From 543b30dba01e12131ca7b48eccc9ea206d8fab1c Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 25 Mar 2026 10:58:57 +0800 Subject: [PATCH 1/8] riscv: kexec_file: Fix crashk_low_res not exclude bug As done in commit 944a45abfabc ("arm64: kdump: Reimplement crashkernel=X") and commit 4831be702b95 ("arm64/kexec: Fix missing extra range for crashkres_low.") for arm64, while implementing crashkernel=X,[high,low], riscv should have excluded the "crashk_low_res" reserved ranges from the crash kernel memory to prevent them from being exported through /proc/vmcore, and the exclusion would need an extra crash_mem range. Fixes: 5882e5acf18d ("riscv: kdump: Implement crashkernel=X,[high,low]") Signed-off-by: Jinjie Ruan Signed-off-by: Linux RISC-V bot --- arch/riscv/kernel/machine_kexec_file.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c index 54e2d9552e930d..3f7766057cac31 100644 --- a/arch/riscv/kernel/machine_kexec_file.c +++ b/arch/riscv/kernel/machine_kexec_file.c @@ -61,7 +61,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz) unsigned int nr_ranges; int ret; - nr_ranges = 1; /* For exclusion of crashkernel region */ + nr_ranges = 2; /* For exclusion of crashkernel region */ walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); cmem = kmalloc_flex(*cmem, ranges, nr_ranges); @@ -76,8 +76,16 @@ static int prepare_elf_headers(void **addr, unsigned long *sz) /* Exclude crashkernel region */ ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); - if (!ret) - ret = crash_prepare_elf64_headers(cmem, true, addr, sz); + if (ret) + goto out; + + if (crashk_low_res.end) { + ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); + if (ret) + goto out; + } + + ret = crash_prepare_elf64_headers(cmem, true, addr, sz); out: kfree(cmem); From 0d770abe643034dbbebdd041dbd28118e443779f Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 25 Mar 2026 10:58:58 +0800 Subject: [PATCH 2/8] powerpc/crash: Fix possible memory leak in update_crash_elfcorehdr() In get_crash_memory_ranges(), if crash_exclude_mem_range() failed after realloc_mem_ranges() has successfully allocated the cmem memory, it just returns an error but leaves cmem pointing to the allocated memory, nor is it freed in the caller update_crash_elfcorehdr(), which cause a memory leak, goto out to free the cmem. Fixes: 849599b702ef ("powerpc/crash: add crash memory hotplug support") Signed-off-by: Jinjie Ruan Signed-off-by: Linux RISC-V bot --- arch/powerpc/kexec/crash.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c index a325c1c02f96dc..1d12cef8e1e0f2 100644 --- a/arch/powerpc/kexec/crash.c +++ b/arch/powerpc/kexec/crash.c @@ -440,7 +440,7 @@ static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify * ret = get_crash_memory_ranges(&cmem); if (ret) { pr_err("Failed to get crash mem range\n"); - return; + goto out; } /* From a71994f0ac499a4bf0f483f82a9f6f34ae5aff36 Mon Sep 17 00:00:00 2001 From: Sourabh Jain Date: Wed, 25 Mar 2026 10:58:59 +0800 Subject: [PATCH 3/8] powerpc/crash: sort crash memory ranges before preparing elfcorehdr During a memory hot-remove event, the elfcorehdr is rebuilt to exclude the removed memory. While updating the crash memory ranges for this operation, the crash memory ranges array can become unsorted. This happens because remove_mem_range() may split a memory range into two parts and append the higher-address part as a separate range at the end of the array. So far, no issues have been observed due to the unsorted crash memory ranges. However, this could lead to problems once crash memory range removal is handled by generic code, as introduced in the upcoming patches in this series. Currently, powerpc uses a platform-specific function, remove_mem_range(), to exclude hot-removed memory from the crash memory ranges. This function performs the same task as the generic crash_exclude_mem_range() in crash_core.c. The generic helper also ensures that the crash memory ranges remain sorted. So remove the redundant powerpc-specific implementation and instead call crash_exclude_mem_range_guarded() (which internally calls crash_exclude_mem_range()) to exclude the hot-removed memory ranges. Cc: Andrew Morton Cc: Baoquan he Cc: Jinjie Ruan Cc: Hari Bathini Cc: Madhavan Srinivasan Cc: Mahesh Salgaonkar Cc: Michael Ellerman Cc: Ritesh Harjani (IBM) Cc: Shivang Upadhyay Cc: linux-kernel@vger.kernel.org Acked-by: Baoquan He Reviewed-by: Ritesh Harjani (IBM) Acked-by: Mike Rapoport (Microsoft) Signed-off-by: Sourabh Jain Signed-off-by: Jinjie Ruan Signed-off-by: Linux RISC-V bot --- arch/powerpc/include/asm/kexec_ranges.h | 4 +- arch/powerpc/kexec/crash.c | 5 +- arch/powerpc/kexec/ranges.c | 87 +------------------------ 3 files changed, 7 insertions(+), 89 deletions(-) diff --git a/arch/powerpc/include/asm/kexec_ranges.h b/arch/powerpc/include/asm/kexec_ranges.h index 14055896cbcbcd..ad95e3792d10cc 100644 --- a/arch/powerpc/include/asm/kexec_ranges.h +++ b/arch/powerpc/include/asm/kexec_ranges.h @@ -7,7 +7,9 @@ void sort_memory_ranges(struct crash_mem *mrngs, bool merge); struct crash_mem *realloc_mem_ranges(struct crash_mem **mem_ranges); int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size); -int