diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2024-09-29 17:42:39 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2024-10-07 10:28:44 +0300 |
| commit | 430af825ba991730f8acc3c804a4aef82e9f7ff6 (patch) | |
| tree | bf3560527a8f0bb5937c3bae5274df3328ba1655 | |
| parent | c7b4133c48445dde789ed30b19ccb0448c7593f7 (diff) | |
| download | linux-430af825ba991730f8acc3c804a4aef82e9f7ff6.tar.xz | |
uprobes: kill the unnecessary put_uprobe/xol_free_insn_slot in uprobe_free_utask()
If pre_ssout() succeeds and sets utask->active_uprobe and utask->xol_vaddr
the task must not exit until it calls handle_singlestep() which does the
necessary put_uprobe() and xol_free_insn_slot().
Remove put_uprobe() and xol_free_insn_slot() from uprobe_free_utask(). With
this change xol_free_insn_slot() can't hit xol_area/utask/xol_vaddr == NULL,
we can kill the unnecessary checks checks and simplify this function more.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240929144239.GA9475@redhat.com
| -rw-r--r-- | kernel/events/uprobes.c | 24 |
1 files changed, 5 insertions, 19 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 3f38be1e736b..03035a859a56 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1673,28 +1673,16 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe) } /* - * xol_free_insn_slot - If slot was earlier allocated by - * @xol_get_insn_slot(), make the slot available for - * subsequent requests. + * xol_free_insn_slot - free the slot allocated by xol_get_insn_slot() */ static void xol_free_insn_slot(struct task_struct *tsk) { - struct xol_area *area; - unsigned long slot_addr; - unsigned long offset; - - if (!tsk->mm || !tsk->mm->uprobes_state.xol_area || !tsk->utask) - return; - - slot_addr = tsk->utask->xol_vaddr; - if (unlikely(!slot_addr)) - return; + struct xol_area *area = tsk->mm->uprobes_state.xol_area; + unsigned long offset = tsk->utask->xol_vaddr - area->vaddr; tsk->utask->xol_vaddr = 0; - area = tsk->mm->uprobes_state.xol_area; - offset = slot_addr - area->vaddr; /* - * slot_addr must fit into [area->vaddr, area->vaddr + PAGE_SIZE). + * xol_vaddr must fit into [area->vaddr, area->vaddr + PAGE_SIZE). * This check can only fail if the "[uprobes]" vma was mremap'ed. */ if (offset < PAGE_SIZE) { @@ -1764,14 +1752,12 @@ void uprobe_free_utask(struct task_struct *t) if (!utask) return; - if (utask->active_uprobe) - put_uprobe(utask->active_uprobe); + WARN_ON_ONCE(utask->active_uprobe || utask->xol_vaddr); ri = utask->return_instances; while (ri) ri = free_ret_instance(ri); - xol_free_insn_slot(t); kfree(utask); t->utask = NULL; } |