Automatically enabling a perf event after attaching a BPF prog to it is
not always desirable.
Add a new "dont_enable" field to struct bpf_perf_event_opts. While
introducing "enable" instead would be nicer in that it would avoid
a double negation in the implementation, it would make
DECLARE_LIBBPF_OPTS() less efficient.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Suggested-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Co-developed-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20250806162417.19666-2-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Pull bpf fixes from Alexei Starovoitov:
- Fix kCFI failures in JITed BPF code on arm64 (Sami Tolvanen, Puranjay
Mohan, Mark Rutland, Maxwell Bland)
- Disallow tail calls between BPF programs that use different cgroup
local storage maps to prevent out-of-bounds access (Daniel Borkmann)
- Fix unaligned access in flow_dissector and netfilter BPF programs
(Paul Chaignon)
- Avoid possible use of uninitialized mod_len in libbpf (Achill
Gilgenast)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: Test for unaligned flow_dissector ctx access
bpf: Improve ctx access verifier error message
bpf: Check netfilter ctx accesses are aligned
bpf: Check flow_dissector ctx accesses are aligned
arm64/cfi,bpf: Support kCFI + BPF on arm64
cfi: Move BPF CFI types and helpers to generic code
cfi: add C CFI type macro
libbpf: Avoid possible use of uninitialized mod_len
bpf: Fix oob access in cgroup local storage
bpf: Move cgroup iterator helpers to bpf.h
bpf: Move bpf map owner out of common struct
bpf: Add cookie object to bpf maps
Build-ID processing goodies
---------------------------
Build-IDs are content based hashes to link regions of memory to ELF files
in post processing. They have been available in distros for quite a while:
$ file /bin/bash
/bin/bash: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV),
dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2,
BuildID[sha1]=707a1c670cd72f8e55ffedfbe94ea98901b7ce3a,
for GNU/Linux 3.2.0, stripped
It is possible to ask the kernel to get it from mmap executable backing
storage at time they are being put in place and send it as metadata at
that moment to have in perf.data.
Prefer that across the board to speed up 'record' time - it post processes
the samples to find binaries touched by any samples and to save them with
build-ID. It can skip reading build-ID in userspace if it comes from the
kernel.
perf record
-----------
* Make --buildid-mmap default. The kernel can generate MMAP2 events
with a build-ID from ELF header. Use that by default instead of using
inode and device ID to identify binaries. It also can be disabled
with --no-buildid-mmap.
* Use BPF for -u/--uid option to sample processes belong to a user.
BPF can track user processes more accurately and the existing logic
often fails to get the list of processes due to race with reading the
/proc filesystem.
* Generate PERF_RECORD_BPF_METADATA when it profiles BPF programs and
they have variables starting with "bpf_metadata_". This will help to
identify BPF objects used in the profile. This has been supported in
bpftool for some time and allows the recording of metadata such as
commit hashes, versions, etc, that now gets recorded in perf.data as
well.
* Collect list of DSOs touched in the sample callchains as well as in
the sample itself. This would increase the processing time at the end
of record, but can improve the data quality.
perf stat
---------
* Add a new 'drm' pseudo-PMU support like in 'hwmon'. It can collect
DRM usage stats using fdinfo in /proc.
On my Intel laptop, it shows like below:
$ perf list drm
...
drm:
drm-active-stolen-system0
[Total memory active in one or more engines. Unit: drm_i915]
drm-active-system0
[Total memory active in one or more engines. Unit: drm_i915]
drm-engine-capacity-video
[Engine capacity. Unit: drm_i915]
drm-engine-copy
[Utilization in ns. Unit: drm_i915]
drm-engine-render
[Utilization in ns. Unit: drm_i915]
drm-engine-video
[Utilization in ns. Unit: drm_i915]
...
$ sudo perf stat -a -e drm-engine-render,drm-engine-video,drm-engine-capacity-video sleep 1
Performance counter stats for 'system wide':
48,137,316,988,873 ns drm-engine-render
34,452,696,746 ns drm-engine-video
20 capacity drm-engine-capacity-video
1.002086194 seconds time elapsed
perf list
---------
* Add description for software events. The description is in JSON format
and the event parser now can handle the software events like others
(for example, it's case-insensitive and subject to wildcard matching).
$ perf list software
List of pre-defined events (to be used in -e or -M):
software:
alignment-faults
[Number of kernel handled memory alignment faults. Unit: software]
bpf-output
[An event used by BPF programs to write to the perf ring buffer. Unit: software]
cgroup-switches
[Number of context switches to a task in a different cgroup. Unit: software]
context-switches
[Number of context switches [This event is an alias of cs]. Unit: software]
cpu-clock
[Per-CPU high-resolution timer based event. Unit: software]
cpu-migrations
[Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software]
cs
[Number of context switches [This event is an alias of context-switches]. Unit: software]
dummy
[A placeholder event that doesn't count anything. Unit: software]
emulation-faults
[Number of kernel handled unimplemented instruction faults handled through emulation. Unit: software]
faults
[Number of page faults [This event is an alias of page-faults]. Unit: software]
major-faults
[Number of major page faults. Major faults require I/O to handle. Unit: software]
migrations
[Number of times a process has migrated to a new CPU [This event is an alias of cpu-migrations]. Unit: software]
minor-faults
[Number of minor page faults. Minor faults don't require I/O to handle. Unit: software]
page-faults
[Number of page faults [This event is an alias of faults]. Unit: software]
task-clock
[Per-task high-resolution timer based event. Unit: software]
perf ftrace
-----------
* Add -e/--events option to perf ftrace latency to measure latency
between the two events instead of a function.
$ sudo perf ftrace latency -ab -e i915_request_wait_begin,i915_request_wait_end --hide-empty -- sleep 1
# DURATION | COUNT | GRAPH |
256 - 512 us | 4 | ###### |
2 - 4 ms | 2 | ### |
4 - 8 ms | 12 | ################### |
8 - 16 ms | 10 | ################ |
# statistics (in usec)
total time: 194915
avg time: 6961
max time: 12855
min time: 373
count: 28
* Add new function graph tracer options (--graph-opts) to display more
info like arguments and return value. They will be passed to the
kernel ftrace directly.
$ sudo perf ftrace -G vfs_write --graph-opts retval,retaddr
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
...
