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Message-ID: <172838551443.1442.17092812194907881401.tip-bot2@tip-bot2>
Date: Tue, 08 Oct 2024 11:05:14 -0000
From: "tip-bot2 for Oleg Nesterov" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Oleg Nesterov <oleg@...hat.com>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [tip: perf/core] uprobes: kill the unnecessary
put_uprobe/xol_free_insn_slot in uprobe_free_utask()
The following commit has been merged into the perf/core branch of tip:
Commit-ID: 430af825ba991730f8acc3c804a4aef82e9f7ff6
Gitweb: https://git.kernel.org/tip/430af825ba991730f8acc3c804a4aef82e9f7ff6
Author: Oleg Nesterov <oleg@...hat.com>
AuthorDate: Sun, 29 Sep 2024 16:42:39 +02:00
Committer: Peter Zijlstra <peterz@...radead.org>
CommitterDate: Mon, 07 Oct 2024 09:28:44 +02:00
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@...hat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lore.kernel.org/r/20240929144239.GA9475@redhat.com
---
kernel/events/uprobes.c | 24 +++++-------------------
1 file changed, 5 insertions(+), 19 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 3f38be1..03035a8 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;
}
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