There are regression reports of soft-reset issue due to the recent changes.
Revert them as they are incomplete/incorrect fix [*].
[*] https://lore.kernel.org/linux-usb/ZW8sJoTEKVmDdk5Y@xhacker/
Thinh Nguyen (2):
Revert "usb: dwc3: Soft reset phy on probe for host"
Revert "usb: dwc3: don't reset device side if dwc3 was configured as host-only"
drivers/usb/dwc3/core.c | 39 +--------------------------------------
1 file changed, 1 insertion(+), 38 deletions(-)
base-commit: ab241a0ab5abd70036c3d959146e534a02447d17
--
2.28.0
From: Huang Ying <ying.huang(a)intel.com>
The decoder_populate_targets() helper walks all of the targets in a port
and makes sure they can be looked up in @target_map. Where @target_map
is a lookup table from target position to target id (corresponding to a
cxl_dport instance). However @target_map is only responsible for
conveying the active dport instances as conveyed by interleave_ways.
When nr_targets > interleave_ways it results in
decoder_populate_targets() walking off the end of the valid entries in
@target_map. Given target_map is initialized to 0 it results in the
dport lookup failing if position 0 is not mapped to a dport with an id
of 0:
cxl_port port3: Failed to populate active decoder targets
cxl_port port3: Failed to add decoder
cxl_port port3: Failed to add decoder3.0
cxl_bus_probe: cxl_port port3: probe: -6
This bug also highlights that when the decoder's ->targets[] array is
written in cxl_port_setup_targets() it is missing a hold of the
targets_lock to synchronize against sysfs readers of the target list. A
fix for that is saved for a later patch.
Fixes: a5c258021689 ("cxl/bus: Populate the target list at decoder create")
Cc: <stable(a)vger.kernel.org>
Signed-off-by: "Huang, Ying" <ying.huang(a)intel.com>
[djbw: rewrite the changelog, find the Fixes: tag]
Co-developed-by: Dan Williams <dan.j.williams(a)intel.com>
Signed-off-by: Dan Williams <dan.j.williams(a)intel.com>
---
drivers/cxl/core/port.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index b7c93bb18f6e..57495cdc181f 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -1644,7 +1644,7 @@ static int decoder_populate_targets(struct cxl_switch_decoder *cxlsd,
return -EINVAL;
write_seqlock(&cxlsd->target_lock);
- for (i = 0; i < cxlsd->nr_targets; i++) {
+ for (i = 0; i < cxlsd->cxld.interleave_ways; i++) {
struct cxl_dport *dport = find_dport(port, target_map[i]);
if (!dport) {
In sniff_min_interval_set():
if (val == 0 || val % 2 || val > hdev->sniff_max_interval)
return -EINVAL;
hci_dev_lock(hdev);
hdev->sniff_min_interval = val;
hci_dev_unlock(hdev);
In sniff_max_interval_set():
if (val == 0 || val % 2 || val < hdev->sniff_min_interval)
return -EINVAL;
hci_dev_lock(hdev);
hdev->sniff_max_interval = val;
hci_dev_unlock(hdev);
The atomicity violation occurs due to concurrent execution of set_min and
set_max funcs. Consider a scenario where setmin writes a new, valid 'min'
value, and concurrently, setmax writes a value that is greater than the
old 'min' but smaller than the new 'min'. In this case, setmax might check
against the old 'min' value (before acquiring the lock) but write its
value after the 'min' has been updated by setmin. This leads to a
situation where the 'max' value ends up being smaller than the 'min'
value, which is an inconsistency.
This possible bug is found by an experimental static analysis tool
developed by our team, BassCheck[1]. This tool analyzes the locking APIs
to extract function pairs that can be concurrently executed, and then
analyzes the instructions in the paired functions to identify possible
concurrency bugs including data races and atomicity violations. The above
possible bug is reported when our tool analyzes the source code of
Linux 5.17.
To resolve this issue, it is suggested to encompass the validity checks
within the locked sections in both set_min and set_max funcs. The
modification ensures that the validation of 'val' against the
current min/max values is atomic, thus maintaining the integrity of the
settings. With this patch applied, our tool no longer reports the bug,
with the kernel configuration allyesconfig for x86_64. Due to the lack of
associated hardware, we cannot test the patch in runtime testing, and just
verify it according to the code logic.
[1] https://sites.google.com/view/basscheck/
Fixes: 71c3b60ec6d2 ("Bluetooth: Move BR/EDR debugfs file creation ...")
Cc: stable(a)vger.kernel.org
Signed-off-by: Gui-Dong Han <2045gemini(a)gmail.com>
---
v2:
* Adjust the format to pass the CI.
