Kprobes save and restore raw stack chunks with memcpy().
With KASAN these chunks can contain poisoned stack redzones,
as the result memcpy() interceptor produces false
stack out-of-bounds reports.
Use __memcpy() instead of memcpy() for stack copying.
__memcpy() is not instrumented by KASAN and does not lead
to the false reports.
Currently there is a spew of KASAN reports during boot
if CONFIG_KPROBES_SANITY_TEST is enabled:
[ ] Kprobe smoke test: started
[ ] ==================================================================
[ ] BUG: KASAN: stack-out-of-bounds in setjmp_pre_handler+0x17c/0x280 at addr ffff88085259fba8
[ ] Read of size 64 by task swapper/0/1
[ ] page:ffffea00214967c0 count:0 mapcount:0 mapping: (null) index:0x0
[ ] flags: 0x2fffff80000000()
[ ] page dumped because: kasan: bad access detected
[...]
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kasan-dev@googlegroups.com
[ Improved various details. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
These files were only including module.h for exception table related
functions. We've now separated that content out into its own file
"extable.h" so now move over to that and avoid all the extra header content
in module.h that we don't really need to compile these files.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/20160919210418.30243-1-paul.gortmaker@windriver.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fix kprobe_fault_handler() to clear the TF (trap flag) bit of
the flags register in the case of a fault fixup on single-stepping.
If we put a kprobe on the instruction which caused a
page fault (e.g. actual mov instructions in copy_user_*),
that fault happens on the single-stepping buffer. In this
case, kprobes resets running instance so that the CPU can
retry execution on the original ip address.
However, current code forgets to reset the TF bit. Since this
fault happens with TF bit set for enabling single-stepping,
when it retries, it causes a debug exception and kprobes
can not handle it because it already reset itself.
On the most of x86-64 platform, it can be easily reproduced
by using kprobe tracer. E.g.
# cd /sys/kernel/debug/tracing
# echo p copy_user_enhanced_fast_string+5 > kprobe_events
# echo 1 > events/kprobes/enable
And you'll see a kernel panic on do_debug(), since the debug
trap is not handled by kprobes.
To fix this problem, we just need to clear the TF bit when
resetting running kprobe.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: systemtap@sourceware.org
Cc: stable@vger.kernel.org # All the way back to ancient kernels
Link: http://lkml.kernel.org/r/20160611140648.25885.37482.stgit@devbox
[ Updated the comments. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
alternative.h pulls in ptrace.h, which means that alternatives can't
be used in anything referenced from ptrace.h, which is a mess.
Break the dependency by pulling text patching helpers into their own
header.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/99b93b13f2c9eb671f5c98bba4c2cbdc061293a2.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
objtool reports the following warning for kretprobe_trampoline():
arch/x86/kernel/kprobes/core.o: warning: objtool: kretprobe_trampoline()+0x20: call without frame pointer save/setup
kretprobes are a special case where the stack is intentionally wrong.
The return address isn't known at the beginning of the trampoline, so
the stack frame can't be set up properly before it calls
trampoline_handler().
Because kretprobe handlers don't sleep, the frame pointer doesn't *have*
to be accurate in the trampoline. So it's ok to tell objtool to ignore
it. This results in no actual changes to the generated code.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/7eaf37de52456ff822ffc86b928edb5d48a40ef1.1456719558.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The kretprobe_trampoline_holder() wrapper around kretprobe_trampoline()
isn't used anywhere and adds some unnecessary frame pointer instructions
which never execute. Instead, just make kretprobe_trampoline() a proper
ELF function.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/92d921b102fb865a7c254cfde9e4a0a72b9a781e.1453405861.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Huge amounts of help from Andy Lutomirski and Borislav Petkov to
produce this. Andy provided the inspiration to add classes to the
exception table with a clever bit-squeezing trick, Boris pointed
out how much cleaner it would all be if we just had a new field.
Linus Torvalds blessed the expansion with:
' I'd rather not be clever in order to save just a tiny amount of space
in the exception table, which isn't really criticial for anybody. '
The third field is another relative function pointer, this one to a
handler that executes the actions.
