From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tonghao Zhang , Bjorn Helgaas , Sasha Levin Subject: [PATCH 4.18 168/350] PCI/MSI: Warn and return error if driver enables MSI/MSI-X twice Date: Sun, 11 Nov 2018 14:20:32 -0800 Message-Id: <20181111221715.069433267@linuxfoundation.org> In-Reply-To: <20181111221707.043394111@linuxfoundation.org> References: <20181111221707.043394111@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tonghao Zhang [ Upstream commit 4c1ef72e9b71a19fb405ebfcd37c0a5e16fa44ca ] It is a serious driver defect to enable MSI or MSI-X more than once. Doing so may panic the kernel as in the stack trace below: Call Trace: sysfs_add_one+0xa5/0xd0 create_dir+0x7c/0xe0 sysfs_create_subdir+0x1c/0x20 internal_create_group+0x6d/0x290 sysfs_create_groups+0x4a/0xa0 populate_msi_sysfs+0x1cd/0x210 pci_enable_msix+0x31c/0x3e0 igbuio_pci_open+0x72/0x300 [igb_uio] uio_open+0xcc/0x120 [uio] chrdev_open+0xa1/0x1e0 [...] do_sys_open+0xf3/0x1f0 SyS_open+0x1e/0x20 system_call_fastpath+0x16/0x1b ---[ end trace 11042e2848880209 ]--- Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffffa056b4fa We want to keep the WARN_ON() and stack trace so the driver can be fixed, but we can avoid the kernel panic by returning an error. We may still get warnings like this: Call Trace: pci_enable_msix+0x3c9/0x3e0 igbuio_pci_open+0x72/0x300 [igb_uio] uio_open+0xcc/0x120 [uio] chrdev_open+0xa1/0x1e0 [...] do_sys_open+0xf3/0x1f0 SyS_open+0x1e/0x20 system_call_fastpath+0x16/0x1b ------------[ cut here ]------------ WARNING: at fs/sysfs/dir.c:526 sysfs_add_one+0xa5/0xd0() sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:03.0/0000:01:00.1/msi_irqs' Signed-off-by: Tonghao Zhang [bhelgaas: changelog, fix patch whitespace, remove !!] Signed-off-by: Bjorn Helgaas Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/pci/msi.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -958,7 +958,6 @@ static int __pci_enable_msix(struct pci_ } } } - WARN_ON(!!dev->msix_enabled); /* Check whether driver already requested for MSI irq */ if (dev->msi_enabled) { @@ -1028,8 +1027,6 @@ static int __pci_enable_msi_range(struct if (!pci_msi_supported(dev, minvec)) return -EINVAL; - WARN_ON(!!dev->msi_enabled); - /* Check whether driver already requested MSI-X irqs */ if (dev->msix_enabled) { pci_info(dev, "can't enable MSI (MSI-X already enabled)\n"); @@ -1039,6 +1036,9 @@ static int __pci_enable_msi_range(struct if (maxvec < minvec) return -ERANGE; + if (WARN_ON_ONCE(dev->msi_enabled)) + return -EINVAL; + nvec = pci_msi_vec_count(dev); if (nvec < 0) return nvec; @@ -1087,6 +1087,9 @@ static int __pci_enable_msix_range(struc if (maxvec < minvec) return -ERANGE; + if (WARN_ON_ONCE(dev->msix_enabled)) + return -EINVAL; + for (;;) { if (affd) { nvec = irq_calc_affinity_vectors(minvec, nvec, affd);