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=1794323480; b=19z02qLylmsUhwzuzcL16LayzzoruBmIisFUoQV0mLHJcTZ02SErxNury8rTcbO3EukF sUkDwURph4uJnrr0N194LoNphIuhMLb9nYTHRODdtzCM6eLHH3AUOjypUZzJIC9QETIDy 4H/K9TO84gfc0wVefRzkNVYubtzAVWixl8iJeYTj9mHW0K0SkHalVFz9ZFpmWCnTKlS0d JGic7tHV0NhZN8E+4hpkHMu+p+Mtr9c+TiMshUy0qSM2Ika1Sy6CtKUo4YBS6sUMOBn3x ZJ/DfrxWbpIx0/NFR75ZYUF+/+GQy25auLvoKExWInEBKL9QR3pMWjxEw/y1jHRu5cQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794323480; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=fFtfEtcSpsmjN4ymDlyAbwugLqNAYnCG5/aGuFQwRVc=; b=bBH1a4C4Qfl1I/qI29of2F/y7KMO6pUMHwQCpxVt0TwIE4t1OTb9SXPlQVtHFXcABOoM GA/g/Y3kvtHaV64r3oB3aSbRh1DZXK0iUNl1GC5OPmjBh3dCUEo9b/xO2Z4Vwxc7eSYlm 912+4uP+9DdvzZZfAUVaKE5z8xqjFythXZaYjyEm/gvXE9xjORsTHhabF/LF/+YTXbBU8 PHgoIzL/6zWecvqSbHG/nagce80g0Cb/Grm9GbOipniCFrSYsNl13vhnj21gFoGKj0W8Z yNKL8juGe3van76gRiRCmQAtV4hYda5qv1jo3nit06qang0jh6yq+BrjjXwGmN0NN0g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=SkHFMygD; 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 C9A37606A33A for ; Tue, 10 Nov 2026 15:11:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=SkHFMygD Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97E0C1F008BC; Tue, 10 Nov 2026 15:11:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794323479; bh=fFtfEtcSpsmjN4ymDlyAbwugLqNAYnCG5/aGuFQwRVc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SkHFMygD/DIYysGOgFBH43clDydzT2q8EdTAhfzrHxN2ZsZRDh0iIfB6vzs/K9GRj gpDKPDNZ5eryeXqD2eO2a10rEO5rZ7pgs0k9c6h2bF7+xyVRVC+W2rR7gOtzDGqbnc nC9FwBRkyC6Q4lMqXIhsvI+eKpOFXhGIPJWM+PVD5UqEyIg7d4wH4H0sPdW1xR5Pqi jLTzYRvH7RVaSdiPoC3eI4uFxMulIZukucQ6BsLLvS5jZANRYC+ALi86eXdr79LuCi vMdzoVsDH+8ttrO1hEkBkh6COumtX4eBev6zLn9K2SILSJhoASFKOrYtzBcESJ1uGG v2VmST1Cq0p6w== From: Sasha Levin To: stable@vger.kernel.org Cc: Dave Jiang , Jonathan Cameron , Li Ming , "Gregory Price (Meta)" , Alison Schofield , Sasha Levin Subject: [PATCH 6.18.y 2/2] cxl/port: Clear cached dport pointers when a dport is removed Date: Tue, 10 Nov 2026 10:11:14 -0500 Message-ID: <20261110151026.2046421-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261110151026.2046421-1-sashal@kernel.org> References: <20261107051004-failed-6.18-019560d23450@kernel.org> <20261110151026.2046421-1-sashal@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Dave Jiang [ Upstream commit 019560d23450a320f4060ff235563a5277ea8033 ] Switch decoders cache dport pointers in cxlsd->target[], and nothing clears them when a dport is freed. Readers then dereference freed memory. KASAN caught it under a cxl_test load/unload loop with concurrent sysfs reads (abbreviated). Clear the matching slots from cxl_dport_remove(), walking the port's decoders the way cxl_port_update_decoder_targets() does on the add side. Scan all nr_targets slots, the target[] allocation size, and clear every hit. Fixes: 8330671c57c7 ("cxl: Add helper to delete dport") Cc: stable@vger.kernel.org Assisted-by: LLM Reviewed-by: Jonathan Cameron Reviewed-by: Li Ming Reviewed-by: Gregory Price (Meta) Reviewed-by: Alison Schofield Link: https://patch.msgid.link/20261001154744.1095902-2-dave.jiang@intel.com Signed-off-by: Dave Jiang Signed-off-by: Sasha Levin --- drivers/cxl/core/port.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index a7d3497f82c05..01655eeb43a8f 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -1105,11 +1105,40 @@ static void cond_cxl_root_unlock(struct cxl_port *port) device_unlock(&port->dev); } +static int clear_decoder_target(struct device *dev, void *data) +{ + struct cxl_dport *dport = data; + struct cxl_switch_decoder *cxlsd; + + if (!is_switch_decoder(dev)) + return 0; + + cxlsd = to_cxl_switch_decoder(dev); + guard(rwsem_write)(&cxl_rwsem.region); + + /* + * A dport can occupy more than one position of an interleave, so + * scan the whole target list rather than stopping at the first hit. + */ + for (int i = 0; i < cxlsd->nr_targets; i++) { + if (cxlsd->target[i] != dport) + continue; + cxlsd->target[i] = NULL; + dev_dbg(dev, "dport%d removed from target list, index %d\n", + dport->port_id, i); + } + + return 0; +} + static void cxl_dport_remove(void *data) { struct cxl_dport *dport = data; struct cxl_port *port = dport->port; + /* counterpart of cxl_port_update_decoder_targets() */ + device_for_each_child(&port->dev, dport, clear_decoder_target); + port->nr_dports--; xa_erase(&port->dports, (unsigned long) dport->dport_dev); put_device(dport->dport_dev); -- 2.53.0