linux-stable.git/tools/lib, branch v6.10.3

libbpf: Fix no-args func prototype BTF dumping syntax

2024-08-03T07:01:01+00:00

[ Upstream commit 189f1a976e426011e6a5588f1d3ceedf71fe2965 ]

For all these years libbpf's BTF dumper has been emitting not strictly
valid syntax for function prototypes that have no input arguments.

Instead of `int (*blah)()` we should emit `int (*blah)(void)`.

This is not normally a problem, but it manifests when we get kfuncs in
vmlinux.h that have no input arguments. Due to compiler internal
specifics, we get no BTF information for such kfuncs, if they are not
declared with proper `(void)`.

The fix is trivial. We also need to adjust a few ancient tests that
happily assumed `()` is correct.

Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion")
Reported-by: Tejun Heo 
Signed-off-by: Andrii Nakryiko 
Signed-off-by: Daniel Borkmann 
Acked-by: Stanislav Fomichev 
Link: https://lore.kernel.org/bpf/20240712224442.282823-1-andrii@kernel.org
Signed-off-by: Sasha Levin

libbpf: Skip base btf sanity checks

2024-08-03T06:59:40+00:00

[ Upstream commit c73a9683cb21012b6c0f14217974837151c527a8 ]

When upgrading to libbpf 1.3 we noticed a big performance hit while
loading programs using CORE on non base-BTF symbols. This was tracked
down to the new BTF sanity check logic. The issue is the base BTF
definitions are checked first for the base BTF and then again for every
module BTF.

Loading 5 dummy programs (using libbpf-rs) that are using CORE on a
non-base BTF symbol on my system:
- Before this fix: 3s.
- With this fix: 0.1s.

Fix this by only checking the types starting at the BTF start id. This
should ensure the base BTF is still checked as expected but only once
(btf->start_id == 1 when creating the base BTF), and then only
additional types are checked for each module BTF.

Fixes: 3903802bb99a ("libbpf: Add basic BTF sanity validation")
Signed-off-by: Antoine Tenart 
Signed-off-by: Andrii Nakryiko 
Reviewed-by: Alan Maguire 
Link: https://lore.kernel.org/bpf/20240624090908.171231-1-atenart@kernel.org
Signed-off-by: Sasha Levin

libbpf: Checking the btf_type kind when fixing variable offsets

2024-08-03T06:59:39+00:00

[ Upstream commit cc5083d1f3881624ad2de1f3cbb3a07e152cb254 ]

I encountered an issue when building the test_progs from the repository [1]:

  $ pwd
  /work/Qemu/x86_64/linux-6.10-rc2/tools/testing/selftests/bpf/

  $ make test_progs V=1
  [...]
  ./tools/sbin/bpftool gen object ./ip_check_defrag.bpf.linked2.o ./ip_check_defrag.bpf.linked1.o
  libbpf: failed to find symbol for variable 'bpf_dynptr_slice' in section '.ksyms'
  Error: failed to link './ip_check_defrag.bpf.linked1.o': No such file or directory (2)
  [...]

Upon investigation, I discovered that the btf_types referenced in the '.ksyms'
section had a kind of BTF_KIND_FUNC instead of BTF_KIND_VAR:

  $ bpftool btf dump file ./ip_check_defrag.bpf.linked1.o
  [...]
  [2] DATASEC '.ksyms' size=0 vlen=2
        type_id=16 offset=0 size=0 (FUNC 'bpf_dynptr_from_skb')
        type_id=17 offset=0 size=0 (FUNC 'bpf_dynptr_slice')
  [...]
  [16] FUNC 'bpf_dynptr_from_skb' type_id=82 linkage=extern
  [17] FUNC 'bpf_dynptr_slice' type_id=85 linkage=extern
  [...]

For a detailed analysis, please refer to [2]. We can add a kind checking to
fix the issue.

  [1] https://github.com/eddyz87/bpf/tree/binsort-btf-dedup
  [2] https://lore.kernel.org/all/0c0ef20c-c05e-4db9-bad7-2cbc0d6dfae7@oracle.com/

Fixes: 8fd27bf69b86 ("libbpf: Add BPF static linker BTF and BTF.ext support")
Signed-off-by: Donglin Peng 
Signed-off-by: Daniel Borkmann 
Reviewed-by: Alan Maguire 
Acked-by: Eduard Zingerman 
Link: https://lore.kernel.org/bpf/20240619122355.426405-1-dolinux.peng@gmail.com
Signed-off-by: Sasha Levin

libbpf: keep FD_CLOEXEC flag when dup()'ing FD

2024-08-03T06:59:36+00:00

[ Upstream commit 531876c80004ecff7bfdbd8ba6c6b48835ef5e22 ]

Make sure to preserve and/or enforce FD_CLOEXEC flag on duped FDs.
Use dup3() with O_CLOEXEC flag for that.

