linux.git/tools/perf/util, branch v6.11

perf python: include "util/sample.h"

2024-09-02T18:59:24+00:00

The 32-bit arm build system will complain:

tools/perf/util/python.c:75:28: error: field ‘sample’ has incomplete type
   75 |         struct perf_sample sample;

However, arm64 build system doesn't complain this.

The root cause is arm64 define "HAVE_KVM_STAT_SUPPORT := 1" in
tools/perf/arch/arm64/Makefile, but arm arch doesn't define this.
This will lead to kvm-stat.h include other header files on arm64 build
system, especially "util/sample.h" for util/python.c.

This will try to directly include "util/sample.h" for "util/python.c" to
avoid such build issue on arm platform.

Signed-off-by: Xu Yang 
Cc: imx@lists.linux.dev
Link: https://lore.kernel.org/r/20240819023403.201324-1-xu.yang_2@nxp.com
Signed-off-by: Namhyung Kim

perf lock contention: Fix spinlock and rwlock accounting

2024-09-02T18:59:24+00:00

The spinlock and rwlock use a single-element per-cpu array to track
current locks due to performance reason.  But this means the key is
always available and it cannot simply account lock stats in the array
because some of them are invalid.

In fact, the contention_end() program in the BPF invalidates the entry
by setting the 'lock' value to 0 instead of deleting the entry for the
hashmap.  So it should skip entries with the lock value of 0 in the
account_end_timestamp().

Otherwise, it'd have spurious high contention on an idle machine:

  $ sudo perf lock con -ab -Y spinlock sleep 3
   contended   total wait     max wait     avg wait         type   caller

           8      4.72 s       1.84 s     590.46 ms     spinlock   rcu_core+0xc7
           8      1.87 s       1.87 s     233.48 ms     spinlock   process_one_work+0x1b5
           2      1.87 s       1.87 s     933.92 ms     spinlock   worker_thread+0x1a2
           3      1.81 s       1.81 s     603.93 ms     spinlock   tmigr_update_events+0x13c
           2      1.72 s       1.72 s     861.98 ms     spinlock   tick_do_update_jiffies64+0x25
           6     42.48 us     13.02 us      7.08 us     spinlock   futex_q_lock+0x2a
           1     13.03 us     13.03 us     13.03 us     spinlock   futex_wake+0xce
           1     11.61 us     11.61 us     11.61 us     spinlock   rcu_core+0xc7

I don't believe it has contention on a spinlock longer than 1 second.
After this change, it only reports some small contentions.

  $ sudo perf lock con -ab -Y spinlock sleep 3
   contended   total wait     max wait     avg wait         type   caller

           4    133.51 us     43.29 us     33.38 us     spinlock   tick_do_update_jiffies64+0x25
           4     69.06 us     31.82 us     17.27 us     spinlock   process_one_work+0x1b5
           2     50.66 us     25.77 us     25.33 us     spinlock   rcu_core+0xc7
           1     28.45 us     28.45 us     28.45 us     spinlock   rcu_core+0xc7
           1     24.77 us     24.77 us     24.77 us     spinlock   tmigr_update_events+0x13c
           1     23.34 us     23.34 us     23.34 us     spinlock   raw_spin_rq_lock_nested+0x15

Fixes: b5711042a1c8 ("perf lock contention: Use per-cpu array map for spinlocks")
Reported-by: Xi Wang 
Cc: Song Liu 
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20240828052953.1445862-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim

perf tool: fix dereferencing NULL al->maps

2024-07-26T18:12:16+00:00

With 0dd5041c9a0e ("perf addr_location: Add init/exit/copy functions"),
when cpumode is 3 (macro PERF_RECORD_MISC_HYPERVISOR),
thread__find_map() could return with al->maps being NULL.

