The patch titled
Subject: slub: track number of slabs irrespective of CONFIG_SLUB_DEBUG
has been removed from the -mm tree. Its filename was
slub-track-number-of-slabs-irrespective-of-config_slub_debug.patch
This patch was dropped because it is obsolete
------------------------------------------------------
From: Shakeel Butt <shakeelb(a)google.com>
Subject: slub: track number of slabs irrespective of CONFIG_SLUB_DEBUG
For !CONFIG_SLUB_DEBUG, SLUB does not maintain the number of slabs
allocated per node for a kmem_cache. Thus, slabs_node() in
__kmem_cache_empty(), __kmem_cache_shrink() and __kmem_cache_destroy()
will always return 0 for such config. This is wrong and can cause issues
for all users of these functions.
In fact in [1] Jason has reported a system crash while using SLUB without
CONFIG_SLUB_DEBUG. The reason was the usage of slabs_node() by
__kmem_cache_empty().
The right solution is to make slabs_node() work even for
!CONFIG_SLUB_DEBUG. The commit 0f389ec63077 ("slub: No need for per node
slab counters if !SLUB_DEBUG") had put the per node slab counter under
CONFIG_SLUB_DEBUG because it was only read through sysfs API and the sysfs
API was disabled on !CONFIG_SLUB_DEBUG. However the users of the per node
slab counter assumed that it will work in the absence of
CONFIG_SLUB_DEBUG. So, make the counter work for !CONFIG_SLUB_DEBUG.
Please note that f9e13c0a5a33 ("slab, slub: skip unnecessary
kasan_cache_shutdown()") exposed this issue but it is present even before.
[1] http://lkml.kernel.org/r/CAHmME9rtoPwxUSnktxzKso14iuVCWT7BE_-_8PAC=pGw1iJnQ…
Link: http://lkml.kernel.org/r/20180620224147.23777-1-shakeelb@google.com
Fixes: f9e13c0a5a33 ("slab, slub: skip unnecessary kasan_cache_shutdown()")
Signed-off-by: Shakeel Butt <shakeelb(a)google.com>
Suggested-by: David Rientjes <rientjes(a)google.com>
Reported-by: Jason A . Donenfeld <Jason(a)zx2c4.com>
Cc: Christoph Lameter <cl(a)linux.com>
Cc: Pekka Enberg <penberg(a)kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim(a)lge.com>
Cc: Andrey Ryabinin <aryabinin(a)virtuozzo.com>
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
---
mm/slab.h | 2 -
mm/slub.c | 80 ++++++++++++++++++++++++----------------------------
2 files changed, 38 insertions(+), 44 deletions(-)
diff -puN mm/slab.h~slub-track-number-of-slabs-irrespective-of-config_slub_debug mm/slab.h
--- a/mm/slab.h~slub-track-number-of-slabs-irrespective-of-config_slub_debug
+++ a/mm/slab.h
@@ -473,8 +473,8 @@ struct kmem_cache_node {
#ifdef CONFIG_SLUB
unsigned long nr_partial;
struct list_head partial;
-#ifdef CONFIG_SLUB_DEBUG
atomic_long_t nr_slabs;
+#ifdef CONFIG_SLUB_DEBUG
atomic_long_t total_objects;
struct list_head full;
#endif
diff -puN mm/slub.c~slub-track-number-of-slabs-irrespective-of-config_slub_debug mm/slub.c
--- a/mm/slub.c~slub-track-number-of-slabs-irrespective-of-config_slub_debug
+++ a/mm/slub.c
@@ -1030,42 +1030,6 @@ static void remove_full(struct kmem_cach
list_del(&page->lru);
}
-/* Tracking of the number of slabs for debugging purposes */
-static inline unsigned long slabs_node(struct kmem_cache *s, int node)
-{
- struct kmem_cache_node *n = get_node(s, node);
-
- return atomic_long_read(&n->nr_slabs);
-}
-
-static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
-{
- return atomic_long_read(&n->nr_slabs);
-}
-
-static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
-{
- struct kmem_cache_node *n = get_node(s, node);
-
- /*
- * May be called early in order to allocate a slab for the
- * kmem_cache_node structure. Solve the chicken-egg
- * dilemma by deferring the increment of the count during
- * bootstrap (see early_kmem_cache_node_alloc).
