I've run into an issue in 6.3.0-rc1 that causes problems with ftrace and I've bisected it to this commit: commit 98c062e8245199fa9121141a0bf1035dc45ae90e (HEAD, refs/bisect/bad) Author: Philipp Jungkamp <p.jungkamp@gmx.net> Date: Fri Nov 25 00:38:38 2022 +0100 HID: hid-sensor-custom: Allow more custom iio sensors The known LUID table for established/known custom HID sensors was limited to sensors with "INTEL" as manufacturer. But some vendors such as Lenovo also include fairly standard iio sensors (e.g. ambient light) in their custom sensors. Expand the known custom sensors table by a tag used for the platform device name and match sensors based on the LUID as well as optionally on model and manufacturer properties. Signed-off-by: Philipp Jungkamp <p.jungkamp@gmx.net> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> You're using raw binary data as part of the devname in the "real_usage" string, but it includes chars other than ASCII, and those chars end up being printed out in the ftrace log which is meant to be ASCII only. - /* HID-SENSOR-INT-REAL_USAGE_ID */ - dev_name = kasprintf(GFP_KERNEL, "HID-SENSOR-INT-%s", real_usage); + /* HID-SENSOR-TAG-REAL_USAGE_ID */ + dev_name = kasprintf(GFP_KERNEL, "HID-SENSOR-%s-%s", + match->tag, real_usage); My sleepgraph tool started to crash because it read these lines from ftrace: device_pm_callback_start: platform HID-SENSOR-INT-020b�.39.auto, parent: 001F:8087:0AC2.0003, [suspend] device_pm_callback_end: platform HID-SENSOR-INT-020b�.39.auto, err=0 The "HID-SENSOR-INT-020b�.39.auto" string includes a binary char that kills python3 code that loops through an ascii file as such: File "/usr/bin/sleepgraph", line 5579, in executeSuspend for line in fp: File "/usr/lib/python3.10/codecs.py", line 322, in decode (result, consumed) = self._buffer_decode(data, self.errors, final) UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 1568: invalid start byte I've updated sleepgraph to handle random non-ascii chars, but other tools may suffer the same fate. In theory all you have to do to fix this is update this section of code to filter out non-ascii characters as well as convert them to lower case: file: drivers/hid/hid-sensor-custom.c func: hid_sensor_register_platform_device /* usage id are all lowcase */ for (c = real_usage; *c != '\0'; c++) *c = tolower(*c);
I spoke with Phillip and he came up with a fix that works. I've posted it here: https://marc.info/?l=linux-iio&m=167849244508779&w=2 I've tested it and it fixes the issue. The problem was with a buffer overrun because the destination string wasn't initialized to 0. It's 5 bytes long with 4 bytes copied and the code expected the 5th byte to be a null char. diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-sensor-custom.c index 3e3f89e01d81..d85398721659 100644 --- a/drivers/hid/hid-sensor-custom.c +++ b/drivers/hid/hid-sensor-custom.c @@ -940,7 +940,7 @@ hid_sensor_register_platform_device(struct platform_device *pdev, struct hid_sensor_hub_device *hsdev, const struct hid_sensor_custom_match *match) { - char real_usage[HID_SENSOR_USAGE_LENGTH]; + char real_usage[HID_SENSOR_USAGE_LENGTH] = { 0 }; struct platform_device *custom_pdev; const char *dev_name; char *c;