lwn.git/tools/perf/util/probe-file.c, branch docs-6.1

perf probe-file: Delete namelist in del_events() on the error path

2021-07-18T12:27:37+00:00

ASan reports some memory leaks when running: # perf test "42: BPF filter" This second leak is caused by a strlist not being dellocated on error inside probe_file__del_events. This patch adds a goto label before the deallocation and makes the error path jump to it. Signed-off-by: Riccardo Mancini Fixes: e7895e422e4da63d ("perf probe: Split del_perf_probe_events()") Cc: Ian Rogers Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/174963c587ae77fa108af794669998e4ae558338.1626343282.git.rickyman7@gmail.com Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Provide clearer message permission error for tracefs access

2021-06-08T17:12:14+00:00

Report permission error for the tracefs open and rewrite whole the error message code around it. You'll see a hint according to what you want to do with perf probe as below. $ perf probe -l No permission to read tracefs. Please try 'sudo mount -o remount,mode=755 /sys/kernel/tracing/' Error: Failed to show event list. $ perf probe -d \* No permission to write tracefs. Please run this command again with sudo. Error: Failed to delete events. This also fixes -ENOTSUP checking for mounting tracefs/debugfs. Actually open returns -ENOENT in that case and we have to check it with current mount point list. If we unmount debugfs and tracefs perf probe shows correct message as below. $ perf probe -l Debugfs or tracefs is not mounted Please try 'sudo mount -t tracefs nodev /sys/kernel/tracing/' Error: Failed to show event list. Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Aneesh Kumar K.V Cc: Ian Rogers Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Link: http://lore.kernel.org/lkml/162299456839.503471.13863002017089255222.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Fixup Arm64 SDT arguments

2020-12-28T12:53:28+00:00

Arm64 ELF section '.note.stapsdt' uses string format "-4@[sp, NUM]" if the probe is to access data in stack, e.g. below is an example for dumping Arm64 ELF file and shows the argument format: Arguments: -4@[sp, 12] -4@[sp, 8] -4@[sp, 4] Comparing against other archs' argument format, Arm64's argument introduces an extra space character in the middle of square brackets, due to argv_split() uses space as splitter, the argument is wrongly divided into two items. To support Arm64 SDT, this patch fixes up for this case, if any item contains sub string "[sp", concatenates the two continuous items. And adds the detailed explaination in comment. Signed-off-by: Leo Yan Cc: Alexander Shishkin Cc: Alexandre Truong Cc: Alexis Berlemont Cc: He Zhe Cc: Ian Rogers Cc: Jiri Olsa Cc: John Garry Cc: Mark Rutland Cc: Masami Hiramatsu Cc: Mathieu Poirier Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sumanth Korikkar Cc: Thomas Richter Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Link: http://lore.kernel.org/lkml/20201225052751.24513-3-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Fix memory leak when synthesizing SDT probes

2020-12-24T13:52:10+00:00

The argv_split() function must be paired with argv_free(), else we must keep a reference to the argv array received or do the freeing ourselves, in synthesize_sdt_probe_command() we were simply leaking that argv[] array. Fixes: 3b1f8311f6963cd1 ("perf probe: Add sdt probes arguments into the uprobe cmd string") Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexandre Truong Cc: Alexis Berlemont Cc: He Zhe Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Garry Cc: Mark Rutland Cc: Masami Hiramatsu Cc: Mathieu Poirier Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Sumanth Korikkar Cc: Thomas Richter Cc: Will Deacon Link: https://lore.kernel.org/r/20201224135139.GF477817@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Fix user attribute access in kprobes

2020-06-09T15:40:04+00:00

Issue: # perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' did not work before. Fix: Make: # perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' output equivalent to ftrace: # echo 'p:probe/do_sched_setscheduler _text+517384 pid=%r2:s32 policy=%r3:s32 sched_priority=+u0(%r4):s32' > /sys/kernel/debug/tracing/kprobe_events Other: 1. Right now, __match_glob() does not handle [u]. For now, use *u]. 2. @user attribute was introduced in commit 1e032f7cfa14 ("perf-probe: Add user memory access attribute support") Test: 1. perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' 2 ./perf script sched 305669 [000] 1614458.838675: perf_bpf_probe:func: (2904e508) pid=261614 policy=2 sched_priority=1 3. cat /sys/kernel/debug/tracing/trace <...>-309956 [006] .... 1616098.093957: 0: prio: 1 Committer testing: Before: # perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' param(type:sched_param) has no member sched_priority@user. Error: Failed to add events. # pahole sched_param struct sched_param { int sched_priority; /* 0 4 */ /* size: 4, cachelines: 1, members: 1 */ /* last cacheline: 4 bytes */ }; # After: # perf probe -a 'do_sched_setscheduler pid policy param->sched_priority@user' Added new event: probe:do_sched_setscheduler (on do_sched_setscheduler with pid policy sched_priority=param->sched_priority) You can now use it in all perf tools, such as: perf record -e probe:do_sched_setscheduler -aR sleep 1 # cat /sys/kernel/debug/tracing/kprobe_events p:probe/do_sched_setscheduler _text+1113792 pid=%di:s32 policy=%si:s32 sched_priority=+u0(%dx):s32 # Fixes: 1e032f7cfa14 ("perf-probe: Add user memory access attribute support") Signed-off-by: Sumanth Korikkar Reviewed-by: Thomas Richter Acked-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Heiko Carstens Cc: Ilya Leoshkevich Cc: Jiri Olsa Cc: Steven Rostedt (VMware) Cc: bpf@vger.kernel.org LPU-Reference: 20200609081019.60234-2-sumanthk@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Fix to delete multiple probe event

