I started seeing this in recent Fedora 42 kernels:
# uname -a
Linux number 6.14.3-300.fc42.x86_64 #1 SMP PREEMPT_DYNAMIC Sun Apr 20 16:08:39 UTC 2025 x86_64 GNU/Linux
#
# perf test vmlinux
1: vmlinux symtab matches kallsyms : FAILED!
#
Where we have Rust enabled:
# grep CONFIG_RUST /boot/config-6.14.3-300.fc42.x86_64
CONFIG_RUSTC_VERSION=108600
CONFIG_RUST_IS_AVAILABLE=y
CONFIG_RUSTC_LLVM_VERSION=200101
CONFIG_RUSTC_HAS_COERCE_POINTEE=y
CONFIG_RUST=y
CONFIG_RUSTC_VERSION_TEXT="rustc 1.86.0 (05f9846f8 2025-03-31) (Fedora 1.86.0-1.fc42)"
CONFIG_RUST_FW_LOADER_ABSTRACTIONS=y
CONFIG_RUST_PHYLIB_ABSTRACTIONS=y
# CONFIG_RUST_DEBUG_ASSERTIONS is not set
CONFIG_RUST_OVERFLOW_CHECKS=y
# CONFIG_RUST_BUILD_ASSERT_ALLOW is not set
#
Looking at the reason for the failure:
# perf test -v vmlinux |& grep ^ERR
ERR : 0xffffffff99efc7d0: __pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_ not on kallsyms
ERR : 0xffffffff99efc7e0: _RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_ not on kallsyms
#
But:
# grep -w u /proc/kallsyms
ffffffff99efc7d0 u __pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
ffffffff99efc7e0 u _RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
#
The test checks that "vmlinux symtab matches kallsyms", so it finds those two
symbols in vmlinux:
# pahole --running_kernel_vmlinux
/usr/lib/debug/lib/modules/6.14.3-300.fc42.x86_64/vmlinux
#
# readelf -sW /usr/lib/debug/lib/modules/6.14.3-300.fc42.x86_64/vmlinux | grep -Ew '(__pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_|_RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_)'
81844: ffffffff81efc7e0 524 FUNC LOCAL DEFAULT 1 _RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
144259: ffffffff81efc7d0 16 FUNC LOCAL DEFAULT 1 __pfx__RNCINvNtNtNtCsf5tcb0XGUW4_4core4iter8adapters3map12map_try_foldjNtCsagR6JbSOIa9_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
#
It is there.
From the nm documentation we can see that:
"U" The symbol is undefined.
"u" The symbol is a unique global symbol. This is a GNU extension to the
standard set of ELF symbol bindings. For such a symbol the dynamic
linker will make sure that in the entire process there is just one
symbol with this name and type in use.
So lets consider 'u' symbols in /proc/kallsyms when loading it to cover this case.
Fedora:40 shows this as a 'l' symbol, so consider that as well.
With this patch 'perf test 1' is happy again:
# perf test vmlinux
1: vmlinux symtab matches kallsyms : Ok
#
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/aBE_n0PGl3g6h-cS@x1
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fedora introduced a "MiniDebuginfo" feature, in which an LZMA-compressed
ELF file is placed inside a section named ".gnu_debugdata". This file
contains nothing but a symbol table, which can be used to supplement the
.dynsym section which only contains required symbols for runtime.
It is supported by GDB for stack traces, but it should be useful for
tracing as well. Implement support for loading symbols from
.gnu_debugdata.
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lore.kernel.org/r/20250307232206.2102440-4-stephen.s.brennan@oracle.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
When there are more than one symbols at the same address, it needs to
choose which one is better. In choose_best_symbol() it didn't check the
type of symbols. It's possible to have labels in other symbols and in
that case, it would be better to pick the actual symbol over the labels.
To minimize the possible impact on other symbols, I only check NOTYPE
symbols specifically.
