| Message ID | ed589c0d8e4130dc68b8ad1625226d28bdc185d4.1702322847.git.robin.murphy@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | perf/arm-cmn: Fail DTC counter allocation correctly | expand |
On Mon, 11 Dec 2023, Robin Murphy wrote: > Calling arm_cmn_event_clear() before all DTC indices are allocated is > wrong, and can lead to arm_cmn_event_add() erroneously clearing live > counters from full DTCs where allocation fails. Since the DTC counters > are only updated by arm_cmn_init_counter() after all DTC and DTM > allocations succeed, nothing actually needs cleaning up in this case > anyway, and it should just return directly as it did before. > > Fixes: 7633ec2c262f ("perf/arm-cmn: Rework DTC counters (again)") > Signed-off-by: Robin Murphy <robin.murphy@arm.com> That's a good catch. Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com> Cheers, Ilkka > --- > drivers/perf/arm-cmn.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c > index 86d970e74129..c584165b13ba 100644 > --- a/drivers/perf/arm-cmn.c > +++ b/drivers/perf/arm-cmn.c > @@ -1816,7 +1816,7 @@ static int arm_cmn_event_add(struct perf_event *event, int flags) > idx = 0; > while (cmn->dtc[j].counters[idx]) > if (++idx == CMN_DT_NUM_COUNTERS) > - goto free_dtms; > + return -ENOSPC; > } > hw->dtc_idx[j] = idx; > } > -- > 2.39.2.101.g768bb238c484.dirty > >
On Mon, Dec 11, 2023 at 07:27:28PM +0000, Robin Murphy wrote: > Calling arm_cmn_event_clear() before all DTC indices are allocated is > wrong, and can lead to arm_cmn_event_add() erroneously clearing live > counters from full DTCs where allocation fails. Since the DTC counters > are only updated by arm_cmn_init_counter() after all DTC and DTM > allocations succeed, nothing actually needs cleaning up in this case > anyway, and it should just return directly as it did before. > > Fixes: 7633ec2c262f ("perf/arm-cmn: Rework DTC counters (again)") > Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > drivers/perf/arm-cmn.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c > index 86d970e74129..c584165b13ba 100644 > --- a/drivers/perf/arm-cmn.c > +++ b/drivers/perf/arm-cmn.c > @@ -1816,7 +1816,7 @@ static int arm_cmn_event_add(struct perf_event *event, int flags) > idx = 0; > while (cmn->dtc[j].counters[idx]) > if (++idx == CMN_DT_NUM_COUNTERS) > - goto free_dtms; > + return -ENOSPC; > } > hw->dtc_idx[j] = idx; > } > -- > 2.39.2.101.g768bb238c484.dirty Acked-by: Will Deacon <will@kernel.org> Catalin -- please can you take this one as a fix? Cheers, Will
On Mon, 11 Dec 2023 19:27:28 +0000, Robin Murphy wrote: > Calling arm_cmn_event_clear() before all DTC indices are allocated is > wrong, and can lead to arm_cmn_event_add() erroneously clearing live > counters from full DTCs where allocation fails. Since the DTC counters > are only updated by arm_cmn_init_counter() after all DTC and DTM > allocations succeed, nothing actually needs cleaning up in this case > anyway, and it should just return directly as it did before. > > [...] Applied to arm64 (for-next/fixes), thanks! [1/1] perf/arm-cmn: Fail DTC counter allocation correctly https://git.kernel.org/arm64/c/1892fe103c3a
diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index 86d970e74129..c584165b13ba 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -1816,7 +1816,7 @@ static int arm_cmn_event_add(struct perf_event *event, int flags) idx = 0; while (cmn->dtc[j].counters[idx]) if (++idx == CMN_DT_NUM_COUNTERS) - goto free_dtms; + return -ENOSPC; } hw->dtc_idx[j] = idx; }
Calling arm_cmn_event_clear() before all DTC indices are allocated is wrong, and can lead to arm_cmn_event_add() erroneously clearing live counters from full DTCs where allocation fails. Since the DTC counters are only updated by arm_cmn_init_counter() after all DTC and DTM allocations succeed, nothing actually needs cleaning up in this case anyway, and it should just return directly as it did before. Fixes: 7633ec2c262f ("perf/arm-cmn: Rework DTC counters (again)") Signed-off-by: Robin Murphy <robin.murphy@arm.com> --- drivers/perf/arm-cmn.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)