
-	} else {
-		trigger_allbutcpu_cpu_backtrace(cpu);
-		cpumask_clear(&wd_smp_cpus_ipi);
 	}
 
+	sys_info(hardlockup_si_mask & ~SYS_INFO_ALL_BT);
 	if (hardlockup_panic)
 		nmi_panic(NULL, "Hard LOCKUP");
 
@@ -415,9 +418,11 @@ DEFINE_INTERRUPT_HANDLER_NMI(soft_nmi_interrupt)
 
 		xchg(&__wd_nmi_output, 1); // see wd_lockup_ipi
 
-		if (sysctl_hardlockup_all_cpu_backtrace)
+		if (sysctl_hardlockup_all_cpu_backtrace ||
+		    (hardlockup_si_mask & SYS_INFO_ALL_BT))
 			trigger_allbutcpu_cpu_backtrace(cpu);
 
+		sys_info(hardlockup_si_mask & ~SYS_INFO_ALL_BT);
 		if (hardlockup_panic)
 			nmi_panic(regs, "Hard LOCKUP");
 

drivers/dax/dax-private.h

@@ -67,14 +67,16 @@ struct dev_dax_range {
 /**
  * struct dev_dax - instance data for a subdivision of a dax region, and
  * data while the device is activated in the driver.
- * @region - parent region
- * @dax_dev - core dax functionality
+ * @region: parent region
+ * @dax_dev: core dax functionality
+ * @align: alignment of this instance
  * @target_node: effective numa node if dev_dax memory range is onlined
  * @dyn_id: is this a dynamic or statically created instance
  * @id: ida allocated id when the dax_region is not static
  * @ida: mapping id allocator
- * @dev - device core
- * @pgmap - pgmap for memmap setup / lifetime (driver owned)
+ * @dev: device core
+ * @pgmap: pgmap for memmap setup / lifetime (driver owned)
+ * @memmap_on_memory: allow kmem to put the memmap in the memory
  * @nr_range: size of @ranges
  * @ranges: range tuples of memory used
  */

drivers/iommu/iommu-sva.c

@@ -3,6 +3,7 @@
  * Helpers for IOMMU drivers implementing SVA
  */
 #include <linux/mmu_context.h>
+#include <linux/mmu_notifier.h>
 #include <linux/mutex.h>
 #include <linux/sched/mm.h>
 #include <linux/iommu.h>

include/linux/kfence.h

@@ -211,6 +211,7 @@ struct kmem_obj_info;
  * __kfence_obj_info() - fill kmem_obj_info struct
  * @kpp: kmem_obj_info to be filled
  * @object: the object
+ * @slab: the slab
  *
  * Return:
  * * false - not a KFENCE object

include/linux/nmi.h

@@ -83,6 +83,7 @@ static inline void reset_hung_task_detector(void) { }
 #if defined(CONFIG_HARDLOCKUP_DETECTOR)
 extern void hardlockup_detector_disable(void);
 extern unsigned int hardlockup_panic;
+extern unsigned long hardlockup_si_mask;
 #else
 static inline void hardlockup_detector_disable(void) {}
 #endif

include/linux/sched/mm.h

@@ -325,6 +325,7 @@ static inline void might_alloc(gfp_t gfp_mask)
 
 /**
  * memalloc_flags_save - Add a PF_* flag to current->flags, save old value
+ * @flags: Flags to add.
  *
  * This allows PF_* flags to be conveniently added, irrespective of current
  * value, and then the old version restored with memalloc_flags_restore().

include/linux/textsearch.h

@@ -35,6 +35,7 @@ struct ts_state
  * @get_pattern: return head of pattern
  * @get_pattern_len: return length of pattern
  * @owner: module reference to algorithm
+ * @list: list to search
  */
 struct ts_ops
 {