From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794591538; b=IAkna5ofhjrW8uIXeTEkr5CrUpjciKLA6l6Ww0+6aNxsWtMv0mJyrf+jlUQm25UnpCvO N8bYuaAUD82TV3wjGbIbOp2ScS0zS371ipMnqFwNsTB/GcH06vvsPnh/2fMdAaRkhTzic Z/lqaiA3IrXf82yWxK0Mpqfxh6GuseLXXzpO00QC+5bQq13tufuHh08C24scLvBhMyDTP 2I9Px3gwQtVOGIn2/JgGVFOuTg8rvCYGVQPYtr2TpGfoHQATTJaMsZ0b/uhjuo7dRHnnR loUvd4P8HVr/n7zTjQHTMzbxnE7c5LVLucqyK6aQD3x/7VLoc3SN6JgOFh/dHYVUVHg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794591538; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=ghCJETSqRFFpBNy6JVR1fXpX937sZsdYeA9TjODeYME=; b=1RmKdXZ+UuJVKqaZXnv8G3wngcYrb6hB7/3hmmhlzG4Y4sHqq78O/uWtUTipJY561nFS lLkiqlFGQdEdsvPDAl1NpezpVy+Q7eKwYY40h8ExwkR7A3Txey8pAZIhznadhzOsemHu+ YXOJ6GgKmmqP9tdTKr7RZiuladEhySH1+roesTjiXXRY1TSBHoX1NcR62OLV3qBQuvSBI XlQk4XAxdi5KbkoPqjhpZxgk6ctiA5ebBbTnRLvuqnSqWSYXAN2jzd2IoJr/nuqJ0XYXv OU+boTKsHh1VrFCvvp16M+VrBM/CocMOHDRnjylvZj460Tj98RX2LYkPocoGIJdR3LQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=QH+xnFCV; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E20FD606D869; Fri, 13 Nov 2026 17:38:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=QH+xnFCV Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DFA11F000C4; Fri, 13 Nov 2026 17:38:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794591537; bh=ghCJETSqRFFpBNy6JVR1fXpX937sZsdYeA9TjODeYME=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QH+xnFCV+EpSXx5tT5rsThfLiBXMoJAEM9abikDAVXAV7GPnnfqbLQZBHiiC+9H76 cYBtKXWaabUTTmKqSNZHrUca3fv8ffBdXfvnnby3NcN0XIYztsfjXwC1u0N79APo4B 5ff+i8RAMP5Bix3EFbdbqLxwRiBjc9CQmrm/KWww= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Josef Bacik , Ming Lei , Jens Axboe , Sasha Levin Subject: [PATCH 6.12 592/670] ublk: mark the io command cancelable before publishing it Date: Fri, 13 Nov 2026 10:52:36 -0500 Message-ID: <20261113153831.897676542@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153811.177190860@linuxfoundation.org> References: <20261113153811.177190860@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei [ Upstream commit a261f0cacacc022e4fab5b8e38c59f74ce4942e8 ] FETCH, COMMIT_AND_FETCH and NEED_GET_DATA publish the command in io->cmd before marking it cancelable. A cancel from the control path (STOP_DEV, QUIESCE_DEV) can complete it in between: issue path control-path cancel io->cmd = C take C, io_uring_cmd_done(C): C not marked, nothing to unlink ublk_prep_cancel(C) the completed C is linked on the cancelable list ring exit: the cancel walk hits it → GPF (KASAN, with a delay added) Mark the command before ublk_fill_io_cmd() publishes it. The handlers run with uring_lock held, as io_uring's cancel walk does, so marking takes no lock and the walk can't see a marked command before it is published. smp_wmb() orders the mark before the io->cmd store; the cancel loads cmd with READ_ONCE(io->cmd) before reading cmd->flags. A marked command has to be completed by io_uring_cmd_done(), so a failed FETCH and the inline UBLK_IO_RES_OK of NEED_GET_DATA now do that. The CQE is the same. Fixes: 216c8f5ef0f2 ("ublk: replace monitor with cancelable uring_cmd") Cc: stable@vger.kernel.org Tested-by: Josef Bacik Signed-off-by: Ming Lei Link: https://patch.msgid.link/20261011063555.1142277-3-tom.leiming@gmail.com Signed-off-by: Jens Axboe [ sashal: Omitted out_done because FETCH validation precedes cancellation marking and NEED_GET_DATA already completes asynchronously. ] Signed-off-by: Sasha Levin --- drivers/block/ublk_drv.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 3e7c3b1f0b8a1..f89b36017d979 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1589,8 +1589,10 @@ static void ublk_cancel_cmd(struct ublk_queue *ubq, unsigned tag, io->flags |= UBLK_IO_FLAG_CANCELED; spin_unlock(&ubq->cancel_lock); + /* dependency ordered against smp_wmb() in ublk_prep_cancel() */ if (!done) - io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0, issue_flags); + io_uring_cmd_done(READ_ONCE(io->cmd), UBLK_IO_RES_ABORT, 0, + issue_flags); } /* @@ -1807,6 +1809,12 @@ static inline void ublk_fill_io_cmd(struct ublk_io *io, io->addr = buf_addr; } +/* + * Call before ublk_fill_io_cmd() publishes @cmd in io->cmd: a control-path + * cancel may complete any command found there, and io_uring_cmd_done() only + * takes it off the cancelable list if it is marked already. The handlers + * hold uring_lock, so marking takes no lock. + */ static inline void ublk_prep_cancel(struct io_uring_cmd *cmd, unsigned int issue_flags, struct ublk_queue *ubq, unsigned int tag) @@ -1820,6 +1828,8 @@ static inline void ublk_prep_cancel(struct io_uring_cmd *cmd, pdu->ubq = ubq; pdu->tag = tag; io_uring_cmd_mark_cancelable(cmd, issue_flags); + /* pairs with the cancel loading cmd from io->cmd, then cmd->flags */ + smp_wmb(); } static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd, @@ -1899,6 +1909,7 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd, goto out; } + ublk_prep_cancel(cmd, issue_flags, ubq, tag); ublk_fill_io_cmd(io, cmd, ub_cmd->addr); ublk_mark_io_ready(ub, ubq); break; @@ -1925,19 +1936,20 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd, goto out; } + ublk_prep_cancel(cmd, issue_flags, ubq, tag); ublk_fill_io_cmd(io, cmd, ub_cmd->addr); ublk_commit_completion(ub, ub_cmd); break; case UBLK_IO_NEED_GET_DATA: if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV)) goto out; + ublk_prep_cancel(cmd, issue_flags, ubq, tag); ublk_fill_io_cmd(io, cmd, ub_cmd->addr); ublk_handle_need_get_data(ub, ub_cmd->q_id, ub_cmd->tag); break; default: goto out; } - ublk_prep_cancel(cmd, issue_flags, ubq, tag); return -EIOCBQUEUED; out: -- 2.53.0