$ readelf -sW vmlinux | grep -e __do_softirq -e __softirqentry_text_start
105089: ffffffff82000000 814 FUNC GLOBAL DEFAULT 1 __do_softirq
111954: ffffffff82000000 0 NOTYPE GLOBAL DEFAULT 1 __softirqentry_text_start
The commit 77b004f4c5 tried to do the same by not giving the size
to the label symbols but it seems there's some label-only symbols in asm
code. Let's restore the original code and choose the right symbol using
type of the symbols.
Fixes: 77b004f4c5 ("perf symbol: Do not fixup end address of labels")
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Link: http://lore.kernel.org/lkml/Z3b-DqBMnNb4ucEm@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When it loads symbols from an ELF file, it loads label symbols which is
0 size. Sometimes it has the same address with other symbols and might
shadow the original symbols because it fixes up the size of the symbol.
For example, in my system __do_softirq is shadowed and only accepts the
__softirqentry_text_start instead. But it should accept __do_softirq.
$ readelf -sW vmlinux | grep -e __do_softirq -e __softirqentry_text_start
105089: ffffffff82000000 814 FUNC GLOBAL DEFAULT 1 __do_softirq
111954: ffffffff82000000 0 NOTYPE GLOBAL DEFAULT 1 __softirqentry_text_start
$ perf annotate --stdio __do_softirq
Error:
The perf.data data has no samples!
$ perf annotate --stdio __softirqentry_text_start | head
Percent | Source code & Disassembly of vmlinux for cycles (26 samples, percent: local period)
---------------------------------------------------------------------------------------------------
: 0 0xffffffff82000000 <__softirqentry_text_start>:
0.00 : ffffffff82000000: nopl (%rax,%rax)
30.77 : ffffffff82000005: pushq %rbp
3.85 : ffffffff82000006: movq %rsp, %rbp
0.00 : ffffffff82000009: pushq %r15
3.85 : ffffffff8200000b: pushq %r14
3.85 : ffffffff8200000d: pushq %r13
0.00 : ffffffff8200000f: pushq %r12
We can ignore NOTYPE symbols in the symbols__fixup_end() so that it can
pick the __do_softirq() in choose_best_symbol(). This should be fine
since most symbols have either STT_FUNC or STT_OBJECT.
Link: https://lore.kernel.org/r/20240912224208.3360116-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Perf test for perf probe of function from different CU fails
as below:
./perf test -vv "test perf probe of function from different CU"
116: test perf probe of function from different CU:
--- start ---
test child forked, pid 2679
Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.Msa7iy89bx/testfile
Error: Failed to add events.
--- Cleaning up ---
"foo" does not hit any event.
Error: Failed to delete events.
---- end(-1) ----
116: test perf probe of function from different CU : FAILED!
The test does below to probe function "foo" :
# gcc -g -Og -flto -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.c
-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
# gcc -g -Og -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.c
-o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
# gcc -g -Og -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
# ./perf probe -x /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile foo
Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
Error: Failed to add events.
Perf probe fails to find symbol foo in the executable placed in
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7
Simple reproduce:
# mktemp -d /tmp/perf-checkXXXXXXXXXX
/tmp/perf-checkcWpuLRQI8j
# gcc -g -o test test.c
# cp test /tmp/perf-checkcWpuLRQI8j/
# nm /tmp/perf-checkcWpuLRQI8j/test | grep foo
00000000100006bc T foo
# ./perf probe -x /tmp/perf-checkcWpuLRQI8j/test foo
Failed to find symbol foo in /tmp/perf-checkcWpuLRQI8j/test
Error: Failed to add events.
But it works with any files like /tmp/perf/test. Only for
patterns with "/tmp/perf-", this fails.
Further debugging, commit 80d496be89 ("perf report: Add support
for profiling JIT generated code") added support for profiling JIT
generated code. This patch handles dso's of form
"/tmp/perf-$PID.map" .
The check used "if (strncmp(self->name, "/tmp/perf-", 10) == 0)"
to match "/tmp/perf-$PID.map". With this commit, any dso in
/tmp/perf- folder will be considered separately for processing
(not only JIT created map files ). Fix this by changing the
string pattern to check for "/tmp/perf-%d.map". Add a helper
function is_perf_pid_map_name to do this check. In "struct dso",
dso->long_name holds the long name of the dso file. Since the
/tmp/perf-$PID.map check uses the complete name, use dso___long_name for
the string name.
