From ec48a1d981fe90ecb5bcfaaf1ae2c69d842cbbbc Mon Sep 17 00:00:00 2001 From: Suzuki K Poulose Date: Tue, 14 Jun 2016 11:17:12 -0600 Subject: 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 : [] lr : [] pstate: 20000145 sp : ffffffc9762c7ba0 [] _coresight_build_path+0x18/0xe4 [] _coresight_build_path+0xc0/0xe4 [] _coresight_build_path+0xc0/0xe4 [] _coresight_build_path+0xc0/0xe4 [] _coresight_build_path+0xc0/0xe4 [] _coresight_build_path+0xc0/0xe4 [] coresight_build_path+0x40/0x68 [] coresight_enable+0x74/0x1bc [] enable_source_store+0x3c/0x6c [] dev_attr_store+0x18/0x28 [] sysfs_kf_write+0x40/0x50 [] kernfs_fop_write+0x140/0x1cc [] __vfs_write+0x28/0x110 [] vfs_write+0xa0/0x174 [] SyS_write+0x44/0xa0 [] el0_svc_naked+0x24/0x28 Cc: Mathieu Poirier Signed-off-by: Suzuki K Poulose Signed-off-by: Mathieu Poirier Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/hwtracing/coresight/coresight.c') 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; } -- cgit v1.2.3-70-g09d2 From 5014e904681ddbdf663bb20f134eb053ddccb181 Mon Sep 17 00:00:00 2001 From: Suzuki K Poulose Date: Fri, 6 May 2016 15:35:50 +0100 Subject: coresight: Handle build path error Enabling a component via sysfs (echo 1 > enable_source), would trigger building a path from the enabled sources to the sink. If there is an error in the process (e.g, sink not enabled or the device (CPU corresponding to ETM) is not online), we never report failure, except for leaving a message in the dmesg. Do proper error checking for the build path and return the error. Before: $ echo 0 > /sys/devices/system/cpu/cpu2/online $ echo 1 > /sys/devices/cs_etm/cpu2/enable_source $ echo $? 0 After: $ echo 0 > /sys/devices/system/cpu/cpu2/online $ echo 1 > /sys/devices/cs_etm/cpu2/enable_source -bash: echo: write error: No such device or address Signed-off-by: Suzuki K Poulose Acked-by: Mathieu Poirier Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'drivers/hwtracing/coresight/coresight.c') diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c index 0fdaaf4a8994..d08d1ab9bba5 100644 --- a/drivers/hwtracing/coresight/coresight.c +++ b/drivers/hwtracing/coresight/coresight.c @@ -425,6 +425,7 @@ out: struct list_head *coresight_build_path(struct coresight_device *csdev) { struct list_head *path; + int rc; path = kzalloc(sizeof(struct list_head), GFP_KERNEL); if (!path) @@ -432,9 +433,10 @@ struct list_head *coresight_build_path(struct coresight_device *csdev) INIT_LIST_HEAD(path); - if (_coresight_build_path(csdev, path)) { + rc = _coresight_build_path(csdev, path); + if (rc) { kfree(path); - path = NULL; + return ERR_PTR(rc); } return path; @@ -507,8 +509,9 @@ int coresight_enable(struct coresight_device *csdev) goto out; path = coresight_build_path(csdev); - if (!path) { + if (IS_ERR(path)) { pr_err("building path(s) failed\n"); + ret = PTR_ERR(path); goto out; } -- cgit v1.2.3-70-g09d2