---
net/bluetooth/hci_debugfs.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/net/bluetooth/hci_debugfs.c b/net/bluetooth/hci_debugfs.c
index 6b7741f6e95b..f032fdf8f481 100644
--- a/net/bluetooth/hci_debugfs.c
+++ b/net/bluetooth/hci_debugfs.c
@@ -566,11 +566,13 @@ DEFINE_DEBUGFS_ATTRIBUTE(idle_timeout_fops, idle_timeout_get,
static int sniff_min_interval_set(void *data, u64 val)
{
struct hci_dev *hdev = data;
-
- if (val == 0 || val % 2 || val > hdev->sniff_max_interval)
+
+ hci_dev_lock(hdev);
+ if (val == 0 || val % 2 || val > hdev->sniff_max_interval) {
+ hci_dev_unlock(hdev);
return -EINVAL;
+ }
- hci_dev_lock(hdev);
hdev->sniff_min_interval = val;
hci_dev_unlock(hdev);
@@ -594,11 +596,13 @@ DEFINE_DEBUGFS_ATTRIBUTE(sniff_min_interval_fops, sniff_min_interval_get,
static int sniff_max_interval_set(void *data, u64 val)
{
struct hci_dev *hdev = data;
-
- if (val == 0 || val % 2 || val < hdev->sniff_min_interval)
+
+ hci_dev_lock(hdev);
+ if (val == 0 || val % 2 || val < hdev->sniff_min_interval) {
+ hci_dev_unlock(hdev);
return -EINVAL;
+ }
- hci_dev_lock(hdev);
hdev->sniff_max_interval = val;
hci_dev_unlock(hdev);
--
2.34.1
In conn_info_min_age_set():
if (val == 0 || val > hdev->conn_info_max_age)
return -EINVAL;
hci_dev_lock(hdev);
hdev->conn_info_min_age = val;
hci_dev_unlock(hdev);
In conn_info_max_age_set():
if (val == 0 || val < hdev->conn_info_min_age)
return -EINVAL;
hci_dev_lock(hdev);
hdev->conn_info_max_age = val;
hci_dev_unlock(hdev);
The atomicity violation occurs due to concurrent execution of set_min and
set_max funcs.Consider a scenario where setmin writes a new, valid 'min'
value, and concurrently, setmax writes a value that is greater than the
old 'min' but smaller than the new 'min'. In this case, setmax might check
against the old 'min' value (before acquiring the lock) but write its
value after the 'min' has been updated by setmin. This leads to a
situation where the 'max' value ends up being smaller than the 'min'
value, which is an inconsistency.
This possible bug is found by an experimental static analysis tool
developed by our team, BassCheck[1]. This tool analyzes the locking APIs
to extract function pairs that can be concurrently executed, and then
analyzes the instructions in the paired functions to identify possible
concurrency bugs including data races and atomicity violations. The above
possible bug is reported when our tool analyzes the source code of
Linux 5.17.
To resolve this issue, it is suggested to encompass the validity checks
within the locked sections in both set_min and set_max funcs. The
modification ensures that the validation of 'val' against the
current min/max values is atomic, thus maintaining the integrity of the
settings. With this patch applied, our tool no longer reports the bug,
with the kernel configuration allyesconfig for x86_64. Due to the lack of
associated hardware, we cannot test the patch in runtime testing, and just
verify it according to the code logic.
[1] https://sites.google.com/view/basscheck/
Fixes: 40ce72b1951c ("Bluetooth: Move common debugfs file creation ...")
Cc: stable(a)vger.kernel.org
Signed-off-by: Gui-Dong Han <2045gemini(a)gmail.com>
---
v2:
* Adjust the format to pass the CI.
---
net/bluetooth/hci_debugfs.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/net/bluetooth/hci_debugfs.c b/net/bluetooth/hci_debugfs.c
index 6b7741f6e95b..d4ce2769c939 100644
--- a/net/bluetooth/hci_debugfs.c
+++ b/net/bluetooth/hci_debugfs.c
@@ -217,11 +217,13 @@ DEFINE_SHOW_ATTRIBUTE(remote_oob);
static int conn_info_min_age_set(void *data, u64 val)
{
struct hci_dev *hdev = data;
-
- if (val == 0 || val > hdev->conn_info_max_age)
+
+ hci_dev_lock(hdev);
+ if (val == 0 || val > hdev->conn_info_max_age) {
+ hci_dev_unlock(hdev);
return -EINVAL;
+ }
- hci_dev_lock(hdev);
hdev->conn_info_min_age = val;
hci_dev_unlock(hdev);
@@ -245,11 +247,13 @@ DEFINE_DEBUGFS_ATTRIBUTE(conn_info_min_age_fops, conn_info_min_age_get,
static int conn_info_max_age_set(void *data, u64 val)
{
struct hci_dev *hdev = data;
-
- if (val == 0 || val < hdev->conn_info_min_age)
+
+ hci_dev_lock(hdev);
+ if (val == 0 || val < hdev->conn_info_min_age) {
+ hci_dev_unlock(hdev);
return -EINVAL;
+ }
- hci_dev_lock(hdev);
hdev->conn_info_max_age = val;
hci_dev_unlock(hdev);
--
2.34.1