The current method for inserting symbols is to use the symbols__insert()
function. However symbols__insert() does not update the dso symbol
cache. This causes problems in the following scenario:
1. symbol not found at addr using dso__find_symbol
2. symbol inserted at addr using the existing symbols__insert function
3. symbol still not found at addr using dso__find_symbol() because cache isn't
updated. This is undesired behavior.
The undesired behavior in (3) is addressed by creating a new function,
dso__insert_symbol() to both insert the symbol and update the symbol
cache if necessary.
If dso__insert_symbol() is used in (2) instead of symbols__insert(),
then the undesired behavior in (3) is avoided.
Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1462937209-6032-2-git-send-email-cphlipot0@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This change introduces a fix to symbols__find, so that it is able to
find symbols of length zero (where start == end).
The current code has the following problem:
- The current implementation of symbols__find is unable to find any symbols
of length zero.
- The db-export framework explicitly creates zero length symbols at
locations where no symbol currently exists.
The combination of the two above behaviors results in behavior similar
to the example below.
1. addr_location is created for a sample, but symbol is unable to be
resolved.
2. db export creates an "unknown" symbol of length zero at that address
and inserts it into the dso.
3. A new sample comes in at the same address, but symbol__find is unable
to find the zero length symbol, so it is still unresolved.
4. db export sees the symbol is unresolved, and allocated a duplicate
symbol, even though it already did this in step 2.
This behavior continues every time an address without symbol information
is seen, which causes a very large number of these symbols to be
allocated.
The effect of this fix can be observed by looking at the contents of an
exported database before/after the fix (generated with
scripts/python/export-to-postgresql.py)
Ex.
BEFORE THE CHANGE:
example_db=# select count(*) from symbols;
count
--------
900213
(1 row)
example_db=# select count(*) from symbols where symbols.name='unknown';
count
--------
897355
(1 row)
example_db=# select count(*) from symbols where symbols.name!='unknown';
count
-------
2858
(1 row)
AFTER THE CHANGE:
example_db=# select count(*) from symbols;
count
-------
25217
(1 row)
example_db=# select count(*) from symbols where name='unknown';
count
-------
22359
(1 row)
example_db=# select count(*) from symbols where name!='unknown';
count
-------
2858
(1 row)
Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1462612620-25008-1-git-send-email-cphlipot0@gmail.com
[ Moved the test to later in the rb_tree tests, as this not the likely case ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The fprintf_sym() and fprintf_callchain() methods now allow users to
change the existing behaviour of showing "[unknown]" as the name of
unresolved symbols to instead show "[0x123456]", i.e. its address.
The current patch doesn't change tools to use this facility, the results
from 'perf trace' and 'perf script' cotinue like:
70.109 ( 0.001 ms): qemu-system-x8/10153 poll(ufds: 0x7f2d93ffe870, nfds: 1) = 0 Timeout
[unknown] (/usr/lib64/libc-2.22.so)
[unknown] (/usr/lib64/libspice-server.so.1.10.0)
[unknown] (/usr/lib64/libspice-server.so.1.10.0)
[unknown] (/usr/lib64/libspice-server.so.1.10.0)
start_thread+0xca (/usr/lib64/libpthread-2.22.so)
__clone+0x6d (/usr/lib64/libc-2.22.so)
The next patch will make 'perf trace' use the new formatting.
Suggested-by: Milian Wolff <milian.wolff@kdab.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-fja1ods5vqpg42mdz09xcz3r@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Before this patch, if a sample is triggered inside a module not in
/lib/modules/`uname -r`/, even if the module is in buildid-cache, 'perf
report' will still be unable to find the correct symbol. For example:
# rm -rf ~/.debug/
# perf buildid-cache -a ./mymodule.ko
# perf probe -m ./mymodule.ko -a get_mymodule_val
Added new event:
probe:get_mymodule_val (on get_mymodule_val in mymodule)
You can now use it in all perf tools, such as:
perf record -e probe:get_mymodule_val -aR sleep 1
# perf record -e probe:get_mymodule_val cat /proc/mymodule
mymodule:3
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.011 MB perf.data (1 samples) ]
# perf report --stdio
[SNIP]
#
# Overhead Command Shared Object Symbol
# ........ ....... ................ ......................
#
100.00% cat [mymodule] [k] 0x0000000000000001
# perf report -vvvv --stdio
dso__load_sym: adjusting symbol: st_value: 0 sh_addr: 0 sh_offset: 0x70
symbol__new: get_mymodule_val 0x70-0x8a
[SNIP]
This is caused by dso__load() -> dso__load_sym(). In dso__load(), kmod
is true only when its file is found in some well know directories. All
files loaded from buildid-cache are treated as user programs. Following
dso__load_sym() set map->pgoff incorrectly.
This patch gives kernel modules in buildid-cache a chance to adjust
value of kmod. After dso__load() get the type of symbols, if it is
buildid, check the last 3 chars of original filename against '.ko', and
adjust the value of kmod if the file is a kernel module.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Cody P Schafer <dev@codyps.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jeremie Galarneau <jeremie.galarneau@efficios.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kirill Smelkov <kirr@nexedi.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1454680939-24963-3-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The event group view feature is to see related events together. To use
the group view, events should be recorded as a group with a dedicated
syntax of surrounding events by braces (-e '{ evt1, evt2, ... }').
Also 'perf report' also requires the --group option to enable it.
However it's almost always beneficial to use the group view to see the
group events as it's more expressive. And I think it's more natural to
see events together if they are recorded as a group.
