kernel.git/tools/perf/util/probe-event.c, branch linux-3.16.y

perf probe: Improve error messages in --line option

2014-06-10T13:02:06Z

Improve error messages of 'perf probe --line' mode. Currently 'perf probe' shows the "Debuginfo analysis failed" message with an error code when the given symbol is not found: ----- # perf probe -L page_cgroup_init_flatmem Debuginfo analysis failed. (-2) Error: Failed to show lines. ----- But -2 (-ENOENT) means that the given source line or function was not found. With this patch, 'perf probe' shows the correct error message: ----- # perf probe -L page_cgroup_init_flatmem Specified source line is not found. Error: Failed to show lines. ----- There is also another debug error code is shown in the same function after get_real_path(). This removes that too. Signed-off-by: Masami Hiramatsu Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20140606071406.6788.47850.stgit@kbuild-fedora.novalocal Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Improve an error message of perf probe --vars mode

2014-06-09T17:35:58Z

Fix an error message when failed to find given address in --vars mode. Without this fix, perf probe -V doesn't show the final "Error" message if it fails to find given source line. Moreover, it tells it fails to find "variables" instead of the source line. ----- # perf probe -V foo@bar Failed to find variables at foo@bar (0) ----- The result also shows mysterious error code. Actually the error returns 0 or -ENOENT means that it just fails to find the address of given source line. (0 means there is no matching address, and -ENOENT means there is an entry(DIE) but it has no instance, e.g. an empty inlined function) This fixes it to show what happened and the final error message as below. ----- # perf probe -V foo@bar Failed to find the address of foo@bar Error: Failed to show vars. ----- Signed-off-by: Masami Hiramatsu Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20140606071359.6788.84716.stgit@kbuild-fedora.novalocal Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Support distro-style debuginfo for uprobe

2014-02-18T12:38:44Z

Support distro-style debuginfo supported by dso for setting uprobes. Note that this tries to find a debuginfo file based on the real path of the target binary. If the debuginfo is not correctly installed on the system, this can not find it. Signed-off-by: Masami Hiramatsu Cc: David Ahern Cc: "David A. Long" Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20140206053227.29635.54434.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Allow to add events on the local functions

2014-02-18T12:38:43Z

Allow to add events on the local functions without debuginfo. (With the debuginfo, we can add events even on inlined functions) Currently, probing on local functions requires debuginfo to locate actual address. It is also possible without debuginfo since we have symbol maps. Without this change; ---- # ./perf probe -a t_show Added new event: probe:t_show (on t_show) You can now use it in all perf tools, such as: perf record -e probe:t_show -aR sleep 1 # ./perf probe -x perf -a identity__map_ip no symbols found in /kbuild/ksrc/linux-3/tools/perf/perf, maybe install a debug package? Failed to load map. Error: Failed to add events. (-22) ---- As the above results, perf probe just put one event on the first found symbol for kprobe event. Moreover, for uprobe event, perf probe failed to find local functions. With this change; ---- # ./perf probe -a t_show Added new events: probe:t_show (on t_show) probe:t_show_1 (on t_show) probe:t_show_2 (on t_show) probe:t_show_3 (on t_show) You can now use it in all perf tools, such as: perf record -e probe:t_show_3 -aR sleep 1 # ./perf probe -x perf -a identity__map_ip Added new events: probe_perf:identity__map_ip (on identity__map_ip in /kbuild/ksrc/linux-3/tools/perf/perf) probe_perf:identity__map_ip_1 (on identity__map_ip in /kbuild/ksrc/linux-3/tools/perf/perf) probe_perf:identity__map_ip_2 (on identity__map_ip in /kbuild/ksrc/linux-3/tools/perf/perf) probe_perf:identity__map_ip_3 (on identity__map_ip in /kbuild/ksrc/linux-3/tools/perf/perf) You can now use it in all perf tools, such as: perf record -e probe_perf:identity__map_ip_3 -aR sleep 1 ---- Now we succeed to put events on every given local functions for both kprobes and uprobes. :) Note that this also introduces some symbol rbtree iteration macros; symbols__for_each, dso__for_each_symbol, and map__for_each_symbol. These are for walking through the symbol list in a map. Changes from v2: - Fix add_exec_to_probe_trace_events() not to convert address to tp->symbol any more. - Fix to set kernel probes based on ref_reloc_sym. Signed-off-by: Masami Hiramatsu Cc: David Ahern Cc: "David A. Long" Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20140206053225.29635.15026.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Show source-level or symbol-level info for uprobes

2014-02-18T12:34:51Z

Show source-level or symbol-level information for uprobe events. Without this change; # ./perf probe -l probe_perf:dso__load_vmlinux (on 0x000000000006d110 in /kbuild/ksrc/linux-3/tools/perf/perf) With this change; # ./perf probe -l probe_perf:dso__load_vmlinux (on dso__load_vmlinux@util/symbol.c in /kbuild/ksrc/linux-3/tools/perf/perf) Changes from v2: - Update according to previous patches. Changes from v1: - Rewrite the code based on new series. Signed-off-by: Masami Hiramatsu Cc: David Ahern Cc: "David A. Long" Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20140206053223.29635.51280.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Show appropriate symbol for ref_reloc_sym based kprobes

2014-02-18T12:34:51Z

Show appropriate symbol for ref_reloc_sym based kprobes instead of refpoint+offset when perf-probe -l runs without debuginfo. Without this change: # ./perf probe -l probe:t_show (on _stext+889880 with m v) probe:t_show_1 (on _stext+928568 with m v t) probe:t_show_2 (on _stext+969512 with m v fmt) probe:t_show_3 (on _stext+1001416 with m v file) With this change: # ./perf probe -l probe:t_show (on t_show with m v) probe:t_show_1 (on t_show with m v t) probe:t_show_2 (on t_show with m v fmt) probe:t_show_3 (on t_show with m v file) Changes from v2: - Check ref_reloc_sym to find correct unrelocated address. Signed-off-by: Masami Hiramatsu Cc: David Ahern Cc: "David A. Long" Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20140206053220.29635.81819.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Find given address from offline dwarf

2014-02-18T12:34:51Z

Find the given address from offline dwarfs instead of online kernel dwarfs. On the KASLR enabled kernel, the kernel text section is loaded with random offset, and the debuginfo__new_online_kernel can't handle it. So let's move to the offline dwarf loader instead of using the online dwarf loader. As a result, since we don't need debuginfo__new_online_kernel any more, this also removes the functions related to that. Without this change; # ./perf probe -l probe:t_show (on _stext+901288 with m v) probe:t_show_1 (on _stext+939624 with m v t) probe:t_show_2 (on _stext+980296 with m v fmt) probe:t_show_3 (on _stext+1014392 with m v file) With this change; # ./perf probe -l probe:t_show (on t_show@linux-3/kernel/trace/ftrace.c with m v) probe:t_show_1 (on t_show@linux-3/kernel/trace/trace.c with m v t) probe:t_show_2 (on t_show@kernel/trace/trace_printk.c with m v fmt) probe:t_show_3 (on t_show@kernel/trace/trace_events.c with m v file) Changes from v2: - Instead of retrying, directly opens offline dwarf. - Remove debuginfo__new_online_kernel and related functions. - Refer map->reloc to get the correct address of a symbol. - Add a special case for handling ref_reloc_sym based address. Signed-off-by: Masami Hiramatsu Cc: David Ahern Cc: "David A. Long" Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20140206053218.29635.74821.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Use ref_reloc_sym based address instead of the symbol name

