genirq: Fix chained interrupt data ordering

commit 2c4569ca26986d18243f282dd727da27e9adae4c upstream.

irq_set_chained_handler_and_data() sets up the chained interrupt and then
stores the handler data.

That's racy against an immediate interrupt which gets handled before the
store of the handler data happened. The handler will dereference a NULL
pointer and crash.

Cure it by storing handler data before installing the chained handler.

Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 15206453b12aab09cf96dd09cc3fa2da92fd9c14..e4453d9f788c211e33695aa4045522884ca1bd9a 100644 (file)
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -810,8 +810,8 @@ irq_set_chained_handler_and_data(unsigned int irq, irq_flow_handler_t handle,
        if (!desc)
                return;
 
-       __irq_do_set_handler(desc, handle, 1, NULL);
        desc->irq_common_data.handler_data = data;
+       __irq_do_set_handler(desc, handle, 1, NULL);
 
        irq_put_desc_busunlock(desc, flags);
 }