The path below could add a callchain_cursor_node with NULL ms.maps.

add_callchain_ip()
  thread__find_symbol(.., &al)
    thread__find_map(.., &al)   // al->maps becomes NULL
  ms.maps = maps__get(al.maps)
  callchain_cursor_append(..., &ms, ...)
    node->ms.maps = maps__get(ms->maps)

Then the path below would dereference NULL maps and get segfault.

fill_callchain_info()
  maps__machine(node->ms.maps);

Fix it by checking if maps is NULL in fill_callchain_info().

Fixes: 0dd5041c9a0e ("perf addr_location: Add init/exit/copy functions")
Signed-off-by: Casey Chen 
Reviewed-by: Ian Rogers 
Reviewed-by: Arnaldo Carvalho de Melo 
Acked-by: Namhyung Kim 
Cc: yzhong@purestorage.com
Link: https://lore.kernel.org/r/20240722211548.61455-1-cachen@purestorage.com
Signed-off-by: Namhyung Kim

perf dso: Fix build when libunwind is enabled

2024-07-17T20:17:57+00:00

Now that symsrc_filename is always accessed through an accessor, we also
need a free() function for it to avoid the following compilation error:

  util/unwind-libunwind-local.c:416:12: error: lvalue required as unary
    ‘&’ operand
  416 |      zfree(&dso__symsrc_filename(dso));

Fixes: 1553419c3c10 ("perf dso: Fix address sanitizer build")
Signed-off-by: James Clark 
Reviewed-by: Ian Rogers 
Tested-by: Leo Yan 
Tested-by: Florian Fainelli 
Cc: Yunseong Kim 
Cc: Athira Rajeev 
Link: https://lore.kernel.org/r/20240715094715.3914813-1-james.clark@linaro.org
Signed-off-by: Namhyung Kim

perf trace: Fix iteration of syscall ids in syscalltbl->entries

2024-07-12T16:49:02+00:00

This is a bug found when implementing pretty-printing for the
landlock_add_rule system call, I decided to send this patch separately
because this is a serious bug that should be fixed fast.

I wrote a test program to do landlock_add_rule syscall in a loop,
yet perf trace -e landlock_add_rule freezes, giving no output.

This bug is introduced by the false understanding of the variable "key"
below:
```
for (key = 0; key < trace->sctbl->syscalls.nr_entries; ++key) {
	struct syscall *sc = trace__syscall_info(trace, NULL, key);
	...
}
```
The code above seems right at the beginning, but when looking at
syscalltbl.c, I found these lines:

```
for (i = 0; i <= syscalltbl_native_max_id; ++i)
	if (syscalltbl_native[i])
		++nr_entries;

entries = tbl->syscalls.entries = malloc(sizeof(struct syscall) * nr_entries);
...

for (i = 0, j = 0; i <= syscalltbl_native_max_id; ++i) {
	if (syscalltbl_native[i]) {
		entries[j].name = syscalltbl_native[i];
		entries[j].id = i;
		++j;
	}
}
```

meaning the key is merely an index to traverse the syscall table,
instead of the actual syscall id for this particular syscall.

So if one uses key to do trace__syscall_info(trace, NULL, key), because
key only goes up to trace->sctbl->syscalls.nr_entries, for example, on
my X86_64 machine, this number is 373, it will end up neglecting all
the rest of the syscall, in my case, everything after `rseq`, because
the traversal will stop at 373, and `rseq` is the last syscall whose id
is lower than 373

in tools/perf/arch/x86/include/generated/asm/syscalls_64.c:
```
	...
	[334] = "rseq",
	[424] = "pidfd_send_signal",
	...
```

The reason why the key is scrambled but perf trace works well is that
key is used in trace__syscall_info(trace, NULL, key) to do
trace->syscalls.table[id], this makes sure that the struct syscall returned
actually has an id the same value as key, making the later bpf_prog
matching all correct.

