5.15-stable patches

added patches:
	x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch

diff --git a/queue-5.15/series b/queue-5.15/series
index ef727cf0cfcedc7ea3b2719120ab4a76cd72ea86..937307e6d15e661fccd84d6cf9537c8e0b766d0c 100644 (file)
--- a/queue-5.15/series
+++ b/queue-5.15/series
@@ -115,3 +115,4 @@ pinctrl-qcom-clear-latched-interrupt-status-when-changing-irq-type.patch
 selftests-mptcp-close-fd_in-before-returning-in-main_loop.patch
 arm64-errata-add-newer-arm-cores-to-the-spectre_bhb_loop_affected-lists.patch
 acpi-platform-profile-fix-cfi-violation-when-accessing-sysfs-files.patch
+x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch

diff --git a/queue-5.15/x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch b/queue-5.15/x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch
new file mode 100644 (file)
index 0000000..83b8697
--- /dev/null
+++ b/queue-5.15/x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch
@@ -0,0 +1,89 @@
+From f2f29da9f0d4367f6ff35e0d9d021257bb53e273 Mon Sep 17 00:00:00 2001
+From: Myrrh Periwinkle <myrrhperiwinkle@qtmlabs.xyz>
+Date: Sun, 6 Apr 2025 11:45:22 +0700
+Subject: x86/e820: Fix handling of subpage regions when calculating nosave ranges in e820__register_nosave_regions()
+
+From: Myrrh Periwinkle <myrrhperiwinkle@qtmlabs.xyz>
+
+commit f2f29da9f0d4367f6ff35e0d9d021257bb53e273 upstream.
+
+While debugging kexec/hibernation hangs and crashes, it turned out that
+the current implementation of e820__register_nosave_regions() suffers from
+multiple serious issues:
+
+ - The end of last region is tracked by PFN, causing it to find holes
+   that aren't there if two consecutive subpage regions are present
+
+ - The nosave PFN ranges derived from holes are rounded out (instead of
+   rounded in) which makes it inconsistent with how explicitly reserved
+   regions are handled
+
+Fix this by:
+
+ - Treating reserved regions as if they were holes, to ensure consistent
+   handling (rounding out nosave PFN ranges is more correct as the
+   kernel does not use partial pages)
+
+ - Tracking the end of the last RAM region by address instead of pages
+   to detect holes more precisely
+
+These bugs appear to have been introduced about ~18 years ago with the very
+first version of e820_mark_nosave_regions(), and its flawed assumptions were
+carried forward uninterrupted through various waves of rewrites and renames.
+
+[ mingo: Added Git archeology details, for kicks and giggles. ]
+
+Fixes: e8eff5ac294e ("[PATCH] Make swsusp avoid memory holes and reserved memory regions on x86_64")
+Reported-by: Roberto Ricci <io@r-ricci.it>
+Tested-by: Roberto Ricci <io@r-ricci.it>
+Signed-off-by: Myrrh Periwinkle <myrrhperiwinkle@qtmlabs.xyz>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+Cc: Ard Biesheuvel <ardb@kernel.org>
+Cc: H. Peter Anvin <hpa@zytor.com>
+Cc: Kees Cook <keescook@chromium.org>
+Cc: Linus Torvalds <torvalds@linux-foundation.org>
+Cc: David Woodhouse <dwmw@amazon.co.uk>
+Cc: Len Brown <len.brown@intel.com>
+Cc: stable@vger.kernel.org
+Link: https://lore.kernel.org/r/20250406-fix-e820-nosave-v3-1-f3787bc1ee1d@qtmlabs.xyz
+Closes: https://lore.kernel.org/all/Z4WFjBVHpndct7br@desktop0a/
+Signed-off-by: Myrrh Periwinkle <myrrhperiwinkle@qtmlabs.xyz>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/kernel/e820.c |   17 ++++++++---------
+ 1 file changed, 8 insertions(+), 9 deletions(-)
+
+--- a/arch/x86/kernel/e820.c
++++ b/arch/x86/kernel/e820.c
+@@ -753,22 +753,21 @@ void __init e820__memory_setup_extended(
+ void __init e820__register_nosave_regions(unsigned long limit_pfn)
+ {
+       int i;
+-      unsigned long pfn = 0;
++      u64 last_addr = 0;
+ 
+       for (i = 0; i < e820_table->nr_entries; i++) {
+               struct e820_entry *entry = &e820_table->entries[i];
+ 
+-              if (pfn < PFN_UP(entry->addr))
+-                      register_nosave_region(pfn, PFN_UP(entry->addr));
+-
+-              pfn = PFN_DOWN(entry->addr + entry->size);
+-
+               if (entry->type != E820_TYPE_RAM && entry->type != E820_TYPE_RESERVED_KERN)
+-                      register_nosave_region(PFN_UP(entry->addr), pfn);
++                      continue;
+ 
+-              if (pfn >= limit_pfn)
+-                      break;
++              if (last_addr < entry->addr)
++                      register_nosave_region(PFN_DOWN(last_addr), PFN_UP(entry->addr));
++
++              last_addr = entry->addr + entry->size;
+       }
++
++      register_nosave_region(PFN_DOWN(last_addr), limit_pfn);
+ }
+ 
+ #ifdef CONFIG_ACPI