- */
- if (likely(n)) {
- atomic_long_inc(&n->nr_slabs);
- atomic_long_add(objects, &n->total_objects);
- }
-}
-static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
-{
- struct kmem_cache_node *n = get_node(s, node);
-
- atomic_long_dec(&n->nr_slabs);
- atomic_long_sub(objects, &n->total_objects);
-}
-
/* Object debug checks for alloc/free paths */
static void setup_object_debug(struct kmem_cache *s, struct page *page,
void *object)
@@ -1321,16 +1285,46 @@ slab_flags_t kmem_cache_flags(unsigned i
#define disable_higher_order_debug 0
+#endif /* CONFIG_SLUB_DEBUG */
+
static inline unsigned long slabs_node(struct kmem_cache *s, int node)
- { return 0; }
+{
+ struct kmem_cache_node *n = get_node(s, node);
+
+ return atomic_long_read(&n->nr_slabs);
+}
+
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
- { return 0; }
-static inline void inc_slabs_node(struct kmem_cache *s, int node,
- int objects) {}
-static inline void dec_slabs_node(struct kmem_cache *s, int node,
- int objects) {}
+{
+ return atomic_long_read(&n->nr_slabs);
+}
-#endif /* CONFIG_SLUB_DEBUG */
+static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
+{
+ struct kmem_cache_node *n = get_node(s, node);
+
+ /*
+ * May be called early in order to allocate a slab for the
+ * kmem_cache_node structure. Solve the chicken-egg
+ * dilemma by deferring the increment of the count during
+ * bootstrap (see early_kmem_cache_node_alloc).
+ */
+ if (likely(n)) {
+ atomic_long_inc(&n->nr_slabs);
+#ifdef CONFIG_SLUB_DEBUG
+ atomic_long_add(objects, &n->total_objects);
+#endif
+ }
+}
+static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
+{
+ struct kmem_cache_node *n = get_node(s, node);
+
+ atomic_long_dec(&n->nr_slabs);
+#ifdef CONFIG_SLUB_DEBUG
+ atomic_long_sub(objects, &n->total_objects);
+#endif
+}
/*
* Hooks for other subsystems that check memory allocations. In a typical
_
Patches currently in -mm which might be from shakeelb(a)google.com are
kvm-mm-account-shadow-page-tables-to-kmemcg.patch
fs-fsnotify-account-fsnotify-metadata-to-kmemcg.patch
fs-fsnotify-account-fsnotify-metadata-to-kmemcg-fix.patch
fs-mm-account-buffer_head-to-kmemcg.patch
fs-mm-account-buffer_head-to-kmemcgpatchfix.patch
memcg-reduce-memcg-tree-traversals-for-stats-collection.patch
From: Snild Dolkow <snild(a)sony.com>
There is a window for racing when printing directly to task->comm,
allowing other threads to see a non-terminated string. The vsnprintf
function fills the buffer, counts the truncated chars, then finally
writes the \0 at the end.
creator other
vsnprintf:
fill (not terminated)
count the rest trace_sched_waking(p):
... memcpy(comm, p->comm, TASK_COMM_LEN)
write \0
The consequences depend on how 'other' uses the string. In our case,
it was copied into the tracing system's saved cmdlines, a buffer of
adjacent TASK_COMM_LEN-byte buffers (note the 'n' where 0 should be):
crash-arm64> x/1024s savedcmd->saved_cmdlines | grep 'evenk'
0xffffffd5b3818640: "irq/497-pwr_evenkworker/u16:12"
...and a strcpy out of there would cause stack corruption:
[224761.522292] Kernel panic - not syncing: stack-protector:
Kernel stack is corrupted in: ffffff9bf9783c78
crash-arm64> kbt | grep 'comm\|trace_print_context'
#6 0xffffff9bf9783c78 in trace_print_context+0x18c(+396)
comm (char [16]) = "irq/497-pwr_even"
crash-arm64> rd 0xffffffd4d0e17d14 8
ffffffd4d0e17d14: 2f71726900000000 5f7277702d373934 ....irq/497-pwr_
ffffffd4d0e17d24: 726f776b6e657665 3a3631752f72656b evenkworker/u16:
ffffffd4d0e17d34: f9780248ff003231 cede60e0ffffff9b 12..H.x......`..
