[Crash-utility] [ANNOUNCE] crash version 7.2.2 is available

Download from: http://people.redhat.com/anderson or https://github.com/crash-utility/crash/releases The github 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 to support Linux 4.16-rc1 and later ARM64 kernels, which fail during session initialization with the error message "crash: cannot determine page size". The failure to determine the page size is due to the combination of the following kernel commits: - Linux 4.6 commit 6ad1fe5d9077a1ab40bf74b61994d2e770b00b14 arm64: avoid R_AARCH64_ABS64 relocations for Image header fields - Linux 4.10 commit 4b65a5db362783ab4b04ca1c1d2ad70ed9b0ba2a arm64: Introduce uaccess_{disable,enable} functionality based on TTBR0_EL1 - Linux 4.16 commit 1e1b8c04fa3451e2b7190930adae43c95f0fae31 arm64: entry: Move the trampoline to be before PAN (takahiro.akashi(a)linaro.org) - Fix the search for the booted kernel on a live system to prevent selecting the unusable "vmlinux.o" file found in private build directories. Without the patch, the non-executable vmlinux.o file may be selected, and the resulting fatal error message indicates a somewhat misleading "crash: cannot resolve _stext". (bhsharma(a)redhat.com, anderson(a)redhat.com) - Implemented a new "ps -A" option that restricts the task output to just the active tasks on each cpu. (atomlin(a)redhat.com) - As the first step in optimizing the is_page_ptr() function, save the maximum SPARSEMEM section number during initialization, and use it as the topmost delimeter in subsequent mem_section searches. Also allow for per-architecture machdep->is_page_ptr() plugin functions. (anderson(a)redhat.com) - Implemented the x86_64 machdep->is_page_ptr() plugin function. If the kernel is configured with CONFIG_SPARSEMEM_VMEMMAP, the plugin function optimizes the mem_section search, reducing the computation effort and time consumed by commands that repeatedly call the is_page_ptr() function on large-memory systems. (k-hagio(a)ab.jp.nec.com) - Fixes for 32-bit X86 "bt" command on kernels that have been compiled with retpoline gcc support. Without the patch, backtraces may fail with the error message "bt: cannot resolve stack trace", followed by the text symbols found on the stack and possible exception frames. (anderson(a)redhat.com) - Fix the "help foreach" argument list to include the new "gleader" task qualifier option that was added in version 7.1.2. (anderson(a)redhat.com) - VMware VMSS dumpfiles contain the state of each vCPU at the time when the VM was suspended. This patch enables crash to read the relevant registers from each vCPU state for use as the starting hooks by the "bt" command. Also, support for "help -[D|n]" to display dumpfile contents, and "help -r" to display vCPU register sets has been implemented. This is also the first step towards implementing automatic KASLR offset calculations for VMSS dumpfiles. (slp(a)redhat.com) - Commit 45b74b89530d611b3fa95a1041e158fbb865fa84 added support for calculating phys_base and the mapped kernel offset for KASLR-enabled kernels on SADUMP dumpfiles by using a technique developed by Takao Indoh. Originally, the patchset included support for kdumps, but this was dropped in v2, as it was deemed unnecessary due to the upstream implementation of the "vmcoreinfo device" in QEMU. However, there are still several reasons for which the vmcoreinfo device may not be present at the time when a memory dump is taken from a VM, ranging from a host running older QEMU/libvirt versions, to misconfigured VMs or environments running Hypervisors that doesn't support this device. This patchset generalizes the KASLR-related functions from sadump.c and moves them to kaslr_helper.c, and makes kdump analysis fall back to KASLR offset calculation if vmcoreinfo data is missing. (slp(a)redhat.com) - Fix for the "bt" command on 4.16 and later kernels size in which the "thread_union" data structure is not contained in the vmlinux file's debuginfo data. Without the patch, the kernel stack size is not calculated correctly, and defaults to 8K. As a result "bt" fails with the message "bt: invalid RSP: <address> bt->stackbase/stacktop: <address>/<address> cpu: <number>". (efault(a)gmx.de) - Fix for the x86_64 "bt" command for kernels that are configured with CONFIG_FRAME_POINTER. Without the patch, the per-text-return-address framesize cache may contain invalid entries for functions that have an "and $0xfffffffffffffff0,%rsp" instruction in their prologue, which aligns the stack on a 16-byte boundary; therefore any cached framesize for a text-return-address in such a function may be incorrect depending upon the alignment of the stack address of a calling function. If an invalid cached framesize is utilized by "bt", the backtrace may skip over several frames, or may display one or more invalid (stale) frames. The patch introduces a new cache that contains functions for which framesize values should not be cached. (anderson(a)redhat.com) - Speed up the "bt" command by avoiding the text value cache that was put in place many years ago when the crash utility supported the analysis of remote dumpfiles using the deprecated "crash daemon" running on the remote host. The performance improvement will be most noticable when running the first instance of "foreach bt", where there would often be a "hitch" when it was determining the framesize of kernel module text return addresses. (anderson(a)redhat.com) - Optimization of the crash startup time and "ps" command processing time when analyzing dumpfiles/systems with extremely large task counts. For example, running with a dumpfile containing over a million tasks, startup time and "ps" processing time was reduced from 90 minutes to less then 40 seconds. (gthelen(a)google.com) - Speed up the "ps -r" option by stashing the length of the task_struct.rlim or signal_struct.rlim array in the internal array_table[]. Without the patch, the