[PATCH v2] mem: allow using ASan in multi-process mode

[Artur Paszkiewicz <artur.paszkiewicz@intel.com>]

Multi-process applications operate on shared hugepage memory but each
process has its own ASan shadow region which is not synchronized with
the other processes. This causes issues when different processes try to
use the same memory because they have their own view of which addresses
are valid.

Fix it by mapping the shadow regions for memseg lists as shared memory.
The primary process is responsible for creating and removing the shared
memory objects.

Disable ASan instrumentation for triggering the page fault in
alloc_seg() because if the segment is already allocated by another
process and is marked as free in the shadow, accessing this address will
cause an ASan error.

Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
---
v2:
- Added checks for config options disabling multi-process support.
- Fixed missing unmap in legacy mode.

 lib/eal/common/eal_common_memory.c |  9 +++
 lib/eal/common/eal_private.h       | 22 +++++++
 lib/eal/linux/eal_memalloc.c       |  9 ++-
 lib/eal/linux/eal_memory.c         | 97 ++++++++++++++++++++++++++++++
 lib/eal/linux/meson.build          |  4 ++
 5 files changed, 140 insertions(+), 1 deletion(-)

diff --git a/lib/eal/common/eal_common_memory.c b/lib/eal/common/eal_common_memory.c
index d9433db623..15f950810b 100644
--- a/lib/eal/common/eal_common_memory.c
+++ b/lib/eal/common/eal_common_memory.c
@@ -263,6 +263,12 @@ eal_memseg_list_alloc(struct rte_memseg_list *msl, int reserve_flags)
 	RTE_LOG(DEBUG, EAL, "VA reserved for memseg list at %p, size %zx\n",
 			addr, mem_sz);
 
+#ifdef RTE_MALLOC_ASAN
+	if (eal_memseg_list_map_asan_shadow(msl) != 0) {
+		RTE_LOG(ERR, EAL, "Failed to map ASan shadow region for memseg list");
+		return -1;
+	}
+#endif
 	return 0;
 }
 
@@ -1050,6 +1056,9 @@ rte_eal_memory_detach(void)
 				RTE_LOG(ERR, EAL, "Could not unmap memory: %s\n",
 						rte_strerror(rte_errno));
 
+#ifdef RTE_MALLOC_ASAN
+		eal_memseg_list_unmap_asan_shadow(msl);
+#endif
 		/*
 		 * we are detaching the fbarray rather than destroying because
 		 * other processes might still reference this fbarray, and we
diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h
index 5eadba4902..48df338cf9 100644
--- a/lib/eal/common/eal_private.h
+++ b/lib/eal/common/eal_private.h
@@ -300,6 +300,28 @@ eal_memseg_list_alloc(struct rte_memseg_list *msl, int reserve_flags);
 void
 eal_memseg_list_populate(struct rte_memseg_list *msl, void *addr, int n_segs);
 
+#ifdef RTE_MALLOC_ASAN
+/**
+ * Map shared memory for MSL ASan shadow region.
+ *
+ * @param msl
+ *  Memory segment list.
+ * @return
+ *  0 on success, (-1) on failure.
+ */
+int
+eal_memseg_list_map_asan_shadow(struct rte_memseg_list *msl);
+
+/**
+ * Unmap the MSL ASan shadow region.
+ *
+ * @param msl
+ *  Memory segment list.
+ */
+void
+eal_memseg_list_unmap_asan_shadow(struct rte_memseg_list *msl);
+#endif
+
 /**
  * Distribute available memory between MSLs.
  *
diff --git a/lib/eal/linux/eal_memalloc.c b/lib/eal/linux/eal_memalloc.c
index f8b1588cae..5212ae6b56 100644
--- a/lib/eal/linux/eal_memalloc.c
+++ b/lib/eal/linux/eal_memalloc.c
@@ -511,6 +511,13 @@ resize_hugefile(int fd, uint64_t fa_offset, uint64_t page_sz, bool grow,
 			grow, dirty);
 }
 
+__rte_no_asan
+static inline void
+page_fault(void *addr)
+{
+	*(volatile int *)addr = *(volatile int *)addr;
+}
+
 static int
 alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
 		struct hugepage_info *hi, unsigned int list_idx,
@@ -641,7 +648,7 @@ alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
 	 * that is already there, so read the old value, and write itback.
 	 * kernel populates the page with zeroes initially.
 	 */
-	*(volatile int *)addr = *(volatile int *)addr;
+	page_fault(addr);
 
 	iova = rte_mem_virt2iova(addr);
 	if (iova == RTE_BAD_PHYS_ADDR) {
diff --git a/lib/eal/linux/eal_memory.c b/lib/eal/linux/eal_memory.c
index 9b6f08fba8..3dca532874 100644
--- a/lib/eal/linux/eal_memory.c
+++ b/lib/eal/linux/eal_memory.c
@@ -41,6 +41,7 @@
 #include "eal_filesystem.h"
 #include "eal_hugepages.h"
 #include "eal_options.h"
+#include "malloc_elem.h"
 
