From e1512566e322eb1fbc8f5d5997f9bfcd022feac7 Mon Sep 17 00:00:00 2001
From: Kiita <yansira@hotmail.com>
Date: Tue, 9 Nov 2021 16:31:46 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20=E8=A7=A3=E5=86=B3dmesg=20-s=E5=8F=82?=
 =?UTF-8?q?=E6=95=B0double=20lock=E9=97=AE=E9=A2=98?=
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【背景】自研shell或者mksh拉起后使用dmesg -s命令出现自旋锁double lock的问题。

【修改方案】
dmesg -s参数设置dmesg缓冲区过程需要访问UartOutput所访问的全局缓冲区，这意味着两个功能模块
使用了同一把自旋锁，若在dmesg命令执行过程使用了打印，则就可能会导致double lock。因此拆分
了dmesg -s命令过程中自旋锁的使用区域，避开内核中必要的打印。

re #I4HIJK

Signed-off-by: yansira <yansira@hotmail.com>
Change-Id: Iad74c058c9a8090fd3d9f338caab7d8f2170f9ac
---
 shell/full/src/cmds/dmesg.c | 49 ++++++++++++++++++++++++++-----------
 1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/shell/full/src/cmds/dmesg.c b/shell/full/src/cmds/dmesg.c
index 0892f169..619a65ab 100644
--- a/shell/full/src/cmds/dmesg.c
+++ b/shell/full/src/cmds/dmesg.c
@@ -177,13 +177,17 @@ STATIC INT32 OsCopyToNew(const VOID *addr, UINT32 size)
     CHAR *newBuf = (CHAR *)addr + sizeof(DmesgInfo);
     UINT32 bufSize = size - sizeof(DmesgInfo);
     INT32 ret;
+    UINT32 intSave;
 
+    LOS_SpinLockSave(&g_dmesgSpin, &intSave);
     if (g_dmesgInfo->logSize == 0) {
+        LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
         return 0;
     }
 
     temp = (CHAR *)malloc(g_dmesgInfo->logSize);
     if (temp == NULL) {
+        LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
         return -1;
     }
 
@@ -195,21 +199,24 @@ STATIC INT32 OsCopyToNew(const VOID *addr, UINT32 size)
 
     ret = OsDmesgRead(temp, g_dmesgInfo->logSize);
     if (ret <= 0) {
-        PRINT_ERR("%s,%d failed, err:%d!\n", __FUNCTION__, __LINE__, ret);
-        free(temp);
-        return -1;
+        goto FREE_OUT;
     }
 
     /* if new buf size smaller than logSize */
     ret = memcpy_s(newBuf, bufSize, temp + copyStart, copyLen);
     if (ret != EOK) {
-        PRINT_ERR("%s,%d memcpy_s failed, err:%d!\n", __FUNCTION__, __LINE__, ret);
-        free(temp);
-        return -1;
+        goto FREE_OUT;
     }
+    LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
     free(temp);
 
     return (INT32)copyLen;
+
+FREE_OUT:
+    LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
+    PRINT_ERR("%s,%d failed, err:%d!\n", __FUNCTION__, __LINE__, ret);
+    free(temp);
+    return -1;
 }
 
 STATIC UINT32 OsDmesgResetMem(const VOID *addr, UINT32 size)
@@ -224,12 +231,13 @@ STATIC UINT32 OsDmesgResetMem(const VOID *addr, UINT32 size)
 
     LOS_SpinLockSave(&g_dmesgSpin, &intSave);
     temp = g_dmesgInfo;
+    LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
     copyLen = OsCopyToNew(addr, size);
     if (copyLen < 0) {
-        LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
         return LOS_NOK;
     }
 
+    LOS_SpinLockSave(&g_dmesgSpin, &intSave);
     g_logBufSize = size - sizeof(DmesgInfo);
     g_dmesgInfo = (DmesgInfo *)addr;
     g_dmesgInfo->logBuf = (CHAR *)addr + sizeof(DmesgInfo);
@@ -239,12 +247,17 @@ STATIC UINT32 OsDmesgResetMem(const VOID *addr, UINT32 size)
 
     /* if old mem came from malloc */
     if (temp == g_mallocAddr) {
-        g_mallocAddr = NULL;
-        free(temp);
+        goto FREE_OUT;
     }
     LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
 
     return LOS_OK;
+
+FREE_OUT:
+    g_mallocAddr = NULL;
+    LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
+    free(temp);
+    return LOS_OK;
 }
 
 STATIC UINT32 OsDmesgChangeSize(UINT32 size)
@@ -265,14 +278,14 @@ STATIC UINT32 OsDmesgChangeSize(UINT32 size)
 
     LOS_SpinLockSave(&g_dmesgSpin, &intSave);
     temp = g_dmesgInfo;
+    LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
 
     copyLen = OsCopyToNew(newString, size + sizeof(DmesgInfo));
     if (copyLen < 0) {
-        LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
-        free(newString);
-        return LOS_NOK;
+        goto ERR_OUT;
     }
 
+    LOS_SpinLockSave(&g_dmesgSpin, &intSave);
     g_logBufSize = size;
     g_dmesgInfo = (DmesgInfo *)newString;
     g_dmesgInfo->logBuf = (CHAR *)newString + sizeof(DmesgInfo);
@@ -281,13 +294,21 @@ STATIC UINT32 OsDmesgChangeSize(UINT32 size)
     g_dmesgInfo->logHead = 0;
 
     if (temp == g_mallocAddr) {
-        g_mallocAddr = NULL;
-        free(temp);
+        goto FREE_OUT;
     }
     g_mallocAddr = newString;
     LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
 
     return LOS_OK;
+
+ERR_OUT:
+    free(newString);
+    return LOS_NOK;
+FREE_OUT:
+    g_mallocAddr = newString;
+    LOS_SpinUnlockRestore(&g_dmesgSpin, intSave);
+    free(temp);
+    return LOS_OK;
 }
 
 UINT32 OsCheckConsoleLock(VOID)
-- 
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