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
  ...

1 files changed, 20 insertions, 12 deletions

diff --git a/lib/buildid.c b/lib/buildid.c
index aaf61dfc0919..818331051afe 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -5,6 +5,7 @@
 #include <linux/elf.h>
 #include <linux/kernel.h>
 #include <linux/pagemap.h>
+#include <linux/fs.h>
 #include <linux/secretmem.h>
 
 #define BUILD_ID 3
@@ -46,20 +47,9 @@ static int freader_get_folio(struct freader *r, loff_t file_off)
 
 	freader_put_folio(r);
 
-	/* reject secretmem folios created with memfd_secret() */
-	if (secretmem_mapping(r->file->f_mapping))
-		return -EFAULT;
-
+	/* only use page cache lookup - fail if not already cached */
 	r->folio = filemap_get_folio(r->file->f_mapping, file_off >> PAGE_SHIFT);
 
-	/* if sleeping is allowed, wait for the page, if necessary */
-	if (r->may_fault && (IS_ERR(r->folio) || !folio_test_uptodate(r->folio))) {
-		filemap_invalidate_lock_shared(r->file->f_mapping);
-		r->folio = read_cache_folio(r->file->f_mapping, file_off >> PAGE_SHIFT,
-					    NULL, r->file);
-		filemap_invalidate_unlock_shared(r->file->f_mapping);
-	}
-
 	if (IS_ERR(r->folio) || !folio_test_uptodate(r->folio)) {
 		if (!IS_ERR(r->folio))
 			folio_put(r->folio);
@@ -97,6 +87,24 @@ const void *freader_fetch(struct freader *r, loff_t file_off, size_t sz)
 		return r->data + file_off;
 	}
 
+	/* reject secretmem folios created with memfd_secret() */
+	if (secretmem_mapping(r->file->f_mapping)) {
+		r->err = -EFAULT;
+		return NULL;
+	}
+
+	/* use __kernel_read() for sleepable context */
+	if (r->may_fault) {
+		ssize_t ret;
+
+		ret = __kernel_read(r->file, r->buf, sz, &file_off);
+		if (ret != sz) {
+			r->err = (ret < 0) ? ret : -EIO;
+			return NULL;
+		}
+		return r->buf;
+	}
+
 	/* fetch or reuse folio for given file offset */
 	r->err = freader_get_folio(r, file_off);
 	if (r->err)