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Lisa Robinson 5b14ce4975 LoongArch: Fix PMU counter allocation for mixed-type event groups 
commit a91f86e270 upstream.

When validating a perf event group, validate_group() unconditionally
attempts to allocate hardware PMU counters for the leader, sibling
events and the new event being added.

This is incorrect for mixed-type groups. If a PERF_TYPE_SOFTWARE event
is part of the group, the current code still tries to allocate a hardware
PMU counter for it, which can wrongly consume hardware PMU resources and
cause spurious allocation failures.

Fix this by only allocating PMU counters for hardware events during group
validation, and skipping software events.

A trimmed down reproducer is as simple as this:

  #include <stdio.h>
  #include <assert.h>
  #include <unistd.h>
  #include <string.h>
  #include <sys/syscall.h>
  #include <linux/perf_event.h>

  int main (int argc, char *argv[])
  {
  	struct perf_event_attr attr = { 0 };
  	int fds[5];

  	attr.disabled = 1;
  	attr.exclude_kernel = 1;
  	attr.exclude_hv = 1;
  	attr.read_format = PERF_FORMAT_TOTAL_TIME_ENABLED |
  		PERF_FORMAT_TOTAL_TIME_RUNNING | PERF_FORMAT_ID | PERF_FORMAT_GROUP;
  	attr.size = sizeof (attr);

  	attr.type = PERF_TYPE_SOFTWARE;
  	attr.config = PERF_COUNT_SW_DUMMY;
  	fds[0] = syscall (SYS_perf_event_open, &attr, 0, -1, -1, 0);
  	assert (fds[0] >= 0);

  	attr.type = PERF_TYPE_HARDWARE;
  	attr.config = PERF_COUNT_HW_CPU_CYCLES;
  	fds[1] = syscall (SYS_perf_event_open, &attr, 0, -1, fds[0], 0);
  	assert (fds[1] >= 0);

  	attr.type = PERF_TYPE_HARDWARE;
  	attr.config = PERF_COUNT_HW_INSTRUCTIONS;
  	fds[2] = syscall (SYS_perf_event_open, &attr, 0, -1, fds[0], 0);
  	assert (fds[2] >= 0);

  	attr.type = PERF_TYPE_HARDWARE;
  	attr.config = PERF_COUNT_HW_BRANCH_MISSES;
  	fds[3] = syscall (SYS_perf_event_open, &attr, 0, -1, fds[0], 0);
  	assert (fds[3] >= 0);

  	attr.type = PERF_TYPE_HARDWARE;
  	attr.config = PERF_COUNT_HW_CACHE_REFERENCES;
  	fds[4] = syscall (SYS_perf_event_open, &attr, 0, -1, fds[0], 0);
  	assert (fds[4] >= 0);

  	printf ("PASSED\n");

