Author: kib Date: Mon Jan 14 07:31:19 2019 New Revision: 343017 URL: https://svnweb.freebsd.org/changeset/base/343017
Log: Handle overflow in calculating max kmem size. vm_kmem_size is u_long, and it might be not capable of holding page count times PAGE_SIZE, even when scaled down by VM_KMEM_SIZE_SCALE. As bde reported, 12G PAE config ends up with zero for kmem size. Explicitly check for overflow and clamp kmem size at vm_kmem_size_max. If we end up at zero size because VM_KMEM_SIZE_MAX is not defined, panic with clear explanation rather then failing in a way which is hard to relate. Reported by: bde, pho Tested by: pho Reviewed by: markj Sponsored by: The FreeBSD Foundation MFC after: 1 week Differential revision: https://reviews.freebsd.org/D18767 Modified: head/sys/kern/kern_malloc.c Modified: head/sys/kern/kern_malloc.c ============================================================================== --- head/sys/kern/kern_malloc.c Mon Jan 14 07:25:44 2019 (r343016) +++ head/sys/kern/kern_malloc.c Mon Jan 14 07:31:19 2019 (r343017) @@ -920,13 +920,16 @@ kmeminit(void) * variable: */ if (vm_kmem_size == 0) { - vm_kmem_size = (mem_size / vm_kmem_size_scale) * PAGE_SIZE; - + vm_kmem_size = mem_size / vm_kmem_size_scale; + vm_kmem_size = vm_kmem_size * PAGE_SIZE < vm_kmem_size ? + vm_kmem_size_max : vm_kmem_size * PAGE_SIZE; if (vm_kmem_size_min > 0 && vm_kmem_size < vm_kmem_size_min) vm_kmem_size = vm_kmem_size_min; if (vm_kmem_size_max > 0 && vm_kmem_size >= vm_kmem_size_max) vm_kmem_size = vm_kmem_size_max; } + if (vm_kmem_size == 0) + panic("Tune VM_KMEM_SIZE_* for the platform"); /* * The amount of KVA space that is preallocated to the _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
