Thread (13 messages) 13 messages, 3 authors, 2019-08-11

Re: [PATCH v8 1/7] powerpc/mce: Schedule work from irq_work

From: Mahesh Jagannath Salgaonkar <hidden>
Date: 2019-08-09 18:55:59
Also in: lkml

On 8/7/19 8:26 PM, Santosh Sivaraj wrote:
quoted hunk ↗ jump to hunk
schedule_work() cannot be called from MCE exception context as MCE can
interrupt even in interrupt disabled context.

fixes: 733e4a4c ("powerpc/mce: hookup memory_failure for UE errors")
Signed-off-by: Santosh Sivaraj <redacted>
---
 arch/powerpc/kernel/mce.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index b18df633eae9..0ab6fa7cbbbb 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -144,7 +144,6 @@ void save_mce_event(struct pt_regs *regs, long handled,
 		if (phys_addr != ULONG_MAX) {
 			mce->u.ue_error.physical_address_provided = true;
 			mce->u.ue_error.physical_address = phys_addr;
-			machine_check_ue_event(mce);
 		}
 	}
 	return;
@@ -275,8 +274,7 @@ static void machine_process_ue_event(struct work_struct *work)
 	}
 }
 /*
- * process pending MCE event from the mce event queue. This function will be
- * called during syscall exit.
+ * process pending MCE event from the mce event queue.
  */
 static void machine_check_process_queued_event(struct irq_work *work)
 {
@@ -292,6 +290,10 @@ static void machine_check_process_queued_event(struct irq_work *work)
 	while (__this_cpu_read(mce_queue_count) > 0) {
 		index = __this_cpu_read(mce_queue_count) - 1;
 		evt = this_cpu_ptr(&mce_event_queue[index]);
+
+		if (evt->error_type == MCE_ERROR_TYPE_UE)
+			machine_check_ue_event(evt);
This will work only for the event that are queued by mce handler, others
will get ignored. I think you should introduce a separate irq work queue
for schedule_work().

Thanks,
-Mahesh.
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