remove_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size); +int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges, + unsigned long long mstart, + unsigned long long mend); int get_exclude_memory_ranges(struct crash_mem **mem_ranges); int get_reserved_memory_ranges(struct crash_mem **mem_ranges); int get_crash_memory_ranges(struct crash_mem **mem_ranges); diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c index 1d12cef8e1e0f2..1426d2099baddc 100644 --- a/arch/powerpc/kexec/crash.c +++ b/arch/powerpc/kexec/crash.c @@ -431,7 +431,7 @@ static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify * struct crash_mem *cmem = NULL; struct kexec_segment *ksegment; void *ptr, *mem, *elfbuf = NULL; - unsigned long elfsz, memsz, base_addr, size; + unsigned long elfsz, memsz, base_addr, size, end; ksegment = &image->segment[image->elfcorehdr_index]; mem = (void *) ksegment->mem; @@ -450,7 +450,8 @@ static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify * if (image->hp_action == KEXEC_CRASH_HP_REMOVE_MEMORY) { base_addr = PFN_PHYS(mn->start_pfn); size = mn->nr_pages * PAGE_SIZE; - ret = remove_mem_range(&cmem, base_addr, size); + end = base_addr + size - 1; + ret = crash_exclude_mem_range_guarded(&cmem, base_addr, end); if (ret) { pr_err("Failed to remove hot-unplugged memory from crash memory ranges\n"); goto out; diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c index 867135560e5c8b..6c58bcc3e13040 100644 --- a/arch/powerpc/kexec/ranges.c +++ b/arch/powerpc/kexec/ranges.c @@ -553,7 +553,7 @@ int get_usable_memory_ranges(struct crash_mem **mem_ranges) #endif /* CONFIG_KEXEC_FILE */ #ifdef CONFIG_CRASH_DUMP -static int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges, +int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges, unsigned long long mstart, unsigned long long mend) { @@ -641,89 +641,4 @@ int get_crash_memory_ranges(struct crash_mem **mem_ranges) pr_err("Failed to setup crash memory ranges\n"); return ret; } - -/** - * remove_mem_range - Removes the given memory range from the range list. - * @mem_ranges: Range list to remove the memory range to. - * @base: Base address of the range to remove. - * @size: Size of the memory range to remove. - * - * (Re)allocates memory, if needed. - * - * Returns 0 on success, negative errno on error. - */ -int remove_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size) -{ - u64 end; - int ret = 0; - unsigned int i; - u64 mstart, mend; - struct crash_mem *mem_rngs = *mem_ranges; - - if (!size) - return 0; - - /* - * Memory range are stored as start and end address, use - * the same format to do remove operation. - */ - end = base + size - 1; - - for (i = 0; i < mem_rngs->nr_ranges; i++) { - mstart = mem_rngs->ranges[i].start; - mend = mem_rngs->ranges[i].end; - - /* - * Memory range to remove is not part of this range entry - * in the memory range list - */ - if (!(base >= mstart && end <= mend)) - continue; - - /* - * Memory range to remove is equivalent to this entry in the - * memory range list. Remove the range entry from the list. - */ - if (base == mstart && end == mend) { - for (; i < mem_rngs->nr_ranges - 1; i++) { - mem_rngs->ranges[i].start = mem_rngs->ranges[i+1].start; - mem_rngs->ranges[i].end = mem_rngs->ranges[i+1].end; - } - mem_rngs->nr_ranges--; - goto out; - } - /* - * Start address of the memory range to remove and the - * current memory range entry in the list is same. Just - * move the start address of the current memory range - * entry in the list to end + 1. - */ - else if (base == mstart) { - mem_rngs->ranges[i].start = end + 1; - goto out; - } - /* - * End address of the memory range to remove and the - * current memory range entry in the list is same. - * Just move the end address of the current memory - * range entry in the list to base - 1. - */ - else if (end == mend) { - mem_rngs->ranges[i].end = base - 1; - goto out; - } - /* - * Memory range to remove is not at the edge of current - * memory range entry. Split the current memory entry into - * two half. - */ - else { - size = mem_rngs->ranges[i].end - end + 1; - mem_rngs->ranges[i].end = base - 1; - ret = add_mem_range(mem_ranges, end + 1, size); - } - } -out: - return ret; -} #endif /* CONFIG_CRASH_DUMP */ From 1560c3d0e7228bc1114ed9a8297d726d21dbb9d2 Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 25 Mar 2026 10:59:00 +0800 Subject: [PATCH 4/8] crash: Exclude crash kernel memory in crash core The crash memory alloc, and the exclude of crashk_res, crashk_low_res and crashk_cma memory are almost identical across different architectures, handling them in the crash core would eliminate a lot of duplication, so do them in the common code. To achieve the above goal, three architecture-specific functions are introduced: - arch_get_system_nr_ranges(). Pre-counts the max number of memory ranges. - arch_crash_populate_cmem(). Collects the memory ranges and fills them into cmem. - arch_crash_exclude_ranges(). Architecture's additional crash memory ranges exclusion, defaulting to empty. Reviewed-by: Sourabh Jain Acked-by: Baoquan He Acked-by: Mike Rapoport (Microsoft) Signed-off-by: Jinjie Ruan Signed-off-by: Linux RISC-V bot --- arch/arm64/kernel/machine_kexec_file.c | 39 +++------- arch/loongarch/kernel/machine_kexec_file.c | 39 +++------- arch/riscv/kernel/machine_kexec_file.c | 46 +++-------- arch/x86/kernel/crash.c | 89 +++------------------- include/linux/crash_core.h | 5 ++ kernel/crash_core.c | 82 +++++++++++++++++++- 6 files changed, 132 insertions(+), 168 deletions(-) diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c index fba260ad87a967..c338506a580bab 100644 --- a/arch/arm64/kernel/machine_kexec_file.c +++ b/arch/arm64/kernel/machine_kexec_file.c @@ -40,23 +40,23 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image) } #ifdef CONFIG_CRASH_DUMP -static int prepare_elf_headers(void **addr, unsigned long *sz) +unsigned int arch_get_system_nr_ranges(void) { - struct crash_mem *cmem; - unsigned int nr_ranges; - int ret; - u64 i; + unsigned int nr_ranges = 2; /* for exclusion of crashkernel region */ phys_addr_t start, end; + u64 i; - nr_ranges = 2; /* for exclusion of crashkernel region */ for_each_mem_range(i, &start, &end) nr_ranges++; - cmem = kmalloc_flex(*cmem, ranges, nr_ranges); - if (!cmem) - return -ENOMEM; + return nr_ranges; +} + +int arch_crash_populate_cmem(struct crash_mem *cmem) +{ + phys_addr_t start, end; + u64 i; - cmem->max_nr_ranges = nr_ranges; cmem->nr_ranges = 0; for_each_mem_range(i, &start, &end) { cmem->ranges[cmem->nr_ranges].start = start; @@ -64,22 +64,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz) cmem->nr_ranges++; } - /* Exclude crashkernel region */ - ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); - if (ret) - goto out; - - if (crashk_low_res.end) { - ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); - if (ret) - goto out; - } - - ret = crash_prepare_elf64_headers(cmem, true, addr, sz); - -out: - kfree(cmem); - return ret; + return 0; } #endif @@ -109,7 +94,7 @@ int load_other_segments(struct kimage *image, void *headers; unsigned long headers_sz; if (image->type == KEXEC_TYPE_CRASH) { - ret = prepare_elf_headers(&headers, &headers_sz); + ret = crash_prepare_headers(true, &headers, &headers_sz, NULL); if (ret) { pr_err("Preparing elf core header failed\n"); goto out_err; diff --git a/arch/loongarch/kernel/machine_kexec_file.c b/arch/loongarch/kernel/machine_kexec_file.c index 5584b798ba4645..4b318a94b5649c 100644 --- a/arch/loongarch/kernel/machine_kexec_file.c +++ b/arch/loongarch/kernel/machine_kexec_file.c @@ -56,23 +56,23 @@ static void cmdline_add_initrd(struct kimage *image, unsigned long *cmdline_tmpl } #ifdef CONFIG_CRASH_DUMP - -static int prepare_elf_headers(void **addr, unsigned long *sz) +unsigned int arch_get_system_nr_ranges(void) { - int ret, nr_ranges; - uint64_t i; + int nr_ranges = 2; /* for exclusion of crashkernel region */ phys_addr_t start, end; - struct crash_mem *cmem; + uint64_t i; - nr_ranges = 2; /* for exclusion of crashkernel region */ for_each_mem_range(i, &start, &end) nr_ranges++; - cmem = kmalloc_flex(*cmem, ranges, nr_ranges); - if (!cmem) - return -ENOMEM; + return nr_ranges; +} + +int arch_crash_populate_cmem(struct crash_mem *cmem) +{ + phys_addr_t start, end; + uint64_t i; - cmem->max_nr_ranges = nr_ranges; cmem->nr_ranges = 0; for_each_mem_range(i, &start, &end) { cmem->ranges[cmem->nr_ranges].start = start; @@ -80,22 +80,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz) cmem->nr_ranges++; } - /* Exclude crashkernel region */ - ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); - if (ret < 0) - goto out; - - if (crashk_low_res.end) { - ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); - if (ret < 0) - goto out; - } - - ret = crash_prepare_elf64_headers(cmem, true, addr, sz); - -out: - kfree(cmem); - return ret; + return 0; } /* @@ -163,7 +148,7 @@ int load_other_segments(struct kimage *image, void *headers; unsigned long headers_sz; - ret = prepare_elf_headers(&headers, &headers_sz); + ret = crash_prepare_headers(true, &headers, &headers_sz, NULL); if (ret < 0) { pr_err("Preparing elf core header failed\n"); goto out_err; diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c index 3f7766057cac31..5a91bdfae162a7 100644 --- a/arch/riscv/kernel/machine_kexec_file.c +++ b/arch/riscv/kernel/machine_kexec_file.c @@ -44,6 +44,15 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg) return 0; } +unsigned int arch_get_system_nr_ranges(void) +{ + unsigned int nr_ranges = 2; /* For exclusion of crashkernel region */ + + walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); + + return nr_ranges; +} + static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) { struct crash_mem *cmem = arg; @@ -55,41 +64,10 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) return 0; } -static int prepare_elf_headers(void **addr, unsigned long *sz) +int arch_crash_populate_cmem(struct crash_mem *cmem) { - struct crash_mem *cmem; - unsigned int nr_ranges; - int ret; - - nr_ranges = 2; /* For exclusion of crashkernel region */ - walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); - - cmem = kmalloc_flex(*cmem, ranges, nr_ranges); - if (!cmem) - return -ENOMEM; - - cmem->max_nr_ranges = nr_ranges; cmem->nr_ranges = 0; - ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback); - if (ret) - goto out; - - /* Exclude crashkernel region */ - ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); - if (ret) - goto out; - - if (crashk_low_res.end) { - ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); - if (ret) - goto out; - } - - ret = crash_prepare_elf64_headers(cmem, true, addr, sz); - -out: - kfree(cmem); - return ret; + return walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback); } static char *setup_kdump_cmdline(struct kimage *image, char *cmdline, @@ -281,7 +259,7 @@ int load_extra_segments(struct kimage *image, unsigned long kernel_start, if (image->type == KEXEC_TYPE_CRASH) { void *headers; unsigned long headers_sz; - ret = prepare_elf_headers(&headers, &headers_sz); + ret = crash_prepare_headers(true, &headers, &headers_sz, NULL); if (ret) { pr_err("Preparing elf core header failed\n"); goto out; diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index 335fd2ee9766dc..3ad3f8b758a480 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -152,16 +152,8 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg) return 0; } -/* Gather all the required information to prepare elf headers for ram regions */ -static struct crash_mem *fill_up_crash_elf_data(void) +unsigned int arch_get_system_nr_ranges(void) { - unsigned int nr_ranges = 0; - struct crash_mem *cmem; - - walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); - if (!nr_ranges) - return NULL; - /* * Exclusion of crash region, crashk_low_res and/or crashk_cma_ranges * may cause range splits. So add extra slots here. @@ -176,49 +168,16 @@ static struct crash_mem *fill_up_crash_elf_data(void) * But in order to lest the low 1M could be changed in the future, * (e.g. [start, 1M]), add a extra slot. */ - nr_ranges += 3 + crashk_cma_cnt; - cmem = vzalloc(struct_size(cmem, ranges, nr_ranges)); - if (!cmem) - return NULL; - - cmem->max_nr_ranges = nr_ranges; + unsigned int nr_ranges = 3 + crashk_cma_cnt; - return cmem; + walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); + return nr_ranges; } -/* - * Look for any unwanted ranges between mstart, mend and remove them. This - * might lead to split and split ranges are put in cmem->ranges[] array - */ -static int elf_header_exclude_ranges(struct crash_mem *cmem) +int arch_crash_exclude_ranges(struct crash_mem *cmem) { - int ret = 0; - int i; - /* Exclude the low 1M because it is always reserved */ - ret = crash_exclude_mem_range(cmem, 0, SZ_1M - 1); - if (ret) - return ret; - - /* Exclude crashkernel region */ - ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); - if (ret) - return ret; - - if (crashk_low_res.end) - ret = crash_exclude_mem_range(cmem, crashk_low_res.start, - crashk_low_res.end); - if (ret) - return ret; - - for (i = 0; i < crashk_cma_cnt; ++i) { - ret = crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start, - crashk_cma_ranges[i].end); - if (ret) - return ret; - } - - return 0; + return crash_exclude_mem_range(cmem, 0, SZ_1M - 1); } static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) @@ -232,35 +191,9 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) return 0; } -/* Prepare elf headers. Return addr and size */ -static int prepare_elf_headers(void **addr, unsigned long *sz, - unsigned long *nr_mem_ranges) +int arch_crash_populate_cmem(struct crash_mem *cmem) { - struct crash_mem *cmem; - int ret; - - cmem = fill_up_crash_elf_data(); - if (!cmem) - return -ENOMEM; - - ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback); - if (ret) - goto out; - - /* Exclude unwanted mem ranges */ - ret = elf_header_exclude_ranges(cmem); - if (ret) - goto out; - - /* Return the computed number of memory ranges, for hotplug usage */ - *nr_mem_ranges = cmem->nr_ranges; - - /* By default prepare 64bit headers */ - ret = crash_prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz); - -out: - vfree(cmem); - return ret; + return walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback); } #endif @@ -418,7 +351,8 @@ int crash_load_segments(struct kimage *image) .buf_max = ULONG_MAX, .top_down = false }; /* Prepare elf headers and add a segment */ - ret = prepare_elf_headers(&kbuf.buffer, &kbuf.bufsz, &pnum); + ret = crash_prepare_headers(IS_ENABLED(CONFIG_X86_64), &kbuf.buffer, + &kbuf.bufsz, &pnum); if (ret) return ret; @@ -529,7 +463,8 @@ void arch_crash_handle_hotplug_event(struct kimage *image, void *arg) * Create the new elfcorehdr reflecting the changes to CPU and/or * memory resources. */ - if (prepare_elf_headers(&elfbuf, &elfsz, &nr_mem_ranges)) { + if (crash_prepare_headers(IS_ENABLED(CONFIG_X86_64), &elfbuf, &elfsz, + &nr_mem_ranges)) { pr_err("unable to create new elfcorehdr"); goto out; } diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h index d35726d6a415bc..033b20204acae3 100644 --- a/include/linux/crash_core.h +++ b/include/linux/crash_core.h @@ -66,6 +66,8 @@ extern int crash_exclude_mem_range(struct crash_mem *mem, unsigned long long mend); extern int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, void **addr, unsigned long *sz); +extern int crash_prepare_headers(int need_kernel_map, void **addr, + unsigned long *sz, unsigned long *nr_mem_ranges); struct kimage; struct kexec_segment; @@ -83,6 +85,9 @@ int kexec_should_crash(struct task_struct *p); int kexec_crash_loaded(void); void crash_save_cpu(struct pt_regs *regs, int cpu); extern int kimage_crash_copy_vmcoreinfo(struct kimage *image); +extern unsigned int arch_get_system_nr_ranges(void); +extern int arch_crash_populate_cmem(struct crash_mem *cmem); +extern int arch_crash_exclude_ranges(struct crash_mem *cmem); #else /* !CONFIG_CRASH_DUMP*/ struct pt_regs; diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 2c1a3791e41014..96a96e511f5a88 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -170,9 +170,6 @@ static inline resource_size_t crash_resource_size(const struct resource *res) return !res->end ? 