[ Upstream commit 48918ca ]

The test starts a workload and then opens events. If the events fail
to open, for example because of perf_event_paranoid, the gopipe of the
workload is leaked and the file descriptor leak check fails when the
test exits. To avoid this cancel the workload when opening the events
fails.

Before:
```
$ perf test -vv 7
  7: PERF_RECORD_* events & perf_sample fields:
 --- start ---
test child forked, pid 1189568
Using CPUID GenuineIntel-6-B7-1
 ------------------------------------------------------------
perf_event_attr:
  type                    	   0 (PERF_TYPE_HARDWARE)
  config                  	   0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                	   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
Attempt to add: software/cpu-clock/
..after resolving event: software/config=0/
cpu-clock -> software/cpu-clock/
 ------------------------------------------------------------
perf_event_attr:
  type                             1 (PERF_TYPE_SOFTWARE)
  size                             136
  config                           0x9 (PERF_COUNT_SW_DUMMY)
  sample_type                      IP|TID|TIME|CPU
  read_format                      ID|LOST
  disabled                         1
  inherit                          1
  mmap                             1
  comm                             1
  enable_on_exec                   1
  task                             1
  sample_id_all                    1
  mmap2                            1
  comm_exec                        1
  ksymbol                          1
  bpf_event                        1
  { wakeup_events, wakeup_watermark } 1
 ------------------------------------------------------------
sys_perf_event_open: pid 1189569  cpu 0  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
perf_evlist__open: Permission denied
 ---- end(-2) ----
Leak of file descriptor 6 that opened: 'pipe:[14200347]'
 ---- unexpected signal (6) ----
iFailed to read build ID for //anon
Failed to read build ID for //anon
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    #0 0x565358f6666e in child_test_sig_handler builtin-test.c:311
    #1 0x7f29ce849df0 in __restore_rt libc_sigaction.c:0
    #2 0x7f29ce89e95c in __pthread_kill_implementation pthread_kill.c:44
    #3 0x7f29ce849cc2 in raise raise.c:27
    #4 0x7f29ce8324ac in abort abort.c:81
    #5 0x565358f662d4 in check_leaks builtin-test.c:226
    #6 0x565358f6682e in run_test_child builtin-test.c:344
    #7 0x565358ef7121 in start_command run-command.c:128
    #8 0x565358f67273 in start_test builtin-test.c:545
    #9 0x565358f6771d in __cmd_test builtin-test.c:647
    #10 0x565358f682bd in cmd_test builtin-test.c:849
    #11 0x565358ee5ded in run_builtin perf.c:349
    #12 0x565358ee6085 in handle_internal_command perf.c:401
    #13 0x565358ee61de in run_argv perf.c:448
    #14 0x565358ee6527 in main perf.c:555
    #15 0x7f29ce833ca8 in __libc_start_call_main libc_start_call_main.h:74
    #16 0x7f29ce833d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128
    #17 0x565358e391c1 in _start perf[851c1]
  7: PERF_RECORD_* events & perf_sample fields                       : FAILED!
```

After:
```
$ perf test 7
  7: PERF_RECORD_* events & perf_sample fields                       : Skip (permissions)
```

Fixes: 16d00fe ("perf tests: Move test__PERF_RECORD into separate object")
Signed-off-by: Ian Rogers <irogers@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: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Howard Chu <howardchu95@gmail.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: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 48918ca ]

The test starts a workload and then opens events. If the events fail
to open, for example because of perf_event_paranoid, the gopipe of the
workload is leaked and the file descriptor leak check fails when the
test exits. To avoid this cancel the workload when opening the events
fails.

