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systemtap release 1.8
- From: "Frank Ch. Eigler" <fche at redhat dot com>
- To: systemtap at sourceware dot org
- Cc: linux-kernel at vger dot kernel dot org, lwn at lwn dot net
- Date: Sun, 17 Jun 2012 13:35:55 -0400
- Subject: systemtap release 1.8
- Reply-to: systemtap at sourceware dot org
The systemtap team announces release 1.8.
user-space probing support with unmodified linus kernel 3.5-rc,
kernel netfilter-hook probing, ipv6 support in tapsets and
compile-server, concurrent compilations in compile-server, improved
dwarf4 support (.debug_types), @var() construct for accessing
variables in global scope, stap resource-limit options, tested on
kernels 3.5-rc through 2.6.9
= Where to get it
http://sourceware.org/systemtap/ - our project page
http://sourceware.org/systemtap/ftp/releases/systemtap-1.8.tar.gz
http://koji.fedoraproject.org/koji/packageinfo?packageID=615
git tag release-1.8 (commit 48fa6b5e)
There have been over 300 commits since the last release.
There have been over 50 bugs/features fixed since the last release.
= How to build it
See the README and NEWS files at
http://sourceware.org/git/?p=systemtap.git;a=tree
Further information at http://sourceware.org/systemtap/wiki/
= Systemtap frontend (stap) changes
- When invoked by systemtap, the kbuild $PATH environment is sanitized
(prefixed with /usr/bin:/bin:) in an attempt to exclude compilers
other than the one the kernel was presumed built with.
- The systemtap compile-server and client now support IPv6 networks.
- Support for DWARF4 .debug_types sections (for executables and shared
libraries compiled with recent GCC's -gdwarf-4 / -fdebug-types-section).
PR12997. SystemTap now requires elfutils 0.148+, full .debug_types support
depends on elfutils 0.154+.
- Systemtap modules are somewhat smaller & faster to compile. Their
debuginfo is now suppressed by default; use -B CONFIG_DEBUG_INFO=y to
re-enable.
- Stap now has resource limit options:
--rlimit-as=NUM
--rlimit-cpu=NUM
--rlimit-nproc=NUM
--rlimit-stack=NUM
--rlimit-fsize=NUM
All resource limiting has been moved from the compile server to stap
itself. When running the server as "stap-server", default resource
limit values are specified in ~stap-server/.systemtap/rc.
= Systemtap script language changes
- @var now an alternative language syntax for accessing DWARF variables
in uprobe and kprobe handlers (process, kernel, module). @var("somevar")
can be used where $somevar can be used. The @var syntax also makes it
possible to access non-local, global compile unit (CU) variables by
specifying the CU source file as follows @var("somevar@some/src/file.c").
This will provide the target variable value of global "somevar" as defined
in the source file "some/src/file.c". The @var syntax combines with all
normal features of DWARF target variables like @defined(), @entry(),
[N] array indexing, field access through ->, taking the address with
the & prefix and shallow or deep pretty printing with a $ or $$ suffix.
- Printf formats can now use "%#c" to escape non-printing characters.
- Pretty-printed bitfields use integers and chars use escaped formatting
for printing.
- SystemTap now mangles local variables to avoid collisions with C
headers included by tapsets. This required a change in how
embedded-C functions access local parameters and the return value slot.
If you need to run code which uses the old THIS-> notation, run stap
with the --compatible=1.7 option.
= Systemtap runtime changes
- There is updated support for user-space probing against kernels >=
3.5, which have no utrace but do have the newer inode-uprobes work
by Srikar Dronamraju and colleagues. For kernels < 3.5, the
following 3 sets of kernel patches would need to be backported to
your kernel to use this preliminary user-space probing support:
- inode-uprobes patches:
- exec tracepoint kernel patch:
- task_work_add kernel patches:
- staprun accepts a -T timeout option to allow less frequent wake-ups
to poll for low-throughput output from scripts.
- Previous fix for bug CVE-2012-0875 (kernel panic when processing malformed
DWARF unwind data) is merged.
- The systemtap compile-server now supports multiple concurrent connections.
Specify the desired maximum number of concurrent connections with
the new stap-server/stap-serverd --max-threads option. Specify a
value of '0' to tell the server not to spawn any new threads (handle
all connections serially in the main thread). The default value is
the number of processor cores on the host.
= Systemtap tapset changes
- The following tapset functions are deprecated in release 1.8 and will be
removed in release 1.9:
daddr_to_string()
- All functions were updated for the new STAP_ARG* embedded-C API.
- More tapsets were added to the generated reference documentation /
man pages.
- New tapsets:
netfilter.stp defines utilities for netfilter scripts
guru-delay.stp inject mdelay/udelay into kernel operation
- Changed tapsets:
syscalls.stp etc. updated for linux 3.5-rc
dentry.stp updated for rhel5, back to the future
context-caller.stp fixed to operate without uretprobes
s390/registers.stp support getting that pesky sixth syscall arg
inet_*.stp make more available to unprivileged users
inet_*.stp expose ipv6 addresses & functionality
= Systemtap sample scripts
- All functions were updated for the new STAP_ARG* embedded-C API.