Thus this patch changes the default value to enable it. If users don't
want to see like it and keep the original behavior, they can set the
report.group config variable to false and/or use --no-group option in
the 'perf report' command line.
Requested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Taeung Song <treeze.taeung@gmail.com>
Link: http://lkml.kernel.org/r/1448807057-3506-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When the root user tries to read a file owned by some other user we get:
# ls -la perf.data
-rw-------. 1 acme acme 20032 Nov 12 15:50 perf.data
# perf report
File perf.data not owned by current user or root (use -f to override)
# perf report -f | grep -v ^# | head -2
30.96% ls [kernel.vmlinux] [k] do_set_pte
28.24% ls libc-2.20.so [.] intel_check_word
#
That wasn't happening when the symbol code tried to read a JIT map,
where the same check was done but no forcing was possible, fix it.
Reported-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Tested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://permalink.gmane.org/gmane.linux.kernel.perf.user/2380
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Normally symbols are read from the DSO and adjusted, if need be, so that
the symbol start matches the file offset in the DSO file (we want the
file offset because that is what we know from MMAP events). That is done
by dso__load_sym() which inserts the symbols *after* adjusting them.
In the case of kcore, the symbols have been read from kallsyms and the
symbol start is the memory address. The symbols have to be adjusted to
match the kcore file offsets. dso__split_kallsyms_for_kcore() does that,
but now the adjustment is being done *after* the symbols have been
inserted. It appears dso__split_kallsyms_for_kcore() was assuming that
changing the symbol start would not change the order in the rbtree -
which is, of course, not guaranteed.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Wang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/563CB241.2090701@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Not as the first attempt at finding a vmlinux for the running kernel,
this way we get a more informative filename to present in tools, it will
check that the build-id is the same as the one previously loaded in the
DSO in dso->build_id, reading from /sys/kernel/notes, for instance.
E.g. in the annotation TUI, going from 'perf top', for the scsi_sg_alloc
kernel function, in the first line:
Before:
scsi_sg_alloc /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1
After:
scsi_sg_alloc /lib/modules/4.3.0-rc1+/build/vmlinux
And:
# ls -la /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1
lrwxrwxrwx. 1 root root 81 Sep 22 16:11 /root/.debug/.build-id/28/2777c262e6b3c0451375163c9a81c893218ab1 -> ../../home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1
# file ~/.debug/home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1
/root/.debug/home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, BuildID[sha1]=282777c262e6b3c0451375163c9a81c893218ab1, not stripped
#
The same as:
# file /lib/modules/4.3.0-rc1+/build/vmlinux
/lib/modules/4.3.0-rc1+/build/vmlinux: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, BuildID[sha1]=282777c262e6b3c0451375163c9a81c893218ab1, not stripped
Furthermore:
# sha256sum /lib/modules/4.3.0-rc1+/build/vmlinux
e7a789bbdc61029ec09140c228e1dd651271f38ef0b8416c0b7d5ff727b98be2 /lib/modules/4.3.0-rc1+/build/vmlinux
# sha256sum ~/.debug/home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1
e7a789bbdc61029ec09140c228e1dd651271f38ef0b8416c0b7d5ff727b98be2 /root/.debug/home/git/build/v4.3.0-rc1+/vmlinux/282777c262e6b3c0451375163c9a81c893218ab1
[root@zoo new]#
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-9y42ikzq3jisiddoi6f07n8z@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The 'annotate' tool does some filtering in the entries in a DSO but
forgot to reset the cache done in dso__find_symbol(), cauxing a SEGV:
[root@zoo ~]# perf annotate netlink_poll
perf: Segmentation fault
-------- backtrace --------
perf[0x526ceb]
/lib64/libc.so.6(+0x34960)[0x7faedfbe0960]
perf(rb_erase+0x223)[0x499d63]
perf[0x4213e9]
perf[0x4bc123]
perf[0x4bc621]
perf[0x4bf26b]
perf[0x4bc855]
perf(perf_session__process_events+0x340)[0x4bddc0]
perf(cmd_annotate+0x6bb)[0x421b5b]
perf[0x479063]
perf(main+0x60a)[0x42098a]
/lib64/libc.so.6(__libc_start_main+0xf0)[0x7faedfbcbfe0]
perf[0x420aa9]
[0x0]
[root@zoo ~]#
Fix it by reseting the find cache when removing symbols.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Fixes: b685ac22b4 ("perf symbols: Add front end cache for DSO symbol lookup")
Link: http://lkml.kernel.org/n/tip-b2y9x46y0t8yem1ive41zqyp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The "/proc/kcore requires CAP_SYS_RAWIO" message comes up all the time
for 'perf script' if vmlinux is not found and the user isn't root, even
when the kernel is not being traced and even though the message is only
really relevant for annotation.
Change it to pr_debug and instead put a note in the message displayed if
annotation is not possible.
Also, the file being accessed might not be /proc/kcore. Tools can be
directed to a different location using the --kallsyms option in which
case kcore is expected to be in the same directory. Adjust the message
so it is not misleading in that case.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Li Zhang <zhlcindy@linux.vnet.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1440065260-8802-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Wang Nan
He Kuang
Masami Hiramatsu
Chris Phlipot
Arnaldo Carvalho de Melo
Jiri Olsa
Ben Hutchings
Namhyung Kim
Ekaterina Tumanova
Adrian Hunter
Jiri Olsa
Dima Kogan
Kan Liang