From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0EE4229B795; Sat, 17 Oct 2026 16:33:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254783; cv=none; b=cJB2KMWMBjQaIqBcKXe4vKd/HEGjEQLO6nQ2/NYFUJepJtVWCsEHi3BPkrjrgBHwUZwb0R0mT+2aZo5VOKlWNGURVnK/0zk0rfdjv/8uZss23UehYHq8Sdj8gradPOrRgBMONXTRqpgy99yJKjgdrL+3fmO8l5w1UkG/kT0YsD8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254783; c=relaxed/simple; bh=BRKOXI0hvZLzzMiSv4CXp5FsUOalhygkFTOHPKJQIrY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uhFIEAppnsnE+4rzzUmwNbWhSB4kdDBGYi4XiFZJix3K8ZxnwerptilwluQ0OkxIvtPqNQM9dPq4S2JI1PIZiZ/UsNLPl7xjww3j0JPnKz9x8EM9gkBBWcJ1PqPz6aMxGR8IRm6eociE5IkEfxEgvZ/tjh6olndcmT69N6kWYsE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KJALUfA4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="KJALUfA4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 923BA1F000C4; Sat, 17 Oct 2026 16:33:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792254782; bh=xhrh33gutxRsiFUpqXlrpty9WEFi3LXoRmYe0DmUJuE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=KJALUfA4oayT5Yd93kjuTcUozrvJCIMT7mUxaVleVsg9c5jC2SDH4cVPcu7BA5Y2A LaDGgln3+WSh02wzwWS2IWnK2K8oTXQkIJzTbkaaP7LfUsyATEL9GVUs5nCOVSIaxU Sji8uMYsFjCI0utSp0FM6PzKFemqKVHerF0c9Jlo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+d30aad27833a559defab@syzkaller.appspotmail.com, Aleksandr Nogikh , Takashi Sakamoto , Sasha Levin Subject: [PATCH 6.12 518/869] firewire: ohci: fix NULL pointer dereference in ar_context_release Date: Sat, 17 Oct 2026 17:55:59 +0200 Message-ID: <20261017160050.390571854@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Aleksandr Nogikh [ Upstream commit 42d217add8d80d6e7d9f58f80d11ea9b07ea113e ] During the error handling path of the driver's probe function, a NULL pointer dereference can occur in ar_context_release(). When pci_probe() fails early (e.g., if pcim_enable_device() or MMIO mapping fails), the devres cleanup mechanism invokes release_ohci(). This function unconditionally calls ar_context_release() to clean up the asynchronous receive contexts. However, if ar_context_init() was not yet called, ctx->ohci remains NULL (as the fw_ohci structure is zero-initialized by devres_alloc()). ar_context_release() immediately dereferences ctx->ohci to get the dev pointer before checking if the context was actually initialized, leading to a crash: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] RIP: 0010:ar_context_release+0x3f/0x380 drivers/firewire/ohci.c:543 Call Trace: release_ohci+0x3f/0x60 drivers/firewire/ohci.c:3567 release_nodes drivers/base/devres.c:546 [inline] devres_release_all+0x1a8/0x260 drivers/base/devres.c:576 device_unbind_cleanup drivers/base/dd.c:597 [inline] really_probe+0x451/0xae0 drivers/base/dd.c:772 To fix this, move the assignment of the dev pointer after the !ctx->buffer check. If ctx->buffer is NULL, it indicates that the context was never successfully initialized and there is nothing to release, safely avoiding the dereference of the uninitialized ctx->ohci pointer. Fixes: 5716e58aecdd ("firewire: ohci: release buffer for AR req/resp contexts when managed resource is released") Assisted-by: Gemini:gemini-3.5-flash Gemini:gemini-3.1-pro-preview syzbot Reported-by: syzbot+d30aad27833a559defab@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d30aad27833a559defab Link: https://syzkaller.appspot.com/ai_job?id=10a18617-7893-42dd-bf1c-cd49e19e95d9 Signed-off-by: Aleksandr Nogikh Link: https://lore.kernel.org/r/90c5db71-dd1f-4d46-b9d3-2f1046cbd5ea@mail.kernel.org Signed-off-by: Takashi Sakamoto Signed-off-by: Sasha Levin --- drivers/firewire/ohci.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index 90fcab1f65bcd..4dca78f859f63 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -753,12 +753,14 @@ static void ar_context_link_page(struct ar_context *ctx, unsigned int index) static void ar_context_release(struct ar_context *ctx) { - struct device *dev = ctx->ohci->card.device; + struct device *dev; unsigned int i; if (!ctx->buffer) return; + dev = ctx->ohci->card.device; + vunmap(ctx->buffer); for (i = 0; i < AR_BUFFERS; i++) { -- 2.53.0