ffffffd4d0e17d44: cede60c8ffffffd4 00000fffffffffd4 .....`..........
The workaround in e09e28671 (use strlcpy in __trace_find_cmdline) was
likely needed because of this same bug.
Solved by vsnprintf:ing to a local buffer, then using set_task_comm().
This way, there won't be a window where comm is not terminated.
Link: http://lkml.kernel.org/r/20180726071539.188015-1-snild@sony.com
Cc: stable(a)vger.kernel.org
Fixes: bc0c38d139ec7 ("ftrace: latency tracer infrastructure")
Reviewed-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
Signed-off-by: Snild Dolkow <snild(a)sony.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
---
kernel/kthread.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 750cb8082694..486dedbd9af5 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -325,8 +325,14 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
task = create->result;
if (!IS_ERR(task)) {
static const struct sched_param param = { .sched_priority = 0 };
+ char name[TASK_COMM_LEN];
- vsnprintf(task->comm, sizeof(task->comm), namefmt, args);
+ /*
+ * task is already visible to other tasks, so updating
+ * COMM must be protected.
+ */
+ vsnprintf(name, sizeof(name), namefmt, args);
+ set_task_comm(task, name);
/*
* root may have changed our (kthreadd's) priority or CPU mask.
* The kernel thread should not inherit these properties.
--
2.17.1
From: "Steven Rostedt (VMware)" <rostedt(a)goodmis.org>
Commit 57ea2a34adf4 ("tracing/kprobes: Fix trace_probe flags on
enable_trace_kprobe() failure") added an if statement that depends on another
if statement that gcc doesn't see will initialize the "link" variable and
gives the warning:
"warning: 'link' may be used uninitialized in this function"
It is really a false positive, but to quiet the warning, and also to make
sure that it never actually is used uninitialized, initialize the "link"
variable to NULL and add an if (!WARN_ON_ONCE(!link)) where the compiler
thinks it could be used uninitialized.
Cc: stable(a)vger.kernel.org
Fixes: 57ea2a34adf4 ("tracing/kprobes: Fix trace_probe flags on enable_trace_kprobe() failure")
Reported-by: kbuild test robot <lkp(a)intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
---
kernel/trace/trace_kprobe.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 27ace4513c43..6b71860f3998 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -400,7 +400,7 @@ static struct trace_kprobe *find_trace_kprobe(const char *event,
static int
enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
{
- struct event_file_link *link;
+ struct event_file_link *link = NULL;
int ret = 0;
if (file) {
@@ -426,7 +426,9 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
if (ret) {
if (file) {
- list_del_rcu(&link->list);
+ /* Notice the if is true on not WARN() */
+ if (!WARN_ON_ONCE(!link))
+ list_del_rcu(&link->list);
kfree(link);
tk->tp.flags &= ~TP_FLAG_TRACE;
} else {
--
2.17.1
From: "Steven Rostedt (VMware)" <rostedt(a)goodmis.org>
There was a case that triggered a double free in event_trigger_callback()
due to the called reg() function freeing the trigger_data and then it
getting freed again by the error return by the caller. The solution there
was to up the trigger_data ref count.
Code inspection found that event_enable_trigger_func() has the same issue,
but is not as easy to trigger (requires harder to trigger failures). It
needs to be solved slightly different as it needs more to clean up when the
reg() function fails.
