From aff19cc96c7b336c207ae51d713237b51b3271d0 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 17 Apr 2025 16:52:25 +0200 Subject: [PATCH] 6.14-stable patches added patches: x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch --- queue-6.14/series | 1 + ...ges-in-e820__register_nosave_regions.patch | 89 +++++++++++++++++++ 2 files changed, 90 insertions(+) create mode 100644 queue-6.14/x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch diff --git a/queue-6.14/series b/queue-6.14/series index d806fc006a..c306942d8c 100644 --- a/queue-6.14/series +++ b/queue-6.14/series @@ -445,3 +445,4 @@ wifi-ath11k-update-channel-list-in-worker-when-wait-flag-is-set.patch arm64-errata-add-newer-arm-cores-to-the-spectre_bhb_loop_affected-lists.patch iommufd-make-attach_handle-generic-than-fault-specific.patch iommufd-fail-replace-if-device-has-not-been-attached.patch +x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch diff --git a/queue-6.14/x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch b/queue-6.14/x86-e820-fix-handling-of-subpage-regions-when-calculating-nosave-ranges-in-e820__register_nosave_regions.patch new file mode 100644 index 0000000000..f366fcfa48 --- /dev/null +++ b/queue-6.14/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 +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 + +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 +Tested-by: Roberto Ricci +Signed-off-by: Myrrh Periwinkle +Signed-off-by: Ingo Molnar +Cc: Rafael J. Wysocki +Cc: Ard Biesheuvel +Cc: H. Peter Anvin +Cc: Kees Cook +Cc: Linus Torvalds +Cc: David Woodhouse +Cc: Len Brown +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 +Signed-off-by: Greg Kroah-Hartman +--- + 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 +@@ -754,22 +754,21 @@ 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 -- 2.47.3