From: "Alexei Starovoitov" <alexei.starovoitov@gmail.com>
To: "Emil Tsalapatis" <emil@etsalapatis.com>, <bpf@vger.kernel.org>
Cc: <andrii@kernel.org>, <eddyz87@gmail.com>, <memxor@gmail.com>,
<daniel@iogearbox.net>
Subject: Re: [PATCH bpf-next v4 1/8] bpf: Use mapping tree to zap arena VMAs
Date: Fri, 16 Oct 2026 02:02:34 +0000 [thread overview]
Message-ID: <DM5W5NS8V9ER.34N5H0EAW44K5@gmail.com> (raw)
In-Reply-To: <20261014233442.8392-2-emil@etsalapatis.com>
On Wed, Oct 14, 2026 at 11:34 PM Emil Tsalapatis <emil@etsalapatis.com> wrote:
> This refactoring is necessary to avoid deadlocks between arena_vm_fault
> and page zapping in subsequent patches.
[...]
> @@ -89,6 +89,7 @@ struct bpf_map_ops {
> /* funcs callable from userspace (via syscall) */
> int (*map_alloc_check)(union bpf_attr *attr);
> struct bpf_map *(*map_alloc)(union bpf_attr *attr);
> + struct file *(*map_get_file)(struct bpf_map *map, int flags);
This is quite heavy.
The deadlock is there only because arena_vm_fault() in patch 7 sleeps
on opref with mmap_lock held. See my reply there.
next prev parent reply other threads:[~2026-10-16 2:02 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-14 23:34 [PATCH bpf-next v4 0/8] bpf: Fix arena memory incoherence Emil Tsalapatis
2026-10-14 23:34 ` [PATCH bpf-next v4 1/8] bpf: Use mapping tree to zap arena VMAs Emil Tsalapatis
2026-10-15 0:33 ` bot+bpf-ci
2026-10-15 15:02 ` Emil Tsalapatis
2026-10-16 2:02 ` Alexei Starovoitov [this message]
2026-10-14 23:34 ` [PATCH bpf-next v4 2/8] bpf: Associate arena pages with their mapping Emil Tsalapatis
2026-10-15 0:01 ` sashiko-bot
2026-10-15 15:15 ` Emil Tsalapatis
2026-10-16 2:02 ` Alexei Starovoitov
2026-10-14 23:34 ` [PATCH bpf-next v4 3/8] bpf: arena: Stop deferred frees before map teardown Emil Tsalapatis
2026-10-14 23:34 ` [PATCH bpf-next v4 4/8] bpf: Update is_range_tree_set to work for consecutive ranges Emil Tsalapatis
2026-10-14 23:34 ` [PATCH bpf-next v4 5/8] bpf: Track availability information for ranges in range tree Emil Tsalapatis
2026-10-14 23:34 ` [PATCH bpf-next v4 6/8] bpf: Fix arena race between page free and alloc leading to incoherency Emil Tsalapatis
2026-10-16 2:02 ` Alexei Starovoitov
2026-10-14 23:34 ` [PATCH bpf-next v4 7/8] bpf: Synchronize arena page faults with page freeing Emil Tsalapatis
2026-10-15 0:33 ` bot+bpf-ci
2026-10-15 15:18 ` Emil Tsalapatis
2026-10-16 2:02 ` Alexei Starovoitov
2026-10-14 23:34 ` [PATCH bpf-next v4 8/8] selftests/bpf: Add arena allocation race tests Emil Tsalapatis
2026-10-14 23:52 ` sashiko-bot
2026-10-16 0:03 ` [PATCH bpf-next v4 0/8] bpf: Fix arena memory incoherence Emil Tsalapatis
2026-10-16 0:04 ` Emil Tsalapatis
2026-10-16 2:03 ` Alexei Starovoitov
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