With the fix,
# ./perf test "test perf probe of function from different CU"
117: test perf probe of function from different CU : Ok
Fixes: 56cbeacf14 ("perf probe: Add test for regression introduced by switch to die_get_decl_file()")
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Reviewed-by: Chaitanya S Prakash <chaitanyas.prakash@arm.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: akanksha@linux.ibm.com
Cc: kjain@linux.ibm.com
Cc: maddy@linux.ibm.com
Cc: disgoel@linux.vnet.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240623064850.83720-1-atrajeev@linux.vnet.ibm.com
The linked commit updated dso__load_vmlinux() to call
dso__set_long_name() before loading the symbols. Loading the symbols may
not succeed but dso__set_long_name() takes ownership of the string. The
two callers of this function free the string themselves on failure
cases, resulting in the following error:
$ perf record -- ls
$ perf report
free(): double free detected in tcache 2
Fix it by always taking ownership of the string, even on failure. This
means the string is either freed at the very first early exit condition,
or later when the dso is deleted or the long name is replaced. Now no
special return value is needed to signify that the caller needs to
free the string.
Fixes: e59fea47f8 ("perf symbols: Fix DSO kernel load and symbol process to correctly map DSO to its long_name, type and adjust_symbols")
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: James Clark <james.clark@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
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/20240507141210.195939-5-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
I got a strange error on ARM to fail on processing FINISHED_ROUND
record. It turned out that it was failing in symbol__alloc_hist()
because the symbol size is too big.
When a sample is captured on a specific BPF program, it failed. I've
added a debug code and found the end address of the symbol is from
the next module which is placed far way.
ffff800008795778-ffff80000879d6d8: bpf_prog_1bac53b8aac4bc58_netcg_sock [bpf]
ffff80000879d6d8-ffff80000ad656b4: bpf_prog_76867454b5944e15_netcg_getsockopt [bpf]
ffff80000ad656b4-ffffd69b7af74048: bpf_prog_1d50286d2eb1be85_hn_egress [bpf] <---------- here
ffffd69b7af74048-ffffd69b7af74048: $x.5 [sha3_generic]
ffffd69b7af74048-ffffd69b7af740b8: crypto_sha3_init [sha3_generic]
ffffd69b7af740b8-ffffd69b7af741e0: crypto_sha3_update [sha3_generic]
The logic in symbols__fixup_end() just uses curr->start to update the
prev->end. But in this case, it won't work as it's too different.
I think ARM has a different kernel memory layout for modules and BPF
than on x86. Actually there's a logic to handle kernel and module
boundary. Let's do the same for symbols between different modules.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Leo Yan <leo.yan@linux.dev>
Cc: Will Deacon <will@kernel.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20240212233322.1855161-1-namhyung@kernel.org
This is a longstanding to do list entry: we need a way to see that a
sample took place while in idle state, as the current way to do it is
to infer that by the name of the functions that in such state have
more samples, IOW: a hack.
Maybe we can do flip a bit in samples that take place inside the
enter/exit idle section in do_idle()?
But till then, add one more :-\
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/ZR66Qgbcltt+zG7F@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Update "struct dso" to include new member "text_end".
This new field will represent the offset for end of text
section for a dso. For elf, this value is derived as:
sh_size (Size of section in byes) + sh_offset (Section file
offst) of the elf header for text.
For bfd, this value is derived as:
1. For PE file,
section->size + ( section->vma - dso->text_offset)
2. Other cases:
section->filepos (file position) + section->size (size of
section)
To resolve the address from a sample, perf looks at the
DSO maps. In case of address from a kernel module, there
were some address found to be not resolved. This was
observed while running perf test for "Object code reading".
Though the ip falls beteen the start address of the loaded
module (perf map->start ) and end address ( perf map->end),
it was unresolved.