We start out with three handlers:
1: Legacy - just jumps the to fixup IP
2: Fault - provide the trap number in %ax to the fixup code
3: Cleaned up legacy for the uaccess error hack
Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f6af78fcbd348cf4939875cfda9c19689b5e50b8.1455732970.git.tony.luck@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf changes from Ingo Molnar:
"Core kernel changes:
- One of the more interesting features in this cycle is the ability
to attach eBPF programs (user-defined, sandboxed bytecode executed
by the kernel) to kprobes.
This allows user-defined instrumentation on a live kernel image
that can never crash, hang or interfere with the kernel negatively.
(Right now it's limited to root-only, but in the future we might
allow unprivileged use as well.)
(Alexei Starovoitov)
- Another non-trivial feature is per event clockid support: this
allows, amongst other things, the selection of different clock
sources for event timestamps traced via perf.
This feature is sought by people who'd like to merge perf generated
events with external events that were measured with different
clocks:
- cluster wide profiling
- for system wide tracing with user-space events,
- JIT profiling events
etc. Matching perf tooling support is added as well, available via
the -k, --clockid <clockid> parameter to perf record et al.
(Peter Zijlstra)
Hardware enablement kernel changes:
- x86 Intel Processor Trace (PT) support: which is a hardware tracer
on steroids, available on Broadwell CPUs.
The hardware trace stream is directly output into the user-space
ring-buffer, using the 'AUX' data format extension that was added
to the perf core to support hardware constraints such as the
necessity to have the tracing buffer physically contiguous.
This patch-set was developed for two years and this is the result.
A simple way to make use of this is to use BTS tracing, the PT
driver emulates BTS output - available via the 'intel_bts' PMU.
More explicit PT specific tooling support is in the works as well -
will probably be ready by 4.2.
(Alexander Shishkin, Peter Zijlstra)
- x86 Intel Cache QoS Monitoring (CQM) support: this is a hardware
feature of Intel Xeon CPUs that allows the measurement and
allocation/partitioning of caches to individual workloads.
These kernel changes expose the measurement side as a new PMU
driver, which exposes various QoS related PMU events. (The
partitioning change is work in progress and is planned to be merged
as a cgroup extension.)
(Matt Fleming, Peter Zijlstra; CPU feature detection by Peter P
Waskiewicz Jr)
- x86 Intel Haswell LBR call stack support: this is a new Haswell
feature that allows the hardware recording of call chains, plus
tooling support. To activate this feature you have to enable it
via the new 'lbr' call-graph recording option:
perf record --call-graph lbr
perf report
or:
perf top --call-graph lbr
This hardware feature is a lot faster than stack walk or dwarf
based unwinding, but has some limitations:
- It reuses the current LBR facility, so LBR call stack and
branch record can not be enabled at the same time.
- It is only available for user-space callchains.
(Yan, Zheng)
- x86 Intel Broadwell CPU support and various event constraints and
event table fixes for earlier models.
(Andi Kleen)
- x86 Intel HT CPUs event scheduling workarounds. This is a complex
CPU bug affecting the SNB,IVB,HSW families that results in counter
value corruption. The mitigation code is automatically enabled and
is transparent.
(Maria Dimakopoulou, Stephane Eranian)
The perf tooling side had a ton of changes in this cycle as well, so
I'm only able to list the user visible changes here, in addition to
the tooling changes outlined above:
User visible changes affecting all tools:
- Improve support of compressed kernel modules (Jiri Olsa)
- Save DSO loading errno to better report errors (Arnaldo Carvalho de Melo)
- Bash completion for subcommands (Yunlong Song)
- Add 'I' event modifier for perf_event_attr.exclude_idle bit (Jiri Olsa)
- Support missing -f to override perf.data file ownership. (Yunlong Song)
- Show the first event with an invalid filter (David Ahern, Arnaldo Carvalho de Melo)
User visible changes in individual tools:
'perf data':
New tool for converting perf.data to other formats, initially
for the CTF (Common Trace Format) from LTTng (Jiri Olsa,
Sebastian Siewior)
'perf diff':
Add --kallsyms option (David Ahern)
