[Crash-utility] [ANNOUNCE] crash version 7.1.4 is available

Download from: http://people.redhat.com/anderson or https://github.com/crash-utility/crash/releases The master branch serves as a development branch that will contain all patches that are queued for the next release: $ git clone git://github.com/crash-utility/crash.git Changelog: - Fix for the ARM64 "vtop" command when translating kernel virtual addresses within a 2MB or 512MB huge page in which the PGD or PMD contains software-defined PTE bits. Without the patch, the "PAGE:" address value will show the software-defined bits, the command will not display the related page structure translation, and will end with the message "WARNING: sparsemem: invalid section number: <number>". (Johan.Erlandsson(a)sonymobile.com, anderson(a)redhat.com) - Fix for the X86_64 "bt" command in Linux 4.2 and later kernels that are configured with both CONFIG_HAVE_COPY_THREAD_TLS and CONFIG_FRAME_POINTER. Without the patch, the fact that the kernel was compiled with framepointers is not recognized, which may result in backtraces containing stale frame references. (anderson(a)redhat.com) - Fix for the "dis" command to support three new x86 instruction extensions that have been added to the Intel instruction set for hardware platforms that support them. The newly-added instructions "clflushopt", "clwb", and "pcommit" prepend 0x66 as a prefix byte to the "clflush", "xsaveopt" and "sfence" instructions respectively. Without the patch: "clflushopt" is disassembled as: "data16" followed by "clflush" "clwb" is disassembled as: "data16" followed by "xsaveopt" "pcommit" is disassembled as: "data16" followed by "sfence" The "clflushopt" instruction was introduced in Linux 3.15 in the clflushopt() function. The "clwb" and "pcommit" instructions were introduced in Linux 4.1 in the clwb() and pcommit_sfence() functions. (anderson(a)redhat.com) - Fix for the extensions/trace.c extension module for Linux 4.2 and later kernels. Without the patch, the module fails to load, with the message "failed to init the offset, struct:ftrace_event_call, member:list". (anderson(a)redhat.com) - For many years, Xen Dom0 dumps could only be saved in ELF format. Since makedumpfile commit 349a0ed1, it is now possible to save Xen dumps in compressed kdump format. This patch set adds support for these files. Two new files, xen_dom0.c and xen_dom0.h, have been added to provide the common functionality required by both ELF and compressed kdump formats. (ptesarik(a)suse.cz) - Since Linux v4.1, specifically, "MIPS: Rearrange PTE bits into fixed positions.", commit be0c37c985eddc46d0d67543898c086f60460e2e, the MIPS PTE bits are at fixed locations. Since they are macros in the kernel, this patch adds an explicit kernel version check in order to determine and set their values. (rabinv(a)axis.com) - Display a machine-type mismatch warning if a little-endian PPC64 compressed kdump created by makedumpfile(8) is used as an argument with a non-PPC64 crash utility binary. Without the patch, the dumpfile is accepted, and the session subsequently fails with a message indicating that that the vmlinux and dumpfile do not match. (anderson(a)redhat.com) - Fix for bitmap-handling in SADUMP dumpfiles, which associate each bit in a bitmap with a physical page in the reverse order that is used in kdump-compressed format. The bug had not been detected for a long time because bitmaps in SADUMP formats consist mostly of 0x00 and 0xff excluding a very limited amount of memory space for firmware. (indou.takao(a)jp.fujitsu.com, d.hatayama(a)jp.fujitsu.com) - Fix for the behavior of the --zero_excluded option when used with SADUMP dumpfiles. Without the patch, the behavior of --zero_excluded option is the opposite to what is expected: reads of filtered pages return successfully with zero-filled memory, while reads of filtered filtered pages fail when --zero_excluded option has been specified. (d.hatayama(a)jp.fujitsu.com) - Fix for the "kmem -i" command in Linux 2.6.27 and later kernels to prevent the possibility that an arbitrary address may be accessed when calculating the number of total huge pages. Without the patch, the command's "COMMIT LIMIT" and "COMMITTED" values may be invalid. (atomlin(a)redhat.com) - Added recognition of the new DUMP_DH_EXCLUDED_VMEMMAP flag in the header of compressed kdumps, which is set by the new -e option to the makedumpfile(8) facility. The -e option excludes kernel pages that contain nothing but kernel page structures for pages that are not being included in the dump. If the bit is set in the dumpfile, the crash utility will issue a warning that the dumpfile is known to be incomplete during initialization, just prior to the system banner display. (anderson(a)redhat.com) - Fix for the handling of compound pages in Linux 4.4 and later kernels, which contain this kernel commit: commit 1d798ca3f16437c71ff63e36597ff07f9c12e4d6 mm: make compound_head() robust The commit above removes the PG_tail and PG_compound page.flags bits and the page.first_page member, and introduces a page.compound_head member, which is a pointer to the head page and whose bit 0 acts as the tail flag. Without the patch, a SLAB or SLUB warning message that indicates "cannot determine how compound pages are linked" is displayed during initialization, and any command that tracks compound pages will be affected. (anderson(a)redhat.com) - Fix for the handling of dynamically-sized task_struct structures in Linux 4.2 and later kernels, which contain these commits: commit 5aaeb5c01c5b6c0be7b7aadbf3ace9f3a4458c3d x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86 commit 0c8c0f03e3a292e031596484275c14cf39c0ab7a x86/fpu, sched: Dynamically allocate 'struct fpu' Without the patch, when running on a filtered kdump dumpfile, it is possible that