10.3.3 iPhone 6s上查看部分帖子会SIGSEGV

在iOS 10.3.3的iPhone 6s下点击部分有复杂排版的帖子会崩溃，包括“帖子格式图片附件排版测试”。崩溃类型为SIGSEGV，stack trace如下：

Thread 0 Crashed:
0   libobjc.A.dylib               	0x00000001875781a0 0x187554000 + 147872
1   CoreFoundation                	0x00000001889dedf4 0x1889ce000 + 69108
2   CoreFoundation                	0x0000000188a1af88 0x1889ce000 + 315272
3   IPA.Wang                      	0x0000000100278154 0x100034000 + 2376020
4   IPA.Wang                      	0x000000010013a79c 0x100034000 + 1075100
5   IPA.Wang                      	0x0000000100139ed8 0x100034000 + 1072856
6   IPA.Wang                      	0x0000000100139c5c 0x100034000 + 1072220
7   IPA.Wang                      	0x000000010013dedc 0x100034000 + 1089244
8   IPA.Wang                      	0x000000010013da28 0x100034000 + 1088040
9   IPA.Wang                      	0x0000000100153830 0x100034000 + 1177648
10  IPA.Wang                      	0x0000000100151fb0 0x100034000 + 1171376
11  IPA.Wang                      	0x0000000100151524 0x100034000 + 1168676
12  libdispatch.dylib             	0x00000001879b29e0 0x1879b1000 + 6624
13  libdispatch.dylib             	0x00000001879b29a0 0x1879b1000 + 6560
14  libdispatch.dylib             	0x00000001879b73c0 0x1879b1000 + 25536
15  CoreFoundation                	0x0000000188aa90c8 0x1889ce000 + 897224
16  CoreFoundation                	0x0000000188aa6ce4 0x1889ce000 + 888036
17  CoreFoundation                	0x00000001889d6da4 0x1889ce000 + 36260
18  GraphicsServices              	0x000000018a441074 0x18a435000 + 49268
19  UIKit                         	0x000000018ec91c9c 0x18ec1d000 + 478364
20  IPA.Wang                      	0x0000000100075a0c 0x100034000 + 268812
21  libdyld.dylib                 	0x00000001879e559c 0x1879e1000 + 17820