5) | mutex_unlock() { /* <-rb_simple_write+0xda/0x150 */
5) 0.188 us | local_clock(); /* <-lock_release+0x2ad/0x440 ret=0x3bf2a3cf90e */
5) | rt_mutex_slowunlock() { /* <-rb_simple_write+0xda/0x150 */
5) | _raw_spin_lock_irqsave() { /* <-rt_mutex_slowunlock+0x4f/0x200 */
5) 0.123 us | preempt_count_add(); /* <-_raw_spin_lock_irqsave+0x23/0x90 ret=0x0 */
5) 0.128 us | local_clock(); /* <-__lock_acquire.isra.0+0x17a/0x740 ret=0x3bf2a3cfc8b */
5) 0.086 us | do_raw_spin_trylock(); /* <-_raw_spin_lock_irqsave+0x4a/0x90 ret=0x1 */
5) 0.845 us | } /* _raw_spin_lock_irqsave ret=0x292 */
...
misc
----
* Add perf archive --exclude-buildids <FILE> option to skip some binaries.
The format of the FILE should be same as an output of perf buildid-list.
* Get rid of dependency of libcrypto. It was just to get SHA-1 hash so
implement it directly like in the kernel. A side effect is that it
needs -fno-strict-aliasing compiler option (again, like in the kernel).
* Convert all shell script tests to use bash.
Reviewed-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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Merge tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf tools updates from Namhyung Kim:
"Build-ID processing goodies:
Build-IDs are content based hashes to link regions of memory to ELF
files in post processing. They have been available in distros for
quite a while:
$ file /bin/bash
/bin/bash: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV),
dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2,
BuildID[sha1]=707a1c670cd72f8e55ffedfbe94ea98901b7ce3a,
for GNU/Linux 3.2.0, stripped
It is possible to ask the kernel to get it from mmap executable
backing storage at time they are being put in place and send it as
metadata at that moment to have in perf.data.
Prefer that across the board to speed up 'record' time - it post
processes the samples to find binaries touched by any samples and
to save them with build-ID. It can skip reading build-ID in
userspace if it comes from the kernel.
perf record:
* Make --buildid-mmap default. The kernel can generate MMAP2 events
with a build-ID from ELF header. Use that by default instead of using
inode and device ID to identify binaries. It also can be disabled
with --no-buildid-mmap.
* Use BPF for -u/--uid option to sample processes belong to a user.
BPF can track user processes more accurately and the existing logic
often fails to get the list of processes due to race with reading the
/proc filesystem.
* Generate PERF_RECORD_BPF_METADATA when it profiles BPF programs and
they have variables starting with "bpf_metadata_". This will help to
identify BPF objects used in the profile. This has been supported in
bpftool for some time and allows the recording of metadata such as
commit hashes, versions, etc, that now gets recorded in perf.data as
well.
* Collect list of DSOs touched in the sample callchains as well as in
the sample itself. This would increase the processing time at the end
of record, but can improve the data quality.
perf stat:
* Add a new 'drm' pseudo-PMU support like in 'hwmon'. It can collect
DRM usage stats using fdinfo in /proc.
On my Intel laptop, it shows like below:
$ perf list drm
...
drm:
drm-active-stolen-system0
[Total memory active in one or more engines. Unit: drm_i915]
drm-active-system0
[Total memory active in one or more engines. Unit: drm_i915]
drm-engine-capacity-video
[Engine capacity. Unit: drm_i915]
drm-engine-copy
[Utilization in ns. Unit: drm_i915]
drm-engine-render
[Utilization in ns. Unit: drm_i915]
drm-engine-video
[Utilization in ns. Unit: drm_i915]
...
$ sudo perf stat -a -e drm-engine-render,drm-engine-video,drm-engine-capacity-video sleep 1
Performance counter stats for 'system wide':
48,137,316,988,873 ns drm-engine-render
34,452,696,746 ns drm-engine-video
20 capacity drm-engine-capacity-video
1.002086194 seconds time elapsed
perf list
* Add description for software events. The description is in JSON format
and the event parser now can handle the software events like others
(for example, it's case-insensitive and subject to wildcard matching).
$ perf list software
List of pre-defined events (to be used in -e or -M):
software:
alignment-faults
[Number of kernel handled memory alignment faults. Unit: software]
bpf-output
[An event used by BPF programs to write to the perf ring buffer. Unit: software]
cgroup-switches
[Number of context switches to a task in a different cgroup. Unit: software]
context-switches
[Number of context switches [This event is an alias of cs]. Unit: software]
cpu-clock
[Per-CPU high-resolution timer based event. Unit: software]
cpu-migrations
[Number of times a process has migrated to a new CPU [This event is an alias of migrations]. Unit: software]
cs
[Number of context switches [This event is an alias of context-switches]. Unit: software]
dummy
[A placeholder event that doesn't count anything. Unit: software]
emulation-faults
[Number of kernel handled unimplemented instruction faults handled through emulation. Unit: software]
faults
[Number of page faults [This event is an alias of page-faults]. Unit: software]
major-faults
[Number of major page faults. Major faults require I/O to handle. Unit: software]
migrations
[Number of times a process has migrated to a new CPU [This event is an alias of cpu-migrations]. Unit: software]
minor-faults
[Number of minor page faults. Minor faults don't require I/O to handle. Unit: software]
page-faults
[Number of page faults [This event is an alias of faults]. Unit: software]
task-clock
[Per-task high-resolution timer based event. Unit: software]
perf ftrace:
* Add -e/--events option to perf ftrace latency to measure latency
between the two events instead of a function.
$ sudo perf ftrace latency -ab -e i915_request_wait_begin,i915_request_wait_end --hide-empty -- sleep 1
# DURATION | COUNT | GRAPH |
256 - 512 us | 4 | ###### |
2 - 4 ms | 2 | ### |
4 - 8 ms | 12 | ################### |
8 - 16 ms | 10 | ################ |
# statistics (in usec)
total time: 194915
avg time: 6961
max time: 12855
min time: 373
count: 28
* Add new function graph tracer options (--graph-opts) to display more
info like arguments and return value. They will be passed to the
kernel ftrace directly.
$ sudo perf ftrace -G vfs_write --graph-opts retval,retaddr
# tracer: function_graph
#
# CPU DURATION FUNCTION CALLS
# | | | | | | |
...