Link: http://lkml.kernel.org/r/20180725124008.7008e586@gandalf.local.home
Cc: stable(a)vger.kernel.org
Fixes: 7862ad1846e99 ("tracing: Add 'enable_event' and 'disable_event' event trigger commands")
Reivewed-by: Masami Hiramatsu <mhiramat(a)kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
---
kernel/trace/trace_events_trigger.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index d18ec0e58be2..5dea177cef53 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -1420,6 +1420,9 @@ int event_enable_trigger_func(struct event_command *cmd_ops,
goto out;
}
+ /* Up the trigger_data count to make sure nothing frees it on failure */
+ event_trigger_init(trigger_ops, trigger_data);
+
if (trigger) {
number = strsep(&trigger, ":");
@@ -1470,6 +1473,7 @@ int event_enable_trigger_func(struct event_command *cmd_ops,
goto out_disable;
/* Just return zero, not the number of enabled functions */
ret = 0;
+ event_trigger_free(trigger_ops, trigger_data);
out:
return ret;
@@ -1480,7 +1484,7 @@ int event_enable_trigger_func(struct event_command *cmd_ops,
out_free:
if (cmd_ops->set_filter)
cmd_ops->set_filter(NULL, trigger_data, NULL);
- kfree(trigger_data);
+ event_trigger_free(trigger_ops, trigger_data);
kfree(enable_data);
goto out;
}
--
2.17.1
From: Masami Hiramatsu <mhiramat(a)kernel.org>
Maintain the tracing on/off setting of the ring_buffer when switching
to the trace buffer snapshot.
Taking a snapshot is done by swapping the backup ring buffer
(max_tr_buffer). But since the tracing on/off setting is defined
by the ring buffer, when swapping it, the tracing on/off setting
can also be changed. This causes a strange result like below:
/sys/kernel/debug/tracing # cat tracing_on
1
/sys/kernel/debug/tracing # echo 0 > tracing_on
/sys/kernel/debug/tracing # cat tracing_on
0
/sys/kernel/debug/tracing # echo 1 > snapshot
/sys/kernel/debug/tracing # cat tracing_on
1
/sys/kernel/debug/tracing # echo 1 > snapshot
/sys/kernel/debug/tracing # cat tracing_on
0
We don't touch tracing_on, but snapshot changes tracing_on
setting each time. This is an anomaly, because user doesn't know
that each "ring_buffer" stores its own tracing-enable state and
the snapshot is done by swapping ring buffers.
Link: http://lkml.kernel.org/r/153149929558.11274.11730609978254724394.stgit@devb…
Cc: Ingo Molnar <mingo(a)redhat.com>
Cc: Shuah Khan <shuah(a)kernel.org>
Cc: Tom Zanussi <tom.zanussi(a)linux.intel.com>
Cc: Hiraku Toyooka <hiraku.toyooka(a)cybertrust.co.jp>
Cc: stable(a)vger.kernel.org
Fixes: debdd57f5145 ("tracing: Make a snapshot feature available from userspace")
Signed-off-by: Masami Hiramatsu <mhiramat(a)kernel.org>
[ Updated commit log and comment in the code ]
Signed-off-by: Steven Rostedt (VMware) <rostedt(a)goodmis.org>
---
include/linux/ring_buffer.h | 1 +
kernel/trace/ring_buffer.c | 16 ++++++++++++++++
kernel/trace/trace.c | 6 ++++++
3 files changed, 23 insertions(+)
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index b72ebdff0b77..003d09ab308d 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -165,6 +165,7 @@ void ring_buffer_record_enable(struct ring_buffer *buffer);
void ring_buffer_record_off(struct ring_buffer *buffer);
void ring_buffer_record_on(struct ring_buffer *buffer);
int ring_buffer_record_is_on(struct ring_buffer *buffer);
+int ring_buffer_record_is_set_on(struct ring_buffer *buffer);
void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 6a46af21765c..0b0b688ea166 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3226,6 +3226,22 @@ int ring_buffer_record_is_on(struct ring_buffer *buffer)
return !atomic_read(&buffer->record_disabled);
}
+/**
+ * ring_buffer_record_is_set_on - return true if the ring buffer is set writable
+ * @buffer: The ring buffer to see if write is set enabled
+ *
+ * Returns true if the ring buffer is set writable by ring_buffer_record_on().
