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=1794064926; b=17N/rOwrfUFx+X3newIPdmLY6sgOcTXNyFdPhH1ioPb60yolI19qKGbknrFAfdzoyXrc ++pw4bbvp9TaNMZAsJMNQQFUZTdAxu25HXKXnR2XAgSu7EubUkZs/vvbFZB7Gl059DNH3 sOyvCflMVsDI5xGOxp0KTTTxz/lp2Tc/pbfsU+G1rGyzFdNo21ZBbUtseXSZB8hehS8Zx KIQIKb8qmCo5SwJMpmaxQkV0ByhdlXt0yGa/tOZrcJdqFuJrb5m64EdJq/JU2uaqGdsx8 ZrvqBRy2ODFqdJ7iC+Ww8tKFlEPoDWdhf94BbzVEusrU4zLbpCjYPiLjXFQbDCDmaIQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064926; 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=9lsK0T0v5lOEkhRxoOxi94XKoHkKaDRvSN9Jk1jCF6g=; b=dYNfslvCe5dntZvFasrSsjWGQG9KcgEyQka1U9uVRqH3DwxQ5rByN1a+z8ueqCDvVahB 8vjxH4Xb8mBV7h9vf2rr0LCISMzY5lsgJxy6say3Y/dC9+X900X2+2Arjbk/tCL3+1Sgi nU56M4JAQP/CC7mFSa1shUhfEqw+fjuNTvQqFZ7EgKPVppP+k1tAkeFrqVq4FeguV9Mpj kHl8Nhd4U5D4Wrh3kVcbi/Yhgp6DFLnmgN8NdSuujCG+S6d++3LL5Jj6nWAzup4gtq86v tNDvmZ8Si8d5AaPAoW8sFKc7sF2t/Q/0yIJSyUsHN+rfxWBJp4bBf18xWRKKGC4tuvA== 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=SAvaTsnv; 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 70D59606A33E; Sat, 7 Nov 2026 15:22:06 +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=SAvaTsnv Received: by smtp.kernel.org (Postfix) with ESMTPSA id F23FA1F008A1; Sat, 7 Nov 2026 15:22:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064926; bh=9lsK0T0v5lOEkhRxoOxi94XKoHkKaDRvSN9Jk1jCF6g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SAvaTsnvI9yu/So0SnRGrgzaCIHwZR/PoCVQEaG4ZJmDqvpWwLm4gwZVKT/0j2Y1e IORTgfDEvYRzGMRpRdf5ftvIB95qv0W2OW00mTskHGZkiJ9gU2JNZlcsuRmm3FOZT/ SLKeGN3cwA4VYDoWHoan8ejO4KDgtchYKnb4X57g= 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 7.3 0821/1257] ublk: mark the io command cancelable before publishing it Date: Sat, 7 Nov 2026 08:51:57 -0500 Message-ID: <20261107135002.017084989@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@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 7.3-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 Signed-off-by: Sasha Levin --- drivers/block/ublk_drv.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 38ed7d0e39793..6015fb2fb925f 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -2800,7 +2800,8 @@ static void ublk_cancel_cmd(struct ublk_queue *ubq, u16 tag, done = !!(io->flags & UBLK_IO_FLAG_CANCELED); if (!done) { io->flags |= UBLK_IO_FLAG_CANCELED; - cmd = io->cmd; + /* dependency ordered against smp_wmb() in ublk_prep_cancel() */ + cmd = READ_ONCE(io->cmd); io->cmd = NULL; } spin_unlock(&ubq->cancel_lock); @@ -3163,6 +3164,12 @@ ublk_fill_io_cmd(struct ublk_io *io, struct io_uring_cmd *cmd) return req; } +/* + * 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, u16 tag) @@ -3176,6 +3183,8 @@ 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 void ublk_io_release(void *priv) @@ -3423,11 +3432,11 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd, ret = ublk_check_fetch_buf(ub, addr); if (ret) goto out; + /* before ublk_fetch() publishes io->cmd, see ublk_prep_cancel() */ + ublk_prep_cancel(cmd, issue_flags, ubq, tag); ret = ublk_fetch(cmd, ub, io, addr, q_id); if (ret) - goto out; - - ublk_prep_cancel(cmd, issue_flags, ubq, tag); + goto out_done; return -EIOCBQUEUED; } @@ -3471,6 +3480,7 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd, if (ret) goto out; io->res = result; + ublk_prep_cancel(cmd, issue_flags, ubq, tag); req = ublk_fill_io_cmd(io, cmd); ublk_apply_io_buf(ub, io, cmd, addr, &auto_buf, &buf_idx); if (buf_idx != UBLK_INVALID_BUF_IDX) @@ -3489,19 +3499,24 @@ static int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd, * uring_cmd active first and prepare for handling new requeued * request */ + ublk_prep_cancel(cmd, issue_flags, ubq, tag); req = ublk_fill_io_cmd(io, cmd); io->buf.addr = addr; if (likely(ublk_get_data(ubq, io, req))) { __ublk_prep_compl_io_cmd(io, req); - return UBLK_IO_RES_OK; + ret = UBLK_IO_RES_OK; + goto out_done; } break; default: goto out; } - ublk_prep_cancel(cmd, issue_flags, ubq, tag); return -EIOCBQUEUED; + out_done: + /* marked cancelable: complete through io_uring_cmd_done() */ + io_uring_cmd_done(cmd, ret, issue_flags); + return -EIOCBQUEUED; out: pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n", __func__, cmd_op, tag, ret, io ? io->flags : 0); -- 2.53.0