Before:
```
$ perf test -vv 7
  7: PERF_RECORD_* events & perf_sample fields:
 --- start ---
test child forked, pid 1189568
Using CPUID GenuineIntel-6-B7-1
 ------------------------------------------------------------
perf_event_attr:
  type                    	   0 (PERF_TYPE_HARDWARE)
  config                  	   0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                	   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
Attempt to add: software/cpu-clock/
..after resolving event: software/config=0/
cpu-clock -> software/cpu-clock/
 ------------------------------------------------------------
perf_event_attr:
  type                             1 (PERF_TYPE_SOFTWARE)
  size                             136
  config                           0x9 (PERF_COUNT_SW_DUMMY)
  sample_type                      IP|TID|TIME|CPU
  read_format                      ID|LOST
  disabled                         1
  inherit                          1
  mmap                             1
  comm                             1
  enable_on_exec                   1
  task                             1
  sample_id_all                    1
  mmap2                            1
  comm_exec                        1
  ksymbol                          1
  bpf_event                        1
  { wakeup_events, wakeup_watermark } 1
 ------------------------------------------------------------
sys_perf_event_open: pid 1189569  cpu 0  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
perf_evlist__open: Permission denied
 ---- end(-2) ----
Leak of file descriptor 6 that opened: 'pipe:[14200347]'
 ---- unexpected signal (6) ----
iFailed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
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Failed to read build ID for //anon
Failed to read build ID for //anon
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Failed to read build ID for //anon
    #0 0x565358f6666e in child_test_sig_handler builtin-test.c:311
    #1 0x7f29ce849df0 in __restore_rt libc_sigaction.c:0
    #2 0x7f29ce89e95c in __pthread_kill_implementation pthread_kill.c:44
    #3 0x7f29ce849cc2 in raise raise.c:27
    #4 0x7f29ce8324ac in abort abort.c:81
    #5 0x565358f662d4 in check_leaks builtin-test.c:226
    #6 0x565358f6682e in run_test_child builtin-test.c:344
    #7 0x565358ef7121 in start_command run-command.c:128
    #8 0x565358f67273 in start_test builtin-test.c:545
    #9 0x565358f6771d in __cmd_test builtin-test.c:647
    #10 0x565358f682bd in cmd_test builtin-test.c:849
    #11 0x565358ee5ded in run_builtin perf.c:349
    #12 0x565358ee6085 in handle_internal_command perf.c:401
    #13 0x565358ee61de in run_argv perf.c:448
    #14 0x565358ee6527 in main perf.c:555
    #15 0x7f29ce833ca8 in __libc_start_call_main libc_start_call_main.h:74
    #16 0x7f29ce833d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128
    #17 0x565358e391c1 in _start perf[851c1]
  7: PERF_RECORD_* events & perf_sample fields                       : FAILED!
```

After:
```
$ perf test 7
  7: PERF_RECORD_* events & perf_sample fields                       : Skip (permissions)
```

Fixes: 16d00fe ("perf tests: Move test__PERF_RECORD into separate object")
Signed-off-by: Ian Rogers <irogers@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: Athira Rajeev <atrajeev@linux.ibm.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Howard Chu <howardchu95@gmail.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: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 163e5f2 ]

When using perf record with the `--overwrite` option, a segmentation fault
occurs if an event fails to open. For example:

  perf record -e cycles-ct -F 1000 -a --overwrite
  Error:
  cycles-ct:H: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'
  perf: Segmentation fault
      #0 0x6466b6 in dump_stack debug.c:366
      #1 0x646729 in sighandler_dump_stack debug.c:378
      #2 0x453fd1 in sigsegv_handler builtin-record.c:722
      #3 0x7f8454e65090 in __restore_rt libc-2.32.so[54090]
      #4 0x6c5671 in __perf_event__synthesize_id_index synthetic-events.c:1862
      #5 0x6c5ac0 in perf_event__synthesize_id_index synthetic-events.c:1943
      #6 0x458090 in record__synthesize builtin-record.c:2075
      #7 0x45a85a in __cmd_record builtin-record.c:2888
      #8 0x45deb6 in cmd_record builtin-record.c:4374
      #9 0x4e5e33 in run_builtin perf.c:349
      #10 0x4e60bf in handle_internal_command perf.c:401
      #11 0x4e6215 in run_argv perf.c:448
      #12 0x4e653a in main perf.c:555
      #13 0x7f8454e4fa72 in __libc_start_main libc-2.32.so[3ea72]
      #14 0x43a3ee in _start ??:0

The --overwrite option implies --tail-synthesize, which collects non-sample
events reflecting the system status when recording finishes. However, when
evsel opening fails (e.g., unsupported event 'cycles-ct'), session->evlist
is not initialized and remains NULL. The code unconditionally calls
record__synthesize() in the error path, which iterates through the NULL
evlist pointer and causes a segfault.

To fix it, move the record__synthesize() call inside the error check block, so
it's only called when there was no error during recording, ensuring that evlist
is properly initialized.

Fixes: 4ea648a ("perf record: Add --tail-synthesize option")
Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

commit 0031241 upstream.

On systems using the hash MMU, there is a software SLB preload cache that
mirrors the entries loaded into the hardware SLB buffer. This preload
cache is subject to periodic eviction — typically after every 256 context
switches — to remove old entry.

To optimize performance, the kernel skips switch_mmu_context() in
switch_mm_irqs_off() when the prev and next mm_struct are the same.
However, on hash MMU systems, this can lead to inconsistencies between
the hardware SLB and the software preload cache.

If an SLB entry for a process is evicted from the software cache on one
CPU, and the same process later runs on another CPU without executing
switch_mmu_context(), the hardware SLB may retain stale entries. If the
kernel then attempts to reload that entry, it can trigger an SLB
multi-hit error.

The following timeline shows how stale SLB entries are created and can
cause a multi-hit error when a process moves between CPUs without a
MMU context switch.

