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/pnp/card.c | 432 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 432 insertions(+) create mode 100644 drivers/pnp/card.c (limited to 'drivers/pnp/card.c') diff --git a/drivers/pnp/card.c b/drivers/pnp/card.c new file mode 100644 index 000000000..df5e3d3cb --- /dev/null +++ b/drivers/pnp/card.c @@ -0,0 +1,432 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * card.c - contains functions for managing groups of PnP devices + * + * Copyright 2002 Adam Belay + */ + +#include +#include +#include +#include +#include +#include +#include "base.h" + +LIST_HEAD(pnp_cards); +static LIST_HEAD(pnp_card_drivers); + +static const struct pnp_card_device_id *match_card(struct pnp_card_driver *drv, + struct pnp_card *card) +{ + const struct pnp_card_device_id *drv_id = drv->id_table; + + while (*drv_id->id) { + if (compare_pnp_id(card->id, drv_id->id)) { + int i = 0; + + for (;;) { + int found; + struct pnp_dev *dev; + + if (i == PNP_MAX_DEVICES || + !*drv_id->devs[i].id) + return drv_id; + found = 0; + card_for_each_dev(card, dev) { + if (compare_pnp_id(dev->id, + drv_id->devs[i].id)) { + found = 1; + break; + } + } + if (!found) + break; + i++; + } + } + drv_id++; + } + return NULL; +} + +static void card_remove(struct pnp_dev *dev) +{ + dev->card_link = NULL; +} + +static void card_remove_first(struct pnp_dev *dev) +{ + struct pnp_card_driver *drv = to_pnp_card_driver(dev->driver); + + if (!dev->card || !drv) + return; + if (drv->remove) + drv->remove(dev->card_link); + drv->link.remove = &card_remove; + kfree(dev->card_link); + card_remove(dev); +} + +static int card_probe(struct pnp_card *card, struct pnp_card_driver *drv) +{ + const struct pnp_card_device_id *id; + struct pnp_card_link *clink; + struct pnp_dev *dev; + + if (!drv->probe) + return 0; + id = match_card(drv, card); + if (!id) + return 0; + + clink = kzalloc_obj(*clink); + if (!clink) + return 0; + clink->card = card; + clink->driver = drv; + clink->pm_state = PMSG_ON; + + if (drv->probe(clink, id) >= 0) + return 1; + + /* Recovery */ + card_for_each_dev(card, dev) { + if (dev->card_link == clink) + pnp_release_card_device(dev); + } + kfree(clink); + return 0; +} + +/** + * pnp_add_card_id - adds an EISA id to the specified card + * @id: pointer to a pnp_id structure + * @card: pointer to the desired card + */ +static struct pnp_id *pnp_add_card_id(struct pnp_card *card, char *id) +{ + struct pnp_id *dev_id, *ptr; + + dev_id = kzalloc_obj(struct pnp_id); + if (!dev_id) + return NULL; + + dev_id->id[0] = id[0]; + dev_id->id[1] = id[1]; + dev_id->id[2] = id[2]; + dev_id->id[3] = tolower(id[3]); + dev_id->id[4] = tolower(id[4]); + dev_id->id[5] = tolower(id[5]); + dev_id->id[6] = tolower(id[6]); + dev_id->id[7] = '\0'; + + dev_id->next = NULL; + ptr = card->id; + while (ptr && ptr->next) + ptr = ptr->next; + if (ptr) + ptr->next = dev_id; + else + card->id = dev_id; + + return dev_id; +} + +static void pnp_free_card_ids(struct pnp_card *card) +{ + struct pnp_id *id; + struct pnp_id *next; + + id = card->id; + while (id) { + next = id->next; + kfree(id); + id = next; + } +} + +static void pnp_release_card(struct device *dmdev) +{ + struct pnp_card *card = to_pnp_card(dmdev); + + pnp_free_card_ids(card); + kfree(card); +} + +struct pnp_card *pnp_alloc_card(struct pnp_protocol *protocol, int id, char *pnpid) +{ + struct pnp_card *card; + struct pnp_id *dev_id; + + card = kzalloc_obj(struct pnp_card); + if (!card) + return NULL; + + card->protocol = protocol; + card->number = id; + + card->dev.parent = &card->protocol->dev; + dev_set_name(&card->dev, "%02x:%02x", card->protocol->number, card->number); + + card->dev.coherent_dma_mask = DMA_BIT_MASK(24); + card->dev.dma_mask = &card->dev.coherent_dma_mask; + + dev_id = pnp_add_card_id(card, pnpid); + if (!dev_id) { + kfree(card); + return NULL; + } + + return card; +} + +static ssize_t name_show(struct device *dmdev, + struct device_attribute *attr, char *buf) +{ + char *str = buf; + struct pnp_card *card = to_pnp_card(dmdev); + + str += sprintf(str, "%s\n", card->name); + return (str - buf); +} + +static DEVICE_ATTR_RO(name); + +static ssize_t card_id_show(struct device *dmdev, + struct device_attribute *attr, char *buf) +{ + char *str = buf; + struct pnp_card *card = to_pnp_card(dmdev); + struct pnp_id *pos = card->id; + + while (pos) { + str += sprintf(str, "%s\n", pos->id); + pos = pos->next; + } + return (str - buf); +} + +static DEVICE_ATTR_RO(card_id); + +static int pnp_interface_attach_card(struct pnp_card *card) +{ + int rc = device_create_file(&card->dev, &dev_attr_name); + + if (rc) + return rc; + + rc = device_create_file(&card->dev, &dev_attr_card_id); + if (rc) + goto err_name; + + return 0; + +err_name: + device_remove_file(&card->dev, &dev_attr_name); + return rc; +} + +/** + * pnp_add_card - adds a PnP card to the PnP Layer + * @card: pointer to the card to add + */ +int pnp_add_card(struct pnp_card *card) +{ + int error; + struct list_head *pos, *temp; + + card->dev.bus = NULL; + card->dev.release = &pnp_release_card; + error = device_register(&card->dev); + if (error) { + dev_err(&card->dev, "could not register (err=%d)\n", error); + put_device(&card->dev); + return error; + } + + pnp_interface_attach_card(card); + mutex_lock(&pnp_lock); + list_add_tail(&card->global_list, &pnp_cards); + list_add_tail(&card->protocol_list, &card->protocol->cards); + mutex_unlock(&pnp_lock); + + /* we wait until now to add devices in order to ensure the drivers + * will be able to use all of the related devices on the card + * without waiting an unreasonable length of time */ + list_for_each_safe(pos, temp, &card->devices) { + struct pnp_dev *dev = card_to_pnp_dev(pos); + error = __pnp_add_device(dev); + if (error) { + mutex_lock(&pnp_lock); + list_del(&dev->card_list); + dev->card = NULL; + mutex_unlock(&pnp_lock); + put_device(&dev->dev); + } + } + + /* match with card drivers */ + list_for_each_safe(pos, temp, &pnp_card_drivers) { + struct pnp_card_driver *drv = + list_entry(pos, struct pnp_card_driver, + global_list); + card_probe(card, drv); + } + return 0; +} + +/** + * pnp_add_card_device - adds a device to the specified card + * @card: pointer to the card to add to + * @dev: pointer to the device to add + */ +int pnp_add_card_device(struct pnp_card *card, struct pnp_dev *dev) +{ + dev->dev.parent = &card->dev; + dev->card_link = NULL; + dev_set_name(&dev->dev, "%02x:%02x.