[PATCH v4 02/12] kexec: Extract kexec_free_segment_cma() from kimage_free_cma()
From: Jinjie Ruan <hidden>
Date: 2026-09-07 12:53:41
Also in:
kexec, linux-fsdevel, linux-mm, lkml, loongarch
Subsystem:
kexec, the rest · Maintainers:
Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds
kimage_free_cma() relies on image->nr_segments to iterate over segments. When an architecture loader (e.g., arm64) truncates nr_segments on a mid-way failure, CMA pages allocated beyond the new boundary become unreachable, causing silent memory leaks. Extract the per-segment freeing logic into the exported helper kexec_free_segment_cma(), so that architecture loaders can release individual segments before nr_segments is truncated. Refactor kimage_free_cma() to loop over the new helper, preserving existing behavior. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Baoquan He <baoquan.he@linux.dev> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Pratyush Yadav <pratyush@kernel.org> Signed-off-by: Jinjie Ruan <redacted> --- include/linux/kexec.h | 2 ++ kernel/kexec_core.c | 27 +++++++++++++++------------ 2 files changed, 17 insertions(+), 12 deletions(-)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 6b1df80524bf..72258d813301 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h@@ -533,6 +533,7 @@ extern bool kexec_file_dbg_print; extern void *kimage_map_segment(struct kimage *image, int idx); extern void kimage_unmap_segment(void *buffer); +void kexec_free_segment_cma(struct kimage *image, unsigned long idx); #else /* !CONFIG_KEXEC_CORE */ struct pt_regs; struct task_struct;
@@ -544,6 +545,7 @@ 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 c6bb9e48c590..5ed8e70dd03e 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c@@ -554,23 +554,26 @@ 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; + unsigned long nr_pages = image->segment_cma_pages[idx]; + struct page *cma = image->segment_cma[idx]; - for (i = 0; i < image->nr_segments; i++) { - struct page *cma = image->segment_cma[i]; - unsigned long nr_pages = image->segment_cma_pages[i]; + if (!cma) + return; - if (!cma) - continue; + arch_kexec_pre_free_pages(page_address(cma), (unsigned int)nr_pages); + dma_release_from_contiguous(NULL, cma, (int)nr_pages); + image->segment_cma[idx] = NULL; + image->segment_cma_pages[idx] = 0; +} - arch_kexec_pre_free_pages(page_address(cma), (unsigned int)nr_pages); - dma_release_from_contiguous(NULL, cma, (int)nr_pages); - image->segment_cma[i] = NULL; - image->segment_cma_pages[i] = 0; - } +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