From 637175ab95ed1dad3790a3c565fe8eaf422aa2c3 Mon Sep 17 00:00:00 2001 From: Dariusz Stojaczyk Date: Fri, 1 Jun 2018 14:59:19 +0200 Subject: [PATCH] mem: do not leave unmapped holes in EAL memory area EAL reserves a huge area in virtual address space to provide virtual address contiguity for e.g. future memory extensions (memory hotplug). During memory hotplug, if the hugepage mmap succeeds but doesn't suffice EAL's requiriments, the EAL would unmap this mapping straight away, leaving a hole in its virtual memory area and making it available to everyone. As EAL still thinks it owns the entire region, it may try to mmap it later with MAP_FIXED, possibly overriding a user's mapping that was made in the meantime. This patch ensures each hole is mapped back by EAL, so that it won't be available to anyone else. Fixes: 582bed1e1d1d ("mem: support mapping hugepages at runtime") Cc: stable@dpdk.org Signed-off-by: Dariusz Stojaczyk Acked-by: Anatoly Burakov --- lib/librte_eal/linuxapp/eal/eal_memalloc.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/lib/librte_eal/linuxapp/eal/eal_memalloc.c b/lib/librte_eal/linuxapp/eal/eal_memalloc.c index 8c11f98c92..6be6680553 100644 --- a/lib/librte_eal/linuxapp/eal/eal_memalloc.c +++ b/lib/librte_eal/linuxapp/eal/eal_memalloc.c @@ -39,6 +39,7 @@ #include "eal_filesystem.h" #include "eal_internal_cfg.h" #include "eal_memalloc.h" +#include "eal_private.h" /* * not all kernel version support fallocate on hugetlbfs, so fall back to @@ -490,6 +491,8 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id, int ret = 0; int fd; size_t alloc_sz; + int flags; + void *new_addr; /* takes out a read lock on segment or segment list */ fd = get_seg_fd(path, sizeof(path), hi, list_idx, seg_idx); @@ -585,6 +588,20 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id, mapped: munmap(addr, alloc_sz); + flags = MAP_FIXED; +#ifdef RTE_ARCH_PPC_64 + flags |= MAP_HUGETLB; +#endif + new_addr = eal_get_virtual_area(addr, &alloc_sz, alloc_sz, 0, flags); + if (new_addr != addr) { + if (new_addr != NULL) + munmap(new_addr, alloc_sz); + /* we're leaving a hole in our virtual address space. if + * somebody else maps this hole now, we could accidentally + * override it in the future. + */ + RTE_LOG(CRIT, EAL, "Can't mmap holes in our virtual address space\n"); + } resized: if (internal_config.single_file_segments) { resize_hugefile(fd, path, list_idx, seg_idx, map_offset, -- 2.20.1