Without this fix libbpf effectively clears FD_CLOEXEC flag on each of BPF
map/prog FD, which is definitely not the right or expected behavior.

Reported-by: Lennart Poettering 
Fixes: bc308d011ab8 ("libbpf: call dup2() syscall directly")
Signed-off-by: Andrii Nakryiko 
Acked-by: Jiri Olsa 
Link: https://lore.kernel.org/r/20240529223239.504241-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

libbpf: don't close(-1) in multi-uprobe feature detector

2024-05-31T21:56:51+00:00

Guard close(link_fd) with extra link_fd >= 0 check to prevent close(-1).

Detected by Coverity static analysis.

Fixes: 04d939a2ab22 ("libbpf: detect broken PID filtering logic for multi-uprobe")
Signed-off-by: Andrii Nakryiko 
Acked-by: Jiri Olsa 
Link: https://lore.kernel.org/r/20240529231212.768828-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov

Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

2024-05-27T23:26:30+00:00

Daniel Borkmann says:

====================
pull-request: bpf 2024-05-27

We've added 15 non-merge commits during the last 7 day(s) which contain
a total of 18 files changed, 583 insertions(+), 55 deletions(-).

The main changes are:

1) Fix broken BPF multi-uprobe PID filtering logic which filtered by thread
   while the promise was to filter by process, from Andrii Nakryiko.

2) Fix the recent influx of syzkaller reports to sockmap which triggered
   a locking rule violation by performing a map_delete, from Jakub Sitnicki.

3) Fixes to netkit driver in particular on skb->pkt_type override upon pass
   verdict, from Daniel Borkmann.

4) Fix an integer overflow in resolve_btfids which can wrongly trigger build
   failures, from Friedrich Vock.

5) Follow-up fixes for ARC JIT reported by static analyzers,
   from Shahab Vahedi.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Cover verifier checks for mutating sockmap/sockhash
  Revert "bpf, sockmap: Prevent lock inversion deadlock in map delete elem"
  bpf: Allow delete from sockmap/sockhash only if update is allowed
  selftests/bpf: Add netkit test for pkt_type
  selftests/bpf: Add netkit tests for mac address
  netkit: Fix pkt_type override upon netkit pass verdict
  netkit: Fix setting mac address in l2 mode
  ARC, bpf: Fix issues reported by the static analyzers
  selftests/bpf: extend multi-uprobe tests with USDTs
  selftests/bpf: extend multi-uprobe tests with child thread case
  libbpf: detect broken PID filtering logic for multi-uprobe
  bpf: remove unnecessary rcu_read_{lock,unlock}() in multi-uprobe attach logic
  bpf: fix multi-uprobe PID filtering logic
  bpf: Fix potential integer overflow in resolve_btfids
  MAINTAINERS: Add myself as reviewer of ARM64 BPF JIT
====================

Link: https://lore.kernel.org/r/20240527203551.29712-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski

libbpf: detect broken PID filtering logic for multi-uprobe

2024-05-25T17:46:02+00:00

Libbpf is automatically (and transparently to user) detecting
multi-uprobe support in the kernel, and, if supported, uses
multi-uprobes to improve USDT attachment speed.

USDTs can be attached system-wide or for the specific process by PID. In
the latter case, we rely on correct kernel logic of not triggering USDT
for unrelated processes.

As such, on older kernels that do support multi-uprobes, but still have
broken PID filtering logic, we need to fall back to singular uprobes.

Unfortunately, whether user is using PID filtering or not is known at
the attachment time, which happens after relevant BPF programs were
loaded into the kernel. Also unfortunately, we need to make a call
whether to use multi-uprobes or singular uprobe for SEC("usdt") programs
during BPF object load time, at which point we have no information about
possible PID filtering.

The distinction between single and multi-uprobes is small, but important
for the kernel. Multi-uprobes get BPF_TRACE_UPROBE_MULTI attach type,
and kernel internally substitiute different implementation of some of
BPF helpers (e.g., bpf_get_attach_cookie()) depending on whether uprobe
is multi or singular. So, multi-uprobes and singular uprobes cannot be
intermixed.

