Re: [ANNOUNCE] v5.12-rc3-rt3

2021-03-25 Thread Kurt Kanzenbach 
On Sat Mar 20 2021, Mike Galbraith wrote:
> On Fri, 2021-03-19 at 23:33 +0100, Sebastian Andrzej Siewior wrote:
>> Dear RT folks!
>>
>> I'm pleased to announce the v5.12-rc3-rt3 patch set.
>
> My little rpi4b is fairly unhappy with 5.12-rt, whereas 5.11-rt works
> fine on it.  The below spew is endless, making boot endless.  I turned
> it into a WARN_ON_ONCE to see if the thing would finish boot, and
> surprisingly, it seems perfectly fine with that bad idea. Having not
> the foggiest clue what I'm doing down in arm arch-land, bug is in no
> immediate danger :)

Yeah, I've had the same issue with my Marvell
ESPRESSObin. WARN_ON_ONCE() made it boot and it runs without any
problems since then. Thanks!

Thanks,
Kurt


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Re: [ANNOUNCE] v5.12-rc3-rt3

2021-03-21 Thread Mike Galbraith 
On Sun, 2021-03-21 at 08:46 +0100, Mike Galbraith wrote:
> On Sat, 2021-03-20 at 09:18 +0100, Mike Galbraith wrote:
> > On Fri, 2021-03-19 at 23:33 +0100, Sebastian Andrzej Siewior wrote:
> > > Dear RT folks!
> > >
> > > I'm pleased to announce the v5.12-rc3-rt3 patch set.
> >
> > My little rpi4b is fairly unhappy with 5.12-rt, whereas 5.11-rt works
> > fine on it.  The below spew is endless, making boot endless.  I turned
> > it into a WARN_ON_ONCE to see if the thing would finish boot, and
> > surprisingly, it seems perfectly fine with that bad idea. Having not
> > the foggiest clue what I'm doing down in arm arch-land, bug is in no
> > immediate danger :)
>
> Actually, it looks like a defenseless little buglet, and this gripe
> simply wants to be disabled for RT.

Or completely removed instead.

It's entirely possible I'm missing something obvious to arm experts,
but I don't _think_ the register read needs protection, leaving me
wondering why arch_faults_on_old_pte() was born with that warning.

-Mike

Re: [ANNOUNCE] v5.12-rc3-rt3

2021-03-21 Thread Mike Galbraith 
On Sat, 2021-03-20 at 09:18 +0100, Mike Galbraith wrote:
> On Fri, 2021-03-19 at 23:33 +0100, Sebastian Andrzej Siewior wrote:
> > Dear RT folks!
> >
> > I'm pleased to announce the v5.12-rc3-rt3 patch set.
>
> My little rpi4b is fairly unhappy with 5.12-rt, whereas 5.11-rt works
> fine on it.  The below spew is endless, making boot endless.  I turned
> it into a WARN_ON_ONCE to see if the thing would finish boot, and
> surprisingly, it seems perfectly fine with that bad idea. Having not
> the foggiest clue what I'm doing down in arm arch-land, bug is in no
> immediate danger :)

Actually, it looks like a defenseless little buglet, and this gripe
simply wants to be disabled for RT.

arm64: disable arch_faults_on_old_pte() preemptible() warning for RT

arch_faults_on_old_pte() was never called in < 5.12-rt, but 5.12 added
arch_wants_old_prefaulted_pte(), which is a wrapper thereof, and thus
finish_fault() -> do_set_pte() -> arch_wants_old_prefaulted_pte() now
calls it, in preemptible context, and a flood of complaints ensues.

Kill it for RT.

Signed-off-by: Mike Galbraith 
---
 arch/arm64/include/asm/pgtable.h |2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -979,7 +979,7 @@ static inline void update_mmu_cache(stru
  */
 static inline bool arch_faults_on_old_pte(void)
 {
-   WARN_ON(preemptible());
+   WARN_ON(!IS_ENABLED(CONFIG_PREEMPT_RT) && preemptible());

