[PATCH v15 06/23] kexec: Extract kexec_free_segment_cma() from kimage_free_cma()
From: Jinjie Ruan <hidden>
Date: 2026-06-01 09:49:00
Also in:
kexec, linux-devicetree, linux-doc, linux-riscv, lkml, loongarch
Subsystem:
kexec, the rest · Maintainers:
Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds
The generic kimage_free_cma() relies on `image->nr_segments` to iterate and free allocated CMA pages. However, during architecture-specific segment placement retry loops (e.g., arm64's image_load()), a mid-way failure will truncate `image->nr_segments` back to its initial value. This truncation permanently hides any CMA pages allocated outside the new boundary from global cleanup, causing silent background memory leaks. To allow architecture-specific loaders to execute fine-grained memory reclamation before truncation occurs, extract the single-pass CMA release logic into a dedicated and exported helper: void kexec_free_segment_cma(struct kimage *image, unsigned long idx); Refactor the main kimage_free_cma() to invoke this helper sequentially to maintain backward compatibility while expanding single-slot flexibility. Signed-off-by: Jinjie Ruan <redacted> --- include/linux/kexec.h | 2 ++ kernel/kexec_core.c | 25 ++++++++++++++----------- 2 files changed, 16 insertions(+), 11 deletions(-)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 8a22bc9b8c6c..6f1eabda0300 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h@@ -532,6 +532,7 @@ extern bool kexec_file_dbg_print; extern void *kimage_map_segment(struct kimage *image, int idx); extern void kimage_unmap_segment(void *buffer); +extern void kexec_free_segment_cma(struct kimage *image, unsigned long idx); #else /* !CONFIG_KEXEC_CORE */ struct pt_regs; struct task_struct;
@@ -543,6 +544,7 @@ static inline int kexec_crash_loaded(void) { return 0; } static inline void *kimage_map_segment(struct kimage *image, int idx) { return NULL; } static inline void kimage_unmap_segment(void *buffer) { } +static inline void kexec_free_segment_cma(struct kimage *image, unsigned long idx) { } #define kexec_in_progress false #endif /* CONFIG_KEXEC_CORE */
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index a43d2da0fe3e..9195f81e53c4 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c@@ -554,22 +554,25 @@ static void kimage_free_entry(kimage_entry_t entry) kimage_free_pages(page); } -static void kimage_free_cma(struct kimage *image) +void kexec_free_segment_cma(struct kimage *image, unsigned long idx) { - unsigned long i; + u32 nr_pages = image->segment[idx].memsz >> PAGE_SHIFT; + struct page *cma = image->segment_cma[idx]; - for (i = 0; i < image->nr_segments; i++) { - struct page *cma = image->segment_cma[i]; - u32 nr_pages = image->segment[i].memsz >> PAGE_SHIFT; + if (!cma) + return; - if (!cma) - continue; + arch_kexec_pre_free_pages(page_address(cma), nr_pages); + dma_release_from_contiguous(NULL, cma, nr_pages); + image->segment_cma[idx] = NULL; +} - arch_kexec_pre_free_pages(page_address(cma), nr_pages); - dma_release_from_contiguous(NULL, cma, nr_pages); - image->segment_cma[i] = NULL; - } +static void kimage_free_cma(struct kimage *image) +{ + unsigned long i; + for (i = 0; i < image->nr_segments; i++) + kexec_free_segment_cma(image, i); } void kimage_free(struct kimage *image)
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2.34.1