After fixing this bug, I can do perf trace on 38 more syscalls, and
because more syscalls are visible, we get 8 more syscalls that can be
augmented.

before:

perf $ perf trace -vv --max-events=1 |& grep Reusing
Reusing "open" BPF sys_enter augmenter for "stat"
Reusing "open" BPF sys_enter augmenter for "lstat"
Reusing "open" BPF sys_enter augmenter for "access"
Reusing "connect" BPF sys_enter augmenter for "accept"
Reusing "sendto" BPF sys_enter augmenter for "recvfrom"
Reusing "connect" BPF sys_enter augmenter for "bind"
Reusing "connect" BPF sys_enter augmenter for "getsockname"
Reusing "connect" BPF sys_enter augmenter for "getpeername"
Reusing "open" BPF sys_enter augmenter for "execve"
Reusing "open" BPF sys_enter augmenter for "truncate"
Reusing "open" BPF sys_enter augmenter for "chdir"
Reusing "open" BPF sys_enter augmenter for "mkdir"
Reusing "open" BPF sys_enter augmenter for "rmdir"
Reusing "open" BPF sys_enter augmenter for "creat"
Reusing "open" BPF sys_enter augmenter for "link"
Reusing "open" BPF sys_enter augmenter for "unlink"
Reusing "open" BPF sys_enter augmenter for "symlink"
Reusing "open" BPF sys_enter augmenter for "readlink"
Reusing "open" BPF sys_enter augmenter for "chmod"
Reusing "open" BPF sys_enter augmenter for "chown"
Reusing "open" BPF sys_enter augmenter for "lchown"
Reusing "open" BPF sys_enter augmenter for "mknod"
Reusing "open" BPF sys_enter augmenter for "statfs"
Reusing "open" BPF sys_enter augmenter for "pivot_root"
Reusing "open" BPF sys_enter augmenter for "chroot"
Reusing "open" BPF sys_enter augmenter for "acct"
Reusing "open" BPF sys_enter augmenter for "swapon"
Reusing "open" BPF sys_enter augmenter for "swapoff"
Reusing "open" BPF sys_enter augmenter for "delete_module"
Reusing "open" BPF sys_enter augmenter for "setxattr"
Reusing "open" BPF sys_enter augmenter for "lsetxattr"
Reusing "openat" BPF sys_enter augmenter for "fsetxattr"
Reusing "open" BPF sys_enter augmenter for "getxattr"
Reusing "open" BPF sys_enter augmenter for "lgetxattr"
Reusing "openat" BPF sys_enter augmenter for "fgetxattr"
Reusing "open" BPF sys_enter augmenter for "listxattr"
Reusing "open" BPF sys_enter augmenter for "llistxattr"
Reusing "open" BPF sys_enter augmenter for "removexattr"
Reusing "open" BPF sys_enter augmenter for "lremovexattr"
Reusing "fsetxattr" BPF sys_enter augmenter for "fremovexattr"
Reusing "open" BPF sys_enter augmenter for "mq_open"
Reusing "open" BPF sys_enter augmenter for "mq_unlink"
Reusing "fsetxattr" BPF sys_enter augmenter for "add_key"
Reusing "fremovexattr" BPF sys_enter augmenter for "request_key"
Reusing "fremovexattr" BPF sys_enter augmenter for "inotify_add_watch"
Reusing "fremovexattr" BPF sys_enter augmenter for "mkdirat"
Reusing "fremovexattr" BPF sys_enter augmenter for "mknodat"
Reusing "fremovexattr" BPF sys_enter augmenter for "fchownat"
Reusing "fremovexattr" BPF sys_enter augmenter for "futimesat"
Reusing "fremovexattr" BPF sys_enter augmenter for "newfstatat"
Reusing "fremovexattr" BPF sys_enter augmenter for "unlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "linkat"
Reusing "open" BPF sys_enter augmenter for "symlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "readlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "fchmodat"
Reusing "fremovexattr" BPF sys_enter augmenter for "faccessat"
Reusing "fremovexattr" BPF sys_enter augmenter for "utimensat"
Reusing "connect" BPF sys_enter augmenter for "accept4"
Reusing "fremovexattr" BPF sys_enter augmenter for "name_to_handle_at"
Reusing "fremovexattr" BPF sys_enter augmenter for "renameat2"
Reusing "open" BPF sys_enter augmenter for "memfd_create"
Reusing "fremovexattr" BPF sys_enter augmenter for "execveat"
Reusing "fremovexattr" BPF sys_enter augmenter for "statx"