All the above implies that we have to make an early and conservative
call about the use of multi-uprobes. And so this patch modifies libbpf's
existing feature detector for multi-uprobe support to also check correct
PID filtering. If PID filtering is not yet fixed, we fall back to
singular uprobes for USDTs.

This extension to feature detection is simple thanks to kernel's -EINVAL
addition for pid < 0.

Acked-by: Jiri Olsa 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/r/20240521163401.3005045-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov

Merge tag 'perf-tools-for-v6.10-1-2024-05-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools

2024-05-21T22:45:14+00:00

Pull perf tools updates from Arnaldo Carvalho de Melo:
 "General:

   - Integrate the shellcheck utility with the build of perf to allow
     catching shell problems early in areas such as 'perf test', 'perf
     trace' scrape scripts, etc

   - Add 'uretprobe' variant in the 'perf bench uprobe' tool

   - Add script to run instances of 'perf script' in parallel

   - Allow parsing tracepoint names that start with digits, such as
     9p/9p_client_req, etc. Make sure 'perf test' tests it even on
     systems where those tracepoints aren't available

   - Add Kan Liang to MAINTAINERS as a perf tools reviewer

   - Add support for using the 'capstone' disassembler library in
     various tools, such as 'perf script' and 'perf annotate'. This is
     an alternative for the use of the 'xed' and 'objdump' disassemblers

  Data-type profiling improvements:

   - Resolve types for a->b->c by backtracking the assignments until it
     finds DWARF info for one of those members

   - Support for global variables, keeping a cache to speed up lookups

   - Handle the 'call' instruction, dealing with effects on registers
     and handling its return when tracking register data types

   - Handle x86's segment based addressing like %gs:0x28, to support
     things like per CPU variables, the stack canary, etc

   - Data-type profiling got big speedups when using capstone for
     disassembling. The objdump outoput parsing method is left as a
     fallback when capstone fails or isn't available. There are patches
     posted for 6.11 that to use a LLVM disassembler

   - Support event group display in the TUI when annotating types with
     --data-type, for instance to show memory load and store events for
     the data type fields

   - Optimize the 'perf annotate' data structures, reducing memory usage

   - Add a initial 'perf test' for 'perf annotate', checking that a
     target symbol appears on the output, specifying objdump via the
     command line, etc

  Vendor Events:

   - Update Intel JSON files for Cascade Lake X, Emerald Rapids, Grand
     Ridge, Ice Lake X, Lunar Lake, Meteor Lake, Sapphire Rapids, Sierra
     Forest, Sky Lake X, Sky Lake and Snow Ridge X. Remove info metrics
     erroneously in TopdownL1

   - Add AMD's Zen 5 core and uncore events and metrics. Those come from
     the "Performance Monitor Counters for AMD Family 1Ah Model 00h- 0Fh
     Processors" document, with events that capture information on op
     dispatch, execution and retirement, branch prediction, L1 and L2
     cache activity, TLB activity, etc

   - Mark L1D_CACHE_INVAL impacted by errata for ARM64's AmpereOne/
     AmpereOneX

  Miscellaneous:

   - Sync header copies with the kernel sources

   - Move some header copies used only for generating translation string
     tables for ioctl cmds and other syscall integer arguments to a new
     directory under tools/perf/beauty/, to separate from copies in
     tools/include/ that are used to build the tools

   - Introduce scrape script for several syscall 'flags'/'mask'
     arguments

   - Improve cpumap utilization, fixing up pairing of refcounts, using
     the right iterators (perf_cpu_map__for_each_cpu), etc

   - Give more details about raw event encodings in 'perf list', show
     tracepoint encoding in the detailed output

   - Refactor the DSOs handling code, reducing memory usage

   - Document the BPF event modifier and add a 'perf test' for it

   - Improve the event parser, better error messages and add further
     'perf test's for it

   - Add reference count checking to 'struct comm_str' and 'struct
     mem_info'

   - Make ARM64's 'perf test' entries for the Neoverse N1 more robust

   - Tweak the ARM64's Coresight 'perf test's

   - Improve ARM64's CoreSight ETM version detection and error reporting

   - Fix handling of symbols when using kcore

   - Fix PAI (Processor Activity Instrumentation) counter names for s390
     virtual machines in 'perf report'

