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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>We just found a worker process was stuck in an infinite loop, in function ngx_open_file_lookup(). Checking the open file cache RB tree with GDB shows the following:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right<o:p></o:p></p><p class=MsoNormal>$3 = (ngx_rbtree_node_t *) 0x80122f900<o:p></o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right<o:p></o:p></p><p class=MsoNormal>$4 = (ngx_rbtree_node_t *) 0x8040ea400<o:p></o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left<o:p></o:p></p><p class=MsoNormal>$5 = (ngx_rbtree_node_t *) 0x801236980<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left->right<o:p></o:p></p><p class=MsoNormal>$6 = (ngx_rbtree_node_t *) 0x8090ee080<o:p></o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left->right->right<o:p></o:p></p><p class=MsoNormal>$7 = (ngx_rbtree_node_t *) 0x804aab280<o:p></o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left->right->right->left<o:p></o:p></p><p class=MsoNormal>$8 = (ngx_rbtree_node_t *) 0x804aabf00<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left->right->right->left->left<o:p></o:p></p><p class=MsoNormal>$9 = (ngx_rbtree_node_t *) 0x8090ee080<o:p></o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left->right->right->left->left->right<o:p></o:p></p><p class=MsoNormal>$10 = (ngx_rbtree_node_t *) 0x804aab280<o:p></o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left->right->right->left->left->right->left<o:p></o:p></p><p class=MsoNormal>$11 = (ngx_rbtree_node_t *) 0x804aabf00<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left->right->right->left->left->right->left->left<o:p></o:p></p><p class=MsoNormal>$12 = (ngx_rbtree_node_t *) 0x8090ee080<o:p></o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left->right->right->left->left->right->left->left->right<o:p></o:p></p><p class=MsoNormal>$13 = (ngx_rbtree_node_t *) 0x804aab280<o:p></o:p></p><p class=MsoNormal>(gdb) p cache->rbtree.root->right->right->left->right->right->left->left->right->left->left->right->left<o:p></o:p></p><p class=MsoNormal>$14 = (ngx_rbtree_node_t *) 0x804aabf00<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Please look at the address of<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> cache->rbtree.root->right->right->left->right->right->left->left ($9)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>It is the same as that of<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> cache->rbtree.root->right->right->left->right ($6)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>That means the $9 == $9->parent->parent->parent, so the infinite loop.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I think there might be a bug in ngx_rbtree.c. I'll really appreciate it if somebody can look into it.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks a lot,<o:p></o:p></p><p class=MsoNormal>Yongfeng Wu<o:p></o:p></p></div></body></html>