0 : resource_size(res); } - - - int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, void **addr, unsigned long *sz) { @@ -274,6 +271,85 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map, return 0; } +static struct crash_mem *alloc_cmem(unsigned int nr_ranges) +{ + struct crash_mem *cmem; + + cmem = kvzalloc_flex(*cmem, ranges, nr_ranges); + if (!cmem) + return NULL; + + cmem->max_nr_ranges = nr_ranges; + return cmem; +} + +unsigned int __weak arch_get_system_nr_ranges(void) { return 0; } +int __weak arch_crash_populate_cmem(struct crash_mem *cmem) { return -1; } +int __weak arch_crash_exclude_ranges(struct crash_mem *cmem) { return 0; } + +static int crash_exclude_core_ranges(struct crash_mem *cmem) +{ + int ret, i; + + /* Exclude crashkernel region */ + ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); + if (ret) + return ret; + + if (crashk_low_res.end) { + ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); + if (ret) + return ret; + } + + for (i = 0; i < crashk_cma_cnt; ++i) { + ret = crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start, + crashk_cma_ranges[i].end); + if (ret) + return ret; + } + + return 0; +} + +int crash_prepare_headers(int need_kernel_map, void **addr, unsigned long *sz, + unsigned long *nr_mem_ranges) +{ + unsigned int max_nr_ranges; + struct crash_mem *cmem; + int ret; + + max_nr_ranges = arch_get_system_nr_ranges(); + if (!max_nr_ranges) + return -ENOMEM; + + cmem = alloc_cmem(max_nr_ranges); + if (!cmem) + return -ENOMEM; + + ret = arch_crash_populate_cmem(cmem); + if (ret) + goto out; + + ret = crash_exclude_core_ranges(cmem); + if (ret) + goto out; + + ret = arch_crash_exclude_ranges(cmem); + if (ret) + goto out; + + /* Return the computed number of memory ranges, for hotplug usage */ + if (nr_mem_ranges) + *nr_mem_ranges = cmem->nr_ranges; + + ret = crash_prepare_elf64_headers(cmem, need_kernel_map, addr, sz); + +out: + kvfree(cmem); + return ret; +} + /** * crash_exclude_mem_range - exclude a mem range for existing ranges * @mem: mem->range contains an array of ranges sorted in ascending order From 7d1882484f15444f26a114bfeae6d2c8517f7504 Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 25 Mar 2026 10:59:01 +0800 Subject: [PATCH 5/8] crash: Use crash_exclude_core_ranges() on powerpc The crash memory exclude of crashk_res and crashk_cma memory on powerpc are almost identical to the generic crash_exclude_core_ranges(). By introducing the architecture-specific arch_crash_exclude_mem_range() function with a default implementation of crash_exclude_mem_range(), and using crash_exclude_mem_range_guarded as powerpc's separate implementation, the generic crash_exclude_core_ranges() helper function can be reused. Acked-by: Baoquan He Reviewed-by: Sourabh Jain Acked-by: Mike Rapoport (Microsoft) Signed-off-by: Jinjie Ruan Signed-off-by: Linux RISC-V bot --- arch/powerpc/include/asm/kexec_ranges.h | 3 --- arch/powerpc/kexec/crash.c | 2 +- arch/powerpc/kexec/ranges.c | 16 ++++------------ include/linux/crash_core.h | 4 ++++ kernel/crash_core.c | 19 +++++++++++++------ 5 files changed, 22 insertions(+), 22 deletions(-) diff --git a/arch/powerpc/include/asm/kexec_ranges.h b/arch/powerpc/include/asm/kexec_ranges.h index ad95e3792d10cc..8489e844b44759 100644 --- a/arch/powerpc/include/asm/kexec_ranges.h +++ b/arch/powerpc/include/asm/kexec_ranges.h @@ -7,9 +7,6 @@ void sort_memory_ranges(struct crash_mem *mrngs, bool merge); struct crash_mem *realloc_mem_ranges(struct crash_mem **mem_ranges); int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size); -int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges, - unsigned long long mstart, - unsigned long long mend); int get_exclude_memory_ranges(struct crash_mem **mem_ranges); int get_reserved_memory_ranges(struct crash_mem **mem_ranges); int get_crash_memory_ranges(struct crash_mem **mem_ranges); diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c index 1426d2099baddc..52992309e28c97 100644 --- a/arch/powerpc/kexec/crash.c +++ b/arch/powerpc/kexec/crash.c @@ -451,7 +451,7 @@ static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify * base_addr = PFN_PHYS(mn->start_pfn); size = mn->nr_pages * PAGE_SIZE; end = base_addr + size - 1; - ret = crash_exclude_mem_range_guarded(&cmem, base_addr, end); + ret = arch_crash_exclude_mem_range(&cmem, base_addr, end); if (ret) { pr_err("Failed to remove hot-unplugged memory from crash memory ranges\n"); goto out; diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c index 6c58bcc3e13040..e5fea23b191b6d 100644 --- a/arch/powerpc/kexec/ranges.c +++ b/arch/powerpc/kexec/ranges.c @@ -553,9 +553,9 @@ int get_usable_memory_ranges(struct crash_mem **mem_ranges) #endif /* CONFIG_KEXEC_FILE */ #ifdef CONFIG_CRASH_DUMP -int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges, - unsigned long long mstart, - unsigned long long mend) +int arch_crash_exclude_mem_range(struct crash_mem **mem_ranges, + unsigned long long mstart, + unsigned long long mend) { struct crash_mem *tmem = *mem_ranges; @@ -604,18 +604,10 @@ int get_crash_memory_ranges(struct crash_mem **mem_ranges) sort_memory_ranges(*mem_ranges, true); } - /* Exclude crashkernel region */ - ret = crash_exclude_mem_range_guarded(mem_ranges, crashk_res.start, crashk_res.end); + ret = crash_exclude_core_ranges(mem_ranges); if (ret) goto out; - for (i = 0; i < crashk_cma_cnt; ++i) { - ret = crash_exclude_mem_range_guarded(mem_ranges, crashk_cma_ranges[i].start, - crashk_cma_ranges[i].end); - if (ret) - goto out; - } - /* * FIXME: For now, stay in parity with kexec-tools but if RTAS/OPAL * regions are exported to save their context at the time of diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h index 033b20204acae3..dbec826dc53b47 100644 --- a/include/linux/crash_core.h +++ b/include/linux/crash_core.h @@ -68,6 +68,7 @@ extern int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_ma void **addr, unsigned long *sz); extern int crash_prepare_headers(int need_kernel_map, void **addr, unsigned long *sz, unsigned long *nr_mem_ranges); +extern int crash_exclude_core_ranges(struct crash_mem **cmem); struct kimage; struct kexec_segment; @@ -88,6 +89,9 @@ extern int kimage_crash_copy_vmcoreinfo(struct kimage *image); extern unsigned int arch_get_system_nr_ranges(void); extern int arch_crash_populate_cmem(struct crash_mem *cmem); extern int arch_crash_exclude_ranges(struct crash_mem *cmem); +extern int arch_crash_exclude_mem_range(struct crash_mem **mem, + unsigned long long mstart, + unsigned long long mend); #else /* !CONFIG_CRASH_DUMP*/ struct pt_regs; diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 96a96e511f5a88..300d44ad547126 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -287,24 +287,31 @@ unsigned int __weak arch_get_system_nr_ranges(void) { return 0; } int __weak arch_crash_populate_cmem(struct crash_mem *cmem) { return -1; } int __weak arch_crash_exclude_ranges(struct crash_mem *cmem) { return 0; } -static int crash_exclude_core_ranges(struct crash_mem *cmem) +int __weak arch_crash_exclude_mem_range(struct crash_mem **mem, + unsigned long long mstart, + unsigned long long mend) +{ + return crash_exclude_mem_range(*mem, mstart, mend); +} + +int crash_exclude_core_ranges(struct crash_mem **cmem) { int ret, i; /* Exclude crashkernel region */ - ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); + ret = arch_crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); if (ret) return ret; if (crashk_low_res.end) { - ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); + ret = arch_crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end); if (ret) return ret; } for (i = 0; i < crashk_cma_cnt; ++i) { - ret = crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start, - crashk_cma_ranges[i].end); + ret = arch_crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start, + crashk_cma_ranges[i].end); if (ret) return ret; } @@ -331,7 +338,7 @@ int crash_prepare_headers(int need_kernel_map, void **addr, unsigned long *sz, if (ret) goto out; - ret = crash_exclude_core_ranges(cmem); + ret = crash_exclude_core_ranges(&cmem); if (ret) goto out; From f723753e281e8858339c0f6826e06da7d69b5503 Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 25 Mar 2026 10:59:02 +0800 Subject: [PATCH 6/8] arm64: kexec: Add support for crashkernel CMA reservation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 35c18f2933c5 ("Add a new optional ",cma" suffix to the crashkernel= command line option") and commit ab475510e042 ("kdump: implement reserve_crashkernel_cma") added CMA support for kdump crashkernel reservation. Crash kernel memory reservation wastes production resources if too large, risks kdump failure if too small, and faces allocation difficulties on fragmented systems due to contiguous block constraints. The new CMA-based crashkernel reservation scheme splits the "large fixed reservation" into a "small fixed region + large CMA dynamic region": the CMA memory is available to userspace during normal operation to avoid waste, and is reclaimed for kdump upon crash—saving memory while improving reliability. So extend crashkernel CMA reservation support to arm64. The following changes are made to enable CMA reservation: - Parse and obtain the CMA reservation size along with other crashkernel parameters. - Call reserve_crashkernel_cma() to allocate the CMA region for kdump. - Include the CMA-reserved ranges for kdump kernel to use. - Exclude the CMA-reserved ranges from the crash kernel memory to prevent them from being exported through /proc/vmcore, which is already done in the crash core. Update kernel-parameters.txt to document CMA support for crashkernel on arm64 architecture. Acked-by: Rob Herring (Arm) Acked-by: Baoquan He Acked-by: Mike Rapoport (Microsoft) Acked-by: Ard Biesheuvel Signed-off-by: Jinjie Ruan