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 --- net/ethtool/module.c | 566 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 566 insertions(+) create mode 100644 net/ethtool/module.c (limited to 'net/ethtool/module.c') diff --git a/net/ethtool/module.c b/net/ethtool/module.c new file mode 100644 index 000000000..9cf670e08 --- /dev/null +++ b/net/ethtool/module.c @@ -0,0 +1,566 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include +#include +#include +#include + +#include "bitset.h" +#include "common.h" +#include "module_fw.h" +#include "netlink.h" + +struct module_req_info { + struct ethnl_req_info base; +}; + +struct module_reply_data { + struct ethnl_reply_data base; + struct ethtool_module_power_mode_params power; +}; + +#define MODULE_REPDATA(__reply_base) \ + container_of(__reply_base, struct module_reply_data, base) + +/* MODULE_GET */ + +const struct nla_policy ethnl_module_get_policy[ETHTOOL_A_MODULE_HEADER + 1] = { + [ETHTOOL_A_MODULE_HEADER] = NLA_POLICY_NESTED(ethnl_header_policy), +}; + +static int module_get_power_mode(struct net_device *dev, + struct module_reply_data *data, + struct netlink_ext_ack *extack) +{ + const struct ethtool_ops *ops = dev->ethtool_ops; + + if (!ops->get_module_power_mode) + return 0; + + if (dev->ethtool->module_fw_flash_in_progress) { + NL_SET_ERR_MSG(extack, + "Module firmware flashing is in progress"); + return -EBUSY; + } + + return ops->get_module_power_mode(dev, &data->power, extack); +} + +static int module_prepare_data(const struct ethnl_req_info *req_base, + struct ethnl_reply_data *reply_base, + const struct genl_info *info) +{ + struct module_reply_data *data = MODULE_REPDATA(reply_base); + struct net_device *dev = reply_base->dev; + int ret; + + ret = ethnl_ops_begin(dev); + if (ret < 0) + return ret; + + ret = module_get_power_mode(dev, data, info->extack); + if (ret < 0) + goto out_complete; + +out_complete: + ethnl_ops_complete(dev); + return ret; +} + +static int module_reply_size(const struct ethnl_req_info *req_base, + const struct ethnl_reply_data *reply_base) +{ + struct module_reply_data *data = MODULE_REPDATA(reply_base); + int len = 0; + + if (data->power.policy) + len += nla_total_size(sizeof(u8)); /* _MODULE_POWER_MODE_POLICY */ + + if (data->power.mode) + len += nla_total_size(sizeof(u8)); /* _MODULE_POWER_MODE */ + + return len; +} + +static int module_fill_reply(struct sk_buff *skb, + const struct ethnl_req_info *req_base, + const struct ethnl_reply_data *reply_base) +{ + const struct module_reply_data *data = MODULE_REPDATA(reply_base); + + if (data->power.policy && + nla_put_u8(skb, ETHTOOL_A_MODULE_POWER_MODE_POLICY, + data->power.policy)) + return -EMSGSIZE; + + if (data->power.mode && + nla_put_u8(skb, ETHTOOL_A_MODULE_POWER_MODE, data->power.mode)) + return -EMSGSIZE; + + return 0; +} + +/* MODULE_SET */ + +const struct nla_policy ethnl_module_set_policy[ETHTOOL_A_MODULE_POWER_MODE_POLICY + 