5) | mutex_unlock() { /* <-rb_simple_write+0xda/0x150 */
5) 0.188 us | local_clock(); /* <-lock_release+0x2ad/0x440 ret=0x3bf2a3cf90e */
5) | rt_mutex_slowunlock() { /* <-rb_simple_write+0xda/0x150 */
5) | _raw_spin_lock_irqsave() { /* <-rt_mutex_slowunlock+0x4f/0x200 */
5) 0.123 us | preempt_count_add(); /* <-_raw_spin_lock_irqsave+0x23/0x90 ret=0x0 */
5) 0.128 us | local_clock(); /* <-__lock_acquire.isra.0+0x17a/0x740 ret=0x3bf2a3cfc8b */
5) 0.086 us | do_raw_spin_trylock(); /* <-_raw_spin_lock_irqsave+0x4a/0x90 ret=0x1 */
5) 0.845 us | } /* _raw_spin_lock_irqsave ret=0x292 */
...
Misc:
* Add perf archive --exclude-buildids <FILE> option to skip some binaries.
The format of the FILE should be same as an output of perf buildid-list.
* Get rid of dependency of libcrypto. It was just to get SHA-1 hash so
implement it directly like in the kernel. A side effect is that it
needs -fno-strict-aliasing compiler option (again, like in the kernel).
* Convert all shell script tests to use bash"
* tag 'perf-tools-for-v6.17-2025-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (179 commits)
perf record: Cache build-ID of hit DSOs only
perf test: Ensure lock contention using pipe mode
perf python: Stop using deprecated PyUnicode_AsString()
perf list: Skip ABI PMUs when printing pmu values
perf list: Remove tracepoint printing code
perf tp_pmu: Add event APIs
perf tp_pmu: Factor existing tracepoint logic to new file
perf parse-events: Remove non-json software events
perf jevents: Add common software event json
perf tools: Remove libtraceevent in .gitignore
perf test: Fix comment ordering
perf sort: Use perf_env to set arch sort keys and header
perf test: Move PERF_SAMPLE_WEIGHT_STRUCT parsing to common test
perf sample: Remove arch notion of sample parsing
perf env: Remove global perf_env
perf trace: Avoid global perf_env with evsel__env
perf auxtrace: Pass perf_env from session through to mmap read
perf machine: Explicitly pass in host perf_env
perf bench synthesize: Avoid use of global perf_env
perf top: Make perf_env locally scoped
...
Though mod_len is only read when mod_name != NULL and both are initialized
together, gcc15 produces a warning with -Werror=maybe-uninitialized:
libbpf.c: In function 'find_kernel_btf_id.constprop':
libbpf.c:10100:33: error: 'mod_len' may be used uninitialized [-Werror=maybe-uninitialized]
10100 | if (mod_name && strncmp(mod->name, mod_name, mod_len) != 0)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libbpf.c:10070:21: note: 'mod_len' was declared here
10070 | int ret, i, mod_len;
| ^~~~~~~
Silence the false positive.
Signed-off-by: Achill Gilgenast <fossdd@pwned.life>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250729094611.2065713-1-fossdd@pwned.life
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Counting events system-wide with a specified CPU prior to this change
worked:
```
$ perf stat -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' -a sleep 1
Performance counter stats for 'system wide':
59,393,419,099 msr/tsc/
33,927,965,927 msr/tsc,cpu=cpu_core/
25,465,608,044 msr/tsc,cpu=cpu_atom/
```
However, when counting with process the counts became system wide:
```
$ perf stat -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' perf test -F 10
10.1: Basic parsing test : Ok
10.2: Parsing without PMU name : Ok
10.3: Parsing with PMU name : Ok
Performance counter stats for 'perf test -F 10':
59,233,549 msr/tsc/
59,227,556 msr/tsc,cpu=cpu_core/
59,224,053 msr/tsc,cpu=cpu_atom/
```
Make the handling of CPU maps with event parsing clearer. When an
event is parsed creating an evsel the cpus should be either the PMU's
cpumask or user specified CPUs.
Update perf_evlist__propagate_maps so that it doesn't clobber the user
specified CPUs. Try to make the behavior clearer, firstly fix up
missing cpumasks. Next, perform sanity checks and adjustments from the
global evlist CPU requests and for the PMU including simplifying to
the "any CPU"(-1) value. Finally remove the event if the cpumask is
empty.
So that events are opened with a CPU and a thread change stat's
create_perf_stat_counter to give both.
With the change things are fixed:
```
$ perf stat --no-scale -e 'msr/tsc/,msr/tsc,cpu=cpu_core/,msr/tsc,cpu=cpu_atom/' perf test -F 10
10.1: Basic parsing test : Ok
10.2: Parsing without PMU name : Ok
10.3: Parsing with PMU name : Ok
Performance counter stats for 'perf test -F 10':
63,704,975 msr/tsc/
47,060,704 msr/tsc,cpu=cpu_core/ (4.62%)
16,640,591 msr/tsc,cpu=cpu_atom/ (2.18%)
```
However, note the "--no-scale" option is used. This is necessary as
the running time for the event on the counter isn't the same as the
enabled time because the thread doesn't necessarily run on the CPUs
specified for the counter. All counter values are scaled with:
scaled_value = value * time_enabled / time_running
and so without --no-scale the scaled_value becomes very large. This
problem already exists on hybrid systems for the same reason. Here are
2 runs of the same code with an instructions event that counts the
same on both types of core, there is no real multiplexing happening on
the event:
```
$ perf stat -e instructions perf test -F 10
...
Performance counter stats for 'perf test -F 10':
87,896,447 cpu_atom/instructions/ (14.37%)
98,171,964 cpu_core/instructions/ (85.63%)
...
$ perf stat --no-scale -e instructions perf test -F 10
...
Performance counter stats for 'perf test -F 10':
13,069,890 cpu_atom/instructions/ (19.32%)
83,460,274 cpu_core/instructions/ (80.68%)
...
```
The scaling has inflated per-PMU instruction counts and the overall
count by 2x.
To fix this the kernel needs changing when a task+CPU event (or just
task event on hybrid) is scheduled out. A fix could be that the state
isn't inactive but off for such events, so that time_enabled counts
don't accumulate on them.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250719030517.1990983-13-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This allows the perf_evsel__exit to be called when the struct
perf_evsel is embedded inside another struct, such as struct evsel in
perf.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-8-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
own_cpus is generally the cpumask from the PMU. Rename to pmu_cpus to
try to make this clearer. Variable rename with no other changes.
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-7-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
FILENAME_MAX is often PATH_MAX (4kb), far more than needed for the
/proc path. Make the buffer size sufficient for the maximum integer
plus "/proc/" and "/status" with a '\0' terminator.
Fixes: 5ce42b5de4 ("tools subcmd: Add non-waitpid check_if_command_finished()")
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250717150855.1032526-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Fuzzer reported a memory access error in bpf_program__record_reloc()
that happens when:
- ".addr_space.1" section exists
- there is a relocation referencing this section
- there are no arena maps defined in BTF.
