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.
Signed-off-by: David Hildenbrand <da...@redhat.com>
---
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 738e84ab63..26c289518c 100644
--- a/subprojects/libvhost-user/libvhost-user.c
+++ b/subprojects/libvhost-user/libvhost-user.c
@@ -458,6 +458,12 @@ _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));
--
2.43.0
