[PATCH] lockdep: s390 turn validator off in machine-check handler

Machine checks on s390 are always enabled (except in the machine check handler
itself).  Therefore use lockdep_off()/on() in the machine check handler to
avoid deadlocks in the lock validator.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/s390/s390mach.c b/drivers/s390/s390mach.c
index 432136f96e643d91a538f96e7ae022311fc59155..ffb3677e354fe9c1a7d0848453d91353fb33cc7e 100644 (file)
--- a/drivers/s390/s390mach.c
+++ b/drivers/s390/s390mach.c
@@ -378,6 +378,8 @@ s390_do_machine_check(struct pt_regs *regs)
        struct mcck_struct *mcck;
        int umode;
 
+       lockdep_off();
+
        mci = (struct mci *) &S390_lowcore.mcck_interruption_code;
        mcck = &__get_cpu_var(cpu_mcck);
        umode = user_mode(regs);
@@ -482,6 +484,7 @@ s390_do_machine_check(struct pt_regs *regs)
                mcck->warning = 1;
                set_thread_flag(TIF_MCCK_PENDING);
        }
+       lockdep_on();
 }
 
 /*