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 --- sound/soc/sof/ipc.c | 232 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 232 insertions(+) create mode 100644 sound/soc/sof/ipc.c (limited to 'sound/soc/sof/ipc.c') diff --git a/sound/soc/sof/ipc.c b/sound/soc/sof/ipc.c new file mode 100644 index 000000000..e6d8894b8 --- /dev/null +++ b/sound/soc/sof/ipc.c @@ -0,0 +1,232 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) +// +// This file is provided under a dual BSD/GPLv2 license. When using or +// redistributing this file, you may do so under either license. +// +// Copyright(c) 2018 Intel Corporation +// +// Author: Liam Girdwood +// +// Generic IPC layer that can work over MMIO and SPI/I2C. PHY layer provided +// by platform driver code. +// + +#include +#include + +#include "sof-priv.h" +#include "sof-audio.h" +#include "ops.h" + +/** + * sof_ipc_send_msg - generic function to prepare and send one IPC message + * @sdev: pointer to SOF core device struct + * @msg_data: pointer to a message to send + * @msg_bytes: number of bytes in the message + * @reply_bytes: number of bytes available for the reply. + * The buffer for the reply data is not passed to this + * function, the available size is an information for the + * reply handling functions. + * + * On success the function returns 0, otherwise negative error number. + * + * Note: higher level sdev->ipc->tx_mutex must be held to make sure that + * transfers are synchronized. + */ +int sof_ipc_send_msg(struct snd_sof_dev *sdev, void *msg_data, size_t msg_bytes, + size_t reply_bytes) +{ + struct snd_sof_ipc *ipc = sdev->ipc; + struct snd_sof_ipc_msg *msg; + int ret; + + if (ipc->disable_ipc_tx || sdev->fw_state != SOF_FW_BOOT_COMPLETE) + return -ENODEV; + + /* + * The spin-lock is needed to protect message objects against other + * atomic contexts. + */ + guard(spinlock_irq)(&sdev->ipc_lock); + + /* initialise the message */ + msg = &ipc->msg; + + /* attach message data */ + msg->msg_data = msg_data; + msg->msg_size = msg_bytes; + + msg->reply_size = reply_bytes; + msg->reply_error = 0; + + sdev->msg = msg; + + ret = snd_sof_dsp_send_msg(sdev, msg); + /* Next reply that we receive will be related to this message */ + if (!ret) + msg->ipc_complete = false; + + return ret; +} + +/* send IPC message from host to DSP */ +int sof_ipc_tx_message(struct snd_sof_ipc *ipc, void *msg_data, size_t msg_bytes, + void *reply_data, size_t reply_bytes) +{ + if (msg_bytes > ipc->max_payload_size || + reply_bytes > ipc->max_payload_size) + return -ENOBUFS; + + return ipc->ops->tx_msg(ipc->sdev, msg_data, msg_bytes, reply_data, + reply_bytes, false); +} +EXPORT_SYMBOL(sof_ipc_tx_message); + +/* IPC set or get data from host to DSP */ +int sof_ipc_set_get_data(struct snd_sof_ipc *ipc, void *msg_data, + size_t msg_bytes, bool set) +{ + return ipc->ops->set_get_data(ipc->sdev, msg_data, msg_bytes, set); +} +EXPORT_SYMBOL(sof_ipc_set_get_data); + +/* + * send IPC message from host to DSP without modifying the DSP state. + * This will be used for IPC's that can be handled by the DSP + * even in a low-power D0 substate. + */ +int sof_ipc_tx_message_no_pm(struct snd_sof_ipc *ipc, void *msg_data, size_t msg_bytes, + void *reply_data, size_t reply_bytes) +{ + if (msg_bytes > ipc->max_payload_size || + reply_bytes > ipc->max_payload_size) + return -ENOBUFS; + + return ipc->ops->tx_msg(ipc->sdev, msg_data, msg_bytes, reply_data, + reply_bytes, true); +} +EXPORT_SYMBOL(sof_ipc_tx_message_no_pm); + +/* Generic helper function to retrieve the reply */ +void snd_sof_ipc_get_reply(struct snd_sof_dev *sdev) +{ + /* + * Sometimes, there is unexpected reply ipc arriving. The reply + * ipc belongs to none of the ipcs sent from driver. + * In this case, the driver must ignore the ipc. + */ + if (!sdev->msg) { + dev_warn(sdev->dev, "unexpected ipc interrupt raised!\n"); + return; + } + + sdev->msg->reply_error = sdev->ipc->ops->get_reply(sdev); +} +EXPORT_SYMBOL(snd_sof_ipc_get_reply); + +/* handle reply message from DSP */ +void snd_sof_ipc_reply(struct snd_sof_dev *sdev, u32 msg_id) +{ + struct snd_sof_ipc_msg *msg = &sdev->ipc->msg; + + if (msg->ipc_complete) { + dev_dbg(sdev->dev, + "no reply expected, received 0x%x, will be ignored", + msg_id); + return; + } + + /* wake up and return the error if we have waiters on this message ? */ + msg->ipc_complete = true; + wake_up(&msg->waitq); +} +EXPORT_SYMBOL(snd_sof_ipc_reply); + +struct snd_sof_ipc *snd_sof_ipc_init(struct snd_sof_dev *sdev) +{ + struct snd_sof_ipc *ipc; + struct snd_sof_ipc_msg *msg; + const struct sof_ipc_ops *ops; + + ipc = devm_kzalloc(sdev->dev, sizeof(*ipc), GFP_KERNEL); + if (!ipc) + return NULL; + + mutex_init(&ipc->tx_mutex); + ipc->sdev = sdev; + msg = &ipc->msg; + + /* indicate that we aren't sending a message ATM */ + msg->ipc_complete = true; + + init_waitqueue_head(&msg->waitq); + + switch (sdev->pdata->ipc_type) { +#if defined(CONFIG_SND_SOC_SOF_IPC3) + case SOF_IPC_TYPE_3: + ops = &ipc3_ops; + break; +#endif +#if defined(CONFIG_SND_SOC_SOF_IPC4) + case SOF_IPC_TYPE_4: + ops = &ipc4_ops; + break; +#endif + default: + dev_err(sdev->dev, "Not supported IPC version: %d\n", + sdev->pdata->ipc_type); + return NULL; + } + + /* check for mandatory ops */ + if (!ops->tx_msg || !ops->rx_msg || !ops->set_get_data || !ops->get_reply) { + dev_err(sdev->dev, "Missing IPC message handling ops\n"); + return NULL; + } + + if (!ops->fw_loader || !ops->fw_loader->validate || + !ops->fw_loader->parse_ext_manifest) { + dev_err(sdev->dev, "Missing IPC firmware loading ops\n"); + return NULL; + } + + if (!ops->pcm) { + dev_err(sdev->dev, "Missing IPC PCM ops\n"); + return NULL; + } + + if (!ops->tplg || !ops->tplg->widget || !ops->tplg->control) { + dev_err(sdev->dev, "Missing IPC topology ops\n"); + return NULL; + } + + if (ops->fw_tracing && (!ops->fw_tracing->init || !ops->fw_tracing->suspend || + !ops->fw_tracing->resume)) { + dev_err(sdev->dev, "Missing firmware tracing ops\n"); + return NULL; + } + + if (ops->init && ops->init(sdev)) + return NULL; + + ipc->ops = ops; + + return ipc; +} +EXPORT_SYMBOL(snd_sof_ipc_init); + +void snd_sof_ipc_free(struct snd_sof_dev *sdev) +{ + struct snd_sof_ipc *ipc = sdev->ipc; + + if (!ipc) + return; + + /* disable sending of ipc's */ + scoped_guard(mutex, &ipc->tx_mutex) + ipc->disable_ipc_tx = true; + + if (ipc->ops->exit) + ipc->ops->exit(sdev); +} +EXPORT_SYMBOL(snd_sof_ipc_free); -- cgit v1.3.1