after

perf $ perf trace -vv --max-events=1 |& grep Reusing
Reusing "open" BPF sys_enter augmenter for "stat"
Reusing "open" BPF sys_enter augmenter for "lstat"
Reusing "open" BPF sys_enter augmenter for "access"
Reusing "connect" BPF sys_enter augmenter for "accept"
Reusing "sendto" BPF sys_enter augmenter for "recvfrom"
Reusing "connect" BPF sys_enter augmenter for "bind"
Reusing "connect" BPF sys_enter augmenter for "getsockname"
Reusing "connect" BPF sys_enter augmenter for "getpeername"
Reusing "open" BPF sys_enter augmenter for "execve"
Reusing "open" BPF sys_enter augmenter for "truncate"
Reusing "open" BPF sys_enter augmenter for "chdir"
Reusing "open" BPF sys_enter augmenter for "mkdir"
Reusing "open" BPF sys_enter augmenter for "rmdir"
Reusing "open" BPF sys_enter augmenter for "creat"
Reusing "open" BPF sys_enter augmenter for "link"
Reusing "open" BPF sys_enter augmenter for "unlink"
Reusing "open" BPF sys_enter augmenter for "symlink"
Reusing "open" BPF sys_enter augmenter for "readlink"
Reusing "open" BPF sys_enter augmenter for "chmod"
Reusing "open" BPF sys_enter augmenter for "chown"
Reusing "open" BPF sys_enter augmenter for "lchown"
Reusing "open" BPF sys_enter augmenter for "mknod"
Reusing "open" BPF sys_enter augmenter for "statfs"
Reusing "open" BPF sys_enter augmenter for "pivot_root"
Reusing "open" BPF sys_enter augmenter for "chroot"
Reusing "open" BPF sys_enter augmenter for "acct"
Reusing "open" BPF sys_enter augmenter for "swapon"
Reusing "open" BPF sys_enter augmenter for "swapoff"
Reusing "open" BPF sys_enter augmenter for "delete_module"
Reusing "open" BPF sys_enter augmenter for "setxattr"
Reusing "open" BPF sys_enter augmenter for "lsetxattr"
Reusing "openat" BPF sys_enter augmenter for "fsetxattr"
Reusing "open" BPF sys_enter augmenter for "getxattr"
Reusing "open" BPF sys_enter augmenter for "lgetxattr"
Reusing "openat" BPF sys_enter augmenter for "fgetxattr"
Reusing "open" BPF sys_enter augmenter for "listxattr"
Reusing "open" BPF sys_enter augmenter for "llistxattr"
Reusing "open" BPF sys_enter augmenter for "removexattr"
Reusing "open" BPF sys_enter augmenter for "lremovexattr"
Reusing "fsetxattr" BPF sys_enter augmenter for "fremovexattr"
Reusing "open" BPF sys_enter augmenter for "mq_open"
Reusing "open" BPF sys_enter augmenter for "mq_unlink"
Reusing "fsetxattr" BPF sys_enter augmenter for "add_key"
Reusing "fremovexattr" BPF sys_enter augmenter for "request_key"
Reusing "fremovexattr" BPF sys_enter augmenter for "inotify_add_watch"
Reusing "fremovexattr" BPF sys_enter augmenter for "mkdirat"
Reusing "fremovexattr" BPF sys_enter augmenter for "mknodat"
Reusing "fremovexattr" BPF sys_enter augmenter for "fchownat"
Reusing "fremovexattr" BPF sys_enter augmenter for "futimesat"
Reusing "fremovexattr" BPF sys_enter augmenter for "newfstatat"
Reusing "fremovexattr" BPF sys_enter augmenter for "unlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "linkat"
Reusing "open" BPF sys_enter augmenter for "symlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "readlinkat"
Reusing "fremovexattr" BPF sys_enter augmenter for "fchmodat"
Reusing "fremovexattr" BPF sys_enter augmenter for "faccessat"
Reusing "fremovexattr" BPF sys_enter augmenter for "utimensat"
Reusing "connect" BPF sys_enter augmenter for "accept4"
Reusing "fremovexattr" BPF sys_enter augmenter for "name_to_handle_at"
Reusing "fremovexattr" BPF sys_enter augmenter for "renameat2"
Reusing "open" BPF sys_enter augmenter for "memfd_create"
Reusing "fremovexattr" BPF sys_enter augmenter for "execveat"
Reusing "fremovexattr" BPF sys_enter augmenter for "statx"

