kernel/linux.git/fs/pstore, branch master

Merge tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2026-04-15T19:59:16+00:00

Pull MM updates from Andrew Morton: - "maple_tree: Replace big node with maple copy" (Liam Howlett) Mainly prepararatory work for ongoing development but it does reduce stack usage and is an improvement. - "mm, swap: swap table phase III: remove swap_map" (Kairui Song) Offers memory savings by removing the static swap_map. It also yields some CPU savings and implements several cleanups. - "mm: memfd_luo: preserve file seals" (Pratyush Yadav) File seal preservation to LUO's memfd code - "mm: zswap: add per-memcg stat for incompressible pages" (Jiayuan Chen) Additional userspace stats reportng to zswap - "arch, mm: consolidate empty_zero_page" (Mike Rapoport) Some cleanups for our handling of ZERO_PAGE() and zero_pfn - "mm/kmemleak: Improve scan_should_stop() implementation" (Zhongqiu Han) A robustness improvement and some cleanups in the kmemleak code - "Improve khugepaged scan logic" (Vernon Yang) Improve khugepaged scan logic and reduce CPU consumption by prioritizing scanning tasks that access memory frequently - "Make KHO Stateless" (Jason Miu) Simplify Kexec Handover by transitioning KHO from an xarray-based metadata tracking system with serialization to a radix tree data structure that can be passed directly to the next kernel - "mm: vmscan: add PID and cgroup ID to vmscan tracepoints" (Thomas Ballasi and Steven Rostedt) Enhance vmscan's tracepointing - "mm: arch/shstk: Common shadow stack mapping helper and VM_NOHUGEPAGE" (Catalin Marinas) Cleanup for the shadow stack code: remove per-arch code in favour of a generic implementation - "Fix KASAN support for KHO restored vmalloc regions" (Pasha Tatashin) Fix a WARN() which can be emitted the KHO restores a vmalloc area - "mm: Remove stray references to pagevec" (Tal Zussman) Several cleanups, mainly udpating references to "struct pagevec", which became folio_batch three years ago - "mm: Eliminate fake head pages from vmemmap optimization" (Kiryl Shutsemau) Simplify the HugeTLB vmemmap optimization (HVO) by changing how tail pages encode their relationship to the head page - "mm/damon/core: improve DAMOS quota efficiency for core layer filters" (SeongJae Park) Improve two problematic behaviors of DAMOS that makes it less efficient when core layer filters are used - "mm/damon: strictly respect min_nr_regions" (SeongJae Park) Improve DAMON usability by extending the treatment of the min_nr_regions user-settable parameter - "mm/page_alloc: pcp locking cleanup" (Vlastimil Babka) The proper fix for a previously hotfixed SMP=n issue. Code simplifications and cleanups ensued - "mm: cleanups around unmapping / zapping" (David Hildenbrand) A bunch of cleanups around unmapping and zapping. Mostly simplifications, code movements, documentation and renaming of zapping functions - "support batched checking of the young flag for MGLRU" (Baolin Wang) Batched checking of the young flag for MGLRU. It's part cleanups; one benchmark shows large performance benefits for arm64 - "memcg: obj stock and slab stat caching cleanups" (Johannes Weiner) memcg cleanup and robustness improvements - "Allow order zero pages in page reporting" (Yuvraj Sakshith) Enhance free page reporting - it is presently and undesirably order-0 pages when reporting free memory. - "mm: vma flag tweaks" (Lorenzo Stoakes) Cleanup work following from the recent conversion of the VMA flags to a bitmap - "mm/damon: add optional debugging-purpose sanity checks" (SeongJae Park) Add some more developer-facing debug checks into DAMON core - "mm/damon: test and document power-of-2 min_region_sz requirement" (SeongJae Park) An additional DAMON kunit test and makes some adjustments to the addr_unit parameter handling - "mm/damon/core: make