'perf list':
Allow listing events with 'tracepoint' prefix (Yunlong Song)
Sort the output of the command (Yunlong Song)
'perf kmem':
Respect -i option (Jiri Olsa)
Print big numbers using thousands' group (Namhyung Kim)
Allow -v option (Namhyung Kim)
Fix alignment of slab result table (Namhyung Kim)
'perf probe':
Support multiple probes on different binaries on the same command line (Masami Hiramatsu)
Support unnamed union/structure members data collection. (Masami Hiramatsu)
Check kprobes blacklist when adding new events. (Masami Hiramatsu)
'perf record':
Teach 'perf record' about perf_event_attr.clockid (Peter Zijlstra)
Support recording running/enabled time (Andi Kleen)
'perf sched':
Improve the performance of 'perf sched replay' on high CPU core count machines (Yunlong Song)
'perf report' and 'perf top':
Allow annotating entries in callchains in the hists browser (Arnaldo Carvalho de Melo)
Indicate which callchain entries are annotated in the
TUI hists browser (Arnaldo Carvalho de Melo)
Add pid/tid filtering to 'report' and 'script' commands (David Ahern)
Consider PERF_RECORD_ events with cpumode == 0 in 'perf top', removing one
cause of long term memory usage buildup, i.e. not processing PERF_RECORD_EXIT
events (Arnaldo Carvalho de Melo)
'perf stat':
Report unsupported events properly (Suzuki K. Poulose)
Output running time and run/enabled ratio in CSV mode (Andi Kleen)
'perf trace':
Handle legacy syscalls tracepoints (David Ahern, Arnaldo Carvalho de Melo)
Only insert blank duration bracket when tracing syscalls (Arnaldo Carvalho de Melo)
Filter out the trace pid when no threads are specified (Arnaldo Carvalho de Melo)
Dump stack on segfaults (Arnaldo Carvalho de Melo)
No need to explicitely enable evsels for workload started from perf, let it
be enabled via perf_event_attr.enable_on_exec, removing some events that take
place in the 'perf trace' before a workload is really started by it.
(Arnaldo Carvalho de Melo)
Allow mixing with tracepoints and suppressing plain syscalls. (Arnaldo Carvalho de Melo)
There's also been a ton of infrastructure work done, such as the
split-out of perf's build system into tools/build/ and other changes -
see the shortlog and changelog for details"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (358 commits)
perf/x86/intel/pt: Clean up the control flow in pt_pmu_hw_init()
perf evlist: Fix type for references to data_head/tail
perf probe: Check the orphaned -x option
perf probe: Support multiple probes on different binaries
perf buildid-list: Fix segfault when show DSOs with hits
perf tools: Fix cross-endian analysis
perf tools: Fix error path to do closedir() when synthesizing threads
perf tools: Fix synthesizing fork_event.ppid for non-main thread
perf tools: Add 'I' event modifier for exclude_idle bit
perf report: Don't call map__kmap if map is NULL.
perf tests: Fix attr tests
perf probe: Fix ARM 32 building error
perf tools: Merge all perf_event_attr print functions
perf record: Add clockid parameter
perf sched replay: Use replay_repeat to calculate the runavg of cpu usage instead of the default value 10
perf sched replay: Support using -f to override perf.data file ownership
perf sched replay: Fix the EMFILE error caused by the limitation of the maximum open files
perf sched replay: Handle the dead halt of sem_wait when create_tasks() fails for any task
perf sched replay: Fix the segmentation fault problem caused by pr_err in threads
perf sched replay: Realloc the memory of pid_to_task stepwise to adapt to the different pid_max configurations
...
user_mode_vm() and user_mode() are now the same. Change all callers
of user_mode_vm() to user_mode().
The next patch will remove the definition of user_mode_vm.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brad Spengler <spender@grsecurity.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/43b1f57f3df70df5a08b0925897c660725015554.1426728647.git.luto@kernel.org
[ Merged to a more recent kernel. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On x86-64, __copy_instruction() always returns 0 (error) if the
instruction uses %rip-relative addressing. This is because
kernel_insn_init() is called the second time for 'insn' instance
in such cases and sets all its fields to 0.
Because of this, trying to place a kprobe on such instruction
will fail, register_kprobe() will return -EINVAL.
This patch fixes the problem.