Example:
Reading object code for memory address: 0xc008000007f0142c
File is: /lib/modules/6.5.0-rc3+/kernel/fs/xfs/xfs.ko
On file address is: 0x1114cc
Objdump command is: objdump -z -d --start-address=0x11142c --stop-address=0x1114ac /lib/modules/6.5.0-rc3+/kernel/fs/xfs/xfs.ko
objdump read too few bytes: 128
test child finished with -1
Here, module is loaded at:
# cat /proc/modules | grep xfs
xfs 2228224 3 - Live 0xc008000007d00000
From objdump for xfs module, text section is:
text 0010f7bc 0000000000000000 0000000000000000 000000a0 2**4
Here the offset for 0xc008000007f0142c ie 0x112074 falls out
.text section which is up to 0x10f7bc.
In this case for module, the address 0xc008000007e11fd4 is pointing
to stub instructions. This address range represents the module stubs
which is allocated on module load and hence is not part of DSO offset.
To identify such address, which falls out of text
section and within module end, added the new field "text_end" to
"struct dso".
Reported-by: Disha Goel <disgoel@linux.ibm.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Kajol Jain <kjain@linux.ibm.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: maddy@linux.ibm.com
Cc: disgoel@linux.vnet.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230928075213.84392-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Test "object code reading" fails sometimes for kernel address as below:
Reading object code for memory address: 0xc000000000004c3c
File is: [kernel.kallsyms]
On file address is: 0x14c3c
dso__data_read_offset failed
test child finished with -1
---- end ----
Object code reading: FAILED!
Here dso__data_read_offset() fails for symbol address
0xc000000000004c3c. This is because the DSO long_name here is
"[kernel.kallsyms]" and hence open_dso() fails to open this file. There
is an incorrect DSO to map handling here. The key points here are:
- The DSO long_name is set to "[kernel.kallsyms]". This file is
not present and hence returns error
- The DSO binary type is set to DSO_BINARY_TYPE__NOT_FOUND
- The DSO adjust_symbols member is set to zero
In the end dso__data_read_offset() returns -1 and the address 0x14c3c
can not be resolved. Hence the test fails. But the address actually maps
to the kernel DSO
# objdump -z -d --start-address=0xc000000000004c3c --stop-address=0xc000000000004cbc /home/athira/linux/vmlinux
/home/athira/linux/vmlinux: file format elf64-powerpcle
Disassembly of section .head.text:
c000000000004c3c <exc_virt_0x4c00_system_call+0x3c>:
c000000000004c3c: a6 02 9b 7d mfsrr1 r12
c000000000004c40: 78 13 42 7c mr r2,r2
c000000000004c44: 18 00 4d e9 ld r10,24(r13)
c000000000004c48: 60 c6 4a 61 ori r10,r10,50784
c000000000004c4c: a6 03 49 7d mtctr r10
Fix dso__process_kernel_symbol() to set the binary_type and
adjust_symbols members. dso->adjust_symbols is used by
map__rip_2objdump() which converts the symbol start address to the
objdump address. Also set dso->long_name in dso__load_vmlinux().
Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Disha Goel <disgoel@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230811051546.70039-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This problem was encountered on an arm64 system with a lot of memory.
Without kernel debug symbols installed, and with both kcore and kallsyms
available, perf managed to get confused and returned "unknown" for all
of the kernel symbols that it tried to look up.
On this system, stext fell within the vmalloc segment. The kcore symbol
matching code tries to find the first segment that contains stext and
uses that to replace the segment generated from just the kallsyms
information. In this case, however, there were two: a very large
vmalloc segment, and the text segment. This caused perf to get confused
because multiple overlapping segments were inserted into the RB tree
that holds the discovered segments. However, that alone wasn't
sufficient to cause the problem. Even when we could find the segment,
the offsets were adjusted in such a way that the newly generated symbols
didn't line up with the instruction addresses in the trace. The most
obvious solution would be to consult which segment type is text from
kcore, but this information is not exposed to users.
Instead, select the smallest matching segment that contains stext
instead of the first matching segment. This allows us to match the text
segment instead of vmalloc, if one is contained within the other.
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Reaver <me@davidreaver.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20230125183418.GD1963@templeofstupid.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