1] = { + [ETHTOOL_A_MODULE_HEADER] = NLA_POLICY_NESTED(ethnl_header_policy), + [ETHTOOL_A_MODULE_POWER_MODE_POLICY] = + NLA_POLICY_RANGE(NLA_U8, ETHTOOL_MODULE_POWER_MODE_POLICY_HIGH, + ETHTOOL_MODULE_POWER_MODE_POLICY_AUTO), +}; + +static int +ethnl_set_module_validate(struct ethnl_req_info *req_info, + struct genl_info *info) +{ + const struct ethtool_ops *ops = req_info->dev->ethtool_ops; + struct nlattr **tb = info->attrs; + + if (!tb[ETHTOOL_A_MODULE_POWER_MODE_POLICY]) + return 0; + + if (!ops->get_module_power_mode || !ops->set_module_power_mode) { + NL_SET_ERR_MSG_ATTR(info->extack, + tb[ETHTOOL_A_MODULE_POWER_MODE_POLICY], + "Setting power mode policy is not supported by this device"); + return -EOPNOTSUPP; + } + + return 1; +} + +static int +ethnl_set_module(struct ethnl_req_info *req_info, struct genl_info *info) +{ + struct ethtool_module_power_mode_params power = {}; + struct ethtool_module_power_mode_params power_new; + const struct ethtool_ops *ops; + struct net_device *dev = req_info->dev; + struct nlattr **tb = info->attrs; + int ret; + + ops = dev->ethtool_ops; + + if (dev->ethtool->module_fw_flash_in_progress) { + NL_SET_ERR_MSG(info->extack, + "Module firmware flashing is in progress"); + return -EBUSY; + } + + power_new.policy = nla_get_u8(tb[ETHTOOL_A_MODULE_POWER_MODE_POLICY]); + ret = ops->get_module_power_mode(dev, &power, info->extack); + if (ret < 0) + return ret; + + if (power_new.policy == power.policy) + return 0; + + ret = ops->set_module_power_mode(dev, &power_new, info->extack); + return ret < 0 ? ret : 1; +} + +const struct ethnl_request_ops ethnl_module_request_ops = { + .request_cmd = ETHTOOL_MSG_MODULE_GET, + .reply_cmd = ETHTOOL_MSG_MODULE_GET_REPLY, + .hdr_attr = ETHTOOL_A_MODULE_HEADER, + .req_info_size = sizeof(struct module_req_info), + .reply_data_size = sizeof(struct module_reply_data), + + .prepare_data = module_prepare_data, + .reply_size = module_reply_size, + .fill_reply = module_fill_reply, + + .set_validate = ethnl_set_module_validate, + .set = ethnl_set_module, + .set_ntf_cmd = ETHTOOL_MSG_MODULE_NTF, +}; + +/* MODULE_FW_FLASH_ACT */ + +const struct nla_policy +ethnl_module_fw_flash_act_policy[ETHTOOL_A_MODULE_FW_FLASH_PASSWORD + 1] = { + [ETHTOOL_A_MODULE_FW_FLASH_HEADER] = + NLA_POLICY_NESTED(ethnl_header_policy), + [ETHTOOL_A_MODULE_FW_FLASH_FILE_NAME] = { .type = NLA_NUL_STRING }, + [ETHTOOL_A_MODULE_FW_FLASH_PASSWORD] = { .type = NLA_U32 }, +}; + +static LIST_HEAD(module_fw_flash_work_list); +static DEFINE_SPINLOCK(module_fw_flash_work_list_lock); + +static int +module_flash_fw_work_list_add(struct ethtool_module_fw_flash *module_fw, + struct genl_info *info) +{ + struct ethtool_module_fw_flash *work; + + /* First, check if already registered. */ + spin_lock(&module_fw_flash_work_list_lock); + list_for_each_entry(work, &module_fw_flash_work_list, list) { + if (work->fw_update.ntf_params.portid == info->snd_portid && + work->fw_update.dev == module_fw->fw_update.dev) { + spin_unlock(&module_fw_flash_work_list_lock); + return -EALREADY; + } + } + + list_add_tail(&module_fw->list, &module_fw_flash_work_list); + spin_unlock(&module_fw_flash_work_list_lock); + + return 