Signed-off-by: Eugene Shatokhin <eugene.shatokhin@rosalab.ru>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20150317100918.28349.94654.stgit@localhost.localdomain
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull perf fixes from Ingo Molnar:
"Two kprobes fixes and a handful of tooling fixes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf tools: Make sparc64 arch point to sparc
perf symbols: Define EM_AARCH64 for older OSes
perf top: Fix SIGBUS on sparc64
perf tools: Fix probing for PERF_FLAG_FD_CLOEXEC flag
perf tools: Fix pthread_attr_setaffinity_np build error
perf tools: Define _GNU_SOURCE on pthread_attr_setaffinity_np feature check
perf bench: Fix order of arguments to memcpy_alloc_mem
kprobes/x86: Check for invalid ftrace location in __recover_probed_insn()
kprobes/x86: Use 5-byte NOP when the code might be modified by ftrace
Pull x86 uprobe/kprobe fixes from Ingo Molnar:
"This contains two uprobes fixes, an uprobes comment update and a
kprobes fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
kprobes/x86: Mark 2 bytes NOP as boostable
uprobes/x86: Fix 2-byte opcode table
uprobes/x86: Fix 1-byte opcode tables
uprobes/x86: Add comment with insn opcodes, mnemonics and why we dont support them
__recover_probed_insn() should always be called from an address
where an instructions starts. The check for ftrace_location()
might help to discover a potential inconsistency.
This patch adds WARN_ON() when the inconsistency is detected.
Also it adds handling of the situation when the original code
can not get recovered.
Suggested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Cc: Ananth NMavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1424441250-27146-3-git-send-email-pmladek@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
can_probe() checks if the given address points to the beginning
of an instruction. It analyzes all the instructions from the
beginning of the function until the given address. The code
might be modified by another Kprobe. In this case, the current
code is read into a buffer, int3 breakpoint is replaced by the
saved opcode in the buffer, and can_probe() analyzes the buffer
instead.
There is a bug that __recover_probed_insn() tries to restore
the original code even for Kprobes using the ftrace framework.
But in this case, the opcode is not stored. See the difference
between arch_prepare_kprobe() and arch_prepare_kprobe_ftrace().
The opcode is stored by arch_copy_kprobe() only from
arch_prepare_kprobe().
This patch makes Kprobe to use the ideal 5-byte NOP when the
code can be modified by ftrace. It is the original instruction,
see ftrace_make_nop() and ftrace_nop_replace().
Note that we always need to use the NOP for ftrace locations.
Kprobes do not block ftrace and the instruction might get
modified at anytime. It might even be in an inconsistent state
because it is modified step by step using the int3 breakpoint.
The patch also fixes indentation of the touched comment.
Note that I found this problem when playing with Kprobes. I did
it on x86_64 with gcc-4.8.3 that supported -mfentry. I modified
samples/kprobes/kprobe_example.c and added offset 5 to put
the probe right after the fentry area:
static struct kprobe kp = {
.symbol_name = "do_fork",
+ .offset = 5,
};
Then I was able to load kprobe_example before jprobe_example
but not the other way around:
$> modprobe jprobe_example
$> modprobe kprobe_example
modprobe: ERROR: could not insert 'kprobe_example': Invalid or incomplete multibyte or wide character
It did not make much sense and debugging pointed to the bug
described above.
Signed-off-by: Petr Mladek <pmladek@suse.cz>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth NMavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1424441250-27146-2-git-send-email-pmladek@suse.cz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, x86 kprobes is unable to boost 2 bytes nop like:
nopl 0x0(%rax,%rax,1)
which is 0x0f 0x1f 0x44 0x00 0x00.
Such nops have exactly 5 bytes to hold a relative jmp
instruction. Boosting them should be obviously safe.
