On Fri, Jun 01, 2012 at 10:59:32AM -0500, Eric Biggers wrote:
> Allow bzImages smaller than 32KiB to be kexec'ed.
>
> The current code will fail to load a bzImage smaller than 32768 bytes (sizeof
> struct x86_linux_header), but the 'memdisk' program that comes with syslinux is
> only about 26 KiB. This patch changes the minimum size to 1024 bytes (2
> sectors), which appears to be the limit that syslinux enforces.
>
> Removed the "tail" field of struct x86_linux_header because it doesn't seem to
> actually be used (is there a reason for it?).
>
> Also, note that bzImage_probe() was incorrectly using `sizeof (header)', even
> though header is a pointer.
Hi Eric,
could you please supply a signed-off-by line so I can apply this patch?
Thanks.
>
> diff --git a/include/x86/x86-linux.h b/include/x86/x86-linux.h
> index 59d35c9..2ebcc3a 100644
> --- a/include/x86/x86-linux.h
> +++ b/include/x86/x86-linux.h
> @@ -233,7 +233,6 @@ struct x86_linux_header {
> uint32_t high_base; /* 0x24C */
> uint32_t high_memsz; /* 0x250 */
> uint32_t high_filesz; /* 0x254 */
> - uint32_t tail[32*1024 - 0x258]; /* 0x258 */
> #else
> uint32_t kernel_alignment; /* 0x230 */
> uint8_t relocatable_kernel; /* 0x234 */
> @@ -241,7 +240,6 @@ struct x86_linux_header {
> uint32_t cmdline_size; /* 0x238 */
> uint32_t hardware_subarch; /* 0x23C */
> uint64_t hardware_subarch_data; /* 0x240 */
> - uint8_t tail[32*1024 - 0x248]; /* 0x248 */
> #endif
> } PACKED;
>
> diff --git a/kexec/arch/i386/kexec-bzImage.c b/kexec/arch/i386/kexec-bzImage.c
> index 54c4427..6998587 100644
> --- a/kexec/arch/i386/kexec-bzImage.c
> +++ b/kexec/arch/i386/kexec-bzImage.c
> @@ -44,7 +44,10 @@ static const int probe_debug = 0;
> int bzImage_probe(const char *buf, off_t len)
> {
> const struct x86_linux_header *header;
> - if ((uintmax_t)len < (uintmax_t)sizeof(header)) {
> + if ((uintmax_t)len < (uintmax_t)(2 * 512)) {
> + if (probe_debug) {
> + fprintf(stderr, "File is too short to be a bzImage!\n");
> + }
> return -1;
> }
> header = (const struct x86_linux_header *)buf;
> @@ -118,7 +121,7 @@ int do_bzImage_load(struct kexec_info *info,
> /*
> * Find out about the file I am about to load.
> */
> - if ((uintmax_t)kernel_len < (uintmax_t)sizeof(setup_header)) {
> + if ((uintmax_t)kernel_len < (uintmax_t)(2 * 512)) {
> return -1;
> }
> memcpy(&setup_header, kernel, sizeof(setup_header));
>
> _______________________________________________
> kexec mailing list
> kexec at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
>