passed_sample_intervals comparisons overflow-safe" (SeongJae Park) Fix a hard-to-hit time overflow issue in DAMON core - "mm/damon: improve/fixup/update ratio calculation, test and documentation" (SeongJae Park) A batch of misc/minor improvements and fixups for DAMON - "mm: move vma_(kernel|mmu)_pagesize() out of hugetlb.c" (David Hildenbrand) Fix a possible issue with dax-device when CONFIG_HUGETLB=n. Some code movement was required. - "zram: recompression cleanups and tweaks" (Sergey Senozhatsky) A somewhat random mix of fixups, recompression cleanups and improvements in the zram code - "mm/damon: support multiple goal-based quota tuning algorithms" (SeongJae Park) Extend DAMOS quotas goal auto-tuning to support multiple tuning algorithms that users can select - "mm: thp: reduce unnecessary start_stop_khugepaged()" (Breno Leitao) Fix the khugpaged sysfs handling so we no longer spam the logs with reams of junk when starting/stopping khugepaged - "mm: improve map count checks" (Lorenzo Stoakes) Provide some cleanups and slight fixes in the mremap, mmap and vma code - "mm/damon: support addr_unit on default monitoring targets for modules" (SeongJae Park) Extend the use of DAMON core's addr_unit tunable - "mm: khugepaged cleanups and mTHP prerequisites" (Nico Pache) Cleanups to khugepaged and is a base for Nico's planned khugepaged mTHP support - "mm: memory hot(un)plug and SPARSEMEM cleanups" (David Hildenbrand) Code movement and cleanups in the memhotplug and sparsemem code - "mm: remove CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE and cleanup CONFIG_MIGRATION" (David Hildenbrand) Rationalize some memhotplug Kconfig support - "change young flag check functions to return bool" (Baolin Wang) Cleanups to change all young flag check functions to return bool - "mm/damon/sysfs: fix memory leak and NULL dereference issues" (Josh Law and SeongJae Park) Fix a few potential DAMON bugs - "mm/vma: convert vm_flags_t to vma_flags_t in vma code" (Lorenzo Stoakes) Convert a lot of the existing use of the legacy vm_flags_t data type to the new vma_flags_t type which replaces it. Mainly in the vma code. - "mm: expand mmap_prepare functionality and usage" (Lorenzo Stoakes) Expand the mmap_prepare functionality, which is intended to replace the deprecated f_op->mmap hook which has been the source of bugs and security issues for some time. Cleanups, documentation, extension of mmap_prepare into filesystem drivers - "mm/huge_memory: refactor zap_huge_pmd()" (Lorenzo Stoakes) Simplify and clean up zap_huge_pmd(). Additional cleanups around vm_normal_folio_pmd() and the softleaf functionality are performed. * tag 'mm-stable-2026-04-13-21-45' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits) mm: fix deferred split queue races during migration mm/khugepaged: fix issue with tracking lock mm/huge_memory: add and use has_deposited_pgtable() mm/huge_memory: add and use normal_or_softleaf_folio_pmd() mm: add softleaf_is_valid_pmd_entry(), pmd_to_softleaf_folio() mm/huge_memory: separate out the folio part of zap_huge_pmd() mm/huge_memory: use mm instead of tlb->mm mm/huge_memory: remove unnecessary sanity checks mm/huge_memory: deduplicate zap deposited table call mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE() mm/huge_memory: add a common exit path to zap_huge_pmd() mm/huge_memory: handle buggy PMD entry in zap_huge_pmd() mm/huge_memory: have zap_huge_pmd return a boolean, add kdoc mm/huge: avoid big else branch in zap_huge_pmd() mm/huge_memory: simplify vma_is_specal_huge() mm: on remap assert that input range within the proposed VMA mm: add mmap_action_map_kernel_pages[_full]() uio: replace deprecated mmap hook with mmap_prepare in uio_info drivers: hv: vmbus: replace deprecated mmap hook with mmap_prepare mm: allow handling of stacked mmap_prepare hooks in more drivers ...