length of the array is determined by a call to the embedded gdb module for each task, and as a result, the command takes a minute or more per 1000 tasks. With the patch applied, it only takes about 0.5 seconds per 1000 tasks. (k-hagio(a)ab.jp.nec.com) - Added a new "tree -l" option for the rbtree display, which dumps the tree sorted in linear order, starting with the leftmost node and progressing to the right. Also, if a corrupted rb_node pointer is encountered, do not fail immediately, but rather display the rb_node address and the corrupt pointer and continue. (neelx(a)redhat.com) - Display a fatal error message if the "tree -l" option is attempted with radix trees. Without the patch, the option would be silently ignored. (neelx(a)redhat.com) - Introduction of a new "bpf" command that displays information about loaded eBFP (extended Berkeley Packet Filter) programs and maps. Because of its upstream fluidity, the capabilities of this command will be an ongoing task. In its initial form, the command displays the addresses, basic information, and key data structures of eBPF programs and maps. It also translates the bytecode, and disassembles the jited code, of loaded eBPF programs. (anderson(a)redhat.com) - Fixes to address several gcc-8.0.1 compiler warnings that are generated when building with "make warn". The warnings are all false alarm messages of type [-Wformat-overflow=], [-Wformat-truncation=] and [-Wstringop-truncation]; the affected files are extensions.c, task.c, kernel.c, memory.c, remote.c, symbols.c, filesys.c and xen_hyper.c. (anderson(a)redhat.com) - Fix for the "ps -a" option for a user task that has utilized "prctl(PR_SET_MM, ...)" to self-modify its memory map such that the stack locations of its command line arguments and environment variables such are not contiguous. Without the patch, the command may fail with a dump of the crash utility's internal buffer usage statistics followed by "ps: cannot allocate any more memory!". (k-hagio(a)ab.jp.nec.com) - Fix for a compilation error on ARM64. Without the patch, the compilation of the new bpf.c file fails with the error message "bpf.c:881:18: error: conflicting types for 'u64'" (anderson(a)redhat.com) - Fix for an s390x session initialization-time warning that indicates "WARNING: cannot determine MAX_PHYSMEM_BITS" on Linux 4.15 and later kernels containing commit 83e3c48729d9ebb7af5a31a504f3fd6aff0348c4, which changed the data type of "mem_section" from an array to a pointer. Without the patch, the s390x manner of determining MAX_PHYSMEM_BITS fails because it presumes that "mem_section" is an array, and as a result, displays the warning message. (anderson(a)redhat.com) - Fix for the determination of the ARM64 phys_offset value when running live against /proc/kcore. Without the patch, the message "WARNING: cannot access vmalloc'd module memory" may be displayed during session initialization, and vmalloc/module memory will be unaccessible. (It should be noted that at the time of this patch, the upstream version of /proc/kcore does not work correctly for ARM64, because PT_LOAD segments for unity-mapped blocks of physical are not generated.) (anderson(a)redhat.com) - For live system analysis, if both "/dev/mem" and the "/dev/crash" memory driver do not exist, try to use "/proc/kcore". Without the patch, the session fails immediately with the error message "crash: /dev/mem: No such file or directory". (anderson(a)redhat.com) - Fix, and an update, for the "ipcs" command. The fix addresses an error where IPCS entries are not displayed because of a faulty read of the "deleted" member of the embedded "kern_ipc_perm" data structure. The "deleted" member was being read as a 4-byte integer, but since it is declared as a "bool" type, only the lowest byte gets set to 1 or 0. Since the structure is not zeroed-out when allocated, stale data may be left in the upper 3 bytes, and the IPCS entry gets rejected. The update is required for Linux 4.11 and greater kernels, which reimplemented the IDR facility to use radix trees in kernel commit 0a835c4f090af2c76fc2932c539c3b32fd21fbbb, titled "Reimplement IDR and IDA using the radix tree". Without the patch, if any IPCS entry exists, the command would fail with the message "ipcs: invalid structure member offset: idr_top" (anderson(a)redhat.com) - Second stage of the new "bpf" command. This patch adds additional per-program and per-map data for the "bpf -p ID" and "bpf -m ID" options, containing data items shown by the "bpftool prog list" and "bpftool map list" options; new "bpf -P" and "bpf -M" options have been added that dump the extra data for all loaded programs or tasks. (anderson(a)redhat.com) - Fix for a compilation error of the new "bpf.c" file when building on older host systems where CLOCK_BOOTTIME does not exist. (anderson(a)redhat.com) - Fix for infrequent failures of the x86 "bt" command to handle cases where a user space task with "resume_userspace" or "entry_INT80_32" at the top of the stack, or which was interrupted by the crash NMI while handling a timer interrupt. Without the patch, the backtrace would be proceeded with the error message "bt: cannot resolve stack trace", and then dump the text symbols found on the stack and all possible exception frames. (anderson(a)redhat.com) - Trivial formatting fix to "bpf" help page. (anderson(a)redhat.com) - Fix the "bpf" command display on Linux 4.17-rc1 and later kernels, which contain two new program types, BPF_PROG_TYPE_RAW_TRACEPOINT and BPF_PROG_TYPE_CGROUP_SOCK_ADDR. Without the patch, the dynamic header string created for bpf programs overran into the bpf map header, creating one long combined header string. (anderson(a)redhat.com) - Updates for the presumption that system call names begin with "sys_". In Linux 4.17, x86_64 system calls may begin with "__x64_sys", where, for example, "sys_read" has been replaced by "__x64_sys_read". (anderson(a)redhat.com)