Fix the following BUG:
BUG: unable to handle kernel NULL pointer dereference at 000000000000000c
Workqueue: events azx_probe_work [snd_hda_intel]
RIP: 0010:snd_hdac_bus_update_rirb+0x80/0x160 [snd_hda_core]
Call Trace:
<IRQ>
azx_interrupt+0x78/0x140 [snd_hda_codec]
__handle_irq_event_percpu+0x49/0x300
handle_irq_event_percpu+0x23/0x60
handle_irq_event+0x3c/0x60
handle_edge_irq+0xdb/0x180
handle_irq+0x23/0x30
do_IRQ+0x6a/0x140
common_interrupt+0xf/0xf
The Call Trace happened when run kdump on a NFS rootfs system.
Exist the following calling sequence when boot the second kernel:
azx_first_init()
--> azx_acquire_irq()
<-- interrupt come in, azx_interrupt() was called
--> hda_intel_init_chip()
--> azx_init_chip()
--> snd_hdac_bus_init_chip()
--> snd_hdac_bus_init_cmd_io();
--> init rirb.buf and corb.buf
Interrupt happened after azx_acquire_irq() while RIRB still didn't got
initialized, then NULL pointer will be used when process the interrupt.
Considering adjust the calling sequence may import new issue like
2eeeb4f4733b ("ASoC: Intel: Skylake: Acquire irq after RIRB allocation")
so here simply check the value of RIRB to avoid using NULL pointer.
Fixes: 14752412721c ("ALSA: hda - Add the controller helper codes to hda-core
module")
Signed-off-by: Liwei Song <liwei.s...@windriver.com>
---
sound/hda/hdac_controller.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/sound/hda/hdac_controller.c b/sound/hda/hdac_controller.c
index 74244d8e2909..2f0fa5353361 100644
--- a/sound/hda/hdac_controller.c
+++ b/sound/hda/hdac_controller.c
@@ -195,6 +195,9 @@ void snd_hdac_bus_update_rirb(struct hdac_bus *bus)
return;
bus->rirb.wp = wp;
+ if (!bus->rirb.buf)
+ return;
+
while (bus->rirb.rp != wp) {
bus->rirb.rp++;
bus->rirb.rp %= AZX_MAX_RIRB_ENTRIES;
--
2.7.4
--
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