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From 71df4d3c4c49639529666bc0a93d5c03ecedf443 Mon Sep 17 00:00:00 2001
From: Colin Ian King <colin.king@canonical.com>
Date: Tue, 1 Sep 2015 16:52:34 +0000
Subject: [PATCH 170/222] vchiq: fix NULL pointer dereference when closing
driver
The following code run as root will cause a null pointer dereference oops:
int fd = open("/dev/vc-cma", O_RDONLY);
if (fd < 0)
err(1, "open failed");
(void)close(fd);
[ 1704.877721] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 1704.877725] pgd = b899c000
[ 1704.877736] [00000000] *pgd=37fab831, *pte=00000000, *ppte=00000000
[ 1704.877748] Internal error: Oops: 817 [#1] PREEMPT SMP ARM
[ 1704.877765] Modules linked in: evdev i2c_bcm2708 uio_pdrv_genirq uio
[ 1704.877774] CPU: 2 PID: 3656 Comm: stress-ng-fstat Not tainted 3.19.1-12-generic-bcm2709 #12-Ubuntu
[ 1704.877777] Hardware name: BCM2709
[ 1704.877783] task: b8ab9b00 ti: b7e68000 task.ti: b7e68000
[ 1704.877798] PC is at __down_interruptible+0x50/0xec
[ 1704.877806] LR is at down_interruptible+0x5c/0x68
[ 1704.877813] pc : [<80630ee8>] lr : [<800704b0>] psr: 60080093
sp : b7e69e50 ip : b7e69e88 fp : b7e69e84
[ 1704.877817] r10: b88123c8 r9 : 00000010 r8 : 00000001
[ 1704.877822] r7 : b8ab9b00 r6 : 7fffffff r5 : 80a1cc34 r4 : 80a1cc34
[ 1704.877826] r3 : b7e69e50 r2 : 00000000 r1 : 00000000 r0 : 80a1cc34
[ 1704.877833] Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment user
[ 1704.877838] Control: 10c5387d Table: 3899c06a DAC: 00000015
[ 1704.877843] Process do-oops (pid: 3656, stack limit = 0xb7e68238)
[ 1704.877848] Stack: (0xb7e69e50 to 0xb7e6a000)
[ 1704.877856] 9e40: 80a1cc3c 00000000 00000010 b88123c8
[ 1704.877865] 9e60: b7e69e84 80a1cc34 fff9fee9 ffffffff b7e68000 00000009 b7e69ea4 b7e69e88
[ 1704.877874] 9e80: 800704b0 80630ea4 fff9fee9 60080013 80a1cc28 fff9fee9 b7e69edc b7e69ea8
[ 1704.877884] 9ea0: 8040f558 80070460 fff9fee9 ffffffff 00000000 00000000 00000009 80a1cb7c
[ 1704.877893] 9ec0: 00000000 80a1cb7c 00000000 00000010 b7e69ef4 b7e69ee0 803e1ba4 8040f514
[ 1704.877902] 9ee0: 00000e48 80a1cb7c b7e69f14 b7e69ef8 803e1c9c 803e1b74 b88123c0 b92acb18
[ 1704.877911] 9f00: b8812790 b8d815d8 b7e69f24 b7e69f18 803e2250 803e1bc8 b7e69f5c b7e69f28
[ 1704.877921] 9f20: 80167bac 803e222c 00000000 00000000 b7e69f54 b8ab9ffc 00000000 8098c794
[ 1704.877930] 9f40: b8ab9b00 8000efc4 b7e68000 00000000 b7e69f6c b7e69f60 80167d6c 80167b28
[ 1704.877939] 9f60: b7e69f8c b7e69f70 80047d38 80167d60 b7e68000 b7e68010 8000efc4 b7e69fb0
[ 1704.877949] 9f80: b7e69fac b7e69f90 80012820 80047c84 01155490 011549a8 00000001 00000006
[ 1704.877957] 9fa0: 00000000 b7e69fb0 8000ee5c 80012790 00000000 353d8c0f 7efc4308 00000000
[ 1704.877966] 9fc0: 01155490 011549a8 00000001 00000006 00000000 00000000 76cf3ba0 00000003
[ 1704.877975] 9fe0: 00000000 7efc42e4 0002272f 76e2ed66 60080030 00000003 00000000 00000000
[ 1704.877998] [<80630ee8>] (__down_interruptible) from [<800704b0>] (down_interruptible+0x5c/0x68)
[ 1704.878015] [<800704b0>] (down_interruptible) from [<8040f558>] (vchiu_queue_push+0x50/0xd8)
[ 1704.878032] [<8040f558>] (vchiu_queue_push) from [<803e1ba4>] (send_worker_msg+0x3c/0x54)
[ 1704.878045] [<803e1ba4>] (send_worker_msg) from [<803e1c9c>] (vc_cma_set_reserve+0xe0/0x1c4)
[ 1704.878057] [<803e1c9c>] (vc_cma_set_reserve) from [<803e2250>] (vc_cma_release+0x30/0x38)
[ 1704.878069] [<803e2250>] (vc_cma_release) from [<80167bac>] (__fput+0x90/0x1e0)
[ 1704.878082] [<80167bac>] (__fput) from [<80167d6c>] (____fput+0x18/0x1c)
[ 1704.878094] [<80167d6c>] (____fput) from [<80047d38>] (task_work_run+0xc0/0xf8)
[ 1704.878109] [<80047d38>] (task_work_run) from [<80012820>] (do_work_pending+0x9c/0xc4)
[ 1704.878123] [<80012820>] (do_work_pending) from [<8000ee5c>] (work_pending+0xc/0x20)
[ 1704.878133] Code: e50b1034 e3a01000 e50b2030 e580300c (e5823000)
..the fix is to ensure that we have actually initialized the queue before we attempt
to push any items onto it. This occurs if we do an open() followed by a close() without
any activity in between.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/misc/vc04_services/interface/vchiq_arm/vchiq_util.c | 4 ++++
drivers/misc/vc04_services/interface/vchiq_arm/vchiq_util.h | 1 +
2 files changed, 5 insertions(+)
--- a/drivers/misc/vc04_services/interface/vchiq_arm/vchiq_util.c
+++ b/drivers/misc/vc04_services/interface/vchiq_arm/vchiq_util.c
@@ -46,6 +46,7 @@ int vchiu_queue_init(VCHIU_QUEUE_T *queu
queue->size = size;
queue->read = 0;
queue->write = 0;
+ queue->initialized = 1;
sema_init(&queue->pop, 0);
sema_init(&queue->push, 0);
@@ -76,6 +77,9 @@ int vchiu_queue_is_full(VCHIU_QUEUE_T *q
void vchiu_queue_push(VCHIU_QUEUE_T *queue, VCHIQ_HEADER_T *header)
{
+ if (!queue->initialized)
+ return;
+
while (queue->write == queue->read + queue->size) {
if (down_interruptible(&queue->pop) != 0) {
flush_signals(current);
--- a/drivers/misc/vc04_services/interface/vchiq_arm/vchiq_util.h
+++ b/drivers/misc/vc04_services/interface/vchiq_arm/vchiq_util.h
@@ -60,6 +60,7 @@ typedef struct {
int size;
int read;
int write;
+ int initialized;
struct semaphore pop;
struct semaphore push;
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