0; +} + +static void module_flash_fw_work_list_del(struct list_head *list) +{ + spin_lock(&module_fw_flash_work_list_lock); + list_del(list); + spin_unlock(&module_fw_flash_work_list_lock); +} + +static void module_flash_fw_work(struct work_struct *work) +{ + struct ethtool_module_fw_flash *module_fw; + struct net_device *dev; + + module_fw = container_of(work, struct ethtool_module_fw_flash, work); + dev = module_fw->fw_update.dev; + + netdev_lock_ops(dev); + ethtool_cmis_fw_update(&module_fw->fw_update); + netdev_unlock_ops(dev); + + module_flash_fw_work_list_del(&module_fw->list); + + rtnl_lock(); + netdev_lock_ops(dev); + dev->ethtool->module_fw_flash_in_progress = false; + netdev_unlock_ops(dev); + rtnl_unlock(); + + netdev_put(dev, &module_fw->dev_tracker); + release_firmware(module_fw->fw_update.fw); + kfree(module_fw); +} + +#define MODULE_EEPROM_PHYS_ID_PAGE 0 +#define MODULE_EEPROM_PHYS_ID_I2C_ADDR 0x50 + +static int module_flash_fw_work_init(struct ethtool_module_fw_flash *module_fw, + struct net_device *dev, + struct netlink_ext_ack *extack) +{ + const struct ethtool_ops *ops = dev->ethtool_ops; + struct ethtool_module_eeprom page_data = {}; + u8 phys_id; + int err; + + /* Fetch the SFF-8024 Identifier Value. For all supported standards, it + * is located at I2C address 0x50, byte 0. See section 4.1 in SFF-8024, + * revision 4.9. + */ + page_data.page = MODULE_EEPROM_PHYS_ID_PAGE; + page_data.offset = SFP_PHYS_ID; + page_data.length = sizeof(phys_id); + page_data.i2c_address = MODULE_EEPROM_PHYS_ID_I2C_ADDR; + page_data.data = &phys_id; + + err = ops->get_module_eeprom_by_page(dev, &page_data, extack); + if (err < 0) + return err; + + switch (phys_id) { + case SFF8024_ID_QSFP_DD: + case SFF8024_ID_OSFP: + case SFF8024_ID_DSFP: + case SFF8024_ID_QSFP_PLUS_CMIS: + case SFF8024_ID_SFP_DD_CMIS: + case SFF8024_ID_SFP_PLUS_CMIS: + INIT_WORK(&module_fw->work, module_flash_fw_work); + break; + default: + NL_SET_ERR_MSG(extack, + "Module type does not support firmware flashing"); + return -EOPNOTSUPP; + } + + return 0; +} + +void ethnl_module_fw_flash_sock_destroy(struct ethnl_sock_priv *sk_priv) +{ + struct ethtool_module_fw_flash *work; + + spin_lock(&module_fw_flash_work_list_lock); + list_for_each_entry(work, &module_fw_flash_work_list, list) { + if (work->fw_update.ntf_params.portid == sk_priv->portid && + dev_net(work->fw_update.dev) == sk_priv->net) + work->fw_update.ntf_params.closed_sock = true; + } + spin_unlock(&module_fw_flash_work_list_lock); +} + +static int +module_flash_fw_schedule(struct net_device *dev, const char *file_name, + struct ethtool_module_fw_flash_params *params, + struct sk_buff *skb, struct genl_info *info) +{ + struct ethtool_cmis_fw_update_params *fw_update; + struct ethtool_module_fw_flash *module_fw; + int err; + + module_fw = kzalloc_obj(*module_fw); + if (!module_fw) + return -ENOMEM; + + fw_update = &module_fw->fw_update; + fw_update->params = *params; + err = request_firmware_direct(&fw_update->fw, + file_name, &dev->dev); + if (err) { + NL_SET_ERR_MSG(info->extack, + "Failed