Commit f9a7febd leads to a fact that mapstart and therefore a page bitmap for bootmem allocator immediately follows initrd_end. This doesn't always work well on Octeon, where there are holes in PFN ranges (refer to 5b3b1688 and 4MB-aligned PFN allocation). Depending on the inird location it could happen, that mapstart would be in an area not allocated by plat_mem_setup() in arch/mips/cavium-octeon/setup.c, but in the alignment hole between initrd and the next PFN area. Later on this memory will be unconditionally made available to buddy allocator at the end of free_all_bootmem_core() (mm/bootmem.c). All of this results in Linux using the memory not designated for Linux in Octeon's plat_mem_setup(), which in turn means corruption of the memory used by another OS/baremetal code on the same SoC. It doesn't look to me as a problem of Octeon platform code, but rather as an inability of f9a7febd to deal correctly with the fragmented memory-mappings. Proposed fix moves the check for initrd address to the same calculation-loop in bootmem_init() (arch/mips/kernel/setup.c), which also accounts for kernel code location. This should result in mapstart located starting from the first PFN area after kernel code AND initrd. Signed-off-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx> --- Tested on CN63xx (Octeon2) -based HW. arch/mips/kernel/setup.c | 13 +++++-------- 1 files changed, 5 insertions(+), 8 deletions(-) diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index be73c49..008b337 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -337,6 +337,11 @@ static void __init bootmem_init(void) min_low_pfn = start; if (end <= reserved_end) continue; +#ifdef CONFIG_BLK_DEV_INITRD + /* mapstart should be after initrd_end */ + if (initrd_end && end <= (unsigned long)PFN_UP(__pa(initrd_end))) + continue; +#endif if (start >= mapstart) continue; mapstart = max(reserved_end, start); @@ -366,14 +371,6 @@ static void __init bootmem_init(void) max_low_pfn = PFN_DOWN(HIGHMEM_START); } -#ifdef CONFIG_BLK_DEV_INITRD - /* - * mapstart should be after initrd_end - */ - if (initrd_end) - mapstart = max(mapstart, (unsigned long)PFN_UP(__pa(initrd_end))); -#endif - /* * Initialize the boot-time allocator with low memory only. */