- New samples:
netfilter_drop.stp netfilter demo: dropping some outgoing packets
netfilter_summary.stp show TCP/IP traffic by src/dest address
psig.stp list active signal handlers of a process
auditbt.stp generate userspace backtraces on kernel audit events
nfsdtop.stp print nfs lookup operation summaries
pf3.stp time-sampling-based profile of kernel+userspace
enospc.stp generate syslog message on filesystem -ENOSPC
- Changed samples:
varwatch.stp produces narrower output
eventcount.stp given new options to periodically monitor/sort
mm*.stp updated for upstream mm kernel tracepoints
ioblktime.stp tries harder to catch merged iorequests
pfiles.stp avoid non-atomic memory allocation
= Contributors for this release
Andreas Müller*, Bryn M. Reeves, Chris Meek, Dave Brolley, David
Smith, Eugene Teo, Felix Lin*, Frank Ch. Eigler, Frederic Turgis,
Josh Stone, Lukas Czerner*, Mark Wielaard, Negreanu Marius Adrian*,
Nitin A Kamble*, Serguei Makarov*, Stan Cox, Timo Juhani Lindfors,
Tom Tromey*, Wade Farnsworth, William Cohen, ch huang*
Special thanks to new contributors, marked with '*' above.
= Examples of tested kernel versions
3.5-rc (x86_64)
3.3.0 (x86_64)
3.2.0 (x86_64)
3.1.0 (x86_64)
2.6.32 (x86_64,i686,ppc64,s390x)
2.6.18 (x86_64,i686)
2.6.9 (i686)
= Known issues with this release
- Some kernel crashes continue to be reported when a script probes
broad kernel function wildcards. (PR2725)
= Bugs fixed for this release <http://sourceware.org/PR#####>
10299 mangle local variable names
11763 on s390x, nd_syscall probes that use $arg6 fail
12331 offer a --sysroot option to aid cross-compiling
12341 deref()/store_deref() variations between arches
13193 Running bz6503.exp results in unresponsive/crashed machine
13370 ipv6 support
13458 sort generated tapset documentation
13461 bring back systemtap-client subpackage
13474 SDT_V3 arm can't parse operand '4@[fp, #-16]'
13475 SDT_V3 arm can't parse operand '-4@r3'
13516 more robust handling of ^C
13609 Consider handling compiler server requests in parallel
13631 Detection of Reqested Privilege Level in stap-serverd
13640 stap-server: don't start by default
13641 pfiles.stp does something nasty
13644 staprun: support --version
13646 ipv6 tapset support
13661 server softening: allow relaxed rlimits
13667 expose netfilter hook
13670 on 3.3 kernels, 'mnt_parent' has been moved from 'struct vfsmount'
13672 on 3.3 kernels, the ioscheduler.stp tapset can't find elevator names
13681 on rhel4, bulk mode flight recording tests leave a module behind
13694 on rhel6, tcp.sendmsg returns incorrect "sock" local variable
13713 MAXTRACE/MAXBACKTRACE undocumented feature
13714 panic when sampling backtrace() in timer.profile
13734 systemtap.stress/current.stp need to be updated for arm
13745 memory tracepoints examples need updating
13768 systemtap.spec Requires should reflect current packaging
13784 Cannot find a defining variable location in different CU
13815 On RHEL5 (2.6.18-308.el5), the dentry.stp tapset is broken
13819 A Call Trace is generated when stap is run if the kernel option "Debug access to per_cpu maps" is enabled
13833 function().library() is not aware of rpath
13868 Use UTRACE_ATTACH_ATOMIC when calling utrace create under lock.
13876 miscompilation for duplicated tapset function
13992 assertion failure on bad stap -d /paths
13998 pretty-printing bitfields shouldn't use %c
13999 pretty-printing shouldn't use %c
14000 crosscompiled uprobe target filename doesn't have the sysroot path removed.
14005 don't freak on overlong kernel module relocs
14057 ERROR: Your privilege credentials (stapsys) are insufficient to run this module (stapdev required).
14078 librpmio.so exports bundled broken glob(3) clone
14079 caller() pass-4 error if no uretprobes in script
14107 Bad user unwinding from kernel fatal signal handler for some x86_64 kernels
14137 buildok/netfilter02.stp not ok
14146 tapset::* man pages should be generated from actual tapset files
14165 netfilter.stp -- extract IPV6 protocol info
14168 sanitize environment better for invoking kernel-module-builder make
14208 Retire obsolete handwritten manpages
14220 stap failes with "error: ...cpu_possible_map undeclared..."
14221 timer.profile probes cause kernel warning
14224 only the 1st of multiple identical perf probes get hit
14240 on RHEL5 (2.6.18-308.el5), netfilter probe cause compilation to fail
14244 Mode 0700 debugfs leads staprun to orphan modules