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dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=eZP2f9RP; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de From: Nam Cao DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1714839326; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fOSfH9/nnC1Iy/NuUJ45BTaE3oHZ9hmim1+dwQeqhyw=; b=SXhdCXlX42rvyWb6EFoyj673ozs/YpddV9Vbup6QSyE0/QETgmv6EOXJo5u++5KwCz3nV8 TW81k6SwF5Ki7rbFAHTRYz4NbsCYFKakfPqLFtFqObBcB/oAM4nUgLrnSDOS3ZP+0bcqOM f1T3leTuQHB07QNbweKL5Z7KByqi0ilueVqfJUP6X8Rvg+y8eHo1ohuxmEjuSHk2jceS5Q eYk9P3Na2MqB09zwB8+eULOzviAl4/0tsRkootbH61EALKbZFDBFkxW9q5fvw71BqrbmP5 UWGCCbYbBbaAp/cdQyhrK9XACZAXQQD4iWW53frmB+hZxrs7rd+wtzyqNYckIA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1714839326; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fOSfH9/nnC1Iy/NuUJ45BTaE3oHZ9hmim1+dwQeqhyw=; b=eZP2f9RP9NxcIJHvOriFyr5G+/4VoDUtZorTM+TqUT/P0Sa1Bk1ClR4j3uf0VvrKWzqjcS dO9pg+xpT7f1cXBA== To: Lukas Wunner , Bjorn Helgaas , Yinghai Lu , Greg Kroah-Hartman , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Nam Cao , stable@vger.kernel.org Subject: [PATCH v2 2/2] PCI: pciehp: Abort hot-plug if pci_hp_add_bridge() fails Date: Sat, 4 May 2024 18:15:22 +0200 Message-Id: In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 If a bridge is hot-added without any bus number available for its downstream bus, pci_hp_add_bridge() will fail. However, the driver proceeds regardless, and the kernel crashes. This crash can be reproduced with the QEMU command: qemu-system-x86_64 -machine pc-q35-2.10 \ -kernel bzImage \ -drive "file=img,format=raw" \ -m 2048 -smp 2 -enable-kvm \ -append "console=ttyS0 root=/dev/sda" \ -nographic \ -device pcie-root-port,bus=pcie.0,id=rp1,slot=1,bus-reserve=0 then hot-plug a bridge at runtime with the QEMU command: device_add pcie-pci-bridge,id=br1,bus=rp1 and the kernel crashes: pcieport 0000:00:03.0: pciehp: Slot(1): Button press: will power on in 5 sec pcieport 0000:00:03.0: pciehp: Slot(1): Card present pcieport 0000:00:03.0: pciehp: Slot(1): Link Up pci 0000:01:00.0: [1b36:000e] type 01 class 0x060400 PCIe to PCI/PCI-X bridge pci 0000:01:00.0: BAR 0 [mem 0x00000000-0x000000ff 64bit] pci 0000:01:00.0: PCI bridge to [bus 00] pci 0000:01:00.0: bridge window [io 0x0000-0x0fff] pci 0000:01:00.0: bridge window [mem 0x00000000-0x000fffff] pci 0000:01:00.0: bridge window [mem 0x00000000-0x000fffff 64bit pref] pci 0000:01:00.0: No bus number available for hot-added bridge (note: kernel should abort hot-plugging right here) pci 0000:01:00.0: BAR 0 [mem 0xfe800000-0xfe8000ff 64bit]: assigned pcieport 0000:00:03.0: PCI bridge to [bus 01] pcieport 0000:00:03.0: bridge window [io 0x1000-0x1fff] pcieport 0000:00:03.0: bridge window [mem 0xfe800000-0xfe9fffff] pcieport 0000:00:03.0: bridge window [mem 0xfe000000-0xfe1fffff 64bit pref] shpchp 0000:01:00.0: HPC vendor_id 1b36 device_id e ss_vid 0 ss_did 0 shpchp 0000:01:00.0: enabling device (0000 -> 0002) BUG: kernel NULL pointer dereference, address: 00000000000000da PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 46 Comm: irq/24-pciehp Not tainted 6.9.0-rc1-00001-g2e0239d47d75 #33 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:shpc_init+0x3fb/0x9d0 [stack dump and register dump cut out] Fix this by aborting the hot-plug if pci_hp_add_bridge() fails. Fixes: 0eb3bcfd088e ("[PATCH] pciehp: allow bridged card hotplug") Signed-off-by: Nam Cao Cc: Reviewed-by: Lukas Wunner --- v2: - remove "Cc: Rajesh Shah " (this address bounce) - add more information to commit message - return 0 instead of -EINVAL - remove pci_stop_and_remove_bus_device() drivers/pci/hotplug/pciehp_pci.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/pci/hotplug/pciehp_pci.c b/drivers/pci/hotplug/pciehp_pci.c index ad12515a4a12..200a7f4a12e0 100644 --- a/drivers/pci/hotplug/pciehp_pci.c +++ b/drivers/pci/hotplug/pciehp_pci.c @@ -58,8 +58,10 @@ int pciehp_configure_device(struct controller *ctrl) goto out; } - for_each_pci_bridge(dev, parent) - pci_hp_add_bridge(dev); + for_each_pci_bridge(dev, parent) { + if (pci_hp_add_bridge(dev)) + goto out; + } pci_assign_unassigned_bridge_resources(bridge); pcie_bus_configure_settings(parent);