CPU 0                                   CPU 1
-----                                    -----
Process P
exec                                    swapper/1
 load_elf_binary
  begin_new_exc
    activate_mm
     switch_mm_irqs_off
      switch_mmu_context
       switch_slb
       /*
        * This invalidates all
        * the entries in the HW
        * and setup the new HW
        * SLB entries as per the
        * preload cache.
        */
context_switch
sched_migrate_task migrates process P to cpu-1

Process swapper/0                       context switch (to process P)
(uses mm_struct of Process P)           switch_mm_irqs_off()
                                         switch_slb
                                           load_slb++
                                            /*
                                            * load_slb becomes 0 here
                                            * and we evict an entry from
                                            * the preload cache with
                                            * preload_age(). We still
                                            * keep HW SLB and preload
                                            * cache in sync, that is
                                            * because all HW SLB entries
                                            * anyways gets evicted in
                                            * switch_slb during SLBIA.
                                            * We then only add those
                                            * entries back in HW SLB,
                                            * which are currently
                                            * present in preload_cache
                                            * (after eviction).
                                            */
                                        load_elf_binary continues...
                                         setup_new_exec()
                                          slb_setup_new_exec()

                                        sched_switch event
                                        sched_migrate_task migrates
                                        process P to cpu-0

context_switch from swapper/0 to Process P
 switch_mm_irqs_off()
  /*
   * Since both prev and next mm struct are same we don't call
   * switch_mmu_context(). This will cause the HW SLB and SW preload
   * cache to go out of sync in preload_new_slb_context. Because there
   * was an SLB entry which was evicted from both HW and preload cache
   * on cpu-1. Now later in preload_new_slb_context(), when we will try
   * to add the same preload entry again, we will add this to the SW
   * preload cache and then will add it to the HW SLB. Since on cpu-0
   * this entry was never invalidated, hence adding this entry to the HW
   * SLB will cause a SLB multi-hit error.
   */
load_elf_binary continues...
 START_THREAD
  start_thread
   preload_new_slb_context
   /*
    * This tries to add a new EA to preload cache which was earlier
    * evicted from both cpu-1 HW SLB and preload cache. This caused the
    * HW SLB of cpu-0 to go out of sync with the SW preload cache. The
    * reason for this was, that when we context switched back on CPU-0,
    * we should have ideally called switch_mmu_context() which will
    * bring the HW SLB entries on CPU-0 in sync with SW preload cache
    * entries by setting up the mmu context properly. But we didn't do
    * that since the prev mm_struct running on cpu-0 was same as the
    * next mm_struct (which is true for swapper / kernel threads). So
    * now when we try to add this new entry into the HW SLB of cpu-0,
    * we hit a SLB multi-hit error.
    */

WARNING: CPU: 0 PID: 1810970 at arch/powerpc/mm/book3s64/slb.c:62
assert_slb_presence+0x2c/0x50(48 results) 02:47:29 [20157/42149]
Modules linked in:
CPU: 0 UID: 0 PID: 1810970 Comm: dd Not tainted 6.16.0-rc3-dirty #12
VOLUNTARY
Hardware name: IBM pSeries (emulated by qemu) POWER8 (architected)
0x4d0200 0xf000004 of:SLOF,HEAD hv:linux,kvm pSeries
NIP:  c00000000015426c LR: c0000000001543b4 CTR: 0000000000000000
REGS: c0000000497c77e0 TRAP: 0700   Not tainted  (6.16.0-rc3-dirty)
MSR:  8000000002823033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE>  CR: 28888482  XER: 00000000
CFAR: c0000000001543b0 IRQMASK: 3
<...>
NIP [c00000000015426c] assert_slb_presence+0x2c/0x50
LR [c0000000001543b4] slb_insert_entry+0x124/0x390
Call Trace:
  0x7fffceb5ffff (unreliable)
  preload_new_slb_context+0x100/0x1a0
  start_thread+0x26c/0x420
  load_elf_binary+0x1b04/0x1c40
  bprm_execve+0x358/0x680
  do_execveat_common+0x1f8/0x240
  sys_execve+0x58/0x70
  system_call_exception+0x114/0x300
  system_call_common+0x160/0x2c4

>From the above analysis, during early exec the hardware SLB is cleared,
and entries from the software preload cache are reloaded into hardware
by switch_slb. However, preload_new_slb_context and slb_setup_new_exec
also attempt to load some of the same entries, which can trigger a
multi-hit. In most cases, these additional preloads simply hit existing
entries and add nothing new. Removing these functions avoids redundant
preloads and eliminates the multi-hit issue. This patch removes these
two functions.

We tested process switching performance using the context_switch
benchmark on POWER9/hash, and observed no regression.

Without this patch: 129041 ops/sec
With this patch:    129341 ops/sec

We also measured SLB faults during boot, and the counts are essentially
the same with and without this patch.

SLB faults without this patch: 19727
SLB faults with this patch:    19786

Fixes: 5434ae7 ("powerpc/64s/hash: Add a SLB preload cache")
cc: stable@vger.kernel.org
Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/0ac694ae683494fe8cadbd911a1a5018d5d3c541.1761834163.git.ritesh.list@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>