error messages like this will be seen when gathering the tasks running on a system: "crash: page excluded: kernel virtual address: <task_struct address> type: "fill_task_struct". (ats-kumagai(a)wm.jp.nec.com) - Fix for the "kmem -s <address>" command in Linux 3.13 and later kernels configured with CONFIG_SLAB. Without the patch, if the address argument is contained within an object in a tail page of a multi-page slab, the command fails with the message "kmem: address is not allocated in slab subsystem: <address>". Furthermore, in Linux 4.4 and later kernels configured with CONFIG_SLAB, addresses that are contained within an object in a tail page of a multi-page slab will not be marked by their slab cache name by the "rd -S" and "bt -F" commands. (anderson(a)redhat.com) - Fix for a segmentation violation when attempting to run live on a a system without the crash.ko memory driver, and whose kernel was configured with CONFIG_STRICT_DEVMEM. Without the patch, if any -d<value> is entered on the command line, the crash session fails during initialization. (dmair(a)suse.com) - Update for the determination of the ARM64 page size for kernels containing this Linux 4.4 commit: commit 9d372c9fab34cd8803141871195141995f85c7f7 arm64: Add page size to the kernel image header Without the patch, the kernel page size is calculated by looking at the size of the "swapper_pg_dir" page directory. With this update, the page size can be determined by checking a flag built into the kernel image header, available in the "_kernel_flags_le" absolute symbol. (drjones(a)redhat.com) - Fix for the handling of ARM and ARM64 QEMU-generated ELF dumpfiles and compressed kdump clones. The patch utilizes the NT_PRSTATUS notes in the dumpfile headers instead of reading them from the kernel's "crash_notes", which are not initialized when QEMU generates a dumpfile. Without the patch, these warning messages are displayed during session initialization: WARNING: invalid note (n_type != NT_PRSTATUS) WARNING: cannot retrieve registers for active tasks and running "bt" on an active task causes a segmentation violation. (drjones(a)redhat.com) - Update to the previous QEMU-specific patch to handle kdump dumpfiles which have offline cpus, and therefore will not contain associated NT_PRSTATUS notes in the dumpfile header. Without the patch, if there are any offline cpus, a segmentation violation is generated during session initialization. (anderson(a)redhat.com) - The s390 stand-alone dump tools may write the kernel memory directly to a block device. When running the crash utility against such a block device, a misleading warning message such as this is displayed: WARNING: /dev/sda1: may be truncated or incomplete PT_LOAD p_offset: 16384 p_filesz: 5497558138880 bytes required: 5497558155264 dumpfile size: 0 With the patch, the warning message above will be replaced by a note using this format: NOTE: /dev/sda1: No dump complete check for block devices (holzheu(a)linux.vnet.ibm.com) - Map CTRL-l to clear the screen while in vi insertion mode. Without the patch, it displays "^L". (kwalker(a)redhat.com) - Introduced a general-purpose handler to register data structures that the kernel has dynamically downsized from the size indicated by the debuginfo data. At this time, only "kmem_cache" and "task_struct" structures that have been downsized are registered, but others may be added in the future. If a downsized data structure is passed to gdb for display, gdb will request a read of the "full" data structure, which may flow into a memory region that was either filtered by makedumpfile(8), or perhaps into non-existent memory, thereby killing the generating command immediately due to a partial read. With this patch, commands such as "struct" and "task" that reference downsized data structures will have their reads flagged to return successfully if partial read error occurs. (anderson(a)redhat.com) - Fix for Linux 3.18 and later 32-bit ARM kernels that are configured with CONFIG_SLAB which contain percpu array_cache structures that were allocated with vmalloc(). Without the patch, during session initialization there will be error messages that indicate "crash: kmem_cache: <vaddr>: invalid array_cache pointer: <vaddr>", and during runtime, the "kmem -[sS]" commands will show kmem_cache lines that marked as "[INVALID/CORRUPTED]". (anderson(a)redhat.com) - Added a new "list -l <offset>" option that can only be used in conjunction with "-s", and requires that the "start" address is the address of a list_head, or other similar list linkage structure whose first member points to the next linkage structure. The "-l <offset>" argument is the offset of the embedded list linkage structure in the specified "-s" data structure; it can be either a number of bytes or expressed in "struct.member" format. (anderson(a)redhat.com) - Enhanced the debug-only display of the first kernel data items read during session initialization. This includes the system's cpu maps, xtime, and utsname data. These require at least "-d1" as a command line option value, and are primarily useful as an aide for debugging suspect dumpfiles that fail during session initialization. (anderson(a)redhat.com) - Added "print_array" as a new internal variable that may be turned on/off with the "set" command. When set to "on", gdb's printing of arrays will be set to "pretty", so that the display of each array element will consume one line. (anderson(a)redhat.com) - Introduction of the "sys -i" option, which displays the kernel's DMI identification string data if available. (atomlin(a)redhat.com, anderson(a)redhat.com) - Fix for "crash --osrelease" on Xen kernels that have both VMCOREINFO and VMCOREINFO_XEN ELF notes. Without the patch, the command returns "(unknown)". (anderson(a)redhat.com, dietmar.hahn(a)ts.fujitsu.com)