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/gpib/pc2/Makefile | 5 + drivers/gpib/pc2/pc2_gpib.c | 685 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 690 insertions(+) create mode 100644 drivers/gpib/pc2/Makefile create mode 100644 drivers/gpib/pc2/pc2_gpib.c (limited to 'drivers/gpib/pc2') diff --git a/drivers/gpib/pc2/Makefile b/drivers/gpib/pc2/Makefile new file mode 100644 index 000000000..481ee4296 --- /dev/null +++ b/drivers/gpib/pc2/Makefile @@ -0,0 +1,5 @@ + +obj-$(CONFIG_GPIB_PC2) += pc2_gpib.o + + + diff --git a/drivers/gpib/pc2/pc2_gpib.c b/drivers/gpib/pc2/pc2_gpib.c new file mode 100644 index 000000000..d72601819 --- /dev/null +++ b/drivers/gpib/pc2/pc2_gpib.c @@ -0,0 +1,685 @@ +// SPDX-License-Identifier: GPL-2.0 + +/*************************************************************************** + * copyright : (C) 2001, 2002 by Frank Mori Hess + ***************************************************************************/ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#define dev_fmt pr_fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "nec7210.h" +#include "gpibP.h" + +// struct which defines private_data for pc2 driver +struct pc2_priv { + struct nec7210_priv nec7210_priv; + unsigned int irq; + // io address that clears interrupt for pc2a (0x2f0 + irq) + unsigned int clear_intr_addr; +}; + +// pc2 uses 8 consecutive io addresses +static const int pc2_iosize = 8; +static const int pc2a_iosize = 8; +static const int pc2_2a_iosize = 16; + +// offset between io addresses of successive nec7210 registers +static const int pc2a_reg_offset = 0x400; +static const int pc2_reg_offset = 1; + +// interrupt service routine +static irqreturn_t pc2_interrupt(int irq, void *arg); +static irqreturn_t pc2a_interrupt(int irq, void *arg); + +// pc2 specific registers and bits + +// interrupt clear register address +static const int pc2a_clear_intr_iobase = 0x2f0; +static inline unsigned int CLEAR_INTR_REG(unsigned int irq) +{ + return pc2a_clear_intr_iobase + irq; +} + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("GPIB driver for PC2/PC2a and compatible devices"); + +/* + * GPIB interrupt service routines + */ + +irqreturn_t pc2_interrupt(int irq, void *arg) +{ + struct gpib_board *board = arg; + struct pc2_priv *priv = board->private_data; + unsigned long flags; + irqreturn_t retval; + + spin_lock_irqsave(&board->spinlock, flags); + retval = nec7210_interrupt(board, &priv->nec7210_priv); + spin_unlock_irqrestore(&board->spinlock, flags); + return retval; +} + +irqreturn_t pc2a_interrupt(int irq, void *arg) +{ + struct gpib_board *board = arg; + struct pc2_priv *priv = board->private_data; + int status1, status2; + unsigned long flags; + irqreturn_t retval; + + spin_lock_irqsave(&board->spinlock, flags); + // read interrupt status (also clears status) + status1 = read_byte(&priv->nec7210_priv, ISR1); + status2 = read_byte(&priv->nec7210_priv, ISR2); + /* clear interrupt circuit */ + if (priv->irq) + outb(0xff, CLEAR_INTR_REG(priv->irq)); + retval = nec7210_interrupt_have_status(board, &priv->nec7210_priv, status1, status2); + spin_unlock_irqrestore(&board->spinlock, flags); + return retval; +} + +// wrappers for interface functions +static int pc2_read(struct gpib_board *board, u8 *buffer, size_t length, int *end, + size_t *bytes_read) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_read(board, &priv->nec7210_priv, buffer, length, end, bytes_read); +} + +static int pc2_write(struct gpib_board *board, u8 *buffer, size_t length, int send_eoi, + size_t *bytes_written) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_write(board, &priv->nec7210_priv, buffer, length, send_eoi, bytes_written); +} + +static int pc2_command(struct gpib_board *board, u8 *buffer, + size_t length, size_t *bytes_written) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_command(board, &priv->nec7210_priv, buffer, length, bytes_written); +} + +static int pc2_take_control(struct gpib_board *board, int