From 76103d1b268e6f45735aa92d70bea5b5e8174a70 Mon Sep 17 00:00:00 2001 From: Pnina Feder Date: Tue, 16 Dec 2025 15:28:00 +0200 Subject: [PATCH] kernel: vmcoreinfo: allocate vmcoreinfo_data based on VMCOREINFO_BYTES Patch series "vmcoreinfo: support VMCOREINFO_BYTES larger than PAGE_SIZE". VMCOREINFO_BYTES is defined as a configurable size, but multiple code paths implicitly assume it always fits into a single page. This series removes that assumption by allocating and mapping vmcoreinfo based on its actual size. Patch 1 updates vmcoreinfo allocation to use get_order(VMCOREINFO_BYTES). Patch 2 updates crash kernel handling to correctly allocate and map multiple pages when copying vmcoreinfo. This makes vmcoreinfo size consistent across the kernel and avoids future breakage if VMCOREINFO_BYTES grows. (No functional change when VMCOREINFO_BYTES == PAGE_SIZE.) This patch (of 2): VMCOREINFO_BYTES defines the size of vmcoreinfo data, but the current implementation assumes a single page allocation. Allocate vmcoreinfo_data using get_order(VMCOREINFO_BYTES) so that vmcoreinfo can safely grow beyond PAGE_SIZE. This avoids hidden assumptions and keeps vmcoreinfo size consistent across the kernel. Link: https://lkml.kernel.org/r/20251216132801.807260-1-pnina.feder@mobileye.com Link: https://lkml.kernel.org/r/20251216132801.807260-2-pnina.feder@mobileye.com Signed-off-by: Pnina Feder Reviewed-by: Andrew Morton Cc: Baoquan He Cc: Dave Young Cc: Vivek Goyal Signed-off-by: Andrew Morton --- kernel/vmcore_info.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/vmcore_info.c b/kernel/vmcore_info.c index fe9bf8db1922e..22b3205dd4dc5 100644 --- a/kernel/vmcore_info.c +++ b/kernel/vmcore_info.c @@ -137,7 +137,9 @@ EXPORT_SYMBOL_GPL(hwerr_log_error_type); static int __init crash_save_vmcoreinfo_init(void) { - vmcoreinfo_data = (unsigned char *)get_zeroed_page(GFP_KERNEL); + int order; + order = get_order(VMCOREINFO_BYTES); + vmcoreinfo_data = (unsigned char *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order); if (!vmcoreinfo_data) { pr_warn("Memory allocation for vmcoreinfo_data failed\n"); return -ENOMEM; @@ -146,7 +148,7 @@ static int __init crash_save_vmcoreinfo_init(void) vmcoreinfo_note = alloc_pages_exact(VMCOREINFO_NOTE_SIZE, GFP_KERNEL | __GFP_ZERO); if (!vmcoreinfo_note) { - free_page((unsigned long)vmcoreinfo_data); + free_pages((unsigned long)vmcoreinfo_data, order); vmcoreinfo_data = NULL; pr_warn("Memory allocation for vmcoreinfo_note failed\n"); return -ENOMEM; -- 2.47.3