to request module firmware image"); + goto err_free; + } + + err = module_flash_fw_work_init(module_fw, dev, info->extack); + if (err < 0) + goto err_release_firmware; + + fw_update->dev = dev; + fw_update->ntf_params.portid = info->snd_portid; + fw_update->ntf_params.seq = info->snd_seq; + fw_update->ntf_params.closed_sock = false; + + err = ethnl_sock_priv_set(skb, dev_net(dev), + fw_update->ntf_params.portid, + ETHTOOL_SOCK_TYPE_MODULE_FW_FLASH); + if (err < 0) + goto err_release_firmware; + + err = module_flash_fw_work_list_add(module_fw, info); + if (err < 0) + goto err_release_firmware; + + dev->ethtool->module_fw_flash_in_progress = true; + netdev_hold(dev, &module_fw->dev_tracker, GFP_KERNEL); + + schedule_work(&module_fw->work); + + return 0; + +err_release_firmware: + release_firmware(fw_update->fw); +err_free: + kfree(module_fw); + return err; +} + +static int module_flash_fw(struct net_device *dev, struct nlattr **tb, + struct sk_buff *skb, struct genl_info *info) +{ + struct ethtool_module_fw_flash_params params = {}; + const char *file_name; + struct nlattr *attr; + + if (GENL_REQ_ATTR_CHECK(info, ETHTOOL_A_MODULE_FW_FLASH_FILE_NAME)) + return -EINVAL; + + file_name = nla_data(tb[ETHTOOL_A_MODULE_FW_FLASH_FILE_NAME]); + + attr = tb[ETHTOOL_A_MODULE_FW_FLASH_PASSWORD]; + if (attr) { + params.password = cpu_to_be32(nla_get_u32(attr)); + params.password_valid = true; + } + + return module_flash_fw_schedule(dev, file_name, ¶ms, skb, info); +} + +static int ethnl_module_fw_flash_validate(struct net_device *dev, + struct netlink_ext_ack *extack) +{ + struct devlink_port *devlink_port = dev->devlink_port; + const struct ethtool_ops *ops = dev->ethtool_ops; + + if (!ops->set_module_eeprom_by_page || + !ops->get_module_eeprom_by_page) { + NL_SET_ERR_MSG(extack, + "Flashing module firmware is not supported by this device"); + return -EOPNOTSUPP; + } + + if (!ops->reset) { + NL_SET_ERR_MSG(extack, + "Reset module is not supported by this device, so flashing is not permitted"); + return -EOPNOTSUPP; + } + + if (dev->ethtool->module_fw_flash_in_progress) { + NL_SET_ERR_MSG(extack, "Module firmware flashing already in progress"); + return -EBUSY; + } + + if (dev->flags & IFF_UP) { + NL_SET_ERR_MSG(extack, "Netdevice is up, so flashing is not permitted"); + return -EBUSY; + } + + if (devlink_port && devlink_port->attrs.split) { + NL_SET_ERR_MSG(extack, "Can't perform firmware flashing on a split port"); + return -EOPNOTSUPP; + } + + return 0; +} + +int ethnl_act_module_fw_flash(struct sk_buff *skb, struct genl_info *info) +{ + struct ethnl_req_info req_info = {}; + struct nlattr **tb = info->attrs; + struct net_device *dev; + int ret; + + ret = ethnl_parse_header_dev_get(&req_info, + tb[ETHTOOL_A_MODULE_FW_FLASH_HEADER], + genl_info_net(info), info->extack, + true); + if (ret < 0) + return ret; + dev = req_info.dev; + + netdev_lock_ops_compat(dev); + ret = ethnl_ops_begin(dev); + if (ret < 0) + goto out_unlock; + + ret = ethnl_module_fw_flash_validate(dev, info->extack); + if (ret < 