   - Fix -g/--call-graph option failure in 'perf sched timehist'

   - Add LIBTRACEEVENT_DIR build option to allow building with
     libtraceevent installed in non-standard directories, such as when
     doing cross builds

   - Various 'perf test' and 'perf bench' fixes

   - Improve 'perf probe' error message for long C++ probe names"

* tag 'perf-tools-for-v6.10-1-2024-05-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (260 commits)
  tools lib subcmd: Show parent options in help
  perf pmu: Count sys and cpuid JSON events separately
  perf stat: Don't display metric header for non-leader uncore events
  perf annotate-data: Ensure the number of type histograms
  perf annotate: Fix segfault on sample histogram
  perf daemon: Fix file leak in daemon_session__control
  libsubcmd: Fix parse-options memory leak
  perf lock: Avoid memory leaks from strdup()
  perf sched: Rename 'switches' column header to 'count' and add usage description, options for latency
  perf tools: Ignore deleted cgroups
  perf parse: Allow tracepoint names to start with digits
  perf parse-events: Add new 'fake_tp' parameter for tests
  perf parse-events: pass parse_state to add_tracepoint
  perf symbols: Fix ownership of string in dso__load_vmlinux()
  perf symbols: Update kcore map before merging in remaining symbols
  perf maps: Re-use __maps__free_maps_by_name()
  perf symbols: Remove map from list before updating addresses
  perf tracepoint: Don't scan all tracepoints to test if one exists
  perf dwarf-aux: Fix build with HAVE_DWARF_CFI_SUPPORT
  perf thread: Fixes to thread__new() related to initializing comm
  ...

Merge tag 'mm-nonmm-stable-2024-05-19-11-56' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2024-05-19T21:02:03+00:00

Pull non-mm updates from Andrew Morton:
 "Mainly singleton patches, documented in their respective changelogs.
  Notable series include:

   - Some maintenance and performance work for ocfs2 in Heming Zhao's
     series "improve write IO performance when fragmentation is high".

   - Some ocfs2 bugfixes from Su Yue in the series "ocfs2 bugs fixes
     exposed by fstests".

   - kfifo header rework from Andy Shevchenko in the series "kfifo:
     Clean up kfifo.h".

   - GDB script fixes from Florian Rommel in the series "scripts/gdb:
     Fixes for $lx_current and $lx_per_cpu".

   - After much discussion, a coding-style update from Barry Song
     explaining one reason why inline functions are preferred over
     macros. The series is "codingstyle: avoid unused parameters for a
     function-like macro""

* tag 'mm-nonmm-stable-2024-05-19-11-56' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (62 commits)
  fs/proc: fix softlockup in __read_vmcore
  nilfs2: convert BUG_ON() in nilfs_finish_roll_forward() to WARN_ON()
  scripts: checkpatch: check unused parameters for function-like macro
  Documentation: coding-style: ask function-like macros to evaluate parameters
  nilfs2: use __field_struct() for a bitwise field
  selftests/kcmp: remove unused open mode
  nilfs2: remove calls to folio_set_error() and folio_clear_error()
  kernel/watchdog_perf.c: tidy up kerneldoc
  watchdog: allow nmi watchdog to use raw perf event
  watchdog: handle comma separated nmi_watchdog command line
  nilfs2: make superblock data array index computation sparse friendly
  squashfs: remove calls to set the folio error flag
  squashfs: convert squashfs_symlink_read_folio to use folio APIs
  scripts/gdb: fix detection of current CPU in KGDB
  scripts/gdb: make get_thread_info accept pointers
  scripts/gdb: fix parameter handling in $lx_per_cpu
  scripts/gdb: fix failing KGDB detection during probe
  kfifo: don't use "proxy" headers
  media: stih-cec: add missing io.h
  media: rc: add missing io.h
  ...

libbpf: fix feature detectors when using token_fd

2024-05-15T16:34:53+00:00

Adjust `union bpf_attr` size passed to kernel in two feature-detecting
functions to take into account prog_token_fd field.

Libbpf is avoiding memset()'ing entire `union bpf_attr` by only using
minimal set of bpf_attr's fields. Two places have been missed when
wiring BPF token support in libbpf's feature detection logic.

Fix them trivially.

Fixes: f3dcee938f48 ("libbpf: Wire up token_fd into feature probing logic")
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/r/20240513180804.403775-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov