[PATCH AUTOSEL 4.19 08/40] s390/cpuinfo: fix wrong output when CPU0 is offline

[PATCH AUTOSEL 4.19 08/40] s390/cpuinfo: fix wrong output when CPU0 is offline

[Sasha Levin]

From: Alexander Gordeev <agordeev@linux.ibm.com>

[ Upstream commit 872f27103874a73783aeff2aac2b41a489f67d7c ]

/proc/cpuinfo should not print information about CPU 0 when it is offline.

Fixes: 281eaa8cb67c ("s390/cpuinfo: simplify locking and skip offline cpus early")
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
[heiko.carstens@de.ibm.com: shortened commit message]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/kernel/processor.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c
index 6fe2e1875058b..675d4be0c2b77 100644
--- a/arch/s390/kernel/processor.c
+++ b/arch/s390/kernel/processor.c
@@ -157,8 +157,9 @@ static void show_cpu_mhz(struct seq_file *m, unsigned long n)
 static int show_cpuinfo(struct seq_file *m, void *v)
 {
 	unsigned long n = (unsigned long) v - 1;
+	unsigned long first = cpumask_first(cpu_online_mask);
 
-	if (!n)
+	if (n == first)
 		show_cpu_summary(m, v);
 	if (!machine_has_cpu_mhz)
 		return 0;
@@ -171,6 +172,8 @@ static inline void *c_update(loff_t *pos)
 {
 	if (*pos)
 		*pos = cpumask_next(*pos - 1, cpu_online_mask);
+	else
+		*pos = cpumask_first(cpu_online_mask);
 	return *pos < nr_cpu_ids ? (void *)*pos + 1 : NULL;
 }
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 11/40] s390/cpum_sf: Fix wrong page count in error message

[Sasha Levin]

From: Thomas Richter <tmricht@linux.ibm.com>

[ Upstream commit 4141b6a5e9f171325effc36a22eb92bf961e7a5c ]

When perf record -e SF_CYCLES_BASIC_DIAG runs with very high
frequency, the samples arrive faster than the perf process can
save them to file. Eventually, for longer running processes, this
leads to the siutation where the trace buffers allocated by perf
slowly fills up. At one point the auxiliary trace buffer is full
and  the CPU Measurement sampling facility is turned off. Furthermore
a warning is printed to the kernel log buffer:

cpum_sf: The AUX buffer with 0 pages for the diagnostic-sampling
	mode is full

The number of allocated pages for the auxiliary trace buffer is shown
as zero pages. That is wrong.

Fix this by saving the number of allocated pages before entering the
work loop in the interrupt handler. When the interrupt handler processes
the samples, it may detect the buffer full condition and stop sampling,
reducing the buffer size to zero.
Print the correct value in the error message:

cpum_sf: The AUX buffer with 256 pages for the diagnostic-sampling
	mode is full

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/kernel/perf_cpum_sf.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index 5bfb1ce129f4b..74a296cea21cc 100644
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1537,6 +1537,7 @@ static void hw_collect_aux(struct cpu_hw_sf *cpuhw)
 	perf_aux_output_end(handle, size);
 	num_sdb = aux->sfb.num_sdb;
 
+	num_sdb = aux->sfb.num_sdb;
 	while (!done) {
 		/* Get an output handle */
 		aux = perf_aux_output_begin(handle, cpuhw->event);
-- 
2.20.1

[PATCH AUTOSEL 4.19 24/40] KVM: s390: vsie: Fix possible race when shadowing region 3 tables

[Sasha Levin]

From: David Hildenbrand <david@redhat.com>

[ Upstream commit 1493e0f944f3c319d11e067c185c904d01c17ae5 ]

We have to properly retry again by returning -EINVAL immediately in case
somebody else instantiated the table concurrently. We missed to add the
goto in this function only. The code now matches the other, similar
shadowing functions.

We are overwriting an existing region 2 table entry. All allocated pages
are added to the crst_list to be freed later, so they are not lost
forever. However, when unshadowing the region 2 table, we wouldn't trigger
unshadowing of the original shadowed region 3 table that we replaced. It
would get unshadowed when the original region 3 table is modified. As it's
not connected to the page table hierarchy anymore, it's not going to get
used anymore. However, for a limited time, this page table will stick
around, so it's in some sense a temporary memory leak.

Identified by manual code inspection. I don't think this classifies as
stable material.

Fixes: 998f637cc4b9 ("s390/mm: avoid races on region/segment/page table shadowing")
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200403153050.20569-4-david@redhat.com
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/mm/gmap.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 911c7ded35f15..fd67684a305d4 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -1834,6 +1834,7 @@ int gmap_shadow_r3t(struct gmap *sg, unsigned long saddr, unsigned long r3t,
 		goto out_free;
 	} else if (*table & _REGION_ENTRY_ORIGIN) {
 		rc = -EAGAIN;		/* Race with shadow */
+		goto out_free;
 	}
 	crst_table_init(s_r3t, _REGION3_ENTRY_EMPTY);
 	/* mark as invalid as long as the parent table is not protected */
-- 
2.20.1