From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- drivers/net/netdevsim/health.c | 231 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 231 insertions(+) create mode 100644 drivers/net/netdevsim/health.c (limited to 'drivers/net/netdevsim/health.c') diff --git a/drivers/net/netdevsim/health.c b/drivers/net/netdevsim/health.c new file mode 100644 index 000000000..3bd0e7a48 --- /dev/null +++ b/drivers/net/netdevsim/health.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2019 Mellanox Technologies. All rights reserved */ + +#include +#include +#include +#include + +#include "netdevsim.h" + +static int +nsim_dev_empty_reporter_dump(struct devlink_health_reporter *reporter, + struct devlink_fmsg *fmsg, void *priv_ctx, + struct netlink_ext_ack *extack) +{ + return 0; +} + +static int +nsim_dev_empty_reporter_diagnose(struct devlink_health_reporter *reporter, + struct devlink_fmsg *fmsg, + struct netlink_ext_ack *extack) +{ + return 0; +} + +static const +struct devlink_health_reporter_ops nsim_dev_empty_reporter_ops = { + .name = "empty", + .dump = nsim_dev_empty_reporter_dump, + .diagnose = nsim_dev_empty_reporter_diagnose, +}; + +struct nsim_dev_dummy_reporter_ctx { + char *break_msg; +}; + +static int +nsim_dev_dummy_reporter_recover(struct devlink_health_reporter *reporter, + void *priv_ctx, + struct netlink_ext_ack *extack) +{ + struct nsim_dev_health *health = devlink_health_reporter_priv(reporter); + struct nsim_dev_dummy_reporter_ctx *ctx = priv_ctx; + + if (health->fail_recover) { + /* For testing purposes, user set debugfs fail_recover + * value to true. Fail right away. + */ + NL_SET_ERR_MSG_MOD(extack, "User setup the recover to fail for testing purposes"); + return -EINVAL; + } + if (ctx) { + kfree(health->recovered_break_msg); + health->recovered_break_msg = kstrdup(ctx->break_msg, + GFP_KERNEL); + if (!health->recovered_break_msg) + return -ENOMEM; + } + return 0; +} + +static int nsim_dev_dummy_fmsg_put(struct devlink_fmsg *fmsg, u32 binary_len) +{ + char *binary; + int i; + + devlink_fmsg_bool_pair_put(fmsg, "test_bool", true); + devlink_fmsg_u8_pair_put(fmsg, "test_u8", 1); + devlink_fmsg_u32_pair_put(fmsg, "test_u32", 3); + devlink_fmsg_u64_pair_put(fmsg, "test_u64", 4); + devlink_fmsg_string_pair_put(fmsg, "test_string", "somestring"); + + binary = kmalloc(binary_len, GFP_KERNEL | __GFP_NOWARN); + if (!binary) + return -ENOMEM; + get_random_bytes(binary, binary_len); + devlink_fmsg_binary_pair_put(fmsg, "test_binary", binary, binary_len); + kfree(binary); + + devlink_fmsg_pair_nest_start(fmsg, "test_nest"); + devlink_fmsg_obj_nest_start(fmsg); + devlink_fmsg_bool_pair_put(fmsg, "nested_test_bool", false); + devlink_fmsg_u8_pair_put(fmsg, "nested_test_u8", false); + devlink_fmsg_obj_nest_end(fmsg); + devlink_fmsg_pair_nest_end(fmsg); + devlink_fmsg_arr_pair_nest_end(fmsg); + devlink_fmsg_arr_pair_nest_start(fmsg, "test_u32_array"); + + for (i = 0; i < 10; i++) + devlink_fmsg_u32_put(fmsg, i); + devlink_fmsg_arr_pair_nest_end(fmsg); + devlink_fmsg_arr_pair_nest_start(fmsg, "test_array_of_objects"); + + for (i = 0; i < 10; i++) { + devlink_fmsg_obj_nest_start(fmsg); + devlink_fmsg_bool_pair_put(fmsg, "in_array_nested_test_bool", + false); + devlink_fmsg_u8_pair_put(fmsg, "in_array_nested_test_u8", i); + devlink_fmsg_obj_nest_end(fmsg); + } + devlink_fmsg_arr_pair_nest_end(fmsg); + + return 0; +} + +static int +nsim_dev_dummy_reporter_dump(struct devlink_health_reporter *reporter, + struct