TL;DR:

These are the new syscalls that can be augmented
Reusing "openat" BPF sys_enter augmenter for "open_tree"
Reusing "openat" BPF sys_enter augmenter for "openat2"
Reusing "openat" BPF sys_enter augmenter for "mount_setattr"
Reusing "openat" BPF sys_enter augmenter for "move_mount"
Reusing "open" BPF sys_enter augmenter for "fsopen"
Reusing "openat" BPF sys_enter augmenter for "fspick"
Reusing "openat" BPF sys_enter augmenter for "faccessat2"
Reusing "openat" BPF sys_enter augmenter for "fchmodat2"

as for the perf trace output:

before

perf $ perf trace -e faccessat2 --max-events=1
[no output]

after

perf $ ./perf trace -e faccessat2 --max-events=1
     0.000 ( 0.037 ms): waybar/958 faccessat2(dfd: 40, filename: "uevent")                               = 0

P.S. The reason why this bug was not found in the past five years is
probably because it only happens to the newer syscalls whose id is
greater, for instance, faccessat2 of id 439, which not a lot of people
care about when using perf trace.

[Arnaldo]: notes

That and the fact that the BPF code was hidden before having to use -e,
that got changed kinda recently when we switched to using BPF skels for
augmenting syscalls in 'perf trace':

⬢[acme@toolbox perf-tools-next]$ git log --oneline tools/perf/util/bpf_skel/augmented_raw_syscalls.bpf.c
a9f4c6c999008c92 perf trace: Collect sys_nanosleep first argument
29d16de26df17e94 perf augmented_raw_syscalls.bpf: Move 'struct timespec64' to vmlinux.h
5069211e2f0b47e7 perf trace: Use the right bpf_probe_read(_str) variant for reading user data
33b725ce7b988756 perf trace: Avoid compile error wrt redefining bool
7d9642311b6d9d31 perf bpf augmented_raw_syscalls: Add an assert to make sure sizeof(augmented_arg->value) is a power of two.
262b54b6c9396823 perf bpf augmented_raw_syscalls: Add an assert to make sure sizeof(saddr) is a power of two.
1836480429d173c0 perf bpf_skel augmented_raw_syscalls: Cap the socklen parameter using &= sizeof(saddr)
cd2cece61ac5f900 perf trace: Tidy comments related to BPF + syscall augmentation
5e6da6be3082f77b perf trace: Migrate BPF augmentation to use a skeleton
⬢[acme@toolbox perf-tools-next]$

⬢[acme@toolbox perf-tools-next]$ git show --oneline --pretty=reference 5e6da6be3082f77b | head -1
5e6da6be3082f77b (perf trace: Migrate BPF augmentation to use a skeleton, 2023-08-10)
⬢[acme@toolbox perf-tools-next]$

I.e. from August, 2023.

One had as well to ask for BUILD_BPF_SKEL=1, which now is default if all
it needs is available on the system.