Sanity checks for maps existence are already present in
bpf_program__record_reloc(), hence this commit adds another one.
[1] https://github.com/libbpf/libbpf/actions/runs/16375110681/job/46272998064
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250718222059.281526-1-eddyz87@gmail.com
When compiling libbpf with some compilers, this warning is triggered:
libbpf.c: In function ‘bpf_object__gen_loader’:
libbpf.c:9209:28: error: ‘calloc’ sizes specified with ‘sizeof’ in the earlier argument and not in the later argument [-Werror=calloc-transposed-args]
9209 | gen = calloc(sizeof(*gen), 1);
| ^
libbpf.c:9209:28: note: earlier argument should specify number of elements, later size of each element
Fix this by inverting the calloc() arguments.
Signed-off-by: Matteo Croce <teknoraver@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20250717200337.49168-1-technoboy85@gmail.com
Initial __arena global variable support implementation in libbpf
contains a bug: it remembers struct bpf_map pointer for arena, which is
used later on to process relocations. Recording this pointer is
problematic because map pointers are not stable during ELF relocation
collection phase, as an array of struct bpf_map's can be reallocated,
invalidating all the pointers. Libbpf is dealing with similar issues by
using a stable internal map index, though for BPF arena map specifically
this approach wasn't used due to an oversight.
The resulting behavior is non-deterministic issue which depends on exact
layout of ELF object file, number of actual maps, etc. We didn't hit
this until very recently, when this bug started triggering crash in BPF
CI when validating one of sched-ext BPF programs.
The fix is rather straightforward: we just follow an established pattern
of remembering map index (just like obj->kconfig_map_idx, for example)
instead of `struct bpf_map *`, and resolving index to a pointer at the
point where map information is necessary.
While at it also add debug-level message for arena-related relocation
resolution information, which we already have for all other kinds of
maps.
Fixes: 2e7ba4f8fd ("libbpf: Recognize __arena global variables.")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250718001009.610955-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce a libbpf API so that users can read data from a given BPF
stream for a BPF prog fd. For now, only the low-level syscall wrapper
is provided, we can add a bpf_program__* accessor as a follow up if
needed.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-11-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a convenience macro to print data to the BPF streams. BPF_STDOUT and
BPF_STDERR stream IDs in the vmlinux.h can be passed to the macro to
print to the respective streams.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-10-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently perf aborts when it finds an invalid command. I guess it
depends on the environment as I have some custom commands in the path.
$ perf bad-command
perf: 'bad-command' is not a perf-command. See 'perf --help'.
Aborted (core dumped)
It's because the exclude_cmds() in libsubcmd has a use-after-free when
it removes some entries. After copying one to another entry, it keeps
the pointer in the both position. And the next copy operation will free
the later one but it's the same entry in the previous one.
For example, let's say cmds = { A, B, C, D, E } and excludes = { B, E }.
ci cj ei cmds-name excludes
-----------+--------------------
0 0 0 | A B : cmp < 0, ci == cj
1 1 0 | B B : cmp == 0
2 1 1 | C E : cmp < 0, ci != cj
At this point, it frees cmds->names[1] and cmds->names[1] is assigned to
cmds->names[2].
3 2 1 | D E : cmp < 0, ci != cj
Now it frees cmds->names[2] but it's the same as cmds->names[1]. So
accessing cmds->names[1] will be invalid.
This makes the subcmd tests succeed.
$ perf test subcmd
69: libsubcmd help tests :
69.1: Load subcmd names : Ok
69.2: Uniquify subcmd names : Ok
69.3: Exclude duplicate subcmd names : Ok
Fixes: 4b96679170 ("libsubcmd: Avoid SEGV/use-after-free when commands aren't excluded")
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250701201027.1171561-3-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cross-merge BPF, perf and other fixes after downstream PRs.
It restores BPF CI to green after critical fix
commit bc4394e5e7 ("perf: Fix the throttle error of some clock events")
No conflicts.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The `name` field in `obj->externs` points into the BTF data at initial
open time. However, some functions may invalidate this after opening and
before loading (e.g. `bpf_map__set_value_size`), which results in
pointers into freed memory and undefined behavior.
The simplest solution is to simply `strdup` these strings, similar to
the `essent_name`, and free them at the same time.
In order to test this path, the `global_map_resize` BPF selftest is
modified slightly to ensure the presence of an extern, which causes this
test to fail prior to the fix. Given there isn't an obvious API or error
to test against, I opted to add this to the existing test as an aspect
of the resizing feature rather than duplicate the test.
Fixes: 9d0a23313b ("libbpf: Add capability for resizing datasec maps")
Signed-off-by: Adin Scannell <amscanne@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250625050215.2777374-1-amscanne@meta.com
A missed evsel__close before evsel__delete was the source of leaking
perf events due to a hybrid test. Add asserts in debug builds so that
this shouldn't happen in the future. Add puts missing on the cpu map
and thread maps.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250617223356.2752099-4-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
When btf_dump__new() fails to allocate memory for the internal hashmap
(btf_dump->type_names), it returns an error code. However, the cleanup
function btf_dump__free() does not check if btf_dump->type_names is NULL
before attempting to free it. This leads to a null pointer dereference
when btf_dump__free() is called on a btf_dump object.
Fixes: 351131b51c ("libbpf: add btf_dump API for BTF-to-C conversion")
Signed-off-by: Yuan Chen <chenyuan@kylinos.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250618011933.11423-1-chenyuan_fl@163.com
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Merge tag 'v6.16-rc3' into perf-tools-next
To get the fixes in libbpf and perf tools.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Look for .rodata maps, find ones with 'bpf_metadata_' variables, extract
their values as strings, and create a new PERF_RECORD_BPF_METADATA
synthetic event using that data. The code gets invoked from the existing
routine perf_event__synthesize_one_bpf_prog().
For example, a BPF program with the following variables:
const char bpf_metadata_version[] SEC(".rodata") = "3.14159";
int bpf_metadata_value[] SEC(".rodata") = 42;
would generate a PERF_RECORD_BPF_METADATA record with:
.prog_name = <BPF program name, e.g. "bpf_prog_a1b2c3_foo">
.nr_entries = 2
.entries[0].key = "version"
.entries[0].value = "3.14159"
.entries[1].key = "value"
.entries[1].value = "42"
Each of the BPF programs and subprograms that share those variables would
get a distinct PERF_RECORD_BPF_METADATA record, with the ".prog_name"
showing the name of each program or subprogram. The prog_name is
deliberately the same as the ".name" field in the corresponding
PERF_RECORD_KSYMBOL record.