return !cpu_has_hw_af();
 }

>
> [2.216913] WARNING: CPU: 0 PID: 1 at arch/arm64/include/asm/pgtable.h:982 
> do_set_pte+0x1cc/0x1d4
> [2.216949] Modules linked in:
> [2.216961] CPU: 0 PID: 1 Comm: init Not tainted 5.12.0.g425ed5a-v8-rt #33
> [2.216973] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
> [2.216979] pstate: 2005 (nzCv daif -PAN -UAO -TCO BTYPE=--)
> [2.216990] pc : do_set_pte+0x1cc/0x1d4
> [2.217004] lr : filemap_map_pages+0x178/0x380
> [2.217016] sp : ffc01153bbb0
> [2.217020] x29: ffc01153bbb0 x28: fffe07d93080
> [2.217033] x27:  x26: ff8101c9e000
> [2.217044] x25: ff8101b40fd8 x24: 
> [2.217054] x23: ff8101674170 x22: 007fb1b4b000
> [2.217064] x21: fffe07d93080 x20: ffc01153bcf0
> [2.217073] x19: 0021f64c2fc3 x18: 
> [2.217082] x17:  x16: 
> [2.217091] x15:  x14: 
> [2.217100] x13:  x12: 
> [2.217108] x11:  x10: 
> [2.217117] x9 : ffc010209068 x8 : 000f
> [2.217126] x7 : ff8101e87c68 x6 : fffe
> [2.217135] x5 : 00101e8b x4 : ff8101e880a8
> [2.217144] x3 : 00200fc3 x2 : 
> [2.217153] x1 :  x0 : 
> [2.217162] Call trace:
> [2.217166]  do_set_pte+0x1cc/0x1d4
> [2.217181]  filemap_map_pages+0x178/0x380
> [2.217189]  __handle_mm_fault+0x75c/0x930
> [2.217202]  handle_mm_fault+0x178/0x25c
> [2.217214]  do_page_fault+0x16c/0x470
> [2.217233]  do_translation_fault+0xbc/0xd8
> [2.217244]  do_mem_abort+0x4c/0xbc
> [2.217259]  el0_ia+0x68/0xcc
> [2.217272]  el0_sync_handler+0x180/0x1b0
> [2.217284]  el0_sync+0x170/0x180

Re: [ANNOUNCE] v5.12-rc3-rt3

2021-03-20 Thread Mike Galbraith 
On Fri, 2021-03-19 at 23:33 +0100, Sebastian Andrzej Siewior wrote:
> Dear RT folks!
>
> I'm pleased to announce the v5.12-rc3-rt3 patch set.

My little rpi4b is fairly unhappy with 5.12-rt, whereas 5.11-rt works
fine on it.  The below spew is endless, making boot endless.  I turned
it into a WARN_ON_ONCE to see if the thing would finish boot, and
surprisingly, it seems perfectly fine with that bad idea. Having not
the foggiest clue what I'm doing down in arm arch-land, bug is in no
immediate danger :)

[2.216913] WARNING: CPU: 0 PID: 1 at arch/arm64/include/asm/pgtable.h:982 
do_set_pte+0x1cc/0x1d4
[2.216949] Modules linked in:
[2.216961] CPU: 0 PID: 1 Comm: init Not tainted 5.12.0.g425ed5a-v8-rt #33
[2.216973] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT)
[2.216979] pstate: 2005 (nzCv daif -PAN -UAO -TCO BTYPE=--)
[2.216990] pc : do_set_pte+0x1cc/0x1d4
[2.217004] lr : filemap_map_pages+0x178/0x380
[2.217016] sp : ffc01153bbb0
[2.217020] x29: ffc01153bbb0 x28: fffe07d93080
[2.217033] x27:  x26: ff8101c9e000
[2.217044] x25: ff8101b40fd8 x24: 
[2.217054] x23: ff8101674170 x22: 007fb1b4b000
[2.217064] x21: fffe07d93080 x20: ffc01153bcf0
[2.217073] x19: 0021f64c2fc3 x18: 
[2.217082] x17:  x16: 
[2.217091] x15:  x14: 
[2.217100] x13:  x12: 
[2.217108] x11:  x10: 
[2.217117] x9 : ffc010209068 x8 : 000f
[2.217126] x7 : ff8101e87c68 x6 : fffe
[2.217135] x5 : 00101e8b x4 : ff8101e880a8
[2.217144] x3 : 00200fc3 x2 : 
[2.217153] x1 :  x0 : 
[2.217162] Call trace:
[2.217166]  do_set_pte+0x1cc/0x1d4
[2.217181]  filemap_map_pages+0x178/0x380
[2.217189]  __handle_mm_fault+0x75c/0x930
[2.217202]  handle_mm_fault+0x178/0x25c
[2.217214]  do_page_fault+0x16c/0x470
[2.217233]  do_translation_fault+0xbc/0xd8
[2.217244]  do_mem_abort+0x4c/0xbc
[2.217259]  el0_ia+0x68/0xcc
[2.217272]  el0_sync_handler+0x180/0x1b0
[2.217284]  el0_sync+0x170/0x180

[ANNOUNCE] v5.12-rc3-rt3

2021-03-19 Thread Sebastian Andrzej Siewior 
Dear RT folks!

