PHP PHP 7 Change. Log. Version 7. 1. Oct 2. 01. 7Core. Fixed bug 7. 52. Null pointer dereference in zendmmallocsmall. Fixed bug 7. 52. Fixed bug 7. Incorrect token formatting on two parse errors in one request. Chapter 3 Memory Management. The memory management subsystem is one of the most important parts of the operating system. Since the early days of computing, there has. PHP 7 ChangeLog Version 7. Core Fixed bug 75241 Null pointer dereference in zendmmallocsmall. Fixed bug 75236 infinite loop when printing. C tutorials, C and C news, and information about the C IDE Visual Studio from the Microsoft C team. During Startup Program Terminated With Signal Sigsegv' title='During Startup Program Terminated With Signal Sigsegv' />Fixed bug 7. Segfault when calling iscallable on parent. Fixed bug 7. 52. Closures of internal functions contain garbage argument names. Date. Fixed bug 7. Android Custom Boot Animation Zip. Out Of Bounds Read in timelibmeridian. Apache. 2Handler. Fixed bug 7. 53. Key in apache. Hash. Fixed bug 7. Intl. Fixed bug 7. The parameter of UConverter get. Aliases is not optional. Fixed bug 7. 52. Binary directory doesnt get created when building only litespeed SAPI. Fixed bug 7. 52. Missing program prefix and suffix. Fixed bug 7. 25. My. SQLi. Fixed bug 7. Data corruption when reading fields of bit type. OCI8. Fixed incorrect reference counting. Opcache. Fixed bug 7. Request hangs and not finish. PCRE. Fixed bug 7. CVE 2. 01. 6 1. PDOmysql. Fixed bug 7. Type bit is fetched as unexpected string. SPL. Fixed bug 7. Spl. Doubly. Linked. List set. Iterator. Mode masks intern flags. Version 7. 0. 2. 52. Oct 2. 01. 7Core. Fixed bug 7. 52. Null pointer dereference in zendmmallocsmall. Fixed bug 7. 52. Fixed bug 7. Incorrect token formatting on two parse errors in one request. Fixed bug 7. 52. Segfault when calling iscallable on parent. Fixed bug 7. 52. Closures of internal functions contain garbage argument names. Apache. 2Handler. Fixed bug 7. 53. Key in apache. Date. Fixed bug 7. Out Of Bounds Read in timelibmeridian. Intl. Fixed bug 7. The parameter of UConverter get. Aliases is not optional. Fixed bug 7. 25. OCI8. Fixed incorrect reference counting. PCRE. Fixed bug 7. CVE 2. 01. 6 1. Fixed bug 7. Binary directory doesnt get created when building only litespeed SAPI. Fixed bug 7. 52. Missing program prefix and suffix. SPL. Fixed bug 7. Spl. Doubly. Linked. List set. Iterator. Mode masks intern flags. Version 7. 1. 1. 02. Sep 2. 01. 7Core. Fixed bug 7. 50. EXTENSION block. BCMath. Fixed bug 4. Fixed bug 4. 67. BC math handles minus zero incorrectly. Fixed bug 5. 45. Fixed bug 7. CLI server. Fixed bug 7. Built in server truncates headers spanning over TCP packets. CURL. Fixed bug 7. Open. SSL support not detected. GD. Fixed bug 7. Image. Gray. Scale may produce colors. Fixed bug 7. 51. Gettext. Fixed bug 7. Intl. Fixed bug 7. Intl. Gregorian. Calendar doesnt have constants from parent class. Fixed bug 7. 51. PDOOCI. Fixed bug 7. PDOPCO with PHP FPM OCI environment initialized before PHP FPM sets it up. SPL. Fixed bug 7. Append. Iterator append is broken when appending another Append. Iterator. Fixed bug 7. Append. Iterator append in foreach loop. Standard. Fixed bug 7. Fixed bug 7. 50. Version 7. Sep 2. 01. 7Core. Fixed bug 7. 50. EXTENSION block. BCMath. Fixed bug 4. Fixed bug 4. 67. BC math handles minus zero incorrectly. Fixed bug 5. 45. Fixed bug 7. CLI server. Fixed bug 7. Built in server truncates headers spanning over TCP packets. CURL. Fixed bug 7. Open. SSL support not detected. GD. Fixed bug 7. Image. Gray. Scale may produce colors. Fixed bug 7. 51. Gettext. Fixed bug 7. Intl. Fixed bug 7. Intl. Gregorian. Calendar doesnt have constants from parent class. PDOOCI. Fixed bug 7. PDOPCO with PHP FPM OCI environment initialized before PHP FPM sets it up. SPL. Fixed bug 7. Append. Iterator append in foreach loop. Standard. Fixed bug 7. Version 7. 1. 9. 31 Aug 2. Core. Fixed bug 7. Segfault in scanner on INF number. Fixed bug 7. 49. Fixed bug 7. Fixed bug 7. 50. Main CWD initialized with wrong codepage. Fixed bug 7. 53. NAN comparison. URL. Fixed bug 7. Fixed finding CURL on systems with multiarch support. Date. Fixed bug 7. Null Pointer Dereference in timelibtimeclone. Intl. Fixed bug 7. Wrong reflection on some locale functions. Mbstring. Fixed bug 7. Segmentation fault mbstrcut with HTML ENTITIES encoding. Fixed bug 6. 29. Fixed bug 7. Wrong reflection on mberegireplace. My. SQLi. Fixed bug 7. PHP crashes when calling mysqliresult fetchobject with an abstract class. OCI8. Expose ociunregistertafcallback Tianfang YangOpcache. Fixed bug 7. 49. Narrowing occurred during type inference. Fixed bug 7. 49. Reflection. Fixed bug 7. Session. Fixed bug 7. Url Rewriting transsid not working on urls that start with. Fixed bug 7. 48. SID constant created with wrong module number. Simple. XML. Fixed bug 7. Doc. Namespaces. SPL. Fixed bug 7. Fixed bug 7. Unserialize Array. Iterator broken. Fixed bug 7. Appending Append. Iterator leads to segfault. Fixed bug 7. 