This code only gets invoked if support for displaying BTF char arrays
as strings is detected.
Signed-off-by: Blake Jones <blakejones@google.com>
Link: https://lore.kernel.org/r/20250612194939.162730-3-blakejones@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Currently libbpf supports bpf_program__attach_cgroup() with signature:
LIBBPF_API struct bpf_link *
bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd);
To support mprog style attachment, additionsl fields like flags,
relative_{fd,id} and expected_revision are needed.
Add a new API:
LIBBPF_API struct bpf_link *
bpf_program__attach_cgroup_opts(const struct bpf_program *prog, int cgroup_fd,
const struct bpf_cgroup_opts *opts);
where bpf_cgroup_opts contains all above needed fields.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250606163146.2429212-1-yonghong.song@linux.dev
libbpf_err_ptr() helpers are meant to return NULL and set errno, if
there is an error. But btf_parse_raw_mmap() is meant to be used
internally and is expected to return ERR_PTR() values. Because of this
mismatch, when libbpf tries to mmap /sys/kernel/btf/vmlinux, we don't
detect the error correctly with IS_ERR() check, and never fallback to
old non-mmap-based way of loading vmlinux BTF.
Fix this by using proper ERR_PTR() returns internally.
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fixes: 3c0421c93c ("libbpf: Use mmap to parse vmlinux BTF from sysfs")
Cc: Lorenz Bauer <lmb@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20250606202134.2738910-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The BTF dumper code currently displays arrays of characters as just that -
arrays, with each character formatted individually. Sometimes this is what
makes sense, but it's nice to be able to treat that array as a string.
This change adds a special case to the btf_dump functionality to allow
0-terminated arrays of single-byte integer values to be printed as
character strings. Characters for which isprint() returns false are
printed as hex-escaped values. This is enabled when the new ".emit_strings"
is set to 1 in the btf_dump_type_data_opts structure.
As an example, here's what it looks like to dump the string "hello" using
a few different field values for btf_dump_type_data_opts (.compact = 1):
- .emit_strings = 0, .skip_names = 0: (char[6])['h','e','l','l','o',]
- .emit_strings = 0, .skip_names = 1: ['h','e','l','l','o',]
- .emit_strings = 1, .skip_names = 0: (char[6])"hello"
- .emit_strings = 1, .skip_names = 1: "hello"
Here's the string "h\xff", dumped with .compact = 1 and .skip_names = 1:
- .emit_strings = 0: ['h',-1,]
- .emit_strings = 1: "h\xff"
Signed-off-by: Blake Jones <blakejones@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250603203701.520541-1-blakejones@google.com
perf report/top/annotate TUI:
- Accept the left arrow key as a Zoom out if done on the first column.
- Show if source code toggle status in title, to help spotting bugs with
the various disassemblers (capstone, llvm, objdump).
- Provide feedback on unhandled hotkeys.
Build:
- Better inform when certain features are not available with warnings in the
build process and in 'perf version --build-options' or 'perf -vv'.
perf record:
- Improve the --off-cpu code by synthesizing events for switch-out -> switch-in
intervals using a BPF program. This can be fine tuned using a --off-cpu-thresh
knob.
perf report:
- Add 'tgid' sort key.
perf mem/c2c:
- Add 'op', 'cache', 'snoop', 'dtlb' output fields.
- Add support for 'ldlat' on AMD IBS (Instruction Based Sampling).
perf ftrace:
- Use process/session specific trace settings instead of messing with
the global ftrace knobs.
perf trace:
- Implement syscall summary in BPF.
- Support --summary-mode=cgroup.
- Always print return value for syscalls returning a pid.
- The rseq and set_robust_list don't return a pid, just -errno.
perf lock contention:
- Symbolize zone->lock using BTF.
- Add -J/--inject-delay option to estimate impact on application performance by
optimization of kernel locking behavior.
perf stat:
- Improve hybrid support for the NMI watchdog warning.
Symbol resolution:
- Handle 'u' and 'l' symbols in /proc/kallsyms, resolving some Rust symbols.
- Improve Rust demangler.
Hardware tracing:
Intel PT:
- Fix PEBS-via-PT data_src.
- Do not default to recording all switch events.
- Fix pattern matching with python3 on the SQL viewer script.
arm64:
- Fixups for the hip08 hha PMU.
Vendor events:
- Update Intel events/metrics files for alderlake, alderlaken, arrowlake,
bonnell, broadwell, broadwellde, broadwellx, cascadelakex, clearwaterforest,
elkhartlake, emeraldrapids, grandridge, graniterapids, haswell, haswellx,
icelake, icelakex, ivybridge, ivytown, jaketown, lunarlake, meteorlake,
nehalemep, nehalemex, rocketlake, sandybridge, sapphirerapids, sierraforest,
skylake, skylakex, snowridgex, tigerlake, westmereep-dp, westmereep-sp,
westmereep-sx.
python support:
- Add support for event counts in the python binding, add a counting.py example.
perf list:
- Display the PMU name associated with a perf metric in JSON.
perf test:
- Hybrid improvements for metric value validation test.
- Fix LBR test by ignoring idle task.
- Add AMD IBS sw filter ana d'ldlat' tests.
- Add 'perf trace --summary-mode=cgroup' test.
- Add tests for the various language symbol demanglers.
Miscellaneous.
- Allow specifying the cpu an event will be tied using '-e event/cpu=N/'.
- Sync various headers with the kernel sources.
- Add annotations to use clang's -Wthread-safety and fix some problems
it detected.
- Make dump_stack() use perf's symbol resolution to provide better backtraces.
- Intel TPEBS support cleanups and fixes. TPEBS stands for Timed PEBS
(Precision Event-Based Sampling), that adds timing info, the retirement
latency of instructions.
- Various memory allocation (some detected by ASAN) and reference counting
fixes.
- Add a 8-byte aligned PERF_RECORD_COMPRESSED2 to replace PERF_RECORD_COMPRESSED.
- Skip unsupported event types in perf.data files, don't stop when finding one.
