From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- drivers/misc/isl29020.c | 226 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 226 insertions(+) create mode 100644 drivers/misc/isl29020.c (limited to 'drivers/misc/isl29020.c') diff --git a/drivers/misc/isl29020.c b/drivers/misc/isl29020.c new file mode 100644 index 000000000..dd966db28 --- /dev/null +++ b/drivers/misc/isl29020.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * isl29020.c - Intersil ALS Driver + * + * Copyright (C) 2008 Intel Corp + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * Data sheet at: http://www.intersil.com/data/fn/fn6505.pdf + */ + +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_MUTEX(mutex); + +static ssize_t als_sensing_range_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + int val; + + val = i2c_smbus_read_byte_data(client, 0x00); + + if (val < 0) + return val; + return sprintf(buf, "%d000\n", 1 << (2 * (val & 3))); + +} + +static ssize_t als_lux_input_data_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + int ret_val, val; + unsigned long int lux; + int temp; + + pm_runtime_get_sync(dev); + msleep(100); + + mutex_lock(&mutex); + temp = i2c_smbus_read_byte_data(client, 0x02); /* MSB data */ + if (temp < 0) { + pm_runtime_put_sync(dev); + mutex_unlock(&mutex); + return temp; + } + + ret_val = i2c_smbus_read_byte_data(client, 0x01); /* LSB data */ + mutex_unlock(&mutex); + + if (ret_val < 0) { + pm_runtime_put_sync(dev); + return ret_val; + } + + ret_val |= temp << 8; + val = i2c_smbus_read_byte_data(client, 0x00); + pm_runtime_put_sync(dev); + if (val < 0) + return val; + lux = ((((1 << (2 * (val & 3))))*1000) * ret_val) / 65536; + return sprintf(buf, "%lu\n", lux); +} + +static ssize_t als_sensing_range_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct i2c_client *client = to_i2c_client(dev); + int ret_val; + unsigned long val; + + ret_val = kstrtoul(buf, 10, &val); + if (ret_val) + return ret_val; + + if (val < 1 || val > 64000) + return -EINVAL; + + /* Pick the smallest sensor range that will meet our requirements */ + if (val <= 1000) + val = 1; + else if (val <= 4000) + val = 2; + else if (val <= 16000) + val = 3; + else + val = 4; + + ret_val = i2c_smbus_read_byte_data(client, 0x00); + if (ret_val < 0) + return ret_val; + + ret_val &= 0xFC; /*reset the bit before setting them */ + ret_val |= val - 1; + ret_val = i2c_smbus_write_byte_data(client, 0x00, ret_val); + + if (ret_val < 0) + return ret_val; + return count; +} + +static void als_set_power_state(struct i2c_client *client, int enable) +{ + int ret_val; + + ret_val = i2c_smbus_read_byte_data(client, 0x00); + if (ret_val < 0) + return; + + if (enable) + ret_val |= 0x80; + else + ret_val &= 0x7F; + + i2c_smbus_write_byte_data(client, 0x00, ret_val); +} + +static DEVICE_ATTR(lux0_sensor_range, S_IRUGO | S_IWUSR, + als_sensing_range_show, als_sensing_range_store); +static DEVICE_ATTR(lux0_input, S_IRUGO, als_lux_input_data_show, NULL); + +static struct attribute *mid_att_als[] = { + &dev_attr_lux0_sensor_range.attr, + &dev_attr_lux0_input.attr, + NULL +}; + +static const struct attribute_group m_als_gr = { + .name = "isl29020", + .attrs = mid_att_als +}; + +static int als_set_default_config(struct i2c_client *client) +{ + int retval; + + retval = i2c_smbus_write_byte_data(client, 0x00, 0xc0); + if (retval < 0) { + dev_err(&client->dev, "default write failed."); + return retval; + } + return 0; +} + +static int isl29020_probe(struct i2c_client *client) +{ + int res; + + res = als_set_default_config(client); + if (res < 0) + return res; + + res = sysfs_create_group(&client->dev.kobj, &m_als_gr); + if (res) { + dev_err(&client->dev, "isl29020: device create file failed\n"); + return res; + } + dev_info(&client->dev, "%s isl29020: ALS chip found\n", client->name); + als_set_power_state(client, 0); + pm_runtime_enable(&client->dev); + return res; +} + +static void isl29020_remove(struct i2c_client *client) +{ + pm_runtime_disable(&client->dev); + sysfs_remove_group(&client->dev.kobj, &m_als_gr); +} + +static const struct i2c_device_id isl29020_id[] = { + { .name = "isl29020" }, + { } +}; + +MODULE_DEVICE_TABLE(i2c, isl29020_id); + +#ifdef CONFIG_PM + +static int isl29020_runtime_suspend(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + als_set_power_state(client, 0); + return 0; +} + +static int isl29020_runtime_resume(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + als_set_power_state(client, 1); + return 0; +} + +static const struct dev_pm_ops isl29020_pm_ops = { + .runtime_suspend = isl29020_runtime_suspend, + .runtime_resume = isl29020_runtime_resume, +}; + +#define ISL29020_PM_OPS (&isl29020_pm_ops) +#else /* CONFIG_PM */ +#define ISL29020_PM_OPS NULL +#endif /* CONFIG_PM */ + +static struct i2c_driver isl29020_driver = { + .driver = { + .name = "isl29020", + .pm = ISL29020_PM_OPS, + }, + .probe = isl29020_probe, + .remove = isl29020_remove, + .id_table = isl29020_id, +}; + +module_i2c_driver(isl29020_driver); + +MODULE_AUTHOR("Kalhan Trisal "); +MODULE_DESCRIPTION("Intersil isl29020 ALS Driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1