Messages in this thread Patch in this message | | | From | Srikar Dronamraju <> | Date | Fri, 18 Nov 2011 16:41:39 +0530 | Subject | [PATCH v7 3.2-rc2 25/30] uprobes: call post_xol() unconditionally |
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Kill sstep_complete(), change uprobe_notify_resume() to use post_xol() unconditionally.
It is wrong to assume that regs->ip always changes after the step. rep or jmp/call to self for example. We know that this task has already done the step, we can rely on DIE_DEBUG notification.
Original-patch-from: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> --- include/linux/uprobes.h | 3 ++- kernel/uprobes.c | 38 ++++++++++++-------------------------- 2 files changed, 14 insertions(+), 27 deletions(-)
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index add5222..70d639c 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -74,7 +74,8 @@ struct uprobe { enum uprobe_task_state { UTASK_RUNNING, UTASK_BP_HIT, - UTASK_SSTEP + UTASK_SSTEP, + UTASK_SSTEP_ACK, }; /* diff --git a/kernel/uprobes.c b/kernel/uprobes.c index b440acd..50cde86 100644 --- a/kernel/uprobes.c +++ b/kernel/uprobes.c @@ -1313,24 +1313,6 @@ static int pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, } /* - * Verify from Instruction Pointer if singlestep has indeed occurred. - * If Singlestep has occurred, then do post singlestep fix-ups. - */ -static bool sstep_complete(struct uprobe *uprobe, struct pt_regs *regs) -{ - unsigned long vaddr = instruction_pointer(regs); - - /* - * If we have executed out of line, Instruction pointer - * cannot be same as virtual address of XOL slot. - */ - if (vaddr == current->utask->xol_vaddr) - return false; - post_xol(uprobe, regs); - return true; -} - -/* * uprobe_notify_resume gets called in task context just before returning * to userspace. * @@ -1377,15 +1359,18 @@ void uprobe_notify_resume(struct pt_regs *regs) else /* Cannot Singlestep; re-execute the instruction. */ goto cleanup_ret; - } else if (utask->state == UTASK_SSTEP) { + } else { u = utask->active_uprobe; - if (sstep_complete(u, regs)) { - put_uprobe(u); - utask->active_uprobe = NULL; - utask->state = UTASK_RUNNING; - user_disable_single_step(current); - xol_free_insn_slot(current); - } + if (utask->state == UTASK_SSTEP_ACK) + post_xol(u, regs); + else + WARN_ON_ONCE(1); + + put_uprobe(u); + utask->active_uprobe = NULL; + utask->state = UTASK_RUNNING; + user_disable_single_step(current); + xol_free_insn_slot(current); } return; @@ -1435,6 +1420,7 @@ int uprobe_post_notifier(struct pt_regs *regs) /* task is currently not uprobed */ return 0; + utask->state = UTASK_SSTEP_ACK; set_thread_flag(TIF_UPROBE); return 1; }
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