- Improve lookups using hashmaps and binary searches.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-tools-for-v6.16-1-2025-06-03' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools
Pull perf tools updates from Arnaldo Carvalho de Melo:
"perf report/top/annotate TUI:
- Accept the left arrow key as a Zoom out if done on the first column
- Show if source code toggle status in title, to help spotting bugs
with the various disassemblers (capstone, llvm, objdump)
- Provide feedback on unhandled hotkeys
Build:
- Better inform when certain features are not available with warnings
in the build process and in 'perf version --build-options' or 'perf -vv'
perf record:
- Improve the --off-cpu code by synthesizing events for switch-out ->
switch-in intervals using a BPF program. This can be fine tuned
using a --off-cpu-thresh knob
perf report:
- Add 'tgid' sort key
perf mem/c2c:
- Add 'op', 'cache', 'snoop', 'dtlb' output fields
- Add support for 'ldlat' on AMD IBS (Instruction Based Sampling)
perf ftrace:
- Use process/session specific trace settings instead of messing with
the global ftrace knobs
perf trace:
- Implement syscall summary in BPF
- Support --summary-mode=cgroup
- Always print return value for syscalls returning a pid
- The rseq and set_robust_list don't return a pid, just -errno
perf lock contention:
- Symbolize zone->lock using BTF
- Add -J/--inject-delay option to estimate impact on application
performance by optimization of kernel locking behavior
perf stat:
- Improve hybrid support for the NMI watchdog warning
Symbol resolution:
- Handle 'u' and 'l' symbols in /proc/kallsyms, resolving some Rust
symbols
- Improve Rust demangler
Hardware tracing:
Intel PT:
- Fix PEBS-via-PT data_src
- Do not default to recording all switch events
- Fix pattern matching with python3 on the SQL viewer script
arm64:
- Fixups for the hip08 hha PMU
Vendor events:
- Update Intel events/metrics files for alderlake, alderlaken,
arrowlake, bonnell, broadwell, broadwellde, broadwellx,
cascadelakex, clearwaterforest, elkhartlake, emeraldrapids,
grandridge, graniterapids, haswell, haswellx, icelake, icelakex,
ivybridge, ivytown, jaketown, lunarlake, meteorlake, nehalemep,
nehalemex, rocketlake, sandybridge, sapphirerapids, sierraforest,
skylake, skylakex, snowridgex, tigerlake, westmereep-dp,
westmereep-sp, westmereep-sx
python support:
- Add support for event counts in the python binding, add a
counting.py example
perf list:
- Display the PMU name associated with a perf metric in JSON
perf test:
- Hybrid improvements for metric value validation test
- Fix LBR test by ignoring idle task
- Add AMD IBS sw filter ana d'ldlat' tests
- Add 'perf trace --summary-mode=cgroup' test
- Add tests for the various language symbol demanglers
Miscellaneous:
- Allow specifying the cpu an event will be tied using '-e
event/cpu=N/'
- Sync various headers with the kernel sources
- Add annotations to use clang's -Wthread-safety and fix some
problems it detected
- Make dump_stack() use perf's symbol resolution to provide better
backtraces
- Intel TPEBS support cleanups and fixes. TPEBS stands for Timed PEBS
(Precision Event-Based Sampling), that adds timing info, the
retirement latency of instructions
- Various memory allocation (some detected by ASAN) and reference
counting fixes
- Add a 8-byte aligned PERF_RECORD_COMPRESSED2 to replace
PERF_RECORD_COMPRESSED
- Skip unsupported event types in perf.data files, don't stop when
finding one
- Improve lookups using hashmaps and binary searches"
* tag 'perf-tools-for-v6.16-1-2025-06-03' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (206 commits)
perf callchain: Always populate the addr_location map when adding IP
perf lock contention: Reject more than 10ms delays for safety
perf trace: Set errpid to false for rseq and set_robust_list
perf symbol: Move demangling code out of symbol-elf.c
perf trace: Always print return value for syscalls returning a pid
perf script: Print PERF_AUX_FLAG_COLLISION flag
perf mem: Show absolute percent in mem_stat output
perf mem: Display sort order only if it's available
perf mem: Describe overhead calculation in brief
perf record: Fix incorrect --user-regs comments
Revert "perf thread: Ensure comm_lock held for comm_list"
perf test trace_summary: Skip --bpf-summary tests if no libbpf
perf test intel-pt: Skip jitdump test if no libelf
perf intel-tpebs: Avoid race when evlist is being deleted
perf test demangle-java: Don't segv if demangling fails
perf symbol: Fix use-after-free in filename__read_build_id
perf pmu: Avoid segv for missing name/alias_name in wildcarding
perf machine: Factor creating a "live" machine out of dwarf-unwind
perf test: Add AMD IBS sw filter test
perf mem: Count L2 HITM for c2c statistic
...
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Merge tag 'bpf-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:
- Fix and improve BTF deduplication of identical BTF types (Alan
Maguire and Andrii Nakryiko)
- Support up to 12 arguments in BPF trampoline on arm64 (Xu Kuohai and
Alexis Lothoré)
- Support load-acquire and store-release instructions in BPF JIT on
riscv64 (Andrea Parri)
- Fix uninitialized values in BPF_{CORE,PROBE}_READ macros (Anton
Protopopov)
- Streamline allowed helpers across program types (Feng Yang)
- Support atomic update for hashtab of BPF maps (Hou Tao)
- Implement json output for BPF helpers (Ihor Solodrai)
- Several s390 JIT fixes (Ilya Leoshkevich)
- Various sockmap fixes (Jiayuan Chen)
- Support mmap of vmlinux BTF data (Lorenz Bauer)
- Support BPF rbtree traversal and list peeking (Martin KaFai Lau)
- Tests for sockmap/sockhash redirection (Michal Luczaj)
- Introduce kfuncs for memory reads into dynptrs (Mykyta Yatsenko)
- Add support for dma-buf iterators in BPF (T.J. Mercier)
- The verifier support for __bpf_trap() (Yonghong Song)
* tag 'bpf-next-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (135 commits)
bpf, arm64: Remove unused-but-set function and variable.
selftests/bpf: Add tests with stack ptr register in conditional jmp
bpf: Do not include stack ptr register in precision backtracking bookkeeping
selftests/bpf: enable many-args tests for arm64
bpf, arm64: Support up to 12 function arguments
bpf: Check rcu_read_lock_trace_held() in bpf_map_lookup_percpu_elem()
bpf: Avoid __bpf_prog_ret0_warn when jit fails
bpftool: Add support for custom BTF path in prog load/loadall
selftests/bpf: Add unit tests with __bpf_trap() kfunc
bpf: Warn with __bpf_trap() kfunc maybe due to uninitialized variable
bpf: Remove special_kfunc_set from verifier
selftests/bpf: Add test for open coded dmabuf_iter
selftests/bpf: Add test for dmabuf_iter
bpf: Add open coded dmabuf iterator
bpf: Add dmabuf iterator
dma-buf: Rename debugfs symbols
bpf: Fix error return value in bpf_copy_from_user_dynptr
libbpf: Use mmap to parse vmlinux BTF from sysfs
selftests: bpf: Add a test for mmapable vmlinux BTF
btf: Allow mmap of vmlinux btf
...