I simplified the code to not expose the 'struct syscall' outside of
tools/perf/util/syscalltbl.c, instead providing a function to go from
the index to the syscall id:

  int syscalltbl__id_at_idx(struct syscalltbl *tbl, int idx);

Signed-off-by: Howard Chu 
Tested-by: Arnaldo Carvalho de Melo 
Link: https://lore.kernel.org/lkml/ZmhlAxbVcAKoPTg8@x1
Link: https://lore.kernel.org/r/20240705132059.853205-2-howardchu95@gmail.com
Signed-off-by: Namhyung Kim

perf dso: Fix address sanitizer build

2024-07-12T16:38:41+00:00

Various files had been missed from having accessor functions added for
the sake of dso reference count checking. Add the function calls and
missing dso accessor functions.

Fixes: ee756ef7491e ("perf dso: Add reference count checking and accessor functions")
Signed-off-by: Ian Rogers 
Cc: James Clark 
Cc: Suzuki K Poulose 
Cc: Yunseong Kim 
Cc: Will Deacon 
Cc: Mike Leach 
Cc: Leo Yan 
Cc: Athira Rajeev 
Cc: John Garry 
Link: https://lore.kernel.org/r/20240704011745.1021288-1-irogers@google.com
Signed-off-by: Namhyung Kim

perf mem: Warn if memory events are not supported on all CPUs

2024-07-12T16:38:40+00:00

It is possible that memory events are not supported on all CPUs.

Prints a warning by dumping the enabled CPU maps in this case.

Signed-off-by: Leo Yan 
Reviewed-by: James Clark 
Cc: Suzuki K Poulose 
Cc: Will Deacon 
Cc: Mike Leach 
Cc: Kajol Jain 
Cc: John Garry 
Cc: linux-arm-kernel@lists.infradead.org
Cc: coresight@lists.linaro.org
Link: https://lore.kernel.org/r/20240706152035.86983-3-leo.yan@arm.com
Signed-off-by: Namhyung Kim

perf dsos: When adding a dso into sorted dsos maintain the sort order

2024-07-03T22:02:53+00:00

dsos__add would add at the end of the dso array possibly requiring a
later find to re-sort the array. Patterns of find then add were
becoming O(n*log n) due to the sorts. Change the add routine to be
O(n) rather than O(1) but to maintain the sorted-ness of the dsos
array so that later finds don't need the O(n*log n) sort.

Fixes: 3f4ac23a9908 ("perf dsos: Switch backing storage to array from rbtree/list")
Reported-by: Namhyung Kim 
Signed-off-by: Ian Rogers 
Cc: Steinar Gunderson 
Cc: Athira Rajeev 
Cc: Matt Fleming 
Link: https://lore.kernel.org/r/20240703172117.810918-3-irogers@google.com
Signed-off-by: Namhyung Kim

perf comm str: Avoid sort during insert

2024-07-03T21:59:15+00:00

The array is sorted, so just move the elements and insert in order.

Fixes: 13ca628716c6 ("perf comm: Add reference count checking to 'struct comm_str'")
Reported-by: Matt Fleming 
Signed-off-by: Ian Rogers 
Tested-by: Matt Fleming 
Cc: Steinar Gunderson 
Cc: Athira Rajeev 
Link: https://lore.kernel.org/r/20240703172117.810918-2-irogers@google.com
Signed-off-by: Namhyung Kim

perf: pmus: Remove unneeded semicolon

2024-06-28T19:55:29+00:00

./tools/perf/util/pmu.c:1776:49-50: Unneeded semicolon

Reported-by: Abaci Robot 
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9443
Signed-off-by: Yang Li 
Reviewed-by: Arnaldo Carvalho de Melo 
Link: https://lore.kernel.org/r/20240628053049.44521-1-yang.lee@linux.alibaba.com
Signed-off-by: Namhyung Kim