Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Haidong Yao <yaohaidong369@gmail.com>
To:     jassisinghbrar@gmail.com, natechancellor@gmail.com,
        ndesaulniers@google.com, linux-kernel@vger.kernel.org,
        clang-built-linux@googlegroups.com, orsonzhai@gmail.com
Cc:     zhang.lyra@gmail.com, Haidong Yao <haidong.yao@unisoc.com>
Subject: [PATCH] add chan->cl check in mbox_chan_received_data()
Date:   Tue, 15 Dec 2020 16:48:38 +0800
Message-Id: <1608022118-29993-1-git-send-email-yaohaidong369@gmail.com>
Precedence: bulk

From: Haidong Yao <haidong.yao@unisoc.com>

mailbox outbox irq is coming, but mbox_request_channel
is not be registered, so cl->rx_callback is NULL.

panic log:
[    9.852090]c0  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
[    9.954634]c0  pstate: 60400089 (nZCv daIf +PAN -UAO)
[    9.954651]c0  pc : mbox_chan_received_data+0x1c/0x88
[    9.954666]c0  lr : sprd_mbox_outbox_isr+0x1d0/0x204 [sprd_mailbox]
[    9.967439]c0  sp : ffffffc010003e10
[    9.967443]c0  x29: ffffffc010003e20 x28: ffffffc011c2f6c0-
[    9.984918]c0  x27: ffffffc010e92e08 x26: 0000000000000001-
[   10.140344]c0  x25: 0000000000000378 x24: ffffff80f4064130-
[   10.145880]c0  x23: 0000000000000001 x22: ffffffc0091072c7-
[   10.151418]c0  x21: ffffffc009107212 x20: 0000000000000005-
[   10.156957]c0  x19: ffffff80f4064080 x18: ffffffc010005038-
[   10.162494]c0  x17: 0000000000000000 x16: ffffffc010e6f844-
[   10.168033]c0  x15: ffffffc0117abac7 x14: 000000000000003f-
[   10.173571]c0  x13: ffff0000ffffff00 x12: ffff0a01ffffff10-
[   10.179110]c0  x11: 0000000000000001 x10: 00000000ffffffff-
[   10.184649]c0  x9 : ffffff80f40644a8 x8 : c366877097809900-
[   10.190187]c0  x7 : 207273695f786f62 x6 : ffffffc011d62231-
[   10.195726]c0  x5 : 0000000000000034 x4 : 000000000000000c-
[   10.201265]c0  x3 : ffffffc010e9842c x2 : 0000000000000001-
[   10.206803]c0  x1 : ffffffc010003e40 x0 : 0000000000000000-
[   10.212343]c0  Call trace:
[   10.215029]c0   mbox_chan_received_data+0x1c/0x88
[   10.219705]c0   sprd_mbox_outbox_isr+0x1d0/0x204 [sprd_mailbox]
[   10.225590]c0   __handle_irq_event_percpu+0x164/0x358
[   10.230604]c0   handle_irq_event+0x60/0xd8
[   10.234675]c0   handle_fasteoi_irq+0x128/0x32c
[   10.239086]c0   __handle_domain_irq+0xa0/0x100
[   10.243502]c0   efi_header_end+0xb8/0x15c
[   10.247478]c0   el1_irq+0x104/0x200
[   10.250945]c0   cpuidle_enter_state+0x158/0x2d8
[   10.255440]c0   cpuidle_enter+0x38/0x50
[   10.259253]c0   do_idle.llvm.10091284334483161164+0x1a4/0x294
[   10.264963]c0   cpu_startup_entry+0x24/0x28
[   10.269120]c0   kernel_init+0x0/0x29c
[   10.272752]c0   start_kernel+0x0/0x418
[   10.276468]c0   start_kernel+0x3a0/0x418
[   10.280371]c0  Code: f90013f3 910043fd aa0003e9 f9400800 (f9401008)-
[   10.286684]c0  ---[ end trace b868997a960c667a ]---

Signed-off-by: Haidong Yao <haidong.yao@unisoc.com>
---
 drivers/mailbox/mailbox.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 3e7d4b20ab34..58697298a95f 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -152,7 +152,7 @@ static enum hrtimer_restart txdone_hrtimer(struct hrtimer *hrtimer)
 void mbox_chan_received_data(struct mbox_chan *chan, void *mssg)
 {
 	/* No buffering the received data */
-	if (chan->cl->rx_callback)
+	if (chan->cl && chan->cl->rx_callback)
 		chan->cl->rx_callback(chan->cl, mssg);
 }
 EXPORT_SYMBOL_GPL(mbox_chan_received_data);
-- 
2.28.0