This patch enable boosting such nops by simply updating
twobyte_is_boostable[] array.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/1423532045-41049-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull ARM updates from Russell King:
- clang assembly fixes from Ard
- optimisations and cleanups for Aurora L2 cache support
- efficient L2 cache support for secure monitor API on Exynos SoCs
- debug menu cleanup from Daniel Thompson to allow better behaviour for
multiplatform kernels
- StrongARM SA11x0 conversion to irq domains, and pxa_timer
- kprobes updates for older ARM CPUs
- move probes support out of arch/arm/kernel to arch/arm/probes
- add inline asm support for the rbit (reverse bits) instruction
- provide an ARM mode secondary CPU entry point (for Qualcomm CPUs)
- remove the unused ARMv3 user access code
- add driver_override support to AMBA Primecell bus
* 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm: (55 commits)
ARM: 8256/1: driver coamba: add device binding path 'driver_override'
ARM: 8301/1: qcom: Use secondary_startup_arm()
ARM: 8302/1: Add a secondary_startup that assumes ARM mode
ARM: 8300/1: teach __asmeq that r11 == fp and r12 == ip
ARM: kprobes: Fix compilation error caused by superfluous '*'
ARM: 8297/1: cache-l2x0: optimize aurora range operations
ARM: 8296/1: cache-l2x0: clean up aurora cache handling
ARM: 8284/1: sa1100: clear RCSR_SMR on resume
ARM: 8283/1: sa1100: collie: clear PWER register on machine init
ARM: 8282/1: sa1100: use handle_domain_irq
ARM: 8281/1: sa1100: move GPIO-related IRQ code to gpio driver
ARM: 8280/1: sa1100: switch to irq_domain_add_simple()
ARM: 8279/1: sa1100: merge both GPIO irqdomains
ARM: 8278/1: sa1100: split irq handling for low GPIOs
ARM: 8291/1: replace magic number with PAGE_SHIFT macro in fixup_pv code
ARM: 8290/1: decompressor: fix a wrong comment
ARM: 8286/1: mm: Fix dma_contiguous_reserve comment
ARM: 8248/1: pm: remove outdated comment
ARM: 8274/1: Fix DEBUG_LL for multi-platform kernels (without PL01X)
ARM: 8273/1: Seperate DEBUG_UART_PHYS from DEBUG_LL on EP93XX
...
If the function graph tracer traces a jprobe callback, the system will
crash. This can easily be demonstrated by compiling the jprobe
sample module that is in the kernel tree, loading it and running the
function graph tracer.
# modprobe jprobe_example.ko
# echo function_graph > /sys/kernel/debug/tracing/current_tracer
# ls
The first two commands end up in a nice crash after the first fork.
(do_fork has a jprobe attached to it, so "ls" just triggers that fork)
The problem is caused by the jprobe_return() that all jprobe callbacks
must end with. The way jprobes works is that the function a jprobe
is attached to has a breakpoint placed at the start of it (or it uses
ftrace if fentry is supported). The breakpoint handler (or ftrace callback)
will copy the stack frame and change the ip address to return to the
jprobe handler instead of the function. The jprobe handler must end
with jprobe_return() which swaps the stack and does an int3 (breakpoint).
This breakpoint handler will then put back the saved stack frame,
simulate the instruction at the beginning of the function it added
a breakpoint to, and then continue on.
For function tracing to work, it hijakes the return address from the
stack frame, and replaces it with a hook function that will trace
the end of the call. This hook function will restore the return
address of the function call.
If the function tracer traces the jprobe handler, the hook function
for that handler will not be called, and its saved return address
will be used for the next function. This will result in a kernel crash.
To solve this, pause function tracing before the jprobe handler is called
and unpause it before it returns back to the function it probed.
Some other updates:
Used a variable "saved_sp" to hold kcb->jprobe_saved_sp. This makes the
code look a bit cleaner and easier to understand (various tries to fix
this bug required this change).
Note, if fentry is being used, jprobes will change the ip address before
the function graph tracer runs and it will not be able to trace the
function that the jprobe is probing.
Link: http://lkml.kernel.org/r/20150114154329.552437962@goodmis.org
Cc: stable@vger.kernel.org # 2.6.30+
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Pass the original kprobe for preparing an optimized kprobe arch-dep
part, since for some architecture (e.g. ARM32) requires the information
in original kprobe.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
to the trace_seq code. It also removed the return values to the
trace_seq_*() functions and use trace_seq_has_overflowed() to see if
the buffer filled up or not. This is similar to work being done to the
seq_file code as well in another tree.
Some of the other goodies include:
o Added some "!" (NOT) logic to the tracing filter.
o Fixed the frame pointer logic to the x86_64 mcount trampolines
o Added the logic for dynamic trampolines on !CONFIG_PREEMPT systems.
That is, the ftrace trampoline can be dynamically allocated
and be called directly by functions that only have a single hook
to them.
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Merge tag 'trace-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"There was a lot of clean ups and minor fixes. One of those clean ups
was to the trace_seq code. It also removed the return values to the
trace_seq_*() functions and use trace_seq_has_overflowed() to see if
the buffer filled up or not. This is similar to work being done to
the seq_file code as well in another tree.
Some of the other goodies include:
- Added some "!" (NOT) logic to the tracing filter.
- Fixed the frame pointer logic to the x86_64 mcount trampolines
- Added the logic for dynamic trampolines on !CONFIG_PREEMPT systems.
