Commit c8fd3704 authored by Robin Murphy's avatar Robin Murphy Committed by Wen Zhiwei
Browse files

perf/arm-cmn: Fail DTC counter allocation correctly 

stable inclusion
from stable-v6.6.54
commit 18b5ee7bf70048d85cc1b424e862cb762421b2c5
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAZ3K2

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=18b5ee7bf70048d85cc1b424e862cb762421b2c5



--------------------------------

commit 1892fe103c3a20fced306c8dafa74f7f6d4ea0a3 upstream.

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: default avatarRobin Murphy <robin.murphy@arm.com>
Reviewed-by: default avatarIlkka Koskinen <ilkka@os.amperecomputing.com>
Acked-by: default avatarWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/ed589c0d8e4130dc68b8ad1625226d28bdc185d4.1702322847.git.robin.murphy@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarWen Zhiwei <wenzhiwei@kylinos.cn>
parent 2f77a557

drivers/perf/arm-cmn.c

+1 −1
Original line number Diff line number Diff line
@@ -1794,7 +1794,7 @@ 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;

	}