+ * Note that this does NOT mean it is in a writable state.
+ *
+ * It may return true when the ring buffer has been disabled by
+ * ring_buffer_record_disable(), as that is a temporary disabling of
+ * the ring buffer.
+ */
+int ring_buffer_record_is_set_on(struct ring_buffer *buffer)
+{
+ return !(atomic_read(&buffer->record_disabled) & RB_BUFFER_OFF);
+}
+
/**
* ring_buffer_record_disable_cpu - stop all writes into the cpu_buffer
* @buffer: The ring buffer to stop writes to.
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 87cf25171fb8..823687997b01 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1373,6 +1373,12 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
arch_spin_lock(&tr->max_lock);
+ /* Inherit the recordable setting from trace_buffer */
+ if (ring_buffer_record_is_set_on(tr->trace_buffer.buffer))
+ ring_buffer_record_on(tr->max_buffer.buffer);
+ else
+ ring_buffer_record_off(tr->max_buffer.buffer);
+
swap(tr->trace_buffer.buffer, tr->max_buffer.buffer);
__update_max_tr(tr, tsk, cpu);
--
2.17.1
The patch below does not apply to the 4.17-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From eb493fbc150f4a28151ae1ee84f24395989f3600 Mon Sep 17 00:00:00 2001
From: Lyude Paul <lyude(a)redhat.com>
Date: Tue, 3 Jul 2018 16:31:41 -0400
Subject: [PATCH] drm/nouveau: Set DRIVER_ATOMIC cap earlier to fix debugfs
Currently nouveau doesn't actually expose the state debugfs file that's
usually provided for any modesetting driver that supports atomic, even
if nouveau is loaded with atomic=1. This is due to the fact that the
standard debugfs files that DRM creates for atomic drivers is called
when drm_get_pci_dev() is called from nouveau_drm.c. This happens well
before we've initialized the display core, which is currently
responsible for setting the DRIVER_ATOMIC cap.
So, move the atomic option into nouveau_drm.c and just add the
DRIVER_ATOMIC cap whenever it's enabled on the kernel commandline. This
shouldn't cause any actual issues, as the atomic ioctl will still fail
as expected even if the display core doesn't disable it until later in
the init sequence. This also provides the added benefit of being able to
use the state debugfs file to check the current display state even if
clients aren't allowed to modify it through anything other than the
legacy ioctls.
Additionally, disable the DRIVER_ATOMIC cap in nv04's display core, as
this was already disabled there previously.
