diff options
| -rw-r--r-- | include/linux/sched.h | 5 | ||||
| -rw-r--r-- | include/linux/unwind_deferred.h | 24 | ||||
| -rw-r--r-- | include/linux/unwind_deferred_types.h | 9 | ||||
| -rw-r--r-- | kernel/fork.c | 4 | ||||
| -rw-r--r-- | kernel/unwind/Makefile | 2 | ||||
| -rw-r--r-- | kernel/unwind/deferred.c | 60 |
6 files changed, 103 insertions, 1 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 4f78a64beb52..59fdf7d9bb1e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -46,6 +46,7 @@ #include <linux/rv.h> #include <linux/uidgid_types.h> #include <linux/tracepoint-defs.h> +#include <linux/unwind_deferred_types.h> #include <asm/kmap_size.h> /* task_struct member predeclarations (sorted alphabetically): */ @@ -1654,6 +1655,10 @@ struct task_struct { struct user_event_mm *user_event_mm; #endif +#ifdef CONFIG_UNWIND_USER + struct unwind_task_info unwind_info; +#endif + /* CPU-specific state of this task: */ struct thread_struct thread; diff --git a/include/linux/unwind_deferred.h b/include/linux/unwind_deferred.h new file mode 100644 index 000000000000..a5f6e8f8a1a2 --- /dev/null +++ b/include/linux/unwind_deferred.h @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_UNWIND_USER_DEFERRED_H +#define _LINUX_UNWIND_USER_DEFERRED_H + +#include <linux/unwind_user.h> +#include <linux/unwind_deferred_types.h> + +#ifdef CONFIG_UNWIND_USER + +void unwind_task_init(struct task_struct *task); +void unwind_task_free(struct task_struct *task); + +int unwind_user_faultable(struct unwind_stacktrace *trace); + +#else /* !CONFIG_UNWIND_USER */ + +static inline void unwind_task_init(struct task_struct *task) {} +static inline void unwind_task_free(struct task_struct *task) {} + +static inline int unwind_user_faultable(struct unwind_stacktrace *trace) { return -ENOSYS; } + +#endif /* !CONFIG_UNWIND_USER */ + +#endif /* _LINUX_UNWIND_USER_DEFERRED_H */ diff --git a/include/linux/unwind_deferred_types.h b/include/linux/unwind_deferred_types.h new file mode 100644 index 000000000000..aa32db574e43 --- /dev/null +++ b/include/linux/unwind_deferred_types.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_UNWIND_USER_DEFERRED_TYPES_H +#define _LINUX_UNWIND_USER_DEFERRED_TYPES_H + +struct unwind_task_info { + unsigned long *entries; +}; + +#endif /* _LINUX_UNWIND_USER_DEFERRED_TYPES_H */ diff --git a/kernel/fork.c b/kernel/fork.c index 1ee8eb11f38b..3341d50c61f2 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -105,6 +105,7 @@ #include <uapi/linux/pidfd.h> #include <linux/pidfs.h> #include <linux/tick.h> +#include <linux/unwind_deferred.h> #include <asm/pgalloc.h> #include <linux/uaccess.h> @@ -732,6 +733,7 @@ void __put_task_struct(struct task_struct *tsk) WARN_ON(refcount_read(&tsk->usage)); WARN_ON(tsk == current); + unwind_task_free(tsk); sched_ext_free(tsk); io_uring_free(tsk); cgroup_free(tsk); @@ -2135,6 +2137,8 @@ __latent_entropy struct task_struct *copy_process( p->bpf_ctx = NULL; #endif + unwind_task_init(p); + /* Perform scheduler related setup. Assign this task to a CPU. */ retval = sched_fork(clone_flags, p); if (retval) diff --git a/kernel/unwind/Makefile b/kernel/unwind/Makefile index 349ce3677526..eae37bea54fd 100644 --- a/kernel/unwind/Makefile +++ b/kernel/unwind/Makefile @@ -1 +1 @@ - obj-$(CONFIG_UNWIND_USER) += user.o + obj-$(CONFIG_UNWIND_USER) += user.o deferred.o diff --git a/kernel/unwind/deferred.c b/kernel/unwind/deferred.c new file mode 100644 index 000000000000..a0badbeb3cc1 --- /dev/null +++ b/kernel/unwind/deferred.c @@ -0,0 +1,60 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Deferred user space unwinding + */ +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/unwind_deferred.h> + +#define UNWIND_MAX_ENTRIES 512 + +/** + * unwind_user_faultable - Produce a user stacktrace in faultable context + * @trace: The descriptor that will store the user stacktrace + * + * This must be called in a known faultable context (usually when entering + * or exiting user space). Depending on the available implementations + * the @trace will be loaded with the addresses of the user space stacktrace + * if it can be found. + * + * Return: 0 on success and negative on error + * On success @trace will contain the user space stacktrace + */ +int unwind_user_faultable(struct unwind_stacktrace *trace) +{ + struct unwind_task_info *info = ¤t->unwind_info; + + /* Should always be called from faultable context */ + might_fault(); + + if (current->flags & PF_EXITING) + return -EINVAL; + + if (!info->entries) { + info->entries = kmalloc_array(UNWIND_MAX_ENTRIES, sizeof(long), + GFP_KERNEL); + if (!info->entries) + return -ENOMEM; + } + + trace->nr = 0; + trace->entries = info->entries; + unwind_user(trace, UNWIND_MAX_ENTRIES); + + return 0; +} + +void unwind_task_init(struct task_struct *task) +{ + struct unwind_task_info *info = &task->unwind_info; + + memset(info, 0, sizeof(*info)); +} + +void unwind_task_free(struct task_struct *task) +{ + struct unwind_task_info *info = &task->unwind_info; + + kfree(info->entries); +} |