That is, the ftrace trampoline can be dynamically allocated and be
called directly by functions that only have a single hook to them"
* tag 'trace-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (55 commits)
tracing: Truncated output is better than nothing
tracing: Add additional marks to signal very large time deltas
Documentation: describe trace_buf_size parameter more accurately
tracing: Allow NOT to filter AND and OR clauses
tracing: Add NOT to filtering logic
ftrace/fgraph/x86: Have prepare_ftrace_return() take ip as first parameter
ftrace/x86: Get rid of ftrace_caller_setup
ftrace/x86: Have save_mcount_regs macro also save stack frames if needed
ftrace/x86: Add macro MCOUNT_REG_SIZE for amount of stack used to save mcount regs
ftrace/x86: Simplify save_mcount_regs on getting RIP
ftrace/x86: Have save_mcount_regs store RIP in %rdi for first parameter
ftrace/x86: Rename MCOUNT_SAVE_FRAME and add more detailed comments
ftrace/x86: Move MCOUNT_SAVE_FRAME out of header file
ftrace/x86: Have static tracing also use ftrace_caller_setup
ftrace/x86: Have static function tracing always test for function graph
kprobes: Add IPMODIFY flag to kprobe_ftrace_ops
ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict
kprobes/ftrace: Recover original IP if pre_handler doesn't change it
tracing/trivial: Fix typos and make an int into a bool
tracing: Deletion of an unnecessary check before iput()
...
Recover original IP register if the pre_handler doesn't change it.
Since current kprobes doesn't expect that another ftrace handler
may change regs->ip, it sets kprobe.addr + MCOUNT_INSN_SIZE to
regs->ip and returns to ftrace.
This seems wrong behavior since kprobes can recover regs->ip
and safely pass it to another handler.
This adds code which recovers original regs->ip passed from
ftrace right before returning to ftrace, so that another ftrace
user can change regs->ip.
Link: http://lkml.kernel.org/r/20141009130106.4698.26362.stgit@kbuild-f20.novalocal
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The current x86 instruction decoder steps along through the
instruction stream but always ensures that it never steps farther
than the largest possible instruction size (MAX_INSN_SIZE).
The MPX code is now going to be doing some decoding of userspace
instructions. We copy those from userspace in to the kernel and
they're obviously completely untrusted coming from userspace. In
addition to the constraint that instructions can only be so long,
we also have to be aware of how long the buffer is that came in
from userspace. This _looks_ to be similar to what the perf and
kprobes is doing, but it's unclear to me whether they are
affected.
The whole reason we need this is that it is perfectly valid to be
executing an instruction within MAX_INSN_SIZE bytes of an
unreadable page. We should be able to gracefully handle short
reads in those cases.
This adds support to the decoder to record how long the buffer
being decoded is and to refuse to "validate" the instruction if
we would have gone over the end of the buffer to decode it.
The kprobes code probably needs to be looked at here a bit more
carefully. This patch still respects the MAX_INSN_SIZE limit
there but the kprobes code does look like it might be able to
be a bit more strict than it currently is.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Jim Keniston <jkenisto@us.ibm.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: x86@kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20141114153957.E6B01535@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This patch frees the 'optinsn' slot when we get a range check error,
to prevent memory leaks.
Before this patch, cache entry in kprobe_insn_cache() won't be freed
if kprobe optimizing fails due to range check failure.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Pei Feiyue <peifeiyue@huawei.com>
Link: http://lkml.kernel.org/r/1406550019-70935-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit:
commit 6f6343f53d
Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Date: Thu Apr 17 17:17:33 2014 +0900
kprobes/x86: Call exception handlers directly from do_int3/do_debug
appears to have inadvertently dropped a check that the int3 came
from kernel mode. Trying to dereference addr when addr is
user-controlled is completely bogus.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/c4e339882c121aa76254f2adde3fcbdf502faec2.1405099506.git.luto@amacapital.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use NOKPROBE_SYMBOL macro for protecting functions
from kprobes instead of __kprobes annotation under
arch/x86.
This applies nokprobe_inline annotation for some cases,
because NOKPROBE_SYMBOL() will inhibit inlining by
referring the symbol address.