synchronous) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_take_control(board, &priv->nec7210_priv, synchronous); +} + +static int pc2_go_to_standby(struct gpib_board *board) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_go_to_standby(board, &priv->nec7210_priv); +} + +static int pc2_request_system_control(struct gpib_board *board, int request_control) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_request_system_control(board, &priv->nec7210_priv, request_control); +} + +static void pc2_interface_clear(struct gpib_board *board, int assert) +{ + struct pc2_priv *priv = board->private_data; + + nec7210_interface_clear(board, &priv->nec7210_priv, assert); +} + +static void pc2_remote_enable(struct gpib_board *board, int enable) +{ + struct pc2_priv *priv = board->private_data; + + nec7210_remote_enable(board, &priv->nec7210_priv, enable); +} + +static int pc2_enable_eos(struct gpib_board *board, u8 eos_byte, int compare_8_bits) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_enable_eos(board, &priv->nec7210_priv, eos_byte, compare_8_bits); +} + +static void pc2_disable_eos(struct gpib_board *board) +{ + struct pc2_priv *priv = board->private_data; + + nec7210_disable_eos(board, &priv->nec7210_priv); +} + +static unsigned int pc2_update_status(struct gpib_board *board, unsigned int clear_mask) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_update_status(board, &priv->nec7210_priv, clear_mask); +} + +static int pc2_primary_address(struct gpib_board *board, unsigned int address) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_primary_address(board, &priv->nec7210_priv, address); +} + +static int pc2_secondary_address(struct gpib_board *board, unsigned int address, int enable) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_secondary_address(board, &priv->nec7210_priv, address, enable); +} + +static int pc2_parallel_poll(struct gpib_board *board, u8 *result) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_parallel_poll(board, &priv->nec7210_priv, result); +} + +static void pc2_parallel_poll_configure(struct gpib_board *board, u8 config) +{ + struct pc2_priv *priv = board->private_data; + + nec7210_parallel_poll_configure(board, &priv->nec7210_priv, config); +} + +static void pc2_parallel_poll_response(struct gpib_board *board, int ist) +{ + struct pc2_priv *priv = board->private_data; + + nec7210_parallel_poll_response(board, &priv->nec7210_priv, ist); +} + +static void pc2_serial_poll_response(struct gpib_board *board, u8 status) +{ + struct pc2_priv *priv = board->private_data; + + nec7210_serial_poll_response(board, &priv->nec7210_priv, status); +} + +static u8 pc2_serial_poll_status(struct gpib_board *board) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_serial_poll_status(board, &priv->nec7210_priv); +} + +static int pc2_t1_delay(struct gpib_board *board, unsigned int nano_sec) +{ + struct pc2_priv *priv = board->private_data; + + return nec7210_t1_delay(board, &priv->nec7210_priv, nano_sec); +} + +static void pc2_return_to_local(struct gpib_board *board) +{ + struct pc2_priv *priv = board->private_data; + + nec7210_return_to_local(board, &priv->nec7210_priv); +} + +static int allocate_private(struct gpib_board *board) +{ + struct pc2_priv *priv; + + board->private_data = kzalloc_obj(struct pc2_priv); + if (!board->private_data) + return -ENOMEM; + priv = board->private_data; + init_nec7210_private(&priv->nec7210_priv); + return 0; +} + +static void free_private(struct gpib_board *board) +{ + kfree(board->private_data); + board->private_data = NULL; +} + +static int pc2_generic_attach(struct gpib_board *board, const struct gpib_board_config *config, + enum nec7210_chipset chipset) +{ + struct pc2_priv *pc2_priv; + struct nec7210_priv *nec_priv; + int retval; + + board->status = 0; + retval = allocate_private(board); + if (retval) + return retval; + pc2_priv = board->private_data; + nec_priv = &pc2_priv->nec7210_priv; + nec_priv->read_byte = nec7210_ioport_read_byte; + nec_priv->write_byte = nec7210_ioport_write_byte; + nec_priv->type = chipset; + +#ifndef PC2_DMA + /* + * board->dev hasn't been initialized, so forget about DMA until this driver + * is adapted to use isa_register_driver. + */ + if (config->ibdma) + // driver needs to be adapted to use isa_register_driver to get a struct device* + dev_err(board->gpib_dev, "DMA disabled for pc2 gpib"); +#else + if (config->ibdma) { + nec_priv->dma_buffer_length = 0x1000; + nec_priv->dma_buffer = dma_alloc_coherent(board->dev, + nec_priv->dma_buffer_length, & + nec_priv->dma_buffer_addr, GFP_ATOMIC); + if (!nec_priv->dma_buffer) + return -ENOMEM; + + // request isa dma channel + if (request_dma(config->ibdma, "pc2")) { + dev_err(board->gpib_dev, "can't request DMA %d\n", config->ibdma); + return -1; + } + nec_priv->dma_channel = config->ibdma; + } +#endif + + return 0; +} + +static int pc2_attach(struct gpib_board *board, const struct gpib_board_config *config) +{ + int isr_flags = 0; + struct pc2_priv *pc2_priv; + struct nec7210_priv *nec_priv; + int retval; + + retval = pc2_generic_attach(board, config, NEC7210); + if (retval) + return retval; + + pc2_priv = board->private_data; + nec_priv = &pc2_priv->nec7210_priv; + nec_priv->offset = pc2_reg_offset; + + if (!request_region(config->ibbase, pc2_iosize, "pc2")) { + dev_err(board->gpib_dev, "ioports are already in use\n"); + return -EBUSY; + } + nec_priv->iobase = config->ibbase; + + nec7210_board_reset(nec_priv, board); + + // install interrupt handler + if (config->ibirq) { + if (request_irq(config->ibirq, pc2_interrupt, isr_flags, "pc2", board)) { + dev_err(board->gpib_dev, "can't request IRQ %d\n", config->ibirq); + return -EBUSY; + } + } + pc2_priv->irq = config->ibirq; + /* poll so we can detect assertion of ATN */ + if (gpib_request_pseudo_irq(board, pc2_interrupt)) { + dev_err(board->gpib_dev, "failed to allocate pseudo_irq\n"); + return -1; + } + /* set internal counter register for 8 MHz input clock */ + write_byte(nec_priv, ICR | 8, AUXMR); + + nec7210_board_online(nec_priv, board); + + return 0; +} + +static void pc2_detach(struct gpib_board *board) +{ + struct pc2_priv *pc2_priv = board->private_data; + struct nec7210_priv *nec_priv; + + if (pc2_priv) { + nec_priv = &pc2_priv->nec7210_priv; +#ifdef PC2_DMA + if (nec_priv->dma_channel) + free_dma(nec_priv->dma_channel); +#endif + gpib_free_pseudo_irq(board); + if (pc2_priv->irq) + free_irq(pc2_priv->irq, board); + if (nec_priv->iobase) { + nec7210_board_reset(nec_priv, board); + release_region(nec_priv->iobase, pc2_iosize); + } + if (nec_priv->dma_buffer) { + dma_free_coherent(board->dev, nec_priv->dma_buffer_length, + nec_priv->dma_buffer, nec_priv->dma_buffer_addr); + nec_priv->dma_buffer = NULL; + } + } + free_private(board); +} + +static int pc2a_common_attach(struct gpib_board *board, const struct gpib_board_config *config, + unsigned int num_registers, enum nec7210_chipset chipset) +{ + unsigned int i, j; + struct pc2_priv *pc2_priv; + struct nec7210_priv *nec_priv; + int retval; + + retval = pc2_generic_attach(board, config, chipset); + if (retval) + return retval; + + pc2_priv = board->private_data; + nec_priv = &pc2_priv->nec7210_priv; + nec_priv->offset = pc2a_reg_offset; + + switch (config->ibbase) { + case 0x02e1: + case 0x22e1: + case 0x42e1: + case 0x62e1: + break; + default: + dev_err(board->gpib_dev, "PCIIa base range invalid, must be one of 0x[0246]2e1, but is 0x%x\n", + config->ibbase); + return -1; + } + + if (config->ibirq) { + if (config->ibirq < 2 || config->ibirq > 7) { + dev_err(board->gpib_dev, "illegal interrupt level %i\n", + config->ibirq); + return -1; + } + } else { + dev_err(board->gpib_dev, "interrupt disabled, using polling mode (slow)\n"); + } +#ifdef CHECK_IOPORTS + unsigned int err = 0; + + for (i = 0; i < num_registers; i++) { + if (check_region(config->ibbase + i * pc2a_reg_offset, 1)) + err++; + } + if (config->ibirq && check_region(pc2a_clear_intr_iobase + config->ibirq, 1)) + err++; + if (err) { + dev_err(board->gpib_dev, "ioports are already in use"); + return -EBUSY; + } +#endif + for (i = 0; i < num_registers; i++) { + if (!request_region(config->ibbase + + i * pc2a_reg_offset, 1, "pc2a")) { + dev_err(board->gpib_dev, "ioports are already in use"); + for (j = 0; j < i; j++) + release_region(config->ibbase + + j * pc2a_reg_offset, 1); + return -EBUSY; + } + } + nec_priv->iobase = config->ibbase; + if (config->ibirq) { + if (!request_region(pc2a_clear_intr_iobase + config->ibirq, 1, "pc2a")) { + dev_err(board->gpib_dev, "ioports are already in use"); + return -1; + } + pc2_priv->clear_intr_addr = pc2a_clear_intr_iobase + config->ibirq; + if (request_irq(config->ibirq, pc2a_interrupt, 0, "pc2a", board)) { + dev_err(board->gpib_dev, "can't request IRQ %d\n", config->ibirq); + return -EBUSY; + } + } + pc2_priv->irq = config->ibirq; + /* poll so we can detect assertion of ATN */ + if (gpib_request_pseudo_irq(board, pc2_interrupt)) { + dev_err(board->gpib_dev, "failed to allocate pseudo_irq\n"); + return -1; + } + + // make sure interrupt is clear + if (pc2_priv->irq) + outb(0xff, CLEAR_INTR_REG(pc2_priv->irq)); + + nec7210_board_reset(nec_priv, board); + + /* set internal counter register for 8 MHz input clock */ + write_byte(nec_priv, ICR | 8, AUXMR); + + nec7210_board_online(nec_priv, board); + + return 0; +} + +static int pc2a_attach(struct gpib_board *board, const struct gpib_board_config *config) +{ + return pc2a_common_attach(board, config, pc2a_iosize, NEC7210); +} + +static int pc2a_cb7210_attach(struct gpib_board *board, const struct gpib_board_config *config) +{ + return pc2a_common_attach(board, config, pc2a_iosize, CB7210); +} + +static int pc2_2a_attach(struct gpib_board *board, const struct gpib_board_config *config) +{ + return pc2a_common_attach(board, config, pc2_2a_iosize, NAT4882); +} + +static void pc2a_common_detach(struct gpib_board *board, unsigned int num_registers) +{ + int i; + struct pc2_priv *pc2_priv = board->private_data; + struct nec7210_priv *nec_priv; + + if (pc2_priv) { + nec_priv = &pc2_priv->nec7210_priv; +#ifdef PC2_DMA + if (nec_priv->dma_channel) + free_dma(nec_priv->dma_channel); +#endif + gpib_free_pseudo_irq(board); + if (pc2_priv->irq) + free_irq(pc2_priv->irq, board); + if (nec_priv->iobase) { + nec7210_board_reset(nec_priv, board); + for (i = 0; i < num_registers; i++) + release_region(nec_priv->iobase + + i * pc2a_reg_offset, 1); + } + if (pc2_priv->clear_intr_addr) + release_region(pc2_priv->clear_intr_addr, 1); + if (nec_priv->dma_buffer) { + dma_free_coherent(board->dev, nec_priv->dma_buffer_length, + nec_priv->dma_buffer, + nec_priv->dma_buffer_addr); + nec_priv->dma_buffer = NULL; + } + } + free_private(board); +} + +static void pc2a_detach(struct gpib_board *board) +{ + pc2a_common_detach(board, pc2a_iosize); +} + +static void pc2_2a_detach(struct gpib_board *board) +{ + pc2a_common_detach(board, pc2_2a_iosize); +} + +static struct gpib_interface pc2_interface = { + .name = "pcII", + .attach = pc2_attach, + .detach = pc2_detach, + .read = pc2_read, + .write = pc2_write, + .command = pc2_command, + .take_control = pc2_take_control, + .go_to_standby = pc2_go_to_standby, + .request_system_control = pc2_request_system_control, + .interface_clear = pc2_interface_clear, + .remote_enable = pc2_remote_enable, + .enable_eos = pc2_enable_eos, + .disable_eos = pc2_disable_eos, + .parallel_poll = pc2_parallel_poll, + .parallel_poll_configure = pc2_parallel_poll_configure, + .parallel_poll_response = pc2_parallel_poll_response, + .local_parallel_poll_mode = NULL, // XXX + .line_status = NULL, + .update_status = pc2_update_status, + .primary_address = pc2_primary_address, + .secondary_address = pc2_secondary_address, + .serial_poll_response = pc2_serial_poll_response, + .serial_poll_status = pc2_serial_poll_status, + .t1_delay = pc2_t1_delay, + .return_to_local = pc2_return_to_local, +}; + +static struct gpib_interface pc2a_interface = { + .name = "pcIIa", + .attach = pc2a_attach, + .detach = pc2a_detach, + .read = pc2_read, + .write = pc2_write, + .command = pc2_command, + .take_control = pc2_take_control, + .go_to_standby = pc2_go_to_standby, + .request_system_control = pc2_request_system_control, + .interface_clear = pc2_interface_clear, + .remote_enable = pc2_remote_enable, + .enable_eos = pc2_enable_eos, + .disable_eos = pc2_disable_eos, + .parallel_poll = pc2_parallel_poll, + .parallel_poll_configure = pc2_parallel_poll_configure, + .parallel_poll_response = pc2_parallel_poll_response, + .local_parallel_poll_mode = NULL, // XXX + .line_status = NULL, + .update_status = pc2_update_status, + .primary_address = pc2_primary_address, + .secondary_address = pc2_secondary_address, + .serial_poll_response = pc2_serial_poll_response, + .serial_poll_status = pc2_serial_poll_status, + .t1_delay = pc2_t1_delay, + .return_to_local = pc2_return_to_local, +}; + +static struct gpib_interface pc2a_cb7210_interface = { + .name = "pcIIa_cb7210", + .attach = pc2a_cb7210_attach, + .detach = pc2a_detach, + .read = pc2_read, + .write = pc2_write, + .command = pc2_command, + .take_control = pc2_take_control, + .go_to_standby = pc2_go_to_standby, + .request_system_control = pc2_request_system_control, + .interface_clear = pc2_interface_clear, + .remote_enable = pc2_remote_enable, + .enable_eos = pc2_enable_eos, + .disable_eos = pc2_disable_eos, + .parallel_poll = pc2_parallel_poll, + .parallel_poll_configure = pc2_parallel_poll_configure, + .parallel_poll_response = pc2_parallel_poll_response, + .local_parallel_poll_mode = NULL, // XXX + .line_status = NULL, // XXX + .update_status = pc2_update_status, + .primary_address = pc2_primary_address, + .secondary_address = pc2_secondary_address, + .serial_poll_response = pc2_serial_poll_response, + .serial_poll_status = pc2_serial_poll_status, + .t1_delay = pc2_t1_delay, + .return_to_local = pc2_return_to_local, +}; + +static struct gpib_interface pc2_2a_interface = { + .name = "pcII_IIa", + .attach = pc2_2a_attach, + .detach = pc2_2a_detach, + .read = pc2_read, + .write = pc2_write, + .command = pc2_command, + .take_control = pc2_take_control, + .go_to_standby = pc2_go_to_standby, + .request_system_control = pc2_request_system_control, + .interface_clear = pc2_interface_clear, + .remote_enable = pc2_remote_enable, + .enable_eos = pc2_enable_eos, + .disable_eos = pc2_disable_eos, + .parallel_poll = pc2_parallel_poll, + .parallel_poll_configure = pc2_parallel_poll_configure, + .parallel_poll_response = pc2_parallel_poll_response, + .local_parallel_poll_mode = NULL, // XXX + .line_status = NULL, + .update_status = pc2_update_status, + .primary_address = pc2_primary_address, + .secondary_address = pc2_secondary_address, + .serial_poll_response = pc2_serial_poll_response, + .serial_poll_status = pc2_serial_poll_status, + .t1_delay = pc2_t1_delay, + .return_to_local = pc2_return_to_local, +}; + +static int __init pc2_init_module(void) +{ + int ret; + + ret = gpib_register_driver(&pc2_interface, THIS_MODULE); + if (ret) { + pr_err("gpib_register_driver failed: error = %d\n", ret); + return ret; + } + + ret = gpib_register_driver(&pc2a_interface, THIS_MODULE); + if (ret) { + pr_err("gpib_register_driver failed: error = %d\n", ret); + goto err_pc2a; + } + + ret = gpib_register_driver(&pc2a_cb7210_interface, THIS_MODULE); + if (ret) { + pr_err("gpib_register_driver failed: error = %d\n", ret); + goto err_cb7210; + } + + ret = gpib_register_driver(&pc2_2a_interface, THIS_MODULE); + if (ret) { + pr_err("gpib_register_driver failed: error = %d\n", ret); + goto err_pc2_2a; + } + + return 0; + +err_pc2_2a: + gpib_unregister_driver(&pc2a_cb7210_interface); +err_cb7210: + gpib_unregister_driver(&pc2a_interface); +err_pc2a: + gpib_unregister_driver(&pc2_interface); + + return ret; +} + +static void __exit pc2_exit_module(void) +{ + gpib_unregister_driver(&pc2_interface); + gpib_unregister_driver(&pc2a_interface); + gpib_unregister_driver(&pc2a_cb7210_interface); + gpib_unregister_driver(&pc2_2a_interface); +} + +module_init(pc2_init_module); +module_exit(pc2_exit_module); + -- cgit v1.3.1