pstore/ftrace: Factor KASLR offset in the core kernel instruction addresses

2026-04-11T06:59:41+00:00

The pstore ftrace frontend works by purely collecting the instruction address, saving it on the persistent area through the backend and when the log is read, on next boot for example, the address is then resolved by using the regular printk symbol lookup (%pS for example). Problem: if we are running a relocatable kernel with KASLR enabled, this is a recipe for failure in the symbol resolution on next boots, since the addresses are offset'ed by the KASLR address. So, naturally the way to go is factor the KASLR address out of instruction address collection, and adding the fresh offset when resolving the symbol on future boots. Problem #2: modules also have varying addresses that float based on module base address and potentially the module ordering in memory, meaning factoring KASLR offset for them is useless. So, let's hereby only take KASLR offset into account for core kernel addresses, leaving module ones as is. And we have yet a 3rd complexity: not necessarily the check range for core kernel addresses holds true on future boots, since the module base address will vary. With that, the choice was to mark the addresses as being core vs module based on its MSB. And with that... ...we have the 4th challenge here: for some "simple" architectures, the CPU number is saved bit-encoded on the instruction pointer, to allow bigger timestamps - this is set through the PSTORE_CPU_IN_IP define for such architectures. Hence, the approach here is to skip such architectures (at least in a first moment). Finished? No. On top of all previous complexities, we have one extra pain point: kaslr_offset() is inlined and fully "resolved" at boot-time, after kernel decompression, through ELF relocation mechanism. Once the offset is known, it's patched to the kernel text area, wherever it is used. The mechanism, and its users, are only built-in - incompatible with module usage. Though there are possibly some hacks (as computing the offset using some kallsym lookup), the choice here is to restrict this optimization to the (hopefully common) case of CONFIG_PSTORE=y. TL;DR: let's factor KASLR offsets on pstore/ftrace for core kernel addresses, only when PSTORE is built-in and leaving module addresses out, as well as architectures that define PSTORE_CPU_IN_IP. Signed-off-by: Guilherme G. Piccoli Link: https://patch.msgid.link/20260410205848.2607169-1-gpiccoli@igalia.com Signed-off-by: Kees Cook

mm: vmalloc: update outdated comment for renamed vread()

2026-04-05T20:53:34+00:00

The function vread() was renamed to vread_iter() in commit 4c91c07c93bb ("mm: vmalloc: convert vread() to vread_iter()"), converting from a buffer-based to an iterator-based interface. Update the kdoc of vread_iter() to reflect the new interface: replace references to @buf with @iter, drop the stale "kernel's buffer" requirement, and update the self-reference from vread() to vread_iter(). Also update the stale vread() reference in pstore's ram_core.c. Assisted-by: unnamed:deepseek-v3.2 coccinelle Link: https://lkml.kernel.org/r/20260321105820.7134-1-kexinsun@smail.nju.edu.cn Signed-off-by: Kexin Sun Reviewed-by: Andrew Morton Cc: "Guilherme G. Piccoli" Cc: Julia Lawall Cc: Kees Cook Cc: Tony Luck Cc: "Uladzislau Rezki (Sony)" Signed-off-by: Andrew Morton

pstore/ftrace: Keep ftrace module parameter and debugfs switch in sync

2026-03-31T21:52:37+00:00

Commit a5d05b07961a ("pstore/ftrace: Allow immediate recording") introduced a kernel parameter to enable early-boot collection for ftrace frontend. But then, if we enable the debugfs later, the parameter remains set as N. This is not a biggie, things work fine; but at the same time, why not have both in sync if possible, right? Cc: Uwe Kleine-König Signed-off-by: Guilherme G. Piccoli Link: https://patch.msgid.link/20260301192704.1263589-1-gpiccoli@igalia.com Signed-off-by: Kees Cook

pstore/ram: fix resource leak when ioremap() fails

2026-03-31T21:52:26+00:00

In persistent_ram_iomap(), ioremap() or ioremap_wc() may return NULL on failure. Currently, if this happens, the function returns NULL without releasing the memory region acquired by request_mem_region(). This leads to a resource leak where the memory region remains reserved but unusable. Additionally, the caller persistent_ram_buffer_map() handles NULL correctly by returning -ENOMEM, but without this check, a NULL return combined with request_mem_region() succeeding leaves resources in an inconsistent state. This is the ioremap() counterpart to commit 05363abc7625 ("pstore: ram_core: fix incorrect success return when vmap() fails") which fixed a similar issue in the vmap() path. Fixes: 404a6043385d ("staging: android: persistent_ram: handle reserving and mapping memory") Signed-off-by: Cole Leavitt Link: https://patch.msgid.link/20260225235406.11790-1-cole@unwrap.rs Signed-off-by: Kees Cook

pstore/ramoops: Fix ECC parameter help text

2026-03-31T21:52:25+00:00

In order to set ECC on ramoops, the parameter "ecc" should be used. The variable that carries this information is "ramoops_ecc". Due to some confusion in the parameter setting functions, modinfo ends-up showing both "ecc" and "ramoops_ecc" as valid parameters, but only "ecc" is the valid one, hence this fix to the parameter help text. Signed-off-by: Guilherme G. Piccoli Link: https://patch.msgid.link/20260218193940.912143-3-gpiccoli@igalia.com Signed-off-by: Kees Cook

