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* [PATCH AUTOSEL 4.4 1/6] jbd2: make sure jh have b_transaction set in refile/unfile_buffer
@ 2020-08-24 16:39 Sasha Levin
  2020-08-24 16:39 ` [PATCH AUTOSEL 4.4 2/6] jbd2: abort journal if free a async write error metadata buffer Sasha Levin
                   ` (4 more replies)
  0 siblings, 5 replies; 9+ messages in thread
From: Sasha Levin @ 2020-08-24 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Lukas Czerner, Jan Kara, Theodore Ts'o, Sasha Levin, linux-ext4

From: Lukas Czerner <lczerner@redhat.com>

[ Upstream commit 24dc9864914eb5813173cfa53313fcd02e4aea7d ]

Callers of __jbd2_journal_unfile_buffer() and
__jbd2_journal_refile_buffer() assume that the b_transaction is set. In
fact if it's not, we can end up with journal_head refcounting errors
leading to crash much later that might be very hard to track down. Add
asserts to make sure that is the case.

We also make sure that b_next_transaction is NULL in
__jbd2_journal_unfile_buffer() since the callers expect that as well and
we should not get into that stage in this state anyway, leading to
problems later on if we do.

Tested with fstests.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200617092549.6712-1-lczerner@redhat.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/jbd2/transaction.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 3233e5ac9774f..622610934c9ad 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1906,6 +1906,9 @@ static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
  */
 static void __jbd2_journal_unfile_buffer(struct journal_head *jh)
 {
+	J_ASSERT_JH(jh, jh->b_transaction != NULL);
+	J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
+
 	__jbd2_journal_temp_unlink_buffer(jh);
 	jh->b_transaction = NULL;
 	jbd2_journal_put_journal_head(jh);
@@ -2453,6 +2456,13 @@ void __jbd2_journal_refile_buffer(struct journal_head *jh)
 
 	was_dirty = test_clear_buffer_jbddirty(bh);
 	__jbd2_journal_temp_unlink_buffer(jh);
+
+	/*
+	 * b_transaction must be set, otherwise the new b_transaction won't
+	 * be holding jh reference
+	 */
+	J_ASSERT_JH(jh, jh->b_transaction != NULL);
+
 	/*
 	 * We set b_transaction here because b_next_transaction will inherit
 	 * our jh reference and thus __jbd2_journal_file_buffer() must not
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH AUTOSEL 4.4 2/6] jbd2: abort journal if free a async write error metadata buffer
  2020-08-24 16:39 [PATCH AUTOSEL 4.4 1/6] jbd2: make sure jh have b_transaction set in refile/unfile_buffer Sasha Levin
@ 2020-08-24 16:39 ` Sasha Levin
  2020-08-24 16:39 ` [PATCH AUTOSEL 4.4 3/6] s390/cio: add cond_resched() in the slow_eval_known_fn() loop Sasha Levin
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 9+ messages in thread
From: Sasha Levin @ 2020-08-24 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: zhangyi (F), Theodore Ts'o, Sasha Levin, linux-ext4

From: "zhangyi (F)" <yi.zhang@huawei.com>

[ Upstream commit c044f3d8360d2ecf831ba2cc9f08cf9fb2c699fb ]

If we free a metadata buffer which has been failed to async write out
in the background, the jbd2 checkpoint procedure will not detect this
failure in jbd2_log_do_checkpoint(), so it may lead to filesystem
inconsistency after cleanup journal tail. This patch abort the journal
if free a buffer has write_io_error flag to prevent potential further
inconsistency.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Link: https://lore.kernel.org/r/20200620025427.1756360-5-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/jbd2/transaction.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 622610934c9ad..ce2bf9d74224c 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -2000,6 +2000,7 @@ int jbd2_journal_try_to_free_buffers(journal_t *journal,
 {
 	struct buffer_head *head;
 	struct buffer_head *bh;
+	bool has_write_io_error = false;
 	int ret = 0;
 