Teach libbpf to use mmap when parsing vmlinux BTF from /sys. We don't
apply this to fall-back paths on the regular file system because there
is no way to ensure that modifications underlying the MAP_PRIVATE
mapping are not visible to the process.
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250520-vmlinux-mmap-v5-3-e8c941acc414@isovalent.com
Allow computation of thread map index from a PID.
Note, with a 'struct perf_cpu_map' the sorted nature allows for a binary
search to compute the index which isn't currently possible with a
'struct perf_thread_map' as they aren't guaranteed sorted.
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Gautam Menghani <gautam@linux.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250519195148.1708988-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf_thread_map__nr() returns length 1 if the perf_thread_map is NULL,
meaning index 0 is valid.
When perf_thread_map__pid() of index 0 is read then return the expected
"any" -1 value.
Assert this is only done for index 0.
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Gautam Menghani <gautam@linux.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250519195148.1708988-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
libbpf handling of split BTF has been written largely with the
assumption that multiple splits are possible, i.e. split BTF on top of
split BTF on top of base BTF. One area where this does not quite work
is string handling in split BTF; the start string offset should be the
base BTF string section length + the base BTF string offset. This
worked in the past because for a single split BTF with base the start
string offset was always 0.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250519165935.261614-2-alan.maguire@oracle.com
The original PERF_RECORD_COMPRESS is not 8-byte aligned, which can cause
asan runtime error:
# Build with asan
$ make -C tools/perf O=/tmp/perf DEBUG=1 EXTRA_CFLAGS="-O0 -g -fno-omit-frame-pointer -fsanitize=undefined"
# Test success with many asan runtime errors:
$ /tmp/perf/perf test "Zstd perf.data compression/decompression" -vv
83: Zstd perf.data compression/decompression:
...
util/session.c:1959:13: runtime error: member access within misaligned address 0x7f69e3f99653 for type 'union perf_event', which requires 13 byte alignment
0x7f69e3f99653: note: pointer points here
d0 3a 50 69 44 00 00 00 00 00 08 00 bb 07 00 00 00 00 00 00 44 00 00 00 00 00 00 00 ff 07 00 00
^
util/session.c:2163:22: runtime error: member access within misaligned address 0x7f69e3f99653 for type 'union perf_event', which requires 8 byte alignment
0x7f69e3f99653: note: pointer points here
d0 3a 50 69 44 00 00 00 00 00 08 00 bb 07 00 00 00 00 00 00 44 00 00 00 00 00 00 00 ff 07 00 00
^
...
Since there is no way to align compressed data in zstd compression, this
patch add a new event type `PERF_RECORD_COMPRESSED2`, which adds a field
`data_size` to specify the actual compressed data size.
The `header.size` contains the total record size, including the padding
at the end to make it 8-byte aligned.
Tested with `Zstd perf.data compression/decompression`
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ben Gainey <ben.gainey@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250303183646.327510-1-ctshao@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Avoid dereferencing bpf_map_skeleton's link field if it's NULL.
If BPF map skeleton is created with the size, that indicates containing
link field, but the field was not actually initialized with valid
bpf_link pointer, libbpf crashes. This may happen when using libbpf-rs
skeleton.
Skeleton loading may still progress, but user needs to attach struct_ops
map separately.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250514113220.219095-1-mykyta.yatsenko5@gmail.com
Return value of the validate_nla() function can be propagated all the
way up to users of libbpf API. In case of error this libbpf version
of validate_nla returns -1 which will be seen as -EPERM from user's
point of view. Instead, return a more reasonable -EINVAL.
Fixes: bbf48c18ee ("libbpf: add error reporting in XDP")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250510182011.2246631-1-a.s.protopopov@gmail.com
Add perf_cpu_map__new_int() so that a CPU map can be created from a
single integer.
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Link: https://lore.kernel.org/r/20250403194337.40202-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
BTF dedup has a strong assumption that compiler with deduplicate identical
types within any given compilation unit (i.e., .c file). This property
is used when establishing equilvalence of two subgraphs of types.
Unfortunately, this property doesn't always holds in practice. We've
seen cases of having truly identical structs, unions, array definitions,
and, most recently, even pointers to the same type being duplicated
within CU.
Previously, we mitigated this on a case-by-case basis, adding a few
simple heuristics for validating that two BTF types (having two
different type IDs) are structurally the same. But this approach scales
poorly, and we can have more weird cases come up in the future.
So let's take a half-step back, and implement a bit more generic
structural equivalence check, recursively. We still limit it to
reasonable depth to avoid long reference loops. Depth-wise limiting of
potentially cyclical graph isn't great, but as I mentioned below doesn't
seem to be detrimental performance-wise. We can always improve this in
the future with per-type visited markers, if necessary.
Performance-wise this doesn't seem too affect vmlinux BTF dedup, which
makes sense because this logic kicks in not so frequently and only if we
already established a canonical candidate type match, but suddenly find
a different (but probably identical) type.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/r/20250501235231.1339822-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
With the latest LLVM bpf selftests build will fail with
the following error message:
progs/profiler.inc.h:710:31: error: default initialization of an object of type 'typeof ((parent_task)->real_cred->uid.val)' (aka 'const unsigned int') leaves the object uninitialized and is incompatible with C++ [-Werror,-Wdefault-const-init-unsafe]
710 | proc_exec_data->parent_uid = BPF_CORE_READ(parent_task, real_cred, uid.val);
| ^
tools/testing/selftests/bpf/tools/include/bpf/bpf_core_read.h:520:35: note: expanded from macro 'BPF_CORE_READ'
520 | ___type((src), a, ##__VA_ARGS__) __r; \
| ^
This happens because BPF_CORE_READ (and other macro) declare the
variable __r using the ___type macro which can inherit const modifier
from intermediate types.
Fix this by using __typeof_unqual__, when supported. (And when it
is not supported, the problem shouldn't appear, as older compilers
haven't complained.)
Fixes: 792001f4f7 ("libbpf: Add user-space variants of BPF_CORE_READ() family of macros")
Fixes: a4b09a9ef9 ("libbpf: Add non-CO-RE variants of BPF_CORE_READ() macro family")
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250502193031.3522715-1-a.s.protopopov@gmail.com
Return values of the linker_append_sec_data() and the
linker_append_elf_relos() functions are propagated all the
way up to users of libbpf API. In some error cases these
functions return -1 which will be seen as -EPERM from user's
point of view. Instead, return a more reasonable -EINVAL.