 #define PFN_MASK_SIZE	8
 
@@ -1469,6 +1470,9 @@ eal_legacy_hugepage_init(void)
 		if (msl->memseg_arr.count > 0)
 			continue;
 		/* this is an unused list, deallocate it */
+#ifdef RTE_MALLOC_ASAN
+		eal_memseg_list_unmap_asan_shadow(msl);
+#endif
 		mem_sz = msl->len;
 		munmap(msl->base_va, mem_sz);
 		msl->base_va = NULL;
@@ -1956,3 +1960,96 @@ rte_eal_memseg_init(void)
 #endif
 			memseg_secondary_init();
 }
+
+#ifdef RTE_MALLOC_ASAN
+int
+eal_memseg_list_map_asan_shadow(struct rte_memseg_list *msl)
+{
+	const struct internal_config *internal_conf =
+			eal_get_internal_configuration();
+	void *addr;
+	void *shadow_addr;
+	size_t shadow_sz;
+	int shm_oflag;
+	char shm_path[PATH_MAX];
+	int shm_fd;
+	int ret = 0;
+
+	if (!msl->heap || internal_conf->hugepage_file.unlink_before_mapping ||
+	    internal_conf->no_shconf || internal_conf->no_hugetlbfs)
+		return 0;
+
+	shadow_addr = ASAN_MEM_TO_SHADOW(msl->base_va);
+	shadow_sz = msl->len >> ASAN_SHADOW_SCALE;
+
+	snprintf(shm_path, sizeof(shm_path), "/%s_%s_shadow",
+		eal_get_hugefile_prefix(), msl->memseg_arr.name);
+
+	shm_oflag = O_RDWR;
+	if (internal_conf->process_type == RTE_PROC_PRIMARY)
+		shm_oflag |= O_CREAT | O_TRUNC;
+
+	shm_fd = shm_open(shm_path, shm_oflag, 0600);
+	if (shm_fd == -1) {
+		RTE_LOG(DEBUG, EAL, "shadow shm_open() failed: %s\n",
+			strerror(errno));
+		return -1;
+	}
+
+	if (internal_conf->process_type == RTE_PROC_PRIMARY) {
+		ret = ftruncate(shm_fd, shadow_sz);
+		if (ret == -1) {
+			RTE_LOG(DEBUG, EAL, "shadow ftruncate() failed: %s\n",
+				strerror(errno));
+			goto out;
+		}
+	}
+
+	addr = mmap(shadow_addr, shadow_sz, PROT_READ | PROT_WRITE,
+		    MAP_SHARED | MAP_FIXED, shm_fd, 0);
+	if (addr == MAP_FAILED) {
+		RTE_LOG(DEBUG, EAL, "shadow mmap() failed: %s\n",
+			strerror(errno));
+		ret = -1;
+		goto out;
+	}
+
+	if (addr != shadow_addr) {
+		RTE_LOG(DEBUG, EAL, "wrong shadow mmap() address\n");
+		munmap(addr, shadow_sz);
+		ret = -1;
+	}
+out:
+	close(shm_fd);
+	if (ret != 0) {
+		if (internal_conf->process_type == RTE_PROC_PRIMARY)
+			shm_unlink(shm_path);
+	}
+
+	return ret;
+}
+
+void
+eal_memseg_list_unmap_asan_shadow(struct rte_memseg_list *msl)
+{
+	const struct internal_config *internal_conf =
+			eal_get_internal_configuration();
+
+	if (!msl->heap || internal_conf->hugepage_file.unlink_before_mapping ||
+	    internal_conf->no_shconf || internal_conf->no_hugetlbfs)
+		return;
+
+	if (munmap(ASAN_MEM_TO_SHADOW(msl->base_va),
+		   msl->len >> ASAN_SHADOW_SCALE) != 0)
+		RTE_LOG(ERR, EAL, "Could not unmap asan shadow memory: %s\n",
+			strerror(errno));
+	if (internal_conf->process_type == RTE_PROC_PRIMARY) {
+		char shm_path[PATH_MAX];
+
+		snprintf(shm_path, sizeof(shm_path), "/%s_%s_shadow",
+			 eal_get_hugefile_prefix(),
+			 msl->memseg_arr.name);
+		shm_unlink(shm_path);
+	}
+}
+#endif
diff --git a/lib/eal/linux/meson.build b/lib/eal/linux/meson.build
index e99ebed256..1e8a48c8d3 100644
--- a/lib/eal/linux/meson.build
+++ b/lib/eal/linux/meson.build
@@ -23,3 +23,7 @@ deps += ['kvargs', 'telemetry']
 if has_libnuma
     dpdk_conf.set10('RTE_EAL_NUMA_AWARE_HUGEPAGES', true)
 endif
+
+if dpdk_conf.has('RTE_MALLOC_ASAN')
+    ext_deps += cc.find_library('rt')
+endif
-- 
2.35.3