On 05/21/25 at 03:47pm, Zhongkun He wrote: > On Wed, May 14, 2025 at 2:40 AM Alexander Graf <g...@amazon.com> wrote: ...... > > /** > > * kexec_locate_mem_hole - find free memory for the purgatory or the next > > kernel > > * @kbuf: Parameters for the memory search. > > @@ -648,6 +684,13 @@ int kexec_locate_mem_hole(struct kexec_buf *kbuf) > > if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN) > > return 0; > > > > + /* > > + * Try to find a free physically contiguous block of memory first. > > With that, we > > + * can avoid any copying at kexec time. > > + */ > > + if (!kexec_alloc_contig(kbuf)) > > + return 0; > > IIUC, The kexec_locate_mem_hole() function is also used in > the KEXEC_TYPE_CRASH kimage, but kexec_alloc_contig() does not skip it. > This can cause kdump to fail and lead to CMA memory leakage.
That is true and good catch, and fix is needed to skip cma alloc for kdump. > > So I ran some tests, as listed below: > The CMA memory decreases with each execution of the kdump-config > reload operation. > > /home/hezhongkun.hzk# kdump-config reload > unloaded kdump kernel. > Creating symlink /var/lib/kdump/vmlinuz. > Creating symlink /var/lib/kdump/initrd.img. > kexec_file_load failed: Cannot assign requested address > failed to load kdump kernel ... failed! > > [ 1387.536346] kexec_file: allocated 1817 DMA pages at 0x11b16e > [ 1399.147677] kexec_file: allocated 113 DMA pages at 0x119087 > [ 1399.148915] kexec_file: allocated 5 DMA pages at 0x1140f8 > [ 1399.150266] kexec_file: allocated 2 DMA pages at 0x1118fd > [ 1399.151474] kexec_file: allocated 8302 DMA pages at 0x11b900 > > /home/hezhongkun.hzk# cat /proc/meminfo | grep Cma > CmaTotal: 1048576 kB > CmaFree: 679972 kB > /home/hezhongkun.hzk# cat /proc/meminfo | grep Cma > CmaTotal: 1048576 kB > CmaFree: 639016 kB > /home/hezhongkun.hzk# cat /proc/meminfo | grep Cma > CmaTotal: 1048576 kB > CmaFree: 557104 kB > > cat /proc/meminfo | grep Cma > CmaTotal: 1048576 kB > CmaFree: 557104 kB > > > + > > if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) > > ret = kexec_walk_resources(kbuf, locate_mem_hole_callback); > > else > > @@ -693,6 +736,7 @@ int kexec_add_buffer(struct kexec_buf *kbuf) > > /* Ensure minimum alignment needed for segments. */ > > kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE); > > kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE); > > + kbuf->cma = NULL; > > > > /* Walk the RAM ranges and allocate a suitable range for the buffer > > */ > > ret = arch_kexec_locate_mem_hole(kbuf); > > @@ -705,6 +749,7 @@ int kexec_add_buffer(struct kexec_buf *kbuf) > > ksegment->bufsz = kbuf->bufsz; > > ksegment->mem = kbuf->mem; > > ksegment->memsz = kbuf->memsz; > > + kbuf->image->segment_cma[kbuf->image->nr_segments] = kbuf->cma; > > kbuf->image->nr_segments++; > > return 0; > > } > > diff --git a/kernel/kexec_internal.h b/kernel/kexec_internal.h > > index d35d9792402d..29e6cebe0c43 100644 > > --- a/kernel/kexec_internal.h > > +++ b/kernel/kexec_internal.h > > @@ -10,7 +10,7 @@ struct kimage *do_kimage_alloc_init(void); > > int sanity_check_segment_list(struct kimage *image); > > void kimage_free_page_list(struct list_head *list); > > void kimage_free(struct kimage *image); > > -int kimage_load_segment(struct kimage *image, struct kexec_segment > > *segment); > > +int kimage_load_segment(struct kimage *image, int idx); > > void kimage_terminate(struct kimage *image); > > int kimage_is_destination_range(struct kimage *image, > > unsigned long start, unsigned long end); > > -- > > 2.34.1 > > > > > > > > > > Amazon Web Services Development Center Germany GmbH > > Tamara-Danz-Str. 13 > > 10243 Berlin > > Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss > > Eingetragen am Amtsgericht Charlottenburg unter HRB 257764 B > > Sitz: Berlin > > Ust-ID: DE 365 538 597 > > > > >