Signed-off-by: Linux RISC-V bot --- Documentation/admin-guide/kernel-parameters.txt | 2 +- arch/arm64/kernel/machine_kexec_file.c | 2 +- arch/arm64/mm/init.c | 5 +++-- drivers/of/fdt.c | 9 +++++---- drivers/of/kexec.c | 9 +++++++++ 5 files changed, 19 insertions(+), 8 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 03a550630644f4..a7055cead40fc8 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1122,7 +1122,7 @@ Kernel parameters It will be ignored when crashkernel=X,high is not used or memory reserved is below 4G. crashkernel=size[KMG],cma - [KNL, X86, ppc] Reserve additional crash kernel memory from + [KNL, X86, ARM64, PPC] Reserve additional crash kernel memory from CMA. This reservation is usable by the first system's userspace memory and kernel movable allocations (memory balloon, zswap). Pages allocated from this memory range diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c index c338506a580bab..cc577d77df0093 100644 --- a/arch/arm64/kernel/machine_kexec_file.c +++ b/arch/arm64/kernel/machine_kexec_file.c @@ -42,7 +42,7 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image) #ifdef CONFIG_CRASH_DUMP unsigned int arch_get_system_nr_ranges(void) { - unsigned int nr_ranges = 2; /* for exclusion of crashkernel region */ + unsigned int nr_ranges = 2 + crashk_cma_cnt; /* for exclusion of crashkernel region */ phys_addr_t start, end; u64 i; diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 96711b8578fd06..144e30fe9a7577 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -96,8 +96,8 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit; static void __init arch_reserve_crashkernel(void) { + unsigned long long crash_base, crash_size, cma_size = 0; unsigned long long low_size = 0; - unsigned long long crash_base, crash_size; bool high = false; int ret; @@ -106,11 +106,12 @@ static void __init arch_reserve_crashkernel(void) ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), &crash_size, &crash_base, - &low_size, NULL, &high); + &low_size, &cma_size, &high); if (ret) return; reserve_crashkernel_generic(crash_size, crash_base, low_size, high); + reserve_crashkernel_cma(cma_size); } static phys_addr_t __init max_zone_phys(phys_addr_t zone_limit) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 331646d667b9be..037926ed30fbcd 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -871,11 +871,12 @@ static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND; /* * The main usage of linux,usable-memory-range is for crash dump kernel. * Originally, the number of usable-memory regions is one. Now there may - * be two regions, low region and high region. - * To make compatibility with existing user-space and older kdump, the low - * region is always the last range of linux,usable-memory-range if exist. + * be 2 + CRASHKERNEL_CMA_RANGES_MAX regions, low region, high region and + * cma regions. To make compatibility with existing user-space and older + * kdump, the high and low region are always the first two ranges of + * linux,usable-memory-range if exist. */ -#define MAX_USABLE_RANGES 2 +#define MAX_USABLE_RANGES (2 + CRASHKERNEL_CMA_RANGES_MAX) /** * early_init_dt_check_for_usable_mem_range - Decode usable memory range diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c index c4cf3552c01838..57950aae80e71f 100644 --- a/drivers/of/kexec.c +++ b/drivers/of/kexec.c @@ -439,6 +439,15 @@ void *of_kexec_alloc_and_setup_fdt(const struct kimage *image, if (ret) goto out; } + + for (int i = 0; i < crashk_cma_cnt; i++) { + ret = fdt_appendprop_addrrange(fdt, 0, chosen_node, + "linux,usable-memory-range", + crashk_cma_ranges[i].start, + crashk_cma_ranges[i].end - crashk_cma_ranges[i].start + 1); + if (ret) + goto out; + } #endif } From 4e59f235531806b1f02a64b928af0e1e1eb5d77f Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 25 Mar 2026 10:59:03 +0800 Subject: [PATCH 7/8] riscv: kexec: Add support for crashkernel CMA reservation Commit 35c18f2933c5 ("Add a new optional ",cma" suffix to the crashkernel= command line option") and commit ab475510e042 ("kdump: implement reserve_crashkernel_cma") added CMA support for kdump crashkernel reservation. This allows the kernel to dynamically allocate contiguous memory for crash dumping when needed, rather than permanently reserving a fixed region at boot time. So extend crashkernel CMA reservation support to riscv. The following changes are made to enable CMA reservation: - Parse and obtain the CMA reservation size along with other crashkernel parameters. - Call reserve_crashkernel_cma() to allocate the CMA region for kdump. - Include the CMA-reserved ranges for kdump kernel to use, which was already done in of_kexec_alloc_and_setup_fdt(). - Exclude the CMA-reserved ranges from the crash kernel memory to prevent them from being exported through /proc/vmcore, which was already done in the crash core. Update kernel-parameters.txt to document CMA support for crashkernel on riscv architecture. Acked-by: Baoquan He Acked-by: Mike Rapoport (Microsoft) Acked-by: Paul Walmsley # arch/riscv Signed-off-by: Jinjie Ruan Signed-off-by: Linux RISC-V bot --- Documentation/admin-guide/kernel-parameters.txt | 16 ++++++++-------- arch/riscv/kernel/machine_kexec_file.c | 2 +- arch/riscv/mm/init.c | 5 +++-- 3 files changed, 12 insertions(+), 11 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index a7055cead40fc8..13ced9ea42f408 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1122,14 +1122,14 @@ Kernel parameters It will be ignored when crashkernel=X,high is not used or memory reserved is below 4G. crashkernel=size[KMG],cma - [KNL, X86, ARM64, PPC] Reserve additional crash kernel memory from - CMA. This reservation is usable by the first system's - userspace memory and kernel movable allocations (memory - balloon, zswap). Pages allocated from this memory range - will not be included in the vmcore so this should not - be used if dumping of userspace memory is intended and - it has to be expected that some movable kernel pages - may be missing from the dump. + [KNL, X86, ARM64, RISCV, PPC] Reserve additional crash + kernel memory from CMA. This reservation is usable by + the first system's userspace memory and kernel movable + allocations (memory balloon, zswap). Pages allocated + from this memory range will not be included in the vmcore + so this should not be used if dumping of userspace memory + is intended and it has to be expected that some movable + kernel pages may be missing from the dump. A standard crashkernel reservation, as described above, is still needed to hold the crash kernel and initrd. diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c index 5a91bdfae162a7..12a6263b01e7ab 100644 --- a/arch/riscv/kernel/machine_kexec_file.c +++ b/arch/riscv/kernel/machine_kexec_file.c @@ -46,7 +46,7 @@ static int get_nr_ram_ranges_callback(struct resource *res, void *arg) unsigned int arch_get_system_nr_ranges(void) { - unsigned int nr_ranges = 2; /* For exclusion of crashkernel region */ + unsigned int nr_ranges = 2 + crashk_cma_cnt; /* For exclusion of crashkernel region */ walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 257df6bd258fa6..5186956db2846a 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -1393,7 +1393,7 @@ static inline void setup_vm_final(void) */ static void __init arch_reserve_crashkernel(void) { - unsigned long long low_size = 0; + unsigned long long low_size = 0, cma_size = 0; unsigned long long crash_base, crash_size; bool high = false; int ret; @@ -1403,11 +1403,12 @@ static void __init arch_reserve_crashkernel(void) ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(), &crash_size, &crash_base, - &low_size, NULL, &high); + &low_size, &cma_size, &high); if (ret) return; reserve_crashkernel_generic(crash_size, crash_base, low_size, high); + reserve_crashkernel_cma(cma_size); } void __init paging_init(void) From 372c2acc5c55f7481a0e5b158200ba4ad3a482fd Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Wed, 25 Mar 2026 10:59:04 +0800 Subject: [PATCH 8/8] crash: Fix race condition between crash kernel loading and memory hotplug There is a race condition between the kexec_load() system call (crash kernel loading path) and memory hotplug operations that can lead to buffer overflow and potential kernel crash. During crash_prepare_headers(), the following steps occur: 1. arch_get_system_nr_ranges() queries current memory ranges from memblock 2. alloc_cmem() allocates buffer based on queried count 3. arch_crash_populate_cmem() populates ranges from memblock If memory hotplug occurs between step 1 and step 3, the number of ranges can increase, causing out-of-bounds write when populating cmem->ranges[]. This happens because kexec_load() uses kexec_trylock (atomic_t) while memory hotplug uses device_hotplug_lock (mutex), so they don't serialize with each other. Fix by adding lock_device_hotplug()/unlock_device_hotplug() around the critical section in crash_prepare_headers(). The lock is only acquired when CONFIG_MEMORY_HOTPLUG is enabled to avoid overhead on systems without hotplug support. Fixes: dd5f726076cc ("kexec: support for kexec on panic using new system call") Fixes: 3751e728cef2 ("arm64: kexec_file: add crash dump support") Fixes: 8acea455fafa ("RISC-V: Support for kexec_file on panic") Fixes: 1bcca8620a91 ("LoongArch: Add crash dump support for kexec_file") Signed-off-by: Jinjie Ruan Signed-off-by: Linux RISC-V bot --- kernel/crash_core.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 300d44ad547126..f01d03d42c6777 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -326,15 +326,25 @@ int crash_prepare_headers(int need_kernel_map, void **addr, unsigned long *sz, struct crash_mem *cmem; int ret; + if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) + lock_device_hotplug(); + max_nr_ranges = arch_get_system_nr_ranges(); - if (!max_nr_ranges) - return -ENOMEM; + if (!max_nr_ranges) { + ret = -ENOMEM; + goto unlock; + } cmem = alloc_cmem(max_nr_ranges); - if (!cmem) - return -ENOMEM; + if (!cmem) { + ret = -ENOMEM; + goto unlock; + } ret = arch_crash_populate_cmem(cmem); + if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) + unlock_device_hotplug(); + if (ret) goto out; @@ -355,6 +365,12 @@ int crash_prepare_headers(int need_kernel_map, void **addr, unsigned long *sz, out: kvfree(cmem); return ret; + +unlock: + if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) + unlock_device_hotplug(); + + return ret; } /**