2020-03-09T13:41:14+00:00

When we put an event with multiple probes, perf-probe fails to delete with filters. This comes from a failure to list up the event name because of overwrapping its name. To fix this issue, skip to list up the event which has same name. Without this patch: # perf probe -l \* probe_perf:map__map_ip (on perf_sample__fprintf_brstackoff:21@ probe_perf:map__map_ip (on perf_sample__fprintf_brstackoff:25@ probe_perf:map__map_ip (on append_inlines:12@util/machine.c in probe_perf:map__map_ip (on unwind_entry:19@util/machine.c in / probe_perf:map__map_ip (on map__map_ip@util/map.h in /home/mhi probe_perf:map__map_ip (on map__map_ip@util/map.h in /home/mhi # perf probe -d \* "*" does not hit any event. Error: Failed to delete events. Reason: No such file or directory (Code: -2) With it: # perf probe -d \* Removed event: probe_perf:map__map_ip # Fixes: 72363540c009 ("perf probe: Support multiprobe event") Reported-by: Arnaldo Carvalho de Melo Reported-by: He Zhe Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Cc: stable@vger.kernel.org Link: http://lore.kernel.org/lkml/158287666197.16697.7514373548551863562.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Check return value of strlist__add() for -ENOMEM

2020-02-27T14:03:13+00:00

strlist__add() may fail with -ENOMEM. Check it and give debugging hint in advance. Signed-off-by: He Zhe Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Kate Stewart Cc: Mark Rutland Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lore.kernel.org/lkml/1582727404-180095-1-git-send-email-zhe.he@windriver.com Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Support DW_AT_const_value constant value

2019-11-18T22:08:02+00:00

Support DW_AT_const_value for variable assignment instead of location. Note that this requires ftrace supporting immediate value. Signed-off-by: Masami Hiramatsu Cc: Namhyung Kim Cc: Ravi Bangoria Cc: Steven Rostedt (VMware) Cc: Tom Zanussi Link: http://lore.kernel.org/lkml/157406476012.24476.16096289871757175775.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Support multiprobe event

2019-11-18T22:03:38+00:00

Support multiprobe event if the event is based on function and lines and kernel supports it. In this case, perf probe creates the first probe with an event, and tries to append following probes on that event, since those probes must be on the same source code line. Before this patch; # perf probe -a vfs_read:18 Added new events: probe:vfs_read_L18 (on vfs_read:18) probe:vfs_read_L18_1 (on vfs_read:18) You can now use it in all perf tools, such as: perf record -e probe:vfs_read_L18_1 -aR sleep 1 # After this patch (on multiprobe supported kernel) # perf probe -a vfs_read:18 Added new events: probe:vfs_read_L18 (on vfs_read:18) probe:vfs_read_L18 (on vfs_read:18) You can now use it in all perf tools, such as: perf record -e probe:vfs_read_L18 -aR sleep 1 # Committer testing: On a kernel that doesn't support multiprobe events, after this patch: # uname -a Linux quaco 5.3.8-200.fc30.x86_64 #1 SMP Tue Oct 29 14:46:22 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux # grep append /sys/kernel/debug/tracing/README be modified by appending '.descending' or '.ascending' to a can be modified by appending any of the following modifiers # # perf probe -a vfs_read:18 Added new events: probe:vfs_read_L18 (on vfs_read:18) probe:vfs_read_L18_1 (on vfs_read:18) You can now use it in all perf tools, such as: perf record -e probe:vfs_read_L18_1 -aR sleep 1 # perf probe -l probe:vfs_read_L18 (on vfs_read:18@fs/read_write.c) probe:vfs_read_L18_1 (on vfs_read:18@fs/read_write.c) # Signed-off-by: Masami Hiramatsu Tested-by: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Ravi Bangoria Cc: Steven Rostedt (VMware) Cc: Tom Zanussi Link: http://lore.kernel.org/lkml/157406475010.24476.586290752591512351.stgit@devnote2 Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Add missing build-id.h header.

2019-09-20T12:19:20+00:00

It uses things defined in that header and was getting it only indirectly, thru dso.h, fix it. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-7u3sf4j5huhi3mqa1q77524b@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo