Messages in this thread Patch in this message | | | From | Srikar Dronamraju <> | Date | Thu, 16 Dec 2010 15:29:12 +0530 | Subject | [RFC] [PATCH 2.6.37-rc5-tip 10/20] 10: uprobes: task specific information. |
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Uprobes needs to maintain some task specific information include if a task is currently uprobed, the currently handing uprobe, any arch specific information (for example to handle rip relative instructions), the per-task slot where the original instruction is copied to before single-stepping.
Provides routines to create/manage and free the task specific information.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> --- include/linux/sched.h | 3 +++ include/linux/uprobes.h | 25 +++++++++++++++++++++++++ kernel/fork.c | 4 ++++ kernel/uprobes.c | 37 +++++++++++++++++++++++++++++++++++++ 4 files changed, 69 insertions(+), 0 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h index f4e90b6..5a3ebea 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1523,6 +1523,9 @@ struct task_struct { unsigned long memsw_bytes; /* uncharged mem+swap usage */ } memcg_batch; #endif +#ifdef CONFIG_UPROBES + struct uprobe_task *utask; +#endif }; /* Future-safe accessor for struct task_struct's cpus_allowed. */ diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index 0d4f5e3..14a4fce 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -26,12 +26,14 @@ #include <linux/rbtree.h> #ifdef CONFIG_ARCH_SUPPORTS_UPROBES #include <asm/uprobes.h> +struct uprobe_task_arch_info; /* arch specific task info */ #else /* * ARCH_SUPPORTS_UPROBES has not be defined. */ typedef u8 uprobe_opcode_t; struct uprobe_arch_info {}; /* arch specific info*/ +struct uprobe_task_arch_info {}; /* arch specific task info */ /* Post-execution fixups. Some architectures may define others. */ #endif /* CONFIG_ARCH_SUPPORTS_UPROBES */ @@ -85,6 +87,27 @@ struct uprobe { u8 insn[MAX_UINSN_BYTES]; /* orig instruction */ }; +enum uprobe_task_state { + UTASK_RUNNING, + UTASK_BP_HIT, + UTASK_SSTEP +}; + +/* + * uprobe_utask -- not a user-visible struct. + * Corresponds to a thread in a probed process. + * Guarded by uproc->mutex. + */ +struct uprobe_task { + unsigned long xol_vaddr; + unsigned long vaddr; + + enum uprobe_task_state state; + struct uprobe_task_arch_info tskinfo; + + struct uprobe *active_uprobe; +}; + /* * Most architectures can use the default versions of @read_opcode(), * @set_bkpt(), @set_orig_insn(), and @is_bkpt_insn(); @@ -108,6 +131,7 @@ extern int register_uprobe(struct inode *inode, unsigned long offset, struct uprobe_consumer *consumer); extern void unregister_uprobe(struct inode *inode, unsigned long offset, struct uprobe_consumer *consumer); +extern void uprobe_free_utask(struct task_struct *tsk); struct vm_area_struct; extern void uprobe_mmap(struct vm_area_struct *vma); @@ -126,6 +150,7 @@ static inline void uprobe_dup_mmap(struct mm_struct *old_mm, struct mm_struct *mm) { } +static inline void uprobe_free_utask(struct task_struct *tsk) {} static inline void uprobe_mmap(struct vm_area_struct *vma) { } #endif /* CONFIG_UPROBES */ #endif /* _LINUX_UPROBES_H */ diff --git a/kernel/fork.c b/kernel/fork.c index b135d1b..ae99239 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -191,6 +191,7 @@ void __put_task_struct(struct task_struct *tsk) delayacct_tsk_free(tsk); put_signal_struct(tsk->signal); + uprobe_free_utask(tsk); if (!profile_handoff_task(tsk)) free_task(tsk); } @@ -1202,6 +1203,9 @@ static struct task_struct *copy_process(unsigned long clone_flags, INIT_LIST_HEAD(&p->pi_state_list); p->pi_state_cache = NULL; #endif +#ifdef CONFIG_UPROBES + p->utask = NULL; +#endif /* * sigaltstack should be cleared when sharing the same VM */ diff --git a/kernel/uprobes.c b/kernel/uprobes.c index 31867a6..f182fe6 100644 --- a/kernel/uprobes.c +++ b/kernel/uprobes.c @@ -745,3 +745,40 @@ void uprobe_mmap(struct vm_area_struct *vma) down_write(&mm->mmap_sem); } +/* + * Called with no locks held. + * Called in context of a exiting or a exec-ing thread. + */ +void uprobe_free_utask(struct task_struct *tsk) +{ + struct uprobe_task *utask = tsk->utask; + + if (!utask) + return; + + if (utask->active_uprobe) + put_uprobe(utask->active_uprobe); + kfree(utask); + tsk->utask = NULL; +} + +/* + * Allocate a uprobe_task object for the task. + * Called when the thread hits a breakpoint for the first time. + * + * Returns: + * - pointer to new uprobe_task on success + * - negative errno otherwise + */ +static struct uprobe_task *add_utask(void) +{ + struct uprobe_task *utask; + + utask = kzalloc(sizeof *utask, GFP_KERNEL); + if (unlikely(utask == NULL)) + return ERR_PTR(-ENOMEM); + + utask->active_uprobe = NULL; + current->utask = utask; + return utask; +}
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