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问题

DPDK 18.11 在使用 GCC 4.8.5 的 ASAN内存检测工具时,
程序会被卡住不动.

影响范围

解决 DPDK[18.11.rc1 – 19.02] 与 ASAN 4.8.5 内存冲突问题

#原因

ASAN 申请了地址空间 与 DPDK 申请的内存地址空间有重叠.
导致 DPDK 一直在 mmap/unmmap, 得不到期望的内存地址空间.

解决机制,如果得不到期望的地址空间, 就这样使用, 不再继续换地址空间.

解决办法

asan.diff

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diff --git a/lib/librte_eal/common/eal_common_memory.c b/lib/librte_eal/common/eal_common_memory.c
index d47ea49..43f7828 100644
--- a/lib/librte_eal/common/eal_common_memory.c
+++ b/lib/librte_eal/common/eal_common_memory.c
@@ -24,7 +24,7 @@
 #include "eal_memalloc.h"
 #include "eal_private.h"
 #include "eal_internal_cfg.h"
-
+#define MAX_MMAP_WITH_DEFINED_ADDR_TRIES 5
 /*
  * Try to mmap *size bytes in /dev/zero. If it is successful, return the
  * pointer to the mmap'd area and keep *size unmodified. Else, retry
@@ -37,7 +37,7 @@
 
 static void *next_baseaddr;
 static uint64_t system_page_sz;
-
+static int warning_already = 0;
 #ifdef RTE_ARCH_64
 /*
  * Linux kernel uses a really high address as starting address for serving
@@ -61,6 +61,7 @@
 {
    bool addr_is_hint, allow_shrink, unmap, no_align;
    uint64_t map_sz;
+   uint32_t try = 0;
    void *mapped_addr, *aligned_addr;
 
    if (system_page_sz == 0)
@@ -112,16 +113,19 @@
 
        mapped_addr = mmap(requested_addr, (size_t)map_sz, PROT_READ,
                mmap_flags, -1, 0);
+        //printf("%s %d requested_addr:%p mapped_addr:%p\n", __func__, __LINE__, requested_addr, mapped_addr);
        if (mapped_addr == MAP_FAILED && allow_shrink)
            *size -= page_sz;
 
        if (mapped_addr != MAP_FAILED && addr_is_hint &&
            mapped_addr != requested_addr) {
-           /* hint was not used. Try with another offset */
-           munmap(mapped_addr, map_sz);
-           mapped_addr = MAP_FAILED;
-           next_baseaddr = RTE_PTR_ADD(next_baseaddr, page_sz);
-           requested_addr = next_baseaddr;
+            try++;
+            next_baseaddr = RTE_PTR_ADD(next_baseaddr, page_sz);
+            if (try <= MAX_MMAP_WITH_DEFINED_ADDR_TRIES) {
+                munmap(mapped_addr, map_sz);
+                mapped_addr = MAP_FAILED;
+                requested_addr = next_baseaddr;
+            }
        }
    } while ((allow_shrink || addr_is_hint) &&
         mapped_addr == MAP_FAILED && *size > 0);
@@ -152,9 +156,16 @@
        return NULL;
    } else if (requested_addr != NULL && addr_is_hint &&
            aligned_addr != requested_addr) {
-       RTE_LOG(WARNING, EAL, "WARNING! Base virtual address hint (%p != %p) not respected!\n",
-           requested_addr, aligned_addr);
-       RTE_LOG(WARNING, EAL, "   This may cause issues with mapping memory into secondary processes\n");
+
+        if(0 == warning_already)
+        {
+            printf("ASAN 与 DPDK[18.11.rc1 -- 19.02] 的内存映射空间有冲突, 这个警告不用管.\n");
+            warning_already = 1;
+        }
+
+       //RTE_LOG(WARNING, EAL, "WARNING! Base virtual address hint (%p != %p) not respected!\n",
+       //  requested_addr, aligned_addr);
+       //RTE_LOG(WARNING, EAL, "   This may cause issues with mapping memory into secondary processes\n");
    } else if (next_baseaddr != NULL) {
        next_baseaddr = RTE_PTR_ADD(aligned_addr, *size);
    }