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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
	Alexey Kardashevskiy <aik@ozlabs.ru>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Sasha Levin <sashal@kernel.org>,
	linuxppc-dev@lists.ozlabs.org
Subject: [PATCH AUTOSEL 4.14 11/11] powerpc/perf: Fix soft lockups due to missed interrupt accounting
Date: Mon, 24 Aug 2020 12:39:14 -0400	[thread overview]
Message-ID: <20200824163914.607152-11-sashal@kernel.org> (raw)
In-Reply-To: <20200824163914.607152-1-sashal@kernel.org>

From: Athira Rajeev <atrajeev@linux.vnet.ibm.com>

[ Upstream commit 17899eaf88d689529b866371344c8f269ba79b5f ]

Performance monitor interrupt handler checks if any counter has
overflown and calls record_and_restart() in core-book3s which invokes
perf_event_overflow() to record the sample information. Apart from
creating sample, perf_event_overflow() also does the interrupt and
period checks via perf_event_account_interrupt().

Currently we record information only if the SIAR (Sampled Instruction
Address Register) valid bit is set (using siar_valid() check) and
hence the interrupt check.

But it is possible that we do sampling for some events that are not
generating valid SIAR, and hence there is no chance to disable the
event if interrupts are more than max_samples_per_tick. This leads to
soft lockup.

Fix this by adding perf_event_account_interrupt() in the invalid SIAR
code path for a sampling event. ie if SIAR is invalid, just do
interrupt check and don't record the sample information.

Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1596717992-7321-1-git-send-email-atrajeev@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/perf/core-book3s.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 3188040022c4f..78f75e48dfe7f 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -2096,6 +2096,10 @@ static void record_and_restart(struct perf_event *event, unsigned long val,
 
 		if (perf_event_overflow(event, &data, regs))
 			power_pmu_stop(event, 0);
+	} else if (period) {
+		/* Account for interrupt in case of invalid SIAR */
+		if (perf_event_account_interrupt(event))
+			power_pmu_stop(event, 0);
 	}
 }
 
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
	Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 4.14 11/11] powerpc/perf: Fix soft lockups due to missed interrupt accounting
Date: Mon, 24 Aug 2020 12:39:14 -0400	[thread overview]
Message-ID: <20200824163914.607152-11-sashal@kernel.org> (raw)
In-Reply-To: <20200824163914.607152-1-sashal@kernel.org>

From: Athira Rajeev <atrajeev@linux.vnet.ibm.com>

[ Upstream commit 17899eaf88d689529b866371344c8f269ba79b5f ]

Performance monitor interrupt handler checks if any counter has
overflown and calls record_and_restart() in core-book3s which invokes
perf_event_overflow() to record the sample information. Apart from
creating sample, perf_event_overflow() also does the interrupt and
period checks via perf_event_account_interrupt().

Currently we record information only if the SIAR (Sampled Instruction
Address Register) valid bit is set (using siar_valid() check) and
hence the interrupt check.

But it is possible that we do sampling for some events that are not
generating valid SIAR, and hence there is no chance to disable the
event if interrupts are more than max_samples_per_tick. This leads to
soft lockup.

Fix this by adding perf_event_account_interrupt() in the invalid SIAR
code path for a sampling event. ie if SIAR is invalid, just do
interrupt check and don't record the sample information.

Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1596717992-7321-1-git-send-email-atrajeev@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/perf/core-book3s.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 3188040022c4f..78f75e48dfe7f 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -2096,6 +2096,10 @@ static void record_and_restart(struct perf_event *event, unsigned long val,
 
 		if (perf_event_overflow(event, &data, regs))
 			power_pmu_stop(event, 0);
+	} else if (period) {
+		/* Account for interrupt in case of invalid SIAR */
+		if (perf_event_account_interrupt(event))
+			power_pmu_stop(event, 0);
 	}
 }
 
-- 
2.25.1


  parent reply	other threads:[~2020-08-24 16:44 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-24 16:39 [PATCH AUTOSEL 4.14 01/11] jbd2: make sure jh have b_transaction set in refile/unfile_buffer Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.14 02/11] ext4: don't BUG on inconsistent journal feature Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.14 03/11] jbd2: abort journal if free a async write error metadata buffer Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.14 04/11] fs: prevent BUG_ON in submit_bh_wbc() Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.14 05/11] spi: stm32: fix stm32_spi_prepare_mbr in case of odd clk_rate Sasha Levin
2020-08-24 16:39   ` Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.14 06/11] s390/cio: add cond_resched() in the slow_eval_known_fn() loop Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.14 07/11] scsi: ufs: Fix possible infinite loop in ufshcd_hold Sasha Levin
2020-08-24 16:39   ` Sasha Levin
2020-08-24 16:39   ` Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.14 08/11] scsi: ufs: Improve interrupt handling for shared interrupts Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.14 09/11] scsi: ufs: Clean up completed request without interrupt notification Sasha Levin
2020-08-24 16:39   ` Sasha Levin
2020-08-24 16:39   ` Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.14 10/11] net: gianfar: Add of_node_put() before goto statement Sasha Levin
2020-08-24 16:39 ` Sasha Levin [this message]
2020-08-24 16:39   ` [PATCH AUTOSEL 4.14 11/11] powerpc/perf: Fix soft lockups due to missed interrupt accounting Sasha Levin

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