From 52767e1063beaa17d59c739efd0b9c342923929d Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Wed, 14 Feb 2024 16:17:01 +0100 Subject: [PATCH] libvhost-user: Mark mmap'ed region memory as MADV_DONTDUMP We already use MADV_NORESERVE to deal with sparse memory regions. Let's also set madvise(MADV_DONTDUMP), otherwise a crash of the process can result in us allocating all memory in the mmap'ed region for dumping purposes. This change implies that the mmap'ed rings won't be included in a coredump. If ever required for debugging purposes, we could mark only the mapped rings MADV_DODUMP. Ignore errors during madvise() for now. Reviewed-by: Raphael Norwitz Acked-by: Stefano Garzarella Signed-off-by: David Hildenbrand Message-Id: <20240214151701.29906-15-david@redhat.com> Tested-by: Mario Casquero Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- subprojects/libvhost-user/libvhost-user.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvhost-user/libvhost-user.c index 61fb3050b3..a879149fef 100644 --- a/subprojects/libvhost-user/libvhost-user.c +++ b/subprojects/libvhost-user/libvhost-user.c @@ -460,6 +460,12 @@ _vu_add_mem_reg(VuDev *dev, VhostUserMemoryRegion *msg_region, int fd) DPRINT(" mmap_addr: 0x%016"PRIx64"\n", (uint64_t)(uintptr_t)mmap_addr); +#if defined(__linux__) + /* Don't include all guest memory in a coredump. */ + madvise(mmap_addr, msg_region->memory_size + mmap_offset, + MADV_DONTDUMP); +#endif + /* Shift all affected entries by 1 to open a hole at idx. */ r = &dev->regions[idx]; memmove(r + 1, r, sizeof(VuDevRegion) * (dev->nregions - idx));