From: Wen Yang <[email protected]> Monitors that instrument user-space function boundaries need to register uprobes and deregister them safely. Provide a thin wrapper so monitors share a single implementation of this boilerplate.
struct rv_uprobe embeds struct uprobe_consumer directly, avoiding a separate heap allocation per probe. The struct holds an inode reference (acquired via igrab()) for the probed binary for the full uprobe lifetime, as uprobe_register() does not take an inode reference. On unregister, the inode reference is released with iput() only after rv_uprobe_unregister_sync(). rv_uprobe_unregister_sync() calls uprobe_unregister_sync(), draining all in-flight handlers before the containing struct may be freed. The API provides register, nosync unregister, a global handler barrier (rv_uprobe_unregister_sync), and an active-state predicate. Suggested-by: Gabriele Monaco <[email protected]> Signed-off-by: Wen Yang <[email protected]> --- include/rv/rv_uprobe.h | 35 +++++++++++++++++++++++ kernel/trace/rv/Kconfig | 4 +++ kernel/trace/rv/Makefile | 1 + kernel/trace/rv/rv_uprobe.c | 56 +++++++++++++++++++++++++++++++++++++ 4 files changed, 96 insertions(+) create mode 100644 include/rv/rv_uprobe.h create mode 100644 kernel/trace/rv/rv_uprobe.c diff --git a/include/rv/rv_uprobe.h b/include/rv/rv_uprobe.h new file mode 100644 index 000000000000..b93c2a81bc22 --- /dev/null +++ b/include/rv/rv_uprobe.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2026 Wen Yang <[email protected]> */ +/* + * Generic uprobe infrastructure for RV monitors. + */ + +#ifndef _RV_UPROBE_H +#define _RV_UPROBE_H + +#include <linux/types.h> +#include <linux/uprobes.h> + +struct inode; +struct pt_regs; + +/* + * Free the containing struct only after rv_uprobe_unregister_nosync() + + * rv_uprobe_unregister_sync() + iput(p->inode). + * + * The inode reference does not pin the dentry, so callers that re-resolve the + * probed path must hold a struct path: 9p cache=none remints an inode per + * lookup. + */ +struct rv_uprobe { + struct uprobe_consumer uc; + struct uprobe *uprobe; + struct inode *inode; +}; + +bool rv_uprobe_is_registered(const struct rv_uprobe *p); +int rv_uprobe_register(struct inode *inode, loff_t offset, struct rv_uprobe *p); +void rv_uprobe_unregister_nosync(struct rv_uprobe *p); +void rv_uprobe_unregister_sync(void); + +#endif /* _RV_UPROBE_H */ diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig index efa930f94ea4..2bc412304293 100644 --- a/kernel/trace/rv/Kconfig +++ b/kernel/trace/rv/Kconfig @@ -86,6 +86,10 @@ source "kernel/trace/rv/monitors/nomiss/Kconfig" # Add new monitors here +config RV_UPROBE + bool + depends on RV && UPROBES + config RV_REACTORS bool "Runtime verification reactors" default y diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile index cdbf68c84f5a..e295c9eb8401 100644 --- a/kernel/trace/rv/Makefile +++ b/kernel/trace/rv/Makefile @@ -22,6 +22,7 @@ obj-$(CONFIG_RV_MON_DEADLINE) += monitors/deadline/deadline.o obj-$(CONFIG_RV_MON_NOMISS) += monitors/nomiss/nomiss.o obj-$(CONFIG_RV_MON_WAKEUP) += monitors/wakeup/wakeup.o # Add new monitors here +obj-$(CONFIG_RV_UPROBE) += rv_uprobe.o obj-$(CONFIG_RV_REACTORS) += rv_reactors.o obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o obj-$(CONFIG_RV_REACT_PANIC) += reactor_panic.o diff --git a/kernel/trace/rv/rv_uprobe.c b/kernel/trace/rv/rv_uprobe.c new file mode 100644 index 000000000000..1c7f8466aeed --- /dev/null +++ b/kernel/trace/rv/rv_uprobe.c @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generic uprobe infrastructure for RV monitors. + */ +#include <linux/fs.h> +#include <linux/uprobes.h> +#include <rv/rv_uprobe.h> + +/* + * uprobe_register() takes no inode reference of its own, so grab one here and + * drop it only after rv_uprobe_unregister_sync(). + */ +int rv_uprobe_register(struct inode *inode, loff_t offset, struct rv_uprobe *p) +{ + int ret; + + p->inode = igrab(inode); + if (!p->inode) + return -ESTALE; + + p->uprobe = uprobe_register(inode, offset, 0, &p->uc); + if (IS_ERR(p->uprobe)) { + ret = PTR_ERR(p->uprobe); + p->uprobe = NULL; + iput(p->inode); + p->inode = NULL; + return ret; + } + + return 0; +} +EXPORT_SYMBOL_GPL(rv_uprobe_register); + +bool rv_uprobe_is_registered(const struct rv_uprobe *p) +{ + return p && p->uprobe; +} +EXPORT_SYMBOL_GPL(rv_uprobe_is_registered); + +/* The inode stays held: in-flight handlers may still reach it. */ +void rv_uprobe_unregister_nosync(struct rv_uprobe *p) +{ + if (!p || !p->uprobe) + return; + + uprobe_unregister_nosync(p->uprobe, &p->uc); + p->uprobe = NULL; +} +EXPORT_SYMBOL_GPL(rv_uprobe_unregister_nosync); + +/* Global barrier over every probe dequeued so far. */ +void rv_uprobe_unregister_sync(void) +{ + uprobe_unregister_sync(); +} +EXPORT_SYMBOL_GPL(rv_uprobe_unregister_sync); -- 2.25.1