50. Crash in recursive iterator destructors. Standard. Fixed bug 7. Xcauses infinity loop. Fixed bug 7. 41. Fixed bug 7. A Denial of Service Vulnerability was found when performing deserialization. WDDX. Fixed bug 7. WDDX uses wrong decimal seperator. XMLRPC. Fixed bug 7. Incorrect xmlrpc serialization for classes with declared properties. Version 7. 0. 2. 33. Aug 2. 01. 7Core. Fixed bug 7. 49. Segfault in scanner on INF number. Fixed bug 7. 49. Fixed bug 7. Fixed bug 7. 53. NAN comparison. URL. Fixed bug 7. Fixed finding CURL on systems with multiarch support. Date. Fixed bug 7. Null Pointer Dereference in timelibtimeclone. Intl. Fixed bug 7. Wrong reflection on some localefunctions. Mbstring. Fixed bug 7. Segmentation fault mbstrcut with HTML ENTITIES encoding. Fixed bug 6. 29. Fixed bug 7. Wrong reflection on mberegireplace. My. SQLi. Fixed bug 7. PHP crashes when calling mysqliresult fetchobject with an abstract class. OCI8. Expose ociunregistertafcallback Tianfang Yangphar. Fixed bug 7. 49. Reflection. Fixed bug 7. Session. Fixed bug 7. SID constant created with wrong module number. Simple. XML. Fixed bug 7. Doc. Namespaces. SPL. Fixed bug 7. Fixed bug 7. Unserialize Array. Iterator broken. Fixed bug 7. Crash in recursive iterator destructors. Standard. Fixed bug 7. Xcauses infinity loop. Fixed bug 7. 41. Fixed bug 7. A Denial of Service Vulnerability was found when performing deserialization. WDDX. Fixed bug 7. WDDX uses wrong decimal seperator. XMLRPC. Fixed bug 7. Incorrect xmlrpc serialization for classes with declared properties. Version 7. 1. 8. 03 Aug 2. Core. Fixed bug 7. Loading PHP extension with already registered function name leads to a crash. Fixed bug 7. 47. Fixed bug 7. Unary operator expected error on some systems. Fixed bug 7. 39. Use After Free in unserialize Spl. Fixed. Array. Fixed bug 7. Crash when crawling through network share. Fixed bug 7. 49. Fixed bug 7. Date. Fixed bug 7. Date. Interval property. OCI8. Fixed bug 7. Integer overflow in ocibindarraybyname. Opcache. Fixed bug 7. Infinite loop in type inference when using HTMLPurifier. Open. SSL. Fixed bug 7. Added OPENSSLDONTZEROPADKEY constant to prevent key padding and fix bug 7. Open. SSL Blowfish encryption is incorrect for short keys. PDO. Fixed bug 6. PDOStatement debug. Dump. Params truncates query. SPL. Fixed bug 7. PHP freezes with Append. Iterator. SQLite. Fixed bug 7. 48. SQLite. Wddx. Fixed bug 7. Fixed bug 7. 39. Version 7. Aug 2. 01. 7Core. Fixed bug 7. 48. Loading PHP extension with already registered function name leads to a crash. Fixed bug 7. 47. Fixed bug 7. Unary operator expected error on some systems. Fixed bug 7. 39. Use After Free in unserialize Spl. The memory management subsystem is one of the most important parts of. Since the early days of computing, there has been a need. Strategies have been developed to overcome this limitation. Virtual memory makes the system appear to have more memory than it actually. Virtual memory does more than just make your computers memory go further. The memory management subsystem provides. Before considering the methods that Linux uses to support virtual. As the processor executes a program it reads an instruction from. In decoding the instruction it may need to fetch or store the. The processor then executes the instruction and moves onto the. In this way the processor is always accessing memory either to fetch. In a virtual memory system all of these addresses are virtual addresses and not. These virtual addresses are converted into physical addresses by the. To make this translation easier, virtual and physical memory are divided into handy sized chunks called. These pages are all the same size, they need not be but if they were not, the system would be very hard. Linux on Alpha AXP systems uses 8 Kbyte pages and on Intel x. Kbyte pages. Each of these pages is given a unique number the page frame number PFN. In this paged model, a virtual address is composed of two parts an offset and a virtual. If the page size is 4 Kbytes, bits 1. Each time the processor encounters a virtual address it must extract the offset and the virtual. The processor must translate the virtual page frame number into a physical one and then access the. To do this the processor uses page tables. Figure  3. 1 shows the virtual address. X and process Y. each with their own page tables. These page tables map each processes virtual pages into physical. This shows that process Xs virtual page frame number 0 is mapped into memory. Ys virtual page frame number 1 is mapped. Each entry in the theoretical page table contains the following information. The page table is accessed using the virtual page frame number as an offset. Virtual page frame 5 would be the 6th element of the table 0 is the first element. To translate a virtual address into a physical one, the processor must first. By making the page size a power of. Looking again at Figures  3. Ys virtual address space then the processor. The processor uses the virtual page frame number as an index into the processes. If the page table entry at that offset is valid, the processor