The commit 4d6101f5fd ("perf probe: Clarify error message about
not finding kernel modules debuginfo") changed the error message "Failed
to find the path for kernel" to "Failed to find the path for the
kernel".
Update the regex so that the tests still skip rather than fail when
kernel debug symbols aren't present.
Signed-off-by: James Clark <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mark Rutland <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
This test places a kprobe to function getname_flags() in the kernel
which has the following prototype:
struct filename *getname_flags(const char __user *filename, int flags, int *empty)
The 'filename' argument points to a filename located in user space memory.
Looking at commit 88903c4643 ("tracing/probe: Add ustring type for
user-space string") the kprobe should indicate that user space memory is
accessed.
Output before:
[root@m35lp76 perf]# ./perf test 66 67
66: Use vfs_getname probe to get syscall args filenames : FAILED!
67: Check open filename arg using perf trace + vfs_getname: FAILED!
[root@m35lp76 perf]#
Output after:
[root@m35lp76 perf]# ./perf test 66 67
66: Use vfs_getname probe to get syscall args filenames : Ok
67: Check open filename arg using perf trace + vfs_getname: Ok
[root@m35lp76 perf]#
Comments from Masami Hiramatsu:
This bug doesn't happen on x86 or other archs on which user address
space and kernel address space is the same. On some arches (ppc64 in
this case?) user address space is partially or completely the same as
kernel address space.
(Yes, they switch the world when running into the kernel) In this case,
we need to use different data access functions for each space.
That is why I introduced the "ustring" type for kprobe events.
As far as I can see, Thomas's patch is sane. Thomas, could you show us
your result on your test environment?
Comments from Thomas Richter:
Test results for s/390 included above.
Signed-off-by: Thomas Richter <[email protected]>
Acked-by: Masami Hiramatsu <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Sumanth Korikkar <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
If perf was built without trace support, the trace+probe_vfs_getname.sh
'perf test' entry fails:
# perf trace -h
perf: 'trace' is not a perf-command. See 'perf --help'
# perf test 64
64: Check open filename arg using perf trace + vfs_getname: FAILED!
Check trace support, so that we'll skip the test in that case:
# perf test 64
64: Check open filename arg using perf trace + vfs_getname: Skip
Signed-off-by: Tommi Rantala <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Hendrik Brueckner <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kim Phillips <[email protected]>
Cc: Michael Petlan <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Some kernels, like 4.19.13-300.fc29.x86_64 in fedora 29, fail with the
existing probe definition asking for the contents of result->name,
working when we ask for the 'filename' variable instead, so add a
fallback to that.
Now those tests are back working on fedora 29 systems with that kernel:
# perf test vfs_getname
65: Use vfs_getname probe to get syscall args filenames : Ok
66: Add vfs_getname probe to get syscall args filenames : Ok
67: Check open filename arg using perf trace + vfs_getname: Ok
#
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
In some situations the vfs_getname is being added both as requested and
with a _1 suffix (inlines?):
probe:vfs_getname_1 (on getname_flags:63@acme/git/linux/fs/namei.c with pathname)
This ends up making the cleanup to miss that one, as it removes just
'probe:vfs_getname', which makes the second test to use this probe point
to fail, since it finds that leftover from the first test, use a
wildcard to remove both.
Before:
# perf test 60 61 62 63
60: Use vfs_getname probe to get syscall args filenames : FAILED!
61: probe libc's inet_pton & backtrace it with ping : Ok
62: Check open filename arg using perf trace + vfs_getname: FAILED!
63: Add vfs_getname probe to get syscall args filenames : Ok
After:
# perf test 60 61 62 63
60: Use vfs_getname probe to get syscall args filenames : Ok
61: probe libc's inet_pton & backtrace it with ping : Ok
62: Check open filename arg using perf trace + vfs_getname: Ok
63: Add vfs_getname probe to get syscall args filenames : Ok
#
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Thomas Richter <[email protected]>
Cc: Wang Nan <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
If that is the case, or if the required lib is not present, e.g.
elfutils-devel in Fedora systems, then just skip the tests requiring
DWARF analysis.
Before:
# rpm -e elfutils-devel
# perf test ping vfs_getname
60: Use vfs_getname probe to get syscall args filenames : FAILED!
61: probe libc's inet_pton & backtrace it with ping : Ok
62: Check open filename arg using perf trace + vfs_getname: FAILED!
63: Add vfs_getname probe to get syscall args filenames : FAILED!
#
After:
# perf test vfs_getname
60: Use vfs_getname probe to get syscall args filenames : Skip
62: Check open filename arg using perf trace + vfs_getname: Skip
63: Add vfs_getname probe to get syscall args filenames : Skip
#
Then, reinstalling elfutils-devel, rebuilding the tool and running
again:
# perf test vfs_getname
60: Use vfs_getname probe to get syscall args filenames : Ok
62: Check open filename arg using perf trace + vfs_getname: Ok
63: Add vfs_getname probe to get syscall args filenames : Ok
#
Reported-by: Kim Phillips <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Michael Petlan <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Thomas Richter <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Add a library function that checks if 'perf probe' is built into the
tool being tested, skipping tests that need it.
Testing it on a system after removing the library needed to build
'probe' as a perf subcommand:
# perf test ping vfs_getname
59: Use vfs_getname probe to get syscall args filenames : Skip
60: probe libc's inet_pton & backtrace it with ping : Skip
61: Check open filename arg using perf trace + vfs_getname: Skip
62: Add vfs_getname probe to get syscall args filenames : Skip
# perf probe
perf: 'probe' is not a perf-command. See 'perf --help'.
#
Now reinstalling elfutils-libelf-devel on this Fedora 26 system to
rebuild perf and then retest this:
# perf test ping vfs_getname
60: Use vfs_getname probe to get syscall args filenames : Ok
61: probe libc's inet_pton & backtrace it with ping : Ok
62: Check open filename arg using perf trace + vfs_getname: Ok
63: Add vfs_getname probe to get syscall args filenames : Ok
#
Reported-by: Kim Phillips <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Michael Petlan <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Thomas Richter <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
James Clark