Signed-off-by: Lyude Paul <lyude(a)redhat.com>
Cc: stable(a)vger.kernel.org
Signed-off-by: Ben Skeggs <bskeggs(a)redhat.com>
diff --git a/drivers/gpu/drm/nouveau/dispnv04/disp.c b/drivers/gpu/drm/nouveau/dispnv04/disp.c
index 501d2d290e9c..70dce544984e 100644
--- a/drivers/gpu/drm/nouveau/dispnv04/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/disp.c
@@ -55,6 +55,9 @@ nv04_display_create(struct drm_device *dev)
nouveau_display(dev)->init = nv04_display_init;
nouveau_display(dev)->fini = nv04_display_fini;
+ /* Pre-nv50 doesn't support atomic, so don't expose the ioctls */
+ dev->driver->driver_features &= ~DRIVER_ATOMIC;
+
nouveau_hw_save_vga_fonts(dev, 1);
nv04_crtc_create(dev, 0);
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 31b12b4f321a..9bae4db84cfb 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -2126,10 +2126,6 @@ nv50_display_destroy(struct drm_device *dev)
kfree(disp);
}
-MODULE_PARM_DESC(atomic, "Expose atomic ioctl (default: disabled)");
-static int nouveau_atomic = 0;
-module_param_named(atomic, nouveau_atomic, int, 0400);
-
int
nv50_display_create(struct drm_device *dev)
{
@@ -2154,8 +2150,6 @@ nv50_display_create(struct drm_device *dev)
disp->disp = &nouveau_display(dev)->disp;
dev->mode_config.funcs = &nv50_disp_func;
dev->driver->driver_features |= DRIVER_PREFER_XBGR_30BPP;
- if (nouveau_atomic)
- dev->driver->driver_features |= DRIVER_ATOMIC;
/* small shared memory area we use for notifiers and semaphores */
ret = nouveau_bo_new(&drm->client, 4096, 0x1000, TTM_PL_FLAG_VRAM,
diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 514903338782..f5d3158f0378 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -81,6 +81,10 @@ MODULE_PARM_DESC(modeset, "enable driver (default: auto, "
int nouveau_modeset = -1;
module_param_named(modeset, nouveau_modeset, int, 0400);
+MODULE_PARM_DESC(atomic, "Expose atomic ioctl (default: disabled)");
+static int nouveau_atomic = 0;
+module_param_named(atomic, nouveau_atomic, int, 0400);
+
MODULE_PARM_DESC(runpm, "disable (0), force enable (1), optimus only default (-1)");
static int nouveau_runtime_pm = -1;
module_param_named(runpm, nouveau_runtime_pm, int, 0400);
@@ -509,6 +513,9 @@ static int nouveau_drm_probe(struct pci_dev *pdev,
pci_set_master(pdev);
+ if (nouveau_atomic)
+ driver_pci.driver_features |= DRIVER_ATOMIC;
+
ret = drm_get_pci_dev(pdev, pent, &driver_pci);
if (ret) {
nvkm_device_del(&device);
Hi Stable Team,
On 13/06/2018 14:20, Neil Armstrong wrote:
> On Amlogic Meson GXBB & GXL platforms, the SCPI Cortex-M4 Co-Processor
> seems to be dependent on the FCLK_DIV2 to be operationnal.
>
> The issue occured since v4.17-rc1 by freezing the kernel boot when
> the 'schedutil' cpufreq governor was selected as default :
>
> [ 12.071837] scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
> domain-0 init dvfs: 4
> [ 12.087757] hctosys: unable to open rtc device (rtc0)
> [ 12.087907] cfg80211: Loading compiled-in X.509 certificates for regulatory database
> [ 12.102241] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
>
> But when disabling the MMC driver, the boot finished but cpufreq failed to
> change the CPU frequency :
>
> [ 12.153045] cpufreq: __target_index: Failed to change cpu frequency: -5
>
> A bisect between v4.16 and v4.16-rc1 gave the 05f814402d61 commit to be
> the first bad commit.
> This commit added support for the missing clock gates before the fixed PLL
> fixed dividers (FCLK_DIVx) and the clock framework basically disabled
> all the unused fixed dividers, thus disabled a critical clock path for
> the SCPI Co-Processor.
>
> This patch simply sets the FCLK_DIV2 gate as critical to ensure
> nobody can disable it.
>
> Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
> Signed-off-by: Neil Armstrong <narmstrong(a)baylibre.com>
This patch hit linux master with commit id c987ac6f1f088663b6dad39281071aeb31d450a8
Could this be backported to the next 4.17 stable release ?
Thanks,
Neil
> ---
> drivers/clk/meson/gxbb.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
> index b1e4d95..0e053c1 100644
> --- a/drivers/clk/meson/gxbb.c
> +++ b/drivers/clk/meson/gxbb.c
> @@ -511,6 +511,7 @@ static struct clk_regmap gxbb_fclk_div2 = {
> .ops = &clk_regmap_gate_ops,
> .parent_names = (const char *[]){ "fclk_div2_div" },
> .num_parents = 1,
> + .flags = CLK_IS_CRITICAL,
> },
> };
>
>