On 10/12/2015:04:12:30 PM, David Long wrote:
On 12/10/2015 03:24 PM, William Cohen wrote:
Hi All,
Dave Long and Pratyush Anand have been working on kprobe and uprobe patches for aarch64. I have built a local version the uprobe/upstream_arm64_devel branch of https://github.com/pratyushanand/linux which includes those patches in a linux-4.4.0-rc3 kernel.
The tests seemed to run fairly well and the results have been uploaded to dejazilla:
https://web.elastic.org/~dejazilla/viewsummary.php?summary=%3D%27%3C56698DCC.3090207%40redhat.com%3E%27
=== systemtap Summary ===
# of expected passes 6096
# of unexpected failures 111
# of unexpected successes 2
# of expected failures 333
# of unknown successes 2
# of known failures 89
# of untested testcases 97
# of unsupported tests 27
runtest completed at Thu Dec 10 05:54:32 2015
There are still some areas needing for for aarch64 such as stack backtrace support.
The following failure looks suspect because the child process died:
spawn stap -g ./systemtap.examples/process/threadstacks.stp -Gsize=65536 -c /root/systemtap_write/systemtap/testsuite/pthread_stacks.x 1024 0 -d /root/systemtap_write/systemtap/testsuite/pthread_stacks.x
pthread_stacks.x: ./systemtap.base/pthread_stacks.c:67: main: Assertion `rc == 0' failed.
WARNING: Child process exited with signal 6 (Aborted)
pthread_stacks.[3567] overwrote __default_stacksize@0x3ffb3be4338 (8388608->65536)
WARNING: /root/systemtap_write/install/bin/staprun exited with status: 1
Pass 5: run failed. [man error::pass5]
FAIL: pthread_stacks -Gsize (0 0)
The fslatency-nd and fsslower-nd tests need further investigation:
PASS: ./systemtap.examples/lwtools/fslatency-nd build
meta taglines 'test_installcheck: stap fslatency-nd.stp 1 1' tag 'test_installcheck' value 'stap fslatency-nd.stp 1 1'
attempting command stap fslatency-nd.stp 1 1
OUT ERROR: read fault [man error::fault] at 0x0000000000000034 (addr) near operator '@cast' at fslatency-nd.stp:66:15
Tracing FS sync reads and writes... Output every 1 secs.
WARNING: Number of errors: 1, skipped probes: 1
WARNING: /root/systemtap_write/install/bin/staprun exited with status: 1
Pass 5: run failed. [man error::pass5]
child process exited abnormally
RC 1
FAIL: ./systemtap.examples/lwtools/fslatency-nd run
PASS: ./systemtap.examples/lwtools/fsslower-nd build
meta taglines 'test_installcheck: stap fsslower-nd.stp -c "sleep 1"' tag 'test_installcheck' value 'stap fsslower-nd.stp -c "sleep 1"'
attempting command stap fsslower-nd.stp -c "sleep 1"
OUT ERROR: read fault [man error::fault] at 0x0000000000000034 (addr) near operator '@cast' at fsslower-nd.stp:68:15
Tracing FS sync reads and writes slower than 10 ms... Hit Ctrl-C to end.
TIME PID COMM FUNC SIZE LAT(ms)
WARNING: Number of errors: 1, skipped probes: 1
WARNING: /root/systemtap_write/install/bin/staprun exited with status: 1
Pass 5: run failed. [man error::pass5]
child process exited abnormally
RC 1
FAIL: ./systemtap.examples/lwtools/fsslower-nd run
Also a number of network tests failed like the following
TEST PWD=/root/systemtap_write/systemtap/testsuite/systemtap.examples/network
meta taglines 'test_check: stap -g -p4 netfilter_drop.stp TCP 1' tag 'test_check' value 'stap -g -p4 netfilter_drop.stp TCP 1'
attempting command stap -g -p4 netfilter_drop.stp TCP 1
OUT /tmp/stapbIEqFl/stap_0c0db8521e3ea3b2d26dcde208a77baf_21082_src.c:2731:1: error: initialization from incompatible pointer type [-Werror]
.hook = enter_netfilter_probe_0,
^
/tmp/stapbIEqFl/stap_0c0db8521e3ea3b2d26dcde208a77baf_21082_src.c:2731:1: error: (near initialization for 'netfilter_opts_0.hook') [-Werror]
/tmp/stapbIEqFl/stap_0c0db8521e3ea3b2d26dcde208a77baf_21082_src.c:2732:1: error: unknown field 'owner' specified in initializer
.owner = THIS_MODULE,
^
/tmp/stapbIEqFl/stap_0c0db8521e3ea3b2d26dcde208a77baf_21082_src.c:2732:1: error: initialization from incompatible pointer type [-Werror]
/tmp/stapbIEqFl/stap_0c0db8521e3ea3b2d26dcde208a77baf_21082_src.c:2732:1: error: (near initialization for 'netfilter_opts_0.dev') [-Werror]
cc1: all warnings being treated as errors
make[4]: *** [/tmp/stapbIEqFl/stap_0c0db8521e3ea3b2d26dcde208a77baf_21082_src.o] Error 1
make[3]: *** [_module_/tmp/stapbIEqFl] Error 2
WARNING: kbuild exited with status: 2
Pass 4: compilation failed. [man error::pass4]
child process exited abnormally
RC 1
FAIL: ./systemtap.examples/network/netfilter_drop build
-Will
Cool. Wish I could make sense of systemtap error messages.
At Will Deacon's suggested I tested probing the instruction in
__copy_to_user that can cause a captured kernel exception when an
application passes in a bad buffer address. Unfortunately the result was a
hang. So copy_to/from user is going to have to be blacklisted for now,
unless there turns out to be a simple fix. I'm worried there might be other
places in the kernel where an otherwise probeable instruction might be
expected to generate an exception.
There are many arm64 specific functions which need blacklisting. I have them
here.
https://github.com/pratyushanand/linux/commit/4098b5ad2c67bf4c375981fc68793f44af005eb9
https://github.com/pratyushanand/linux/commit/df3e76cbf70a8e1af42951d4b30587f022d25938
I think uprobe_pre/post_sstep_notifier() should also be blacklisted.
https://github.com/pratyushanand/linux/commit/99c89512931a46582d2f026b7288c895b8ef320c
Certainly, there could be some more functions which need kprobe blacklisting.
Because I remember, I had kprobe at every function of kallsyms on a x86
platform, and it had crashed.
~Pratyush