This just folds a bunch of previous NOKPROBE_SYMBOL()
cleanup patches for x86 to one patch.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Link: http://lkml.kernel.org/r/20140417081814.26341.51656.stgit@ltc230.yrl.intra.hitachi.co.jp
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fernando Luis Vázquez Cao <fernando_b1@lab.ntt.co.jp>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Lebon <jlebon@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is no need to prohibit probing on the functions
used in preparation phase. Those are safely probed because
those are not invoked from breakpoint/fault/debug handlers,
there is no chance to cause recursive exceptions.
Following functions are now removed from the kprobes blacklist:
can_boost
can_probe
can_optimize
is_IF_modifier
__copy_instruction
copy_optimized_instructions
arch_copy_kprobe
arch_prepare_kprobe
arch_arm_kprobe
arch_disarm_kprobe
arch_remove_kprobe
arch_trampoline_kprobe
arch_prepare_kprobe_ftrace
arch_prepare_optimized_kprobe
arch_check_optimized_kprobe
arch_within_optimized_kprobe
__arch_remove_optimized_kprobe
arch_remove_optimized_kprobe
arch_optimize_kprobes
arch_unoptimize_kprobe
I tested those functions by putting kprobes on all
instructions in the functions with the bash script
I sent to LKML. See:
https://lkml.org/lkml/2014/3/27/33
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jonathan Lebon <jlebon@redhat.com>
Link: http://lkml.kernel.org/r/20140417081747.26341.36065.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
To avoid a kernel crash by probing on lockdep code, call
kprobe_int3_handler() and kprobe_debug_handler()(which was
formerly called post_kprobe_handler()) directly from
do_int3 and do_debug.
Currently kprobes uses notify_die() to hook the int3/debug
exceptoins. Since there is a locking code in notify_die,
the lockdep code can be invoked. And because the lockdep
involves printk() related things, theoretically, we need to
prohibit probing on such code, which means much longer blacklist
we'll have. Instead, hooking the int3/debug for kprobes before
notify_die() can avoid this problem.
Anyway, most of the int3 handlers in the kernel are already
called from do_int3 directly, e.g. ftrace_int3_handler,
poke_int3_handler, kgdb_ll_trap. Actually only
kprobe_exceptions_notify is on the notifier_call_chain.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jonathan Lebon <jlebon@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/20140417081733.26341.24423.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
.entry.text is a code area which is used for interrupt/syscall
entries, which includes many sensitive code.
Thus, it is better to prohibit probing on all of such code
instead of a part of that.
Since some symbols are already registered on kprobe blacklist,
this also removes them from the blacklist.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jonathan Lebon <jlebon@redhat.com>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Link: http://lkml.kernel.org/r/20140417081658.26341.57354.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since the NMI handlers(e.g. perf) can interrupt in the
single stepping (or preparing the single stepping, do_debug
etc.), we should consider a kprobe is hit in the NMI
handler. Even in that case, the kprobe is allowed to be
reentered as same as the kprobes hit in kprobe handlers
(KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE).
The real issue will happen when a kprobe hit while another
reentered kprobe is processing (KPROBE_REENTER), because
we already consumed a saved-area for the previous kprobe.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jonathan Lebon <jlebon@redhat.com>
Link: http://lkml.kernel.org/r/20140417081651.26341.10593.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Current kprobes in-kernel page fault handler doesn't
expect that its single-stepping can be interrupted by
an NMI handler which may cause a page fault(e.g. perf
with callback tracing).
In that case, the page-fault handled by kprobes and it
misunderstands the page-fault has been caused by the
single-stepping code and tries to recover IP address
to probed address.
But the truth is the page-fault has been caused by the
NMI handler, and do_page_fault failes to handle real
page fault because the IP address is modified and
causes Kernel BUGs like below.
----
[ 2264.726905] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
[ 2264.727190] IP: [<ffffffff813c46e0>] copy_user_generic_string+0x0/0x40
To handle this correctly, I fixed the kprobes fault
handler to ensure the faulted ip address is its own
single-step buffer instead of checking current kprobe
state.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Sandeepa Prabhu <sandeepa.prabhu@linaro.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: fche@redhat.com
Cc: systemtap@sourceware.org
Link: http://lkml.kernel.org/r/20140417081644.26341.52351.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86/asmlinkage changes from Ingo Molnar:
"As a preparation for Andi Kleen's LTO patchset (link time
optimizations using GCC's -flto which build time optimization has
steadily increased in quality over the past few years and might
eventually be usable for the kernel too) this tree includes a handful
of preparatory patches that make function calling convention
annotations consistent again:
- Mark every function without arguments (or 64bit only) that is used
by assembly code with asmlinkage()
- Mark every function with parameters or variables that is used by
assembly code as __visible.
