From: John Fastabend <john.fastabend@gmail.com>
To: patchwork-bot+netdevbpf@kernel.org,
Dave Marchevsky <davemarchevsky@fb.com>
Cc: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
andrii@kernel.org, martin.lau@kernel.org, kernel-team@fb.com
Subject: Re: [PATCH v1 bpf-next] bpf: Disable migration when freeing stashed local kptr using obj drop
Date: Mon, 13 Mar 2023 22:35:38 -0700 [thread overview]
Message-ID: <641007aa17a0a_42581208a0@john.notmuch> (raw)
In-Reply-To: <167875201690.9292.11466523661883628604.git-patchwork-notify@kernel.org>
patchwork-bot+netdevbpf@ wrote:
> Hello:
>
> This patch was applied to bpf/bpf-next.git (master)
> by Alexei Starovoitov <ast@kernel.org>:
>
> On Mon, 13 Mar 2023 14:46:41 -0700 you wrote:
> > When a local kptr is stashed in a map and freed when the map goes away,
> > currently an error like the below appears:
> >
> > [ 39.195695] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u32:15/2875
> > [ 39.196549] caller is bpf_mem_free+0x56/0xc0
> > [ 39.196958] CPU: 15 PID: 2875 Comm: kworker/u32:15 Tainted: G O 6.2.0-13016-g22df776a9a86 #4477
> > [ 39.197897] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
> > [ 39.198949] Workqueue: events_unbound bpf_map_free_deferred
> > [ 39.199470] Call Trace:
> > [ 39.199703] <TASK>
> > [ 39.199911] dump_stack_lvl+0x60/0x70
> > [ 39.200267] check_preemption_disabled+0xbf/0xe0
> > [ 39.200704] bpf_mem_free+0x56/0xc0
> > [ 39.201032] ? bpf_obj_new_impl+0xa0/0xa0
> > [ 39.201430] bpf_obj_free_fields+0x1cd/0x200
> > [ 39.201838] array_map_free+0xad/0x220
> > [ 39.202193] ? finish_task_switch+0xe5/0x3c0
> > [ 39.202614] bpf_map_free_deferred+0xea/0x210
> > [ 39.203006] ? lockdep_hardirqs_on_prepare+0xe/0x220
> > [ 39.203460] process_one_work+0x64f/0xbe0
> > [ 39.203822] ? pwq_dec_nr_in_flight+0x110/0x110
> > [ 39.204264] ? do_raw_spin_lock+0x107/0x1c0
> > [ 39.204662] ? lockdep_hardirqs_on_prepare+0xe/0x220
> > [ 39.205107] worker_thread+0x74/0x7a0
> > [ 39.205451] ? process_one_work+0xbe0/0xbe0
> > [ 39.205818] kthread+0x171/0x1a0
> > [ 39.206111] ? kthread_complete_and_exit+0x20/0x20
> > [ 39.206552] ret_from_fork+0x1f/0x30
> > [ 39.206886] </TASK>
> >
> > [...]
>
> Here is the summary with links:
> - [v1,bpf-next] bpf: Disable migration when freeing stashed local kptr using obj drop
> https://git.kernel.org/bpf/bpf-next/c/9e36a204bd43
>
> You are awesome, thank you!
> --
> Deet-doot-dot, I am a bot.
> https://korg.docs.kernel.org/patchwork/pwbot.html
>
>
Alexei is quick but FWIW LGTM as well.
next prev parent reply other threads:[~2023-03-14 5:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-13 21:46 [PATCH v1 bpf-next] bpf: Disable migration when freeing stashed local kptr using obj drop Dave Marchevsky
2023-03-14 0:00 ` patchwork-bot+netdevbpf
2023-03-14 5:35 ` John Fastabend [this message]
2023-03-15 0:07 ` Alexei Starovoitov
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