0) + goto out_complete; + + ret = module_flash_fw(dev, tb, skb, info); + +out_complete: + ethnl_ops_complete(dev); + +out_unlock: + netdev_unlock_ops_compat(dev); + ethnl_parse_header_dev_put(&req_info); + return ret; +} + +/* MODULE_FW_FLASH_NTF */ + +static int +ethnl_module_fw_flash_ntf_put_err(struct sk_buff *skb, char *err_msg, + char *sub_err_msg) +{ + int err_msg_len, sub_err_msg_len, total_len; + struct nlattr *attr; + + if (!err_msg) + return 0; + + err_msg_len = strlen(err_msg); + total_len = err_msg_len + 2; /* For period and NUL. */ + + if (sub_err_msg) { + sub_err_msg_len = strlen(sub_err_msg); + total_len += sub_err_msg_len + 2; /* For ", ". */ + } + + attr = nla_reserve(skb, ETHTOOL_A_MODULE_FW_FLASH_STATUS_MSG, + total_len); + if (!attr) + return -ENOMEM; + + if (sub_err_msg) + sprintf(nla_data(attr), "%s, %s.", err_msg, sub_err_msg); + else + sprintf(nla_data(attr), "%s.", err_msg); + + return 0; +} + +static void +ethnl_module_fw_flash_ntf(struct net_device *dev, + enum ethtool_module_fw_flash_status status, + struct ethnl_module_fw_flash_ntf_params *ntf_params, + char *err_msg, char *sub_err_msg, + u64 done, u64 total) +{ + struct sk_buff *skb; + void *hdr; + int ret; + + if (ntf_params->closed_sock) + return; + + skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL); + if (!skb) + return; + + hdr = ethnl_unicast_put(skb, ntf_params->portid, ++ntf_params->seq, + ETHTOOL_MSG_MODULE_FW_FLASH_NTF); + if (!hdr) + goto err_skb; + + ret = ethnl_fill_reply_header(skb, dev, + ETHTOOL_A_MODULE_FW_FLASH_HEADER); + if (ret < 0) + goto err_skb; + + if (nla_put_u32(skb, ETHTOOL_A_MODULE_FW_FLASH_STATUS, status)) + goto err_skb; + + ret = ethnl_module_fw_flash_ntf_put_err(skb, err_msg, sub_err_msg); + if (ret < 0) + goto err_skb; + + if (nla_put_uint(skb, ETHTOOL_A_MODULE_FW_FLASH_DONE, done)) + goto err_skb; + + if (nla_put_uint(skb, ETHTOOL_A_MODULE_FW_FLASH_TOTAL, total)) + goto err_skb; + + genlmsg_end(skb, hdr); + genlmsg_unicast(dev_net(dev), skb, ntf_params->portid); + return; + +err_skb: + nlmsg_free(skb); +} + +void ethnl_module_fw_flash_ntf_err(struct net_device *dev, + struct ethnl_module_fw_flash_ntf_params *params, + char *err_msg, char *sub_err_msg) +{ + ethnl_module_fw_flash_ntf(dev, ETHTOOL_MODULE_FW_FLASH_STATUS_ERROR, + params, err_msg, sub_err_msg, 0, 0); +} + +void +ethnl_module_fw_flash_ntf_start(struct net_device *dev, + struct ethnl_module_fw_flash_ntf_params *params) +{ + ethnl_module_fw_flash_ntf(dev, ETHTOOL_MODULE_FW_FLASH_STATUS_STARTED, + params, NULL, NULL, 0, 0); +} + +void +ethnl_module_fw_flash_ntf_complete(struct net_device *dev, + struct ethnl_module_fw_flash_ntf_params *params) +{ + ethnl_module_fw_flash_ntf(dev, ETHTOOL_MODULE_FW_FLASH_STATUS_COMPLETED, + params, NULL, NULL, 0, 0); +} + +void +ethnl_module_fw_flash_ntf_in_progress(struct net_device *dev, + struct ethnl_module_fw_flash_ntf_params *params, + u64 done, u64 total) +{ + ethnl_module_fw_flash_ntf(dev, + ETHTOOL_MODULE_FW_FLASH_STATUS_IN_PROGRESS, + params, NULL, NULL, done, total); +} -- cgit v1.3.1