%02x", + dev->protocol->number, card->number, dev->number); + mutex_lock(&pnp_lock); + dev->card = card; + list_add_tail(&dev->card_list, &card->devices); + mutex_unlock(&pnp_lock); + return 0; +} + +/** + * pnp_request_card_device - Searches for a PnP device under the specified card + * @clink: pointer to the card link, cannot be NULL + * @id: pointer to a PnP ID structure that explains the rules for finding the device + * @from: Starting place to search from. If NULL it will start from the beginning. + */ +struct pnp_dev *pnp_request_card_device(struct pnp_card_link *clink, + const char *id, struct pnp_dev *from) +{ + struct list_head *pos; + struct pnp_dev *dev; + struct pnp_card_driver *drv; + struct pnp_card *card; + + if (!clink || !id) + return NULL; + + card = clink->card; + drv = clink->driver; + if (!from) { + pos = card->devices.next; + } else { + if (from->card != card) + return NULL; + pos = from->card_list.next; + } + while (pos != &card->devices) { + dev = card_to_pnp_dev(pos); + if ((!dev->card_link) && compare_pnp_id(dev->id, id)) + goto found; + pos = pos->next; + } + + return NULL; + +found: + dev->card_link = clink; + dev->dev.driver = &drv->link.driver; + if (pnp_bus_type.probe(&dev->dev)) + goto err_out; + if (device_bind_driver(&dev->dev)) + goto err_out; + + return dev; + +err_out: + dev->dev.driver = NULL; + dev->card_link = NULL; + return NULL; +} +EXPORT_SYMBOL(pnp_request_card_device); + +/** + * pnp_release_card_device - call this when the driver no longer needs the device + * @dev: pointer to the PnP device structure + */ +void pnp_release_card_device(struct pnp_dev *dev) +{ + struct pnp_card_driver *drv = dev->card_link->driver; + + drv->link.remove = &card_remove; + device_release_driver(&dev->dev); + drv->link.remove = &card_remove_first; +} +EXPORT_SYMBOL(pnp_release_card_device); + +/* + * suspend/resume callbacks + */ +static int card_suspend(struct pnp_dev *dev, pm_message_t state) +{ + struct pnp_card_link *link = dev->card_link; + + if (link->pm_state.event == state.event) + return 0; + link->pm_state = state; + return link->driver->suspend(link, state); +} + +static int card_resume(struct pnp_dev *dev) +{ + struct pnp_card_link *link = dev->card_link; + + if (link->pm_state.event == PM_EVENT_ON) + return 0; + link->pm_state = PMSG_ON; + link->driver->resume(link); + return 0; +} + +/** + * pnp_register_card_driver - registers a PnP card driver with the PnP Layer + * @drv: pointer to the driver to register + */ +int pnp_register_card_driver(struct pnp_card_driver *drv) +{ + int error; + struct list_head *pos, *temp; + + drv->link.name = drv->name; + drv->link.id_table = NULL; /* this will disable auto matching */ + drv->link.flags = drv->flags; + drv->link.probe = NULL; + drv->link.remove = &card_remove_first; + drv->link.suspend = drv->suspend ? card_suspend : NULL; + drv->link.resume = drv->resume ? card_resume : NULL; + + error = pnp_register_driver(&drv->link); + if (error < 0) + return error; + + mutex_lock(&pnp_lock); + list_add_tail(&drv->global_list, &pnp_card_drivers); + mutex_unlock(&pnp_lock); + + list_for_each_safe(pos, temp, &pnp_cards) { + struct pnp_card *card = + list_entry(pos, struct pnp_card, global_list); + card_probe(card, drv); + } + return 0; +} +EXPORT_SYMBOL(pnp_register_card_driver); + +/** + * pnp_unregister_card_driver - unregisters a PnP card driver from the PnP Layer + * @drv: pointer to the driver to unregister + */ +void pnp_unregister_card_driver(struct pnp_card_driver *drv) +{ + mutex_lock(&pnp_lock); + list_del(&drv->global_list); + mutex_unlock(&pnp_lock); + pnp_unregister_driver(&drv->link); +} +EXPORT_SYMBOL(pnp_unregister_card_driver); -- cgit v1.3.1