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authorSuzuki K Poulose <suzuki.poulose@arm.com>2016-06-14 11:17:12 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-06-16 00:13:06 -0700
commitec48a1d981fe90ecb5bcfaaf1ae2c69d842cbbbc (patch)
treedc131b4ce24ff4f7766dc305564e55bb05f4754b
parentd74ef24841a972a9abe3742a7eff51cdac73db3a (diff)
coresight: Fix NULL pointer dereference in _coresight_build_path
_coresight_build_path assumes that all the connections of a csdev has the child_dev initialised. This may not be true if the particular component is not supported by the kernel config(e.g TPIU) but is present in the DT. In which case, building a path can cause a crash like this : Unable to handle kernel NULL pointer dereference at virtual address 00000010 pgd = ffffffc9750dd000 [00000010] *pgd=00000009f5e90003, *pud=00000009f5e90003, *pmd=0000000000000000 Internal error: Oops: 96000006 [#1] PREEMPT SMP Modules linked in: CPU: 4 PID: 1348 Comm: bash Not tainted 4.6.0-next-20160517 #1646 Hardware name: ARM Juno development board (r0) (DT) task: ffffffc97517a280 ti: ffffffc9762c4000 task.ti: ffffffc9762c4000 PC is at _coresight_build_path+0x18/0xe4 LR is at _coresight_build_path+0xc0/0xe4 pc : [<ffffff80083d5130>] lr : [<ffffff80083d51d8>] pstate: 20000145 sp : ffffffc9762c7ba0 [<ffffff80083d5130>] _coresight_build_path+0x18/0xe4 [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4 [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4 [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4 [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4 [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4 [<ffffff80083d5cdc>] coresight_build_path+0x40/0x68 [<ffffff80083d5e14>] coresight_enable+0x74/0x1bc [<ffffff80083d60a0>] enable_source_store+0x3c/0x6c [<ffffff800830b17c>] dev_attr_store+0x18/0x28 [<ffffff80081ca9c4>] sysfs_kf_write+0x40/0x50 [<ffffff80081c9e38>] kernfs_fop_write+0x140/0x1cc [<ffffff8008163ec8>] __vfs_write+0x28/0x110 [<ffffff8008164bf0>] vfs_write+0xa0/0x174 [<ffffff8008165d18>] SyS_write+0x44/0xa0 [<ffffff8008084e70>] el0_svc_naked+0x24/0x28 Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/hwtracing/coresight/coresight.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 5443d03a1eec..0fdaaf4a8994 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -385,7 +385,6 @@ static int _coresight_build_path(struct coresight_device *csdev,
int i;
bool found = false;
struct coresight_node *node;
- struct coresight_connection *conn;
/* An activated sink has been found. Enqueue the element */
if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
@@ -394,8 +393,9 @@ static int _coresight_build_path(struct coresight_device *csdev,
/* Not a sink - recursively explore each port found on this element */
for (i = 0; i < csdev->nr_outport; i++) {
- conn = &csdev->conns[i];
- if (_coresight_build_path(conn->child_dev, path) == 0) {
+ struct coresight_device *child_dev = csdev->conns[i].child_dev;
+
+ if (child_dev && _coresight_build_path(child_dev, path) == 0) {
found = true;
break;
}