I'm pleased to announce the v5.12-rc3-rt3 patch set. 

Changes since v5.12-rc3-rt2:

  - Update the softirq/tasklet patches to the latest version which has
been merged into the tip tree. Only the comments have changed.

  - In certain conditions the SLAB_TYPESAFE_BY_RCU marked SLAB pages may
have been returned to the page-allocator without waiting for
required grace period. The problem has been introduced during the
rework in v5.11.2-rt9.

  - Update John's printk patches.
With this update I can strike 
 - kdb/kgdb can easily deadlock.

off the known issues list.

Known issues
 - netconsole triggers WARN.

The delta patch against v5.12-rc3-rt2 is appended below and can be found here:
 
 
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.12/incr/patch-5.12-rc3-rt2-rt3.patch.xz

You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git 
v5.12-rc3-rt3

The RT patch against v5.12-rc3 can be found here:


https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.12/older/patch-5.12-rc3-rt3.patch.xz

The split quilt queue is available at:


https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.12/older/patches-5.12-rc3-rt3.tar.xz

Sebastian

diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index 7a13bc20f0a0c..e0ced3afc667f 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -57,6 +57,7 @@ struct smp_ops_t {
 
 extern int smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 
delay_us);
 extern int smp_send_safe_nmi_ipi(int cpu, void (*fn)(struct pt_regs *), u64 
delay_us);
+extern void smp_send_debugger_break_cpu(unsigned int cpu);
 extern void smp_send_debugger_break(void);
 extern void start_secondary_resume(void);
 extern void smp_generic_give_timebase(void);
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index 409080208a6c4..1f716688c9775 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -20,6 +20,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 #include 
@@ -120,11 +121,19 @@ int kgdb_skipexception(int exception, struct pt_regs 
*regs)
 
 static int kgdb_debugger_ipi(struct pt_regs *regs)
 {
-   kgdb_nmicallback(raw_smp_processor_id(), regs);
+   int cpu = raw_smp_processor_id();
+
+   if (!console_atomic_kgdb_cpu_delay(cpu))
+   kgdb_nmicallback(cpu, regs);
return 0;
 }
 
 #ifdef CONFIG_SMP
+void kgdb_roundup_cpu(unsigned int cpu)
+{
+   smp_send_debugger_break_cpu(cpu);
+}
+
 void kgdb_roundup_cpus(void)
 {
smp_send_debugger_break();
diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
index 1ef55f4b389a2..3c8d9bbb51cfa 100644
--- a/arch/powerpc/kernel/nvram_64.c
+++ b/arch/powerpc/kernel/nvram_64.c
@@ -73,8 +73,7 @@ static const char *nvram_os_partitions[] = {
 };
 
 static void oops_to_nvram(struct kmsg_dumper *dumper,
- enum kmsg_dump_reason reason,
- struct kmsg_dumper_iter *iter);
+ enum kmsg_dump_reason reason);
 
 static struct kmsg_dumper nvram_kmsg_dumper = {
.dump = oops_to_nvram
@@ -644,11 +643,11 @@ void __init nvram_init_oops_partition(int 
rtas_partition_exists)
  * partition.  If that's too much, go back and capture uncompressed text.
  */
 static void oops_to_nvram(struct kmsg_dumper *dumper,
- enum kmsg_dump_reason reason,
- struct kmsg_dumper_iter *iter)
+ enum kmsg_dump_reason reason)
 {
struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
static unsigned int oops_count = 0;
+   static struct kmsg_dump_iter iter;
static bool panicking = false;
static DEFINE_SPINLOCK(lock);
unsigned long flags;
@@ -683,13 +682,14 @@ static void oops_to_nvram(struct kmsg_dumper *dumper,
return;
 
if (big_oops_buf) {
-   kmsg_dump_get_buffer(iter, false,
+   kmsg_dump_rewind();
+   kmsg_dump_get_buffer(, false,
 big_oops_buf, big_oops_buf_sz, _len);
rc = zip_oops(text_len);
}
if (rc != 0) {
-   kmsg_dump_rewind(iter);
-   kmsg_dump_get_buffer(iter, false,
+   kmsg_dump_rewind();
+   kmsg_dump_get_buffer(, false,
 oops_data, oops_data_sz, _len);
err_type = ERR_TYPE_KERNEL_PANIC;
oops_hdr->version = cpu_to_be16(OOPS_HDR_VERSION);
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 5a4d59a1070d5..b396c6eafce38 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -582,6 +582,11 @@ static void debugger_ipi_callback(struct pt_regs *regs)
debugger_ipi(regs);
 }
 
+void