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From: Oleg Nesterov <oleg@redhat.com>
To: andrii@kernel.org, mhiramat@kernel.org, peterz@infradead.org
Cc: clm@meta.com, jolsa@kernel.org, mingo@kernel.org,
	paulmck@kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] uprobes: is_trap_at_addr: don't use get_user_pages_remote()
Date: Wed, 10 Jul 2024 16:01:08 +0200	[thread overview]
Message-ID: <20240710140108.GB1084@redhat.com> (raw)
In-Reply-To: <20240710140017.GA1074@redhat.com>

get_user_pages_remote() and the comment above it make no sense.

There is no task_struct passed into get_user_pages_remote() anymore, and
nowadays mm_account_fault() increments the current->min/maj_flt counters
regardless of FAULT_FLAG_REMOTE.

Reported-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 kernel/events/uprobes.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index d52b624a50fa..1bdf386485d4 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -453,7 +453,7 @@ static int update_ref_ctr(struct uprobe *uprobe, struct mm_struct *mm,
  * @vaddr: the virtual address to store the opcode.
  * @opcode: opcode to be written at @vaddr.
  *
- * Called with mm->mmap_lock held for read or write.
+ * Called with mm->mmap_lock held.
  * Return 0 (success) or a negative errno.
  */
 int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
@@ -2024,13 +2024,7 @@ static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
 	if (likely(result == 0))
 		goto out;
 
-	/*
-	 * The NULL 'tsk' here ensures that any faults that occur here
-	 * will not be accounted to the task.  'mm' *is* current->mm,
-	 * but we treat this as a 'remote' access since it is
-	 * essentially a kernel access to the memory.
-	 */
-	result = get_user_pages_remote(mm, vaddr, 1, FOLL_FORCE, &page, NULL);
+	result = get_user_pages(vaddr, 1, FOLL_FORCE, &page);
 	if (result < 0)
 		return result;
 
-- 
2.25.1.362.g51ebf55



  parent reply	other threads:[~2024-07-10 14:02 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-10 14:00 [PATCH 0/2] uprobes: document mmap_lock, don't abuse get_user_pages_remote() Oleg Nesterov
2024-07-10 14:00 ` [PATCH 1/2] uprobes: document the usage of mm->mmap_lock Oleg Nesterov
2024-07-10 14:51   ` Masami Hiramatsu
2024-07-10 15:10     ` Oleg Nesterov
2024-07-11  0:07       ` Masami Hiramatsu
2024-07-11  9:49         ` Oleg Nesterov
2024-07-11 14:19           ` Masami Hiramatsu
2024-07-11 15:25             ` Oleg Nesterov
2024-07-10 14:01 ` Oleg Nesterov [this message]
2024-07-10 15:15   ` [PATCH 2/2] uprobes: is_trap_at_addr: don't use get_user_pages_remote() Andrii Nakryiko
2024-07-10 16:30 ` [PATCH 0/3] uprobes: future cleanups for review Oleg Nesterov
2024-07-10 16:30   ` [PATCH 1/3] uprobes: kill uprobe_register_refctr() Oleg Nesterov
2024-07-10 18:03     ` Andrii Nakryiko
2024-07-10 19:32       ` Oleg Nesterov
2024-07-10 16:31   ` [PATCH 2/3] uprobes: simplify error handling for alloc_uprobe() Oleg Nesterov
2024-07-11 15:18     ` Masami Hiramatsu
2024-07-10 16:31   ` [PATCH 3/3] uprobes: make uprobe_register() return struct uprobe * Oleg Nesterov
2024-07-10 16:48     ` Jiri Olsa
2024-07-10 18:23       ` Andrii Nakryiko
2024-07-10 19:38         ` Jiri Olsa
2024-07-10 19:48           ` Andrii Nakryiko
2024-07-10 19:20       ` Oleg Nesterov
2024-07-10 18:21     ` Andrii Nakryiko
2024-07-10 20:16       ` Oleg Nesterov
2024-07-10 20:46         ` Andrii Nakryiko
2024-07-11  9:26     ` Oleg Nesterov
2024-07-11 17:11       ` Andrii Nakryiko
2024-07-11 18:26         ` Oleg Nesterov
2024-07-11  8:27   ` [PATCH 0/3] uprobes: future cleanups for review Peter Zijlstra
2024-07-11  8:45     ` Oleg Nesterov

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