Fixes: faf6ed321c ("libbpf: Add BPF static linker APIs")
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250430120820.2262053-1-a.s.protopopov@gmail.com
When libperf is built alone in-source, $(OUTPUT) isn't set. This causes
the generated uapi path to resolve to '/../arch' which results in a
permissions error:
mkdir: cannot create directory '/../arch': Permission denied
Fix it by removing the preceding '/..' which means that it gets
generated either in the tools/lib/perf part of the tree or the OUTPUT
folder. Some other rules that rely on OUTPUT further refine this
conditionally depending on whether it's an in-source or out-of-source
build, but I don't think we need the extra complexity here. And this
rule is slightly different to others because the header is needed by
both libperf and Perf. This is further complicated by the fact that Perf
always passes O=... to libperf even for in source builds, meaning that
OUTPUT isn't set consistently between projects.
Because we're no longer going one level up to try to generate the file
in the tools/ folder, Perf's include rule needs to descend into libperf.
Also fix the clean rule while we're here.
Reported-by: Thorsten Leemhuis <linux@leemhuis.info>
Closes: https://lore.kernel.org/linux-perf-users/7703f88e-ccb7-4c98-9da4-8aad224e780f@leemhuis.info/
Fixes: bfb713ea53 ("perf tools: Fix arm64 build by generating unistd_64.h")
Signed-off-by: James Clark <james.clark@linaro.org>
Tested-by: Thorsten Leemhuis <linux@leemhuis.info>
Link: https://lore.kernel.org/r/20250429-james-perf-fix-libperf-in-source-build-v1-1-a1a827ac15e5@linaro.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Recently as a side-effect of
commit ac053946f5 ("compiler.h: introduce TYPEOF_UNQUAL() macro")
issues were observed in deduplication between modules and kernel BTF
such that a large number of kernel types were not deduplicated so
were found in module BTF (task_struct, bpf_prog etc). The root cause
appeared to be a failure to dedup struct types, specifically those
with members that were pointers with __percpu annotations.
The issue in dedup is at the point that we are deduplicating structures,
we have not yet deduplicated reference types like pointers. If multiple
copies of a pointer point at the same (deduplicated) integer as in this
case, we do not see them as identical. Special handling already exists
to deal with structures and arrays, so add pointer handling here too.
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250429161042.2069678-1-alan.maguire@oracle.com
This patch fixes a thread safety bug where libbpf_print uses the
global variable storing the print function pointer rather than the local
variable that had the print function set via __atomic_load_n.
Fixes: f1cb927cdb ("libbpf: Ensure print callback usage is thread-safe")
Signed-off-by: Jonathan Wiepert <jonathan.wiepert@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>
Link: https://lore.kernel.org/bpf/20250424221457.793068-1-jonathan.wiepert@gmail.com
It seems that sample_period is not used in perf buffer. Actually, only
wakeup_events are meaningful to enable events aggregation for wakeup notification.
Remove sample_period setting code to avoid confusion.
Fixes: fb84b82246 ("libbpf: add perf buffer API")
Signed-off-by: Tao Chen <chen.dylane@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/bpf/20250423163901.2983689-1-chen.dylane@linux.dev
Since pulling in the kernel changes in commit 22f72088ff ("tools
headers: Update the syscall table with the kernel sources"), arm64 is
no longer using a generic syscall header and generates one from the
syscall table. Therefore we must also generate the syscall header for
arm64 before building Perf.
Add it as a dependency to libperf which uses one syscall number. Perf
uses more, but as libperf is a dependency of Perf it will be generated
for both.
Future platforms that need this will have to add their own syscall-y
targets in libperf manually. Unfortunately the arch specific files that
do this (e.g. arch/arm64/include/asm/Kbuild) can't easily be imported
into the Perf build. But Perf only needs a subset of the generated files
anyway, so redefining them is probably the correct thing to do.
Fixes: 22f72088ff ("tools headers: Update the syscall table with the kernel sources")
Signed-off-by: James Clark <james.clark@linaro.org>
Tested-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Link: https://lore.kernel.org/r/20250417-james-perf-fix-gen-syscall-v1-1-1d268c923901@linaro.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Extend struct bpf_tc_hook with handle, qdisc name and a new attach type,
BPF_TC_QDISC, to allow users to add or remove any qdisc specified in
addition to clsact.
Signed-off-by: Amery Hung <amery.hung@bytedance.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250409214606.2000194-8-ameryhung@gmail.com
As shown in [1], it is possible to corrupt a BPF ELF file such that
arbitrary BPF instructions are loaded by libbpf. This can be done by
setting a symbol (BPF program) section offset to a large (unsigned)
number such that <section start + symbol offset> overflows and points
before the section data in the memory.
Consider the situation below where:
- prog_start = sec_start + symbol_offset <-- size_t overflow here
- prog_end = prog_start + prog_size
prog_start sec_start prog_end sec_end
| | | |
v v v v
.....................|################################|............
The report in [1] also provides a corrupted BPF ELF which can be used as
a reproducer:
$ readelf -S crash
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040
0000000000000068 0000000000000000 AX 0 0 8
$ readelf -s crash
Symbol table '.symtab' contains 8 entries:
Num: Value Size Type Bind Vis Ndx Name
...
6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp
Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will
point before the actual memory where section 2 is allocated.
This is also reported by AddressSanitizer:
=================================================================
==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490
READ of size 104 at 0x7c7302fe0000 thread T0
#0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76)
#1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856
#2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928
#3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930
#4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067
#5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090
#6 0x000000400c16 in main /poc/poc.c:8
#7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4)
#8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667)
#9 0x000000400b34 in _start (/poc/poc+0x400b34)
0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8)
allocated by thread T0 here:
#0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b)
#1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600)
#2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018)
#3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740
The problem here is that currently, libbpf only checks that the program
end is within the section bounds. There used to be a check
`while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was
removed by commit 6245947c1b ("libbpf: Allow gaps in BPF program
sections to support overriden weak functions").
Add a check for detecting the overflow of `sec_off + prog_sz` to
bpf_object__init_prog to fix this issue.
[1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
Fixes: 6245947c1b ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Reported-by: lmarch2 <2524158037@qq.com>
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
Link: https://lore.kernel.org/bpf/20250415155014.397603-1-vmalik@redhat.com