 	J_ASSERT(PageLocked(page));
@@ -2024,11 +2025,26 @@ int jbd2_journal_try_to_free_buffers(journal_t *journal,
 		jbd_unlock_bh_state(bh);
 		if (buffer_jbd(bh))
 			goto busy;
+
+		/*
+		 * If we free a metadata buffer which has been failed to
+		 * write out, the jbd2 checkpoint procedure will not detect
+		 * this failure and may lead to filesystem inconsistency
+		 * after cleanup journal tail.
+		 */
+		if (buffer_write_io_error(bh)) {
+			pr_err("JBD2: Error while async write back metadata bh %llu.",
+			       (unsigned long long)bh->b_blocknr);
+			has_write_io_error = true;
+		}
 	} while ((bh = bh->b_this_page) != head);
 
 	ret = try_to_free_buffers(page);
 
 busy:
+	if (has_write_io_error)
+		jbd2_journal_abort(journal, -EIO);
+
 	return ret;
 }
 
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH AUTOSEL 4.4 3/6] s390/cio: add cond_resched() in the slow_eval_known_fn() loop
  2020-08-24 16:39 [PATCH AUTOSEL 4.4 1/6] jbd2: make sure jh have b_transaction set in refile/unfile_buffer Sasha Levin
  2020-08-24 16:39 ` [PATCH AUTOSEL 4.4 2/6] jbd2: abort journal if free a async write error metadata buffer Sasha Levin
@ 2020-08-24 16:39 ` Sasha Levin
  2020-08-24 16:39   ` Sasha Levin
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 9+ messages in thread
From: Sasha Levin @ 2020-08-24 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Vineeth Vijayan, Peter Oberparleiter, Heiko Carstens,
	Sasha Levin, linux-s390

From: Vineeth Vijayan <vneethv@linux.ibm.com>

[ Upstream commit 0b8eb2ee9da1e8c9b8082f404f3948aa82a057b2 ]

The scanning through subchannels during the time of an event could
take significant amount of time in case of platforms with lots of
known subchannels. This might result in higher scheduling latencies
for other tasks especially on systems with a single CPU. Add
cond_resched() call, as the loop in slow_eval_known_fn() can be
executed for a longer duration.

Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/s390/cio/css.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 8ecc956ecb59c..370a3a2c6de73 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -529,6 +529,11 @@ static int slow_eval_known_fn(struct subchannel *sch, void *data)
 		rc = css_evaluate_known_subchannel(sch, 1);
 		if (rc == -EAGAIN)
 			css_schedule_eval(sch->schid);
+		/*
+		 * The loop might take long time for platforms with lots of
+		 * known devices. Allow scheduling here.
+		 */
+		cond_resched();
 	}
 	return 0;
 }
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH AUTOSEL 4.4 4/6] scsi: ufs: Fix possible infinite loop in ufshcd_hold
  2020-08-24 16:39 [PATCH AUTOSEL 4.4 1/6] jbd2: make sure jh have b_transaction set in refile/unfile_buffer Sasha Levin
  2020-08-24 16:39 ` [PATCH AUTOSEL 4.4 2/6] jbd2: abort journal if free a async write error metadata buffer Sasha Levin
@ 2020-08-24 16:39   ` Sasha Levin
  2020-08-24 16:39   ` Sasha Levin
                     ` (2 subsequent siblings)
  4 siblings, 0 replies; 9+ messages in thread
From: Sasha Levin @ 2020-08-24 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Stanley Chu, Avri Altman, Andy Teng, Martin K . Petersen,
	Sasha Levin, linux-scsi, linux-arm-kernel, linux-mediatek

From: Stanley Chu <stanley.chu@mediatek.com>

[ Upstream commit 93b6c5db06028a3b55122bbb74d0715dd8ca4ae0 ]

In ufshcd_suspend(), after clk-gating is suspended and link is set
as Hibern8 state, ufshcd_hold() is still possibly invoked before
ufshcd_suspend() returns. For example, MediaTek's suspend vops may
issue UIC commands which would call ufshcd_hold() during the command
issuing flow.

Now if UFSHCD_CAP_HIBERN8_WITH_CLK_GATING capability is enabled,
then ufshcd_hold() may enter infinite loops because there is no
clk-ungating work scheduled or pending. In this case, ufshcd_hold()
shall just bypass, and keep the link as Hibern8 state.