pstore/ramoops: Remove useless memblock header

2026-03-31T21:52:25+00:00

Seems the linux/memblock.h inclusion was added early on due to usage of some memblock allocation routine. But that was removed, header was forgotten, hence let's remove that. Signed-off-by: Guilherme G. Piccoli Link: https://patch.msgid.link/20260218193940.912143-2-gpiccoli@igalia.com Signed-off-by: Kees Cook

pstore: fix ftrace dump, when ECC is enabled

2026-03-31T21:52:25+00:00

total_size is sum of record->size and record->ecc_notice_size (ECC: No errors detected). When ECC is not used, then there is no problem. When ECC is enabled, then ftrace dump is decoded incorrectly after restart. First this affects starting offset calculation, that breaks reading of all ftrace records. CPU:66 ts:51646260179894273 3818ffff80008002 fe00ffff800080f0 0x3818ffff80008002 <- 0xfe00ffff800080f0 CPU:66 ts:56589664458375169 3818ffff80008002 ff02ffff800080f0 0x3818ffff80008002 <- 0xff02ffff800080f0 CPU:67 ts:13194139533313 afe4ffff80008002 1ffff800080f0 0xafe4ffff80008002 <- 0x1ffff800080f0 CPU:67 ts:13194139533313 b7d0ffff80008001 100ffff80008002 0xb7d0ffff80008001 <- 0x100ffff80008002 CPU:67 ts:51646260179894273 8de0ffff80008001 202ffff80008002 0x8de0ffff80008001 <- 0x202ffff80008002 Second ECC notice message is printed like ftrace record and as a result couple of last records are completely wrong. For example, when the starting offset is fixed: CPU:0 ts:113 ffffffc00879bd04 ffffffc0080dc08c cpuidle_enter <- do_idle+0x20c/0x290 CPU:0 ts:114 ffffffc00879bd04 ffffffc0080dc08c cpuidle_enter <- do_idle+0x20c/0x290 CPU:100 ts:28259048229270629 6f4e203a4343450a 2073726f72726520 0x6f4e203a4343450a <- 0x2073726f72726520 Signed-off-by: Andrey Skvortsov Tested-by: Guilherme G. Piccoli Link: https://patch.msgid.link/20260215185156.317394-1-andrej.skvortzov@gmail.com Signed-off-by: Kees Cook

Convert remaining multi-line kmalloc_obj/flex GFP_KERNEL uses

2026-02-22T16:26:33+00:00

Conversion performed via this Coccinelle script: // SPDX-License-Identifier: GPL-2.0-only // Options: --include-headers-for-types --all-includes --include-headers --keep-comments virtual patch @gfp depends on patch && !(file in "tools") && !(file in "samples")@ identifier ALLOC = {kmalloc_obj,kmalloc_objs,kmalloc_flex, kzalloc_obj,kzalloc_objs,kzalloc_flex, kvmalloc_obj,kvmalloc_objs,kvmalloc_flex, kvzalloc_obj,kvzalloc_objs,kvzalloc_flex}; @@ ALLOC(... - , GFP_KERNEL ) $ make coccicheck MODE=patch COCCI=gfp.cocci Build and boot tested x86_64 with Fedora 42's GCC and Clang: Linux version 6.19.0+ (user@host) (gcc (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7), GNU ld version 2.44-12.fc42) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Linux version 6.19.0+ (user@host) (clang version 20.1.8 (Fedora 20.1.8-4.fc42), LLD 20.1.8) #1 SMP PREEMPT_DYNAMIC 1970-01-01 Signed-off-by: Kees Cook Signed-off-by: Linus Torvalds

Convert more 'alloc_obj' cases to default GFP_KERNEL arguments

2026-02-22T04:03:00+00:00

This converts some of the visually simpler cases that have been split over multiple lines. I only did the ones that are easy to verify the resulting diff by having just that final GFP_KERNEL argument on the next line. Somebody should probably do a proper coccinelle script for this, but for me the trivial script actually resulted in an assertion failure in the middle of the script. I probably had made it a bit _too_ trivial. So after fighting that far a while I decided to just do some of the syntactically simpler cases with variations of the previous 'sed' scripts. The more syntactically complex multi-line cases would mostly really want whitespace cleanup anyway. Signed-off-by: Linus Torvalds