2282cbfe5a
When grub_memalign() encounters out-of-memory, it will try grub_mm_add_region_fn() to request more memory from system firmware. However, the size passed to it doesn't take region management overhead into account. Adding a memory area of "size" bytes may result in a heap region of less than "size" bytes really available. Thus, the new region may not be adequate for current allocation request, confusing out-of-memory handling code. This patch introduces GRUB_MM_MGMT_OVERHEAD to address the region management overhead (e.g. metadata, padding). The value of this new constant must be large enough to make sure grub_memalign(align, size) always succeeds after a successful call to grub_mm_init_region(addr, size + align + GRUB_MM_MGMT_OVERHEAD), for any given addr and size (assuming no integer overflow). The size passed to grub_mm_add_region_fn() is now correctly adjusted, thus if grub_mm_add_region_fn() succeeded, current allocation request can always succeed. Signed-off-by: Zhang Boyang <zhangboyang.id@gmail.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This is GRUB 2, the second version of the GRand Unified Bootloader. GRUB 2 is rewritten from scratch to make GNU GRUB cleaner, safer, more robust, more powerful, and more portable. See the file NEWS for a description of recent changes to GRUB 2. See the file INSTALL for instructions on how to build and install the GRUB 2 data and program files. See the file MAINTAINERS for information about the GRUB maintainers, etc. If you found a security vulnerability in the GRUB please check the SECURITY file to get more information how to properly report this kind of bugs to the maintainers. Please visit the official web page of GRUB 2, for more information. The URL is <http://www.gnu.org/software/grub/grub.html>. More extensive documentation is available in the Info manual, accessible using 'info grub' after building and installing GRUB 2. There are a number of important user-visible differences from the first version of GRUB, now known as GRUB Legacy. For a summary, please see: info grub Introduction 'Changes from GRUB Legacy'