Link: https://lore.kernel.org/r/20200809050734.18740-1-stanley.chu@mediatek.com
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Co-developed-by: Andy Teng <andy.teng@mediatek.com>
Signed-off-by: Andy Teng <andy.teng@mediatek.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/ufs/ufshcd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index d15cd7a02f9b4..d7a0a64f64536 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -575,6 +575,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
 int ufshcd_hold(struct ufs_hba *hba, bool async)
 {
 	int rc = 0;
+	bool flush_result;
 	unsigned long flags;
 
 	if (!ufshcd_is_clkgating_allowed(hba))
@@ -601,7 +602,9 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
 				break;
 			}
 			spin_unlock_irqrestore(hba->host->host_lock, flags);
-			flush_work(&hba->clk_gating.ungate_work);
+			flush_result = flush_work(&hba->clk_gating.ungate_work);
+			if (hba->clk_gating.is_suspended && !flush_result)
+				goto out;
 			spin_lock_irqsave(hba->host->host_lock, flags);
 			goto start;
 		}
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH AUTOSEL 4.4 4/6] scsi: ufs: Fix possible infinite loop in ufshcd_hold
@ 2020-08-24 16:39   ` Sasha Levin
  0 siblings, 0 replies; 9+ messages in thread
From: Sasha Levin @ 2020-08-24 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Sasha Levin, Martin K . Petersen, linux-scsi, Andy Teng,
	Avri Altman, linux-mediatek, Stanley Chu, linux-arm-kernel

From: Stanley Chu <stanley.chu@mediatek.com>

[ Upstream commit 93b6c5db06028a3b55122bbb74d0715dd8ca4ae0 ]

In ufshcd_suspend(), after clk-gating is suspended and link is set
as Hibern8 state, ufshcd_hold() is still possibly invoked before
ufshcd_suspend() returns. For example, MediaTek's suspend vops may
issue UIC commands which would call ufshcd_hold() during the command
issuing flow.

Now if UFSHCD_CAP_HIBERN8_WITH_CLK_GATING capability is enabled,
then ufshcd_hold() may enter infinite loops because there is no
clk-ungating work scheduled or pending. In this case, ufshcd_hold()
shall just bypass, and keep the link as Hibern8 state.

Link: https://lore.kernel.org/r/20200809050734.18740-1-stanley.chu@mediatek.com
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Co-developed-by: Andy Teng <andy.teng@mediatek.com>
Signed-off-by: Andy Teng <andy.teng@mediatek.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/ufs/ufshcd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index d15cd7a02f9b4..d7a0a64f64536 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -575,6 +575,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
 int ufshcd_hold(struct ufs_hba *hba, bool async)
 {
 	int rc = 0;
+	bool flush_result;
 	unsigned long flags;
 
 	if (!ufshcd_is_clkgating_allowed(hba))
@@ -601,7 +602,9 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
 				break;
 			}
 			spin_unlock_irqrestore(hba->host->host_lock, flags);
-			flush_work(&hba->clk_gating.ungate_work);
+			flush_result = flush_work(&hba->clk_gating.ungate_work);
+			if (hba->clk_gating.is_suspended && !flush_result)
+				goto out;
 			spin_lock_irqsave(hba->host->host_lock, flags);
 			goto start;
 		}
-- 
2.25.1


_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH AUTOSEL 4.4 4/6] scsi: ufs: Fix possible infinite loop in ufshcd_hold
@ 2020-08-24 16:39   ` Sasha Levin
  0 siblings, 0 replies; 9+ messages in thread
From: Sasha Levin @ 2020-08-24 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Sasha Levin, Martin K . Petersen, linux-scsi, Andy Teng,
	Avri Altman, linux-mediatek, Stanley Chu, linux-arm-kernel

From: Stanley Chu <stanley.chu@mediatek.com>

[ Upstream commit 93b6c5db06028a3b55122bbb74d0715dd8ca4ae0 ]

In ufshcd_suspend(), after clk-gating is suspended and link is set
as Hibern8 state, ufshcd_hold() is still possibly invoked before
ufshcd_suspend() returns. For example, MediaTek's suspend vops may
issue UIC commands which would call ufshcd_hold() during the command
issuing flow.

Now if UFSHCD_CAP_HIBERN8_WITH_CLK_GATING capability is enabled,
then ufshcd_hold() may enter infinite loops because there is no
clk-ungating work scheduled or pending. In this case, ufshcd_hold()
shall just bypass, and keep the link as Hibern8 state.