takes the physical. If the entry is invalid, the process has accessed a non existent area of its virtual memory. In this case, the processor cannot resolve the address and must pass control to the. Just how the processor notifies the operating system that the correct process has. However the processor delivers it, this is known as a page fault and the operating. Assuming that this is a valid page table entry. Finally, the processor adds in the offset to the instruction or data that it needs. Using the above example again, process Ys virtual page frame number 1 is. Adding in the 0x. By mapping virtual to physical addresses this way. For example, in Figure  3. Xs. virtual page frame number 0 is mapped to. This demonstrates an interesting byproduct of virtual memory the pages of. As there is much less physical memory than virtual memory the operating. One way to save physical memory is to only load virtual pages that are. For example, a database program may be run to query a database. In this case not all of the database needs to be loaded into memory, just. If the database query is a search query then it does not make. This technique of only loading virtual pages into memory as they are. When a process attempts to access a virtual address that is not currently. For example, in Figure  3. Xs page table for virtual page frame number 2 and. X attempts to read from an address within. At this point the processor notifies the operating system that a page fault has occurred. If the faulting virtual address is invalid this means that the process has attempted to access. Maybe the application has gone wrong in some way, for example writing to random addresses in memory. In this case the operating system will terminate it, protecting the other processes in the. If the faulting virtual address was valid but the page that it refers to is not currently in. Disk access takes a long time, relatively speaking, and so the process must. If there are other processes that could run then the operating. The fetched page is written into a free physical page frame and an entry. The process is then restarted at the machine instruction where the memory fault. This time the virtual memory access is made, the processor can make the. Linux uses demand paging to load executable images into a processes virtual memory. Whenever a command is executed, the file containing it is opened. This is done by modifying the data structures describing this. However, only the first part of the image is actually brought into. The rest of the image is left on disk. As the image executes, it generates page faults and Linux uses the. If a process needs to bring a virtual page into physical memory. If the page to be discarded from physical memory came from an image or data file and has. Instead it can be discarded and if the process needs that page. However, if the page has been modified, the operating system must. This type of page is known as a dirty page and when it is removed from. Accesses to the swap file are very long relative to the speed of the processor and physical. If the algorithm used to decide which pages to discard or swap the swap algorithm. In this case, pages are constantly being written to disk and then. If, for example, physical page frame number 1 in Figure  3. The set of pages that a process is currently using is called the working set. An efficient swap scheme would make sure that all processes have their working set in. Linux uses a Least Recently Used LRU page aging technique to fairly choose pages which might. This scheme involves every page in the system having an age which. The more that a page is accessed, the younger it is the less that. Old pages are good candidates for swapping. Virtual memory makes it easy for several processes to share memory. All memory access are made via page tables and each process has its own separate page table. For two processes sharing a physical page of memory, its physical page frame number must appear. Figure  3. 1 shows two processes that each share physical page frame number 4. For process X this is virtual page frame number 4 whereas for process Y this is virtual page frame number. This illustrates an interesting point about sharing pages the shared physical page does not have. The Alpha AXP processor does not have a special physical addressing mode. Instead, it divides up the memory space into several areas and designates. This kernel address space is known as KSEG address. In order to execute from code linked in KSEG by definition, kernel code. The Linux kernel on Alpha is linked to execute from address. The page table entries also contain access control information. As the processor is already using the page table entry to map a processes virtual address. There are many reasons why you would want to restrict access to areas of memory. Some memory, such as that containing executable code, is naturally read only memory the. By contrast, pages containing data can be written to but attempts to execute that memory. Most processors have at least two modes of execution kernel and user.