For the vanilla kernel this has documentation, consistency and
debuggability advantages, for the time being"
* 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/asmlinkage: Fix warning in xen asmlinkage change
x86, asmlinkage, vdso: Mark vdso variables __visible
x86, asmlinkage, power: Make various symbols used by the suspend asm code visible
x86, asmlinkage: Make dump_stack visible
x86, asmlinkage: Make 64bit checksum functions visible
x86, asmlinkage, paravirt: Add __visible/asmlinkage to xen paravirt ops
x86, asmlinkage, apm: Make APM data structure used from assembler visible
x86, asmlinkage: Make syscall tables visible
x86, asmlinkage: Make several variables used from assembler/linker script visible
x86, asmlinkage: Make kprobes code visible and fix assembler code
x86, asmlinkage: Make various syscalls asmlinkage
x86, asmlinkage: Make 32bit/64bit __switch_to visible
x86, asmlinkage: Make _*_start_kernel visible
x86, asmlinkage: Make all interrupt handlers asmlinkage / __visible
x86, asmlinkage: Change dotraplinkage into __visible on 32bit
x86: Fix sys_call_table type in asm/syscall.h
- Make all the external assembler template symbols __visible
- Move the templates inline assembler code into a top level
assembler statement, not inside a function. This avoids it being
optimized away or cloned.
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1375740170-7446-8-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Use text_poke_bp() for optimizing kprobes instead of
text_poke_smp*(). Since the number of kprobes is usually not so
large (<100) and text_poke_bp() is much lighter than
text_poke_smp() [which uses stop_machine()], this just stops
using batch processing.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Borislav Petkov <bpetkov@suse.de>
Link: http://lkml.kernel.org/r/20130718114750.26675.9174.stgit@mhiramat-M0-7522
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fix arch_prepare_kprobe() to handle failures in copy instruction
correctly. This fix is related to the previous fix: 8101376
which made __copy_instruction return an error result if failed,
but caller site was not updated to handle it. Thus, this is the
other half of the bugfix.
This fix is also related to the following bug-report:
https://bugzilla.redhat.com/show_bug.cgi?id=910649
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Jonathan Lebon <jlebon@redhat.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: systemtap@sourceware.org
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20130605031216.15285.2001.stgit@mhiramat-M0-7522
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Return an error from __copy_instruction() and use printk() to
give us a more productive message, since this is just an error
case which we can handle and also the BUG_ON() never tells us
why and what happened.
This is related to the following bug-report:
https://bugzilla.redhat.com/show_bug.cgi?id=910649
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20130404104230.22862.85242.stgit@mhiramat-M0-7522
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently kprobes check whether the copied instruction modifies
IF (interrupt flag) on each probe hit. This results not only in
introducing overhead but also involving
inat_get_opcode_attribute into the kprobes hot path, and it can
cause an infinite recursive call (and kernel panic in the end).
Actually, since the copied instruction itself can never be modified
on the buffer, it is needless to analyze the instruction on every
probe hit.
To fix this issue, we check it only once when registering probe
and store the result on ainsn->if_modifier.
Reported-by: Timo Juhani Lindfors <timo.lindfors@iki.fi>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20130314115242.19690.33573.stgit@mhiramat-M0-7522
Signed-off-by: Ingo Molnar <mingo@kernel.org>
I'm not sure why, but the hlist for each entry iterators were conceived
list_for_each_entry(pos, head, member)
The hlist ones were greedy and wanted an extra parameter:
hlist_for_each_entry(tpos, pos, head, member)
Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.
Besides the semantic patch, there was some manual work required:
- Fix up the actual hlist iterators in linux/list.h
- Fix up the declaration of other iterators based on the hlist ones.
- A very small amount of places were using the 'node' parameter, this
was modified to use 'obj->member' instead.
- Coccinelle didn't handle the hlist_for_each_entry_safe iterator
properly, so those had to be fixed up manually.
The semantic patch which is mostly the work of Peter Senna Tschudin is here:
@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;
type T;
expression a,c,d,e;
identifier b;
statement S;
@@
-T b;
<+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
...+>
[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