Link: https://lore.kernel.org/r/20200809050734.18740-1-stanley.chu@mediatek.com
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Co-developed-by: Andy Teng <andy.teng@mediatek.com>
Signed-off-by: Andy Teng <andy.teng@mediatek.com>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/ufs/ufshcd.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index d15cd7a02f9b4..d7a0a64f64536 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -575,6 +575,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
 int ufshcd_hold(struct ufs_hba *hba, bool async)
 {
 	int rc = 0;
+	bool flush_result;
 	unsigned long flags;
 
 	if (!ufshcd_is_clkgating_allowed(hba))
@@ -601,7 +602,9 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
 				break;
 			}
 			spin_unlock_irqrestore(hba->host->host_lock, flags);
-			flush_work(&hba->clk_gating.ungate_work);
+			flush_result = flush_work(&hba->clk_gating.ungate_work);
+			if (hba->clk_gating.is_suspended && !flush_result)
+				goto out;
 			spin_lock_irqsave(hba->host->host_lock, flags);
 			goto start;
 		}
-- 
2.25.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH AUTOSEL 4.4 5/6] net: gianfar: Add of_node_put() before goto statement
  2020-08-24 16:39 [PATCH AUTOSEL 4.4 1/6] jbd2: make sure jh have b_transaction set in refile/unfile_buffer Sasha Levin
                   ` (2 preceding siblings ...)
  2020-08-24 16:39   ` Sasha Levin
@ 2020-08-24 16:39 ` Sasha Levin
  2020-08-24 16:39   ` Sasha Levin
  4 siblings, 0 replies; 9+ messages in thread
From: Sasha Levin @ 2020-08-24 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Sumera Priyadarsini, David S . Miller, Sasha Levin, netdev

From: Sumera Priyadarsini <sylphrenadin@gmail.com>

[ Upstream commit 989e4da042ca4a56bbaca9223d1a93639ad11e17 ]

Every iteration of for_each_available_child_of_node() decrements
reference count of the previous node, however when control
is transferred from the middle of the loop, as in the case of
a return or break or goto, there is no decrement thus ultimately
resulting in a memory leak.

Fix a potential memory leak in gianfar.c by inserting of_node_put()
before the goto statement.

Issue found with Coccinelle.

Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/freescale/gianfar.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index 37cc1f838dd8b..96310e2ee5458 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -845,8 +845,10 @@ static int gfar_of_init(struct platform_device *ofdev, struct net_device **pdev)
 				continue;
 
 			err = gfar_parse_group(child, priv, model);
-			if (err)
+			if (err) {
+				of_node_put(child);
 				goto err_grp_init;
+			}
 		}
 	} else { /* SQ_SG_MODE */
 		err = gfar_parse_group(np, priv, model);
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH AUTOSEL 4.4 6/6] powerpc/perf: Fix soft lockups due to missed interrupt accounting
  2020-08-24 16:39 [PATCH AUTOSEL 4.4 1/6] jbd2: make sure jh have b_transaction set in refile/unfile_buffer Sasha Levin
@ 2020-08-24 16:39   ` Sasha Levin
  2020-08-24 16:39 ` [PATCH AUTOSEL 4.4 3/6] s390/cio: add cond_resched() in the slow_eval_known_fn() loop Sasha Levin
                     ` (3 subsequent siblings)
  4 siblings, 0 replies; 9+ messages in thread
From: Sasha Levin @ 2020-08-24 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Athira Rajeev, Alexey Kardashevskiy, Michael Ellerman,
	Sasha Levin, linuxppc-dev

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 30e2e8efbe6b7..aab13558e9700 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -2040,6 +2040,10 @@ 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


^ permalink raw reply related	[flat|nested] 9+ messages in thread

* [PATCH AUTOSEL 4.4 6/6] powerpc/perf: Fix soft lockups due to missed interrupt accounting
@ 2020-08-24 16:39   ` Sasha Levin
  0 siblings, 0 replies; 9+ messages in thread
From: Sasha Levin @ 2020-08-24 16:39 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Alexey Kardashevskiy, Athira Rajeev, linuxppc-dev, Sasha Levin

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 30e2e8efbe6b7..aab13558e9700 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -2040,6 +2040,10 @@ 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


^ permalink raw reply related	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2020-08-24 17:04 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-24 16:39 [PATCH AUTOSEL 4.4 1/6] jbd2: make sure jh have b_transaction set in refile/unfile_buffer Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.4 2/6] jbd2: abort journal if free a async write error metadata buffer Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.4 3/6] s390/cio: add cond_resched() in the slow_eval_known_fn() loop Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.4 4/6] 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 4.4 5/6] net: gianfar: Add of_node_put() before goto statement Sasha Levin
2020-08-24 16:39 ` [PATCH AUTOSEL 4.4 6/6] powerpc/perf: Fix soft lockups due to missed interrupt accounting Sasha Levin
2020-08-24 16:39   ` Sasha Levin

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