* [PATCH] powerpc/perf: Fix oops when grouping different pmu events
@ 2017-11-30 8:33 Ravi Bangoria
2017-12-01 5:05 ` Madhavan Srinivasan
2017-12-06 12:59 ` Michael Ellerman
0 siblings, 2 replies; 3+ messages in thread
From: Ravi Bangoria @ 2017-11-30 8:33 UTC (permalink / raw)
To: mpe
Cc: benh, paulus, maddy, tglx, kan.liang, sukadev, linuxppc-dev,
linux-kernel, Ravi Bangoria
When user tries to group imc (In-Memory Collections) event with
normal event, (sometime) kernel crashes with following log:
Faulting instruction address: 0x00000000
[link register ] c00000000010ce88 power_check_constraints+0x128/0x980
...
c00000000010e238 power_pmu_event_init+0x268/0x6f0
c0000000002dc60c perf_try_init_event+0xdc/0x1a0
c0000000002dce88 perf_event_alloc+0x7b8/0xac0
c0000000002e92e0 SyS_perf_event_open+0x530/0xda0
c00000000000b004 system_call+0x38/0xe0
'event_base' field of 'struct hw_perf_event' is used as flags for
normal hw events and used as memory address for imc events. While
grouping these two types of events, collect_events() tries to
interpret imc 'event_base' as a flag, which causes a corruption
resulting in a crash.
Consider only those events which belongs to 'perf_hw_context' in
collect_events().
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
---
arch/powerpc/perf/core-book3s.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 9e3da16..1538129 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1415,7 +1415,7 @@ static int collect_events(struct perf_event *group, int max_count,
int n = 0;
struct perf_event *event;
- if (!is_software_event(group)) {
+ if (group->pmu->task_ctx_nr == perf_hw_context) {
if (n >= max_count)
return -1;
ctrs[n] = group;
@@ -1423,7 +1423,7 @@ static int collect_events(struct perf_event *group, int max_count,
events[n++] = group->hw.config;
}
list_for_each_entry(event, &group->sibling_list, group_entry) {
- if (!is_software_event(event) &&
+ if (event->pmu->task_ctx_nr == perf_hw_context &&
event->state != PERF_EVENT_STATE_OFF) {
if (n >= max_count)
return -1;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] powerpc/perf: Fix oops when grouping different pmu events
2017-11-30 8:33 [PATCH] powerpc/perf: Fix oops when grouping different pmu events Ravi Bangoria
@ 2017-12-01 5:05 ` Madhavan Srinivasan
2017-12-06 12:59 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Madhavan Srinivasan @ 2017-12-01 5:05 UTC (permalink / raw)
To: Ravi Bangoria, mpe
Cc: benh, paulus, tglx, kan.liang, sukadev, linuxppc-dev,
linux-kernel
On Thursday 30 November 2017 02:03 PM, Ravi Bangoria wrote:
> When user tries to group imc (In-Memory Collections) event with
> normal event, (sometime) kernel crashes with following log:
>
> Faulting instruction address: 0x00000000
> [link register ] c00000000010ce88 power_check_constraints+0x128/0x980
> ...
> c00000000010e238 power_pmu_event_init+0x268/0x6f0
> c0000000002dc60c perf_try_init_event+0xdc/0x1a0
> c0000000002dce88 perf_event_alloc+0x7b8/0xac0
> c0000000002e92e0 SyS_perf_event_open+0x530/0xda0
> c00000000000b004 system_call+0x38/0xe0
>
> 'event_base' field of 'struct hw_perf_event' is used as flags for
> normal hw events and used as memory address for imc events. While
> grouping these two types of events, collect_events() tries to
> interpret imc 'event_base' as a flag, which causes a corruption
> resulting in a crash.
>
> Consider only those events which belongs to 'perf_hw_context' in
> collect_events().
Reviewed-By: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> ---
> arch/powerpc/perf/core-book3s.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
> index 9e3da16..1538129 100644
> --- a/arch/powerpc/perf/core-book3s.c
> +++ b/arch/powerpc/perf/core-book3s.c
> @@ -1415,7 +1415,7 @@ static int collect_events(struct perf_event *group, int max_count,
> int n = 0;
> struct perf_event *event;
>
> - if (!is_software_event(group)) {
> + if (group->pmu->task_ctx_nr == perf_hw_context) {
> if (n >= max_count)
> return -1;
> ctrs[n] = group;
> @@ -1423,7 +1423,7 @@ static int collect_events(struct perf_event *group, int max_count,
> events[n++] = group->hw.config;
> }
> list_for_each_entry(event, &group->sibling_list, group_entry) {
> - if (!is_software_event(event) &&
> + if (event->pmu->task_ctx_nr == perf_hw_context &&
> event->state != PERF_EVENT_STATE_OFF) {
> if (n >= max_count)
> return -1;
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: powerpc/perf: Fix oops when grouping different pmu events
2017-11-30 8:33 [PATCH] powerpc/perf: Fix oops when grouping different pmu events Ravi Bangoria
2017-12-01 5:05 ` Madhavan Srinivasan
@ 2017-12-06 12:59 ` Michael Ellerman
1 sibling, 0 replies; 3+ messages in thread
From: Michael Ellerman @ 2017-12-06 12:59 UTC (permalink / raw)
To: Ravi Bangoria
Cc: maddy, linux-kernel, Ravi Bangoria, paulus, kan.liang, tglx,
sukadev, linuxppc-dev
On Thu, 2017-11-30 at 08:33:22 UTC, Ravi Bangoria wrote:
> When user tries to group imc (In-Memory Collections) event with
> normal event, (sometime) kernel crashes with following log:
>
> Faulting instruction address: 0x00000000
> [link register ] c00000000010ce88 power_check_constraints+0x128/0x980
> ...
> c00000000010e238 power_pmu_event_init+0x268/0x6f0
> c0000000002dc60c perf_try_init_event+0xdc/0x1a0
> c0000000002dce88 perf_event_alloc+0x7b8/0xac0
> c0000000002e92e0 SyS_perf_event_open+0x530/0xda0
> c00000000000b004 system_call+0x38/0xe0
>
> 'event_base' field of 'struct hw_perf_event' is used as flags for
> normal hw events and used as memory address for imc events. While
> grouping these two types of events, collect_events() tries to
> interpret imc 'event_base' as a flag, which causes a corruption
> resulting in a crash.
>
> Consider only those events which belongs to 'perf_hw_context' in
> collect_events().
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> Reviewed-By: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/5aa04b3eb6fca63d2e9827be656dca
cheers
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-11-30 8:33 [PATCH] powerpc/perf: Fix oops when grouping different pmu events Ravi Bangoria
2017-12-01 5:05 ` Madhavan Srinivasan
2017-12-06 12:59 ` Michael Ellerman
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