devlink_fmsg *fmsg, void *priv_ctx, + struct netlink_ext_ack *extack) +{ + struct nsim_dev_health *health = devlink_health_reporter_priv(reporter); + struct nsim_dev_dummy_reporter_ctx *ctx = priv_ctx; + + if (ctx) + devlink_fmsg_string_pair_put(fmsg, "break_message", ctx->break_msg); + + return nsim_dev_dummy_fmsg_put(fmsg, health->binary_len); +} + +static int +nsim_dev_dummy_reporter_diagnose(struct devlink_health_reporter *reporter, + struct devlink_fmsg *fmsg, + struct netlink_ext_ack *extack) +{ + struct nsim_dev_health *health = devlink_health_reporter_priv(reporter); + + if (health->recovered_break_msg) + devlink_fmsg_string_pair_put(fmsg, "recovered_break_message", + health->recovered_break_msg); + + return nsim_dev_dummy_fmsg_put(fmsg, health->binary_len); +} + +static const +struct devlink_health_reporter_ops nsim_dev_dummy_reporter_ops = { + .name = "dummy", + .recover = nsim_dev_dummy_reporter_recover, + .dump = nsim_dev_dummy_reporter_dump, + .diagnose = nsim_dev_dummy_reporter_diagnose, +}; + +static ssize_t nsim_dev_health_break_write(struct file *file, + const char __user *data, + size_t count, loff_t *ppos) +{ + struct nsim_dev_health *health = file->private_data; + struct nsim_dev_dummy_reporter_ctx ctx; + char *break_msg; + int err; + + if (count == 0 || count > PAGE_SIZE) + return -EINVAL; + break_msg = memdup_user_nul(data, count); + if (IS_ERR(break_msg)) + return PTR_ERR(break_msg); + + if (break_msg[count - 1] == '\n') + break_msg[count - 1] = '\0'; + + ctx.break_msg = break_msg; + err = devlink_health_report(health->dummy_reporter, break_msg, &ctx); + if (err) + goto out; + +out: + kfree(break_msg); + return err ?: count; +} + +static const struct file_operations nsim_dev_health_break_fops = { + .open = simple_open, + .write = nsim_dev_health_break_write, + .llseek = generic_file_llseek, + .owner = THIS_MODULE, +}; + +int nsim_dev_health_init(struct nsim_dev *nsim_dev, struct devlink *devlink) +{ + struct nsim_dev_health *health = &nsim_dev->health; + int err; + + health->empty_reporter = + devl_health_reporter_create(devlink, + &nsim_dev_empty_reporter_ops, + health); + if (IS_ERR(health->empty_reporter)) + return PTR_ERR(health->empty_reporter); + + health->dummy_reporter = + devl_health_reporter_create(devlink, + &nsim_dev_dummy_reporter_ops, + health); + if (IS_ERR(health->dummy_reporter)) { + err = PTR_ERR(health->dummy_reporter); + goto err_empty_reporter_destroy; + } + + health->ddir = debugfs_create_dir("health", nsim_dev->ddir); + if (IS_ERR(health->ddir)) { + err = PTR_ERR(health->ddir); + goto err_dummy_reporter_destroy; + } + + health->recovered_break_msg = NULL; + debugfs_create_file("break_health", 0200, health->ddir, health, + &nsim_dev_health_break_fops); + health->binary_len = 16; + debugfs_create_u32("binary_len", 0600, health->ddir, + &health->binary_len); + health->fail_recover = false; + debugfs_create_bool("fail_recover", 0600, health->ddir, + &health->fail_recover); + return 0; + +err_dummy_reporter_destroy: + devl_health_reporter_destroy(health->dummy_reporter); +err_empty_reporter_destroy: + devl_health_reporter_destroy(health->empty_reporter); + return err; +} + +void nsim_dev_health_exit(struct nsim_dev *nsim_dev) +{ + struct nsim_dev_health *health = &nsim_dev->health; + + debugfs_remove_recursive(health->ddir); + kfree(health->recovered_break_msg); + devl_health_reporter_destroy(health->dummy_reporter); + devl_health_reporter_destroy(health->empty_reporter); +} -- cgit v1.3.1