  	return 0;
  }

Cc: stable@vger.kernel.org
Fixes: b37042b2bb ("LoongArch: Add perf events support")
Signed-off-by: Lisa Robinson <lisa@bytefly.space>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2026-01-23 11:21:30 +01:00
..
.gitignore LoongArch: Add build infrastructure 2022-06-03 20:09:27 +08:00
access-helper.h LoongArch: Add exception/interrupt handling 2022-06-03 20:09:28 +08:00
acpi.c LoongArch: Fix build warnings about export.h 2025-06-26 20:07:18 +08:00
alternative.c LoongArch: Fix build warnings about export.h 2025-06-26 20:07:18 +08:00
asm-offsets.c arch: Add the macro COMPILE_OFFSETS to all the asm-offsets.c 2025-09-25 09:57:15 +02:00
cacheinfo.c LoongArch: Correct the cacheinfo sharing information 2025-01-25 18:51:33 +08:00
cpu-probe.c LoongArch: Consolidate CPU names in /proc/cpuinfo 2025-11-20 14:42:05 +08:00
crash_dump.c LoongArch: Add kdump support 2022-10-12 16:36:19 +08:00
dma.c dma-mapping: Add helpers for dma_range_map bounds 2024-04-26 12:07:24 +02:00
efi-header.S include: pe.h: Fix PE definitions 2025-05-21 16:46:37 +02:00
efi.c LoongArch: Reserve the EFI memory map region 2025-06-26 20:07:18 +08:00
elf.c LoongArch: Fix build warnings about export.h 2025-06-26 20:07:18 +08:00
entry.S LoongArch: Enable HAVE_ARCH_STACKLEAK 2025-05-30 21:45:42 +08:00
env.c LoongArch: Replace sprintf() with sysfs_emit() 2025-09-18 19:44:04 +08:00
fpu.S LoongArch: Handle fp, lsx, lasx and lbt assembly symbols 2025-04-26 09:58:12 +08:00
ftrace.c LoongArch/ftrace: Add basic support 2022-12-14 08:41:53 +08:00
ftrace_dyn.c LoongArch: ftrace: Use RCU in all users of __module_text_address(). 2025-03-10 11:54:45 +01:00
genex.S LoongArch: Move __arch_cpu_idle() to .cpuidle.text section 2025-05-14 22:17:52 +08:00
head.S include: pe.h: Fix PE definitions 2025-05-21 16:46:37 +02:00
hw_breakpoint.c LoongArch: Change 8 to 14 for LOONGARCH_MAX_{BRP,WRP} 2025-01-26 21:49:59 +08:00
idle.c LoongArch: Fix idle VS timer enqueue 2025-02-13 12:02:35 +08:00
image-vars.h efi/loongarch: Directly position the loaded image file 2023-12-19 11:16:37 +01:00
inst.c LoongArch: Handle new atomic instructions for probes 2025-10-02 22:39:35 +08:00
irq.c LoongArch: Switch to irq_set_nr_irqs() 2024-10-16 21:56:56 +02:00
jump_label.c LoongArch: Add jump-label implementation 2023-06-29 20:58:44 +08:00
kdebugfs.c LoongArch: Add debugfs entries to switch SFB/TSO state 2025-01-26 21:49:59 +08:00
kexec_efi.c LoongArch: kexec: Initialize the kexec_buf structure 2025-11-10 08:37:07 +08:00
kexec_elf.c LoongArch: kexec: Initialize the kexec_buf structure 2025-11-10 08:37:07 +08:00
kfpu.c LoongArch: Fix build warnings about export.h 2025-06-26 20:07:18 +08:00
kgdb.c LoongArch: Rework the arch_kgdb_breakpoint() implementation 2025-03-30 16:31:09 +08:00
kprobes.c LoongArch: Make the users of larch_insn_gen_break() constant 2024-07-20 22:41:07 +08:00
lbt.S LoongArch: Handle fp, lsx, lasx and lbt assembly symbols 2025-04-26 09:58:12 +08:00
machine_kexec.c LoongArch: Mask all interrupts during kexec/kdump 2025-11-20 14:42:05 +08:00
machine_kexec_file.c LoongArch: kexec: Initialize the kexec_buf structure 2025-11-10 08:37:07 +08:00
Makefile LoongArch: Add ELF binary support for kexec_file 2025-10-02 22:39:08 +08:00
Makefile.syscalls syscalls: fix syscall macros for newfstat/newfstatat 2024-08-02 15:20:47 +02:00
mcount.S fgraph: Replace fgraph_ret_regs with ftrace_regs 2024-12-26 10:50:02 -05:00
mcount_dyn.S LoongArch: Refactor register restoration in ftrace_common_return 2026-01-08 10:17:12 +01:00
mem.c LoongArch: Consolidate max_pfn & max_low_pfn calculation 2025-11-10 08:37:06 +08:00
module-sections.c LoongArch: Optimize module load time by optimizing PLT/GOT counting 2025-08-20 22:23:44 +08:00
module.c arch: make execmem setup available regardless of CONFIG_MODULES 2024-05-14 00:31:44 -07:00
numa.c LoongArch: Fix NUMA node parsing with numa_memblks 2025-11-20 14:42:05 +08:00
paravirt.c LoongArch: Fix build warnings about export.h 2025-06-26 20:07:18 +08:00
perf_event.c LoongArch: Fix PMU counter allocation for mixed-type event groups 2026-01-23 11:21:30 +01:00
perf_regs.c LoongArch: Add perf events support 2022-10-12 16:36:14 +08:00
proc.c LoongArch: Consolidate CPU names in /proc/cpuinfo 2025-11-20 14:42:05 +08:00
process.c LoongArch: Fix arch_dup_task_struct() for CONFIG_RANDSTRUCT 2026-01-08 10:17:06 +01:00
ptrace.c LoongArch: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names 2025-07-14 22:27:47 -07:00
relocate.c LoongArch: Use unsigned long for _end and _text 2026-01-08 10:17:06 +01:00
relocate_kernel.S LoongArch: Make relocate_new_kernel_size be a .quad value 2025-08-03 22:49:47 +08:00
reset.c LoongArch: Fix idle VS timer enqueue 2025-02-13 12:02:35 +08:00
rethook.c LoongArch: Replace kretprobe with rethook 2023-06-29 20:58:44 +08:00
rethook.h LoongArch: Replace kretprobe with rethook 2023-06-29 20:58:44 +08:00
rethook_trampoline.S LoongArch: Add ORC stack unwinder support 2024-03-11 22:23:47 +08:00
setup.c LoongArch: Correct the calculation logic of thread_count 2026-01-08 10:17:06 +01:00
signal.c LoongArch: Save LBT before FPU in setup_sigcontext() 2025-08-20 22:23:44 +08:00
smp.c LoongArch: Add SCHED_MC (Multi-core scheduler) support 2025-05-30 21:45:42 +08:00
stacktrace.c LoongArch: Fix unreliable stack for live patching 2025-09-18 19:44:08 +08:00
switch.S LoongArch: Fix build errors for CONFIG_RANDSTRUCT 2026-01-08 10:17:06 +01:00
syscall.c LoongArch: Remove STACK_FRAME_NON_STANDARD(do_syscall) 2024-09-17 22:23:10 +08:00
sysrq.c tty: sysrq: switch sysrq handlers from int to u8 2023-07-25 19:21:03 +02:00
time.c LoongArch: Remove clockevents shutdown call on offlining 2025-09-09 13:39:00 +02:00
topology.c LoongArch: convert to use arch_cpu_is_hotpluggable() 2023-12-06 12:41:50 +09:00
traps.c LoongArch: Use physical addresses for CSR_MERRENTRY/CSR_TLBRENTRY 2025-11-10 08:37:06 +08:00
unaligned.c LoongArch: Add debugfs entries to switch SFB/TSO state 2025-01-26 21:49:59 +08:00
unwind.c LoongArch: Set unwind stack type to unknown rather than set error flag 2023-12-09 15:49:15 +08:00
unwind_guess.c LoongArch: Fix build warnings about export.h 2025-06-26 20:07:18 +08:00
unwind_orc.c LoongArch: Don't use %pK through printk() in unwinder 2025-08-03 22:49:47 +08:00
unwind_prologue.c LoongArch: Fix build warnings about export.h 2025-06-26 20:07:18 +08:00
uprobes.c LoongArch: uprobes: Remove redundant code about resume_era 2025-05-14 22:18:10 +08:00
vdso.c LoongArch: vDSO: Check kcalloc() result in init_vdso() 2025-09-18 19:44:10 +08:00
vmlinux.lds.S LoongArch: Add support for relocating the kernel with RELR relocation 2024-07-20 22:41:07 +08:00