s390/etr,stp: fix possible deadlock on machine check
The first level machine check handler for etr and stp machine checks may
call queue_work() while in nmi context. This may deadlock e.g. if the
machine check happened when the interrupted context did hold a lock, that
also will be acquired by queue_work().
Therefore split etr and stp machine check handling into first and second
level handling. The second level handling will then issue the queue_work()
call in process context which avoids the potential deadlock.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/include/asm/etr.h b/arch/s390/include/asm/etr.h
index f7e5c36..105f90e 100644
--- a/arch/s390/include/asm/etr.h
+++ b/arch/s390/include/asm/etr.h
@@ -211,8 +211,9 @@
#define ETR_PTFF_SGS 0x43 /* set gross steering rate */
/* Functions needed by the machine check handler */
-void etr_switch_to_local(void);
-void etr_sync_check(void);
+int etr_switch_to_local(void);
+int etr_sync_check(void);
+void etr_queue_work(void);
/* notifier for syncs */
extern struct atomic_notifier_head s390_epoch_delta_notifier;
@@ -253,7 +254,8 @@
} __attribute__ ((packed));
/* Functions needed by the machine check handler */
-void stp_sync_check(void);
-void stp_island_check(void);
+int stp_sync_check(void);
+int stp_island_check(void);
+void stp_queue_work(void);
#endif /* __S390_ETR_H */