2014-02-18T12:34:51Z

Since several local symbols can have same name (e.g. t_show), we need to use the relative address from the symbol referred by kmap->ref_reloc_sym instead of the target symbol name itself. Because the kernel address space layout randomize (kASLR) changes the absolute address of kernel symbols, we can't rely on the absolute address. Note that this works only with debuginfo. E.g. without this change; ---- # ./perf probe -a "t_show \$vars" Added new events: probe:t_show (on t_show with $vars) probe:t_show_1 (on t_show with $vars) probe:t_show_2 (on t_show with $vars) probe:t_show_3 (on t_show with $vars) You can now use it in all perf tools, such as: perf record -e probe:t_show_3 -aR sleep 1 ---- OK, we have 4 different t_show()s. All functions have different arguments as below; ---- # cat /sys/kernel/debug/tracing/kprobe_events p:probe/t_show t_show m=%di:u64 v=%si:u64 p:probe/t_show_1 t_show m=%di:u64 v=%si:u64 t=%si:u64 p:probe/t_show_2 t_show m=%di:u64 v=%si:u64 fmt=%si:u64 p:probe/t_show_3 t_show m=%di:u64 v=%si:u64 file=%si:u64 ---- However, all of them have been put on the *same* address. ---- # cat /sys/kernel/debug/kprobes/list ffffffff810d9720 k t_show+0x0 [DISABLED] ffffffff810d9720 k t_show+0x0 [DISABLED] ffffffff810d9720 k t_show+0x0 [DISABLED] ffffffff810d9720 k t_show+0x0 [DISABLED] ---- With this change; ---- # ./perf probe -a "t_show \$vars" Added new events: probe:t_show (on t_show with $vars) probe:t_show_1 (on t_show with $vars) probe:t_show_2 (on t_show with $vars) probe:t_show_3 (on t_show with $vars) You can now use it in all perf tools, such as: perf record -e probe:t_show_3 -aR sleep 1 # cat /sys/kernel/debug/tracing/kprobe_events p:probe/t_show _stext+889880 m=%di:u64 v=%si:u64 p:probe/t_show_1 _stext+928568 m=%di:u64 v=%si:u64 t=%si:u64 p:probe/t_show_2 _stext+969512 m=%di:u64 v=%si:u64 fmt=%si:u64 p:probe/t_show_3 _stext+1001416 m=%di:u64 v=%si:u64 file=%si:u64 # cat /sys/kernel/debug/kprobes/list ffffffffb50d95e0 k t_show+0x0 [DISABLED] ffffffffb50e2d00 k t_show+0x0 [DISABLED] ffffffffb50f4990 k t_show+0x0 [DISABLED] ffffffffb50eccf0 k t_show+0x0 [DISABLED] ---- This time, each event is put in different address correctly. Note that currently this doesn't support address-based probe on modules (thus the probes on modules are symbol based), since it requires relative address probe syntax for kprobe-tracer, and it isn't implemented yet. One more note, this allows us to put events on correct address, but --list option should be updated to show correct corresponding source code. Changes from v2: - Refer kmap->ref_reloc_sym instead of "_stext". - Refer map->reloc to catch up the kASLR perf fix. Changes from v1: - Use _stext relative address instead of actual absolute address recorded in debuginfo. Signed-off-by: Masami Hiramatsu Cc: David Ahern Cc: "David A. Long" Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20140206053216.29635.22584.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Show in what binaries/modules probes are set

2014-02-18T12:34:50Z

Show the name of binary file or modules in which the probes are set with --list option. Without this change; # ./perf probe -m drm drm_av_sync_delay # ./perf probe -x perf dso__load_vmlinux # ./perf probe -l probe:drm_av_sync_delay (on drm_av_sync_delay) probe_perf:dso__load_vmlinux (on 0x000000000006d110) With this change; # ./perf probe -l probe:drm_av_sync_delay (on drm_av_sync_delay in drm) probe_perf:dso__load_vmlinux (on 0x000000000006d110 in /kbuild/ksrc/linux-3/tools/perf/perf) Signed-off-by: Masami Hiramatsu Cc: David Ahern Cc: "David A. Long" Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20140206053213.29635.69948.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Unify show_available_functions for uprobes/kprobes

2014-02-18T12:34:50Z

Unify show_available_functions for uprobes/kprobes to cleanup and reduce the code. This also improves error messages. Signed-off-by: Masami Hiramatsu Cc: David Ahern Cc: "David A. Long" Cc: Ingo Molnar Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Srikar Dronamraju Cc: Steven Rostedt Cc: yrl.pp-manager.tt@hitachi.com Link: http://lkml.kernel.org/r/20140206053211.29635.20563.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp Signed-off-by: Arnaldo Carvalho de Melo