From: sashiko-bot@kernel.org
To: "Jing Lin" <kayano050408@gmail.com>
Cc: linux-usb@vger.kernel.org
Subject: Re: [PATCH v5 2/3] usb: gadget: gadgetfs: prevent ep0 event counter underflow
Date: Mon, 09 Nov 2026 06:08:32 +0000 [thread overview]
Message-ID: <sashiko-outbox-204485@kernel.org> (raw)
In-Reply-To: <20261109-b4-gadgetfs-ep0-v5-2-f16d0b648bc2@gmail.com>
> From: Jing Lin <kayano050408@gmail.com>
>
> ep0_read() snapshots dev->ev_next, drops dev->lock while copy_to_user()
> runs directly from dev->event[], and subtracts the snapshot afterwards.
> A concurrent disconnect, connect, setup, or another reader can reset,
> deduplicate, or consume the queue in that window. This races on
> dev->event[], can drop newly arrived GADGETFS_SETUP events, and wraps
> dev->ev_next if the queue shrinks below the snapshot.
>
> Dequeue the events into the local buffer and update dev->ev_next before
> dropping dev->lock for copy_to_user().
>
> Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2")
> Cc: stable@vger.kernel.org
> Signed-off-by: Jing Lin <kayano050408@gmail.com>
Sashiko has reviewed this patch and found no issues.
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261109-b4-gadgetfs-ep0-v5-0-f16d0b648bc2@gmail.com?part=2
next prev parent reply other threads:[~2026-11-09 6:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-09 5:55 [PATCH v5 0/3] usb: gadget: gadgetfs: fix ep0 request lifetime and event counter Jing Lin
2026-11-09 5:55 ` Jing Lin via B4 Relay
2026-11-09 5:55 ` [PATCH v5 1/3] usb: gadget: gadgetfs: fix ep0 request lifetime on disconnect Jing Lin
2026-11-09 5:55 ` Jing Lin via B4 Relay
2026-11-09 6:16 ` sashiko-bot
2026-11-09 5:55 ` [PATCH v5 2/3] usb: gadget: gadgetfs: prevent ep0 event counter underflow Jing Lin
2026-11-09 5:55 ` Jing Lin via B4 Relay
2026-11-09 6:08 ` sashiko-bot [this message]
2026-11-09 5:55 ` [PATCH v5 3/3] usb: gadget: gadgetfs: avoid writing through the const setup pointer Jing Lin
2026-11-09 5:55 ` Jing Lin via B4 Relay
2026-11-09 6:00 ` sashiko-bot
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