From: Christian Brauner <brauner@kernel.org>
To: Andrii Nakryiko <andrii@kernel.org>
Cc: linux-trace-kernel@vger.kernel.org, peterz@infradead.org,
oleg@redhat.com, rostedt@goodmis.org, mhiramat@kernel.org,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
jolsa@kernel.org, paulmck@kernel.org, willy@infradead.org,
surenb@google.com, akpm@linux-foundation.org,
linux-mm@kvack.org, mjguzik@gmail.com, jannh@google.com,
mhocko@kernel.org, vbabka@suse.cz, mingo@kernel.org,
Amir Goldstein <amir73il@gmail.com>
Subject: Re: [PATCH v2 tip/perf/core 3/5] fs: add back RCU-delayed freeing of FMODE_BACKING file
Date: Thu, 3 Oct 2024 11:13:46 +0200 [thread overview]
Message-ID: <20241003-lachs-handel-4f3a9f31403d@brauner> (raw)
In-Reply-To: <20241001225207.2215639-4-andrii@kernel.org>
On Tue, Oct 01, 2024 at 03:52:05PM GMT, Andrii Nakryiko wrote:
> 6cf41fcfe099 ("backing file: free directly") switched FMODE_BACKING
> files to direct freeing as back then there were no use cases requiring
> RCU protected access to such files.
>
> Now, with speculative lockless VMA-to-uprobe lookup logic, we do need to
> have a guarantee that struct file memory is not going to be freed from
> under us during speculative check. So add back RCU-delayed freeing
> logic.
>
> We use headless kfree_rcu_mightsleep() variant, as file_free() is only
> called for FMODE_BACKING files in might_sleep() context.
>
> Suggested-by: Suren Baghdasaryan <surenb@google.com>
> Cc: Christian Brauner <brauner@kernel.org>
> Cc: Amir Goldstein <amir73il@gmail.com>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---
Reviewed-by: Christian Brauner <brauner@kernel.org>
next prev parent reply other threads:[~2024-10-03 9:13 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-01 22:52 [PATCH v2 tip/perf/core 0/5] uprobes,mm: speculative lockless VMA-to-uprobe lookup Andrii Nakryiko
2024-10-01 22:52 ` [PATCH v2 tip/perf/core 1/5] mm: introduce mmap_lock_speculation_{start|end} Andrii Nakryiko
2024-10-07 17:05 ` Andrii Nakryiko
2024-10-01 22:52 ` [PATCH v2 tip/perf/core 2/5] mm: switch to 64-bit mm_lock_seq/vm_lock_seq on 64-bit architectures Andrii Nakryiko
2024-10-01 22:52 ` [PATCH v2 tip/perf/core 3/5] fs: add back RCU-delayed freeing of FMODE_BACKING file Andrii Nakryiko
2024-10-03 9:13 ` Christian Brauner [this message]
2024-10-04 8:01 ` Christian Brauner
2024-10-04 19:58 ` Andrii Nakryiko
2024-10-09 10:35 ` Christian Brauner
2024-10-09 19:37 ` Andrii Nakryiko
2024-10-01 22:52 ` [PATCH v2 tip/perf/core 4/5] uprobes: simplify find_active_uprobe_rcu() VMA checks Andrii Nakryiko
2024-10-02 6:22 ` Oleg Nesterov
2024-10-01 22:52 ` [PATCH v2 tip/perf/core 5/5] uprobes: add speculative lockless VMA-to-inode-to-uprobe resolution Andrii Nakryiko
2024-10-02 7:25 ` Oleg Nesterov
2024-10-02 20:02 ` Andrii Nakryiko
2024-10-03 9:32 ` Oleg Nesterov
2024-10-04 23:59 ` kernel test robot
2024-10-05 1:12 ` kernel test robot
2024-10-08 15:20 ` [PATCH v2 tip/perf/core 0/5] uprobes,mm: speculative lockless VMA-to-uprobe lookup Oleg Nesterov
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