| Message ID | 1513218083-5461-2-git-send-email-cao.zou@windriver.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
[+Marc] On Thu, Dec 14, 2017 at 10:21:23AM +0800, cao.zou@windriver.com wrote: > From: Zou Cao <cao.zou@windriver.com> > > When PCIE host setup, 32 MSI irq descriptions are created, but its > msi_desc is NULL, msi_desc is bound in MSI irq requested by PCI device, > normally just part of MSI are used, for others not used MSI irqs, its > msi_desc is NULL, it is dangerous for MSI irq mask when MSI irq mask use > the msi_desc to mask irq without checking, normally not used MSI irqs are > never masked, it looks fine, but in some specified case, such as kdump, > machine_kexec_mask_interrupts will force to mask these not used MSI irqs, > than a crash will happen with NULL msi_desc. it is necessary to add check > of msi_desc in irqchip, if we still bind the msi_desc only in irqs request > and mask MSI irq by msi_desc. > > Add dwc_pci_msi_mask/unmask_irq, so we can get a chance to check the > msi_desc. > > here is reproduced crash log in IMX7-SABER board with Intel 1030 PCI, > when running kdump by "echo c > /proc/sysrq-trigger": > > sysrq: SysRq : Trigger a crash > Unable to handle kernel NULL pointer dereference at virtual address 00000000 > pgd = 98ee1839 > [00000000] *pgd=00000000 > Internal error: Oops: 805 [#1] SMP ARM > Modules linked in: > CPU: 0 PID: 1370 Comm: sh Not tainted 4.15.0-rc3-00033-ga638349 #1 > Hardware name: Freescale i.MX7 Dual (Device Tree) > PC is at sysrq_handle_crash+0x50/0x98 > LR is at sysrq_handle_crash+0x50/0x98 > <snip> > Backtrace: > [<c047a15c>] (msi_set_mask_bit) from [<c047a1f0>] (pci_msi_mask_irq+0x14/0x18) > [<c047a1dc>] (pci_msi_mask_irq) from [<c011142c>] (machine_crash_shutdown+0xd8/0x190) > [<c0111354>] (machine_crash_shutdown) from [<c01b2924>] (__crash_kexec+0x5c/0xa0) > [<c01b28c8>] (__crash_kexec) from [<c01b29dc>] (crash_kexec+0x74/0x80) > [<c01b2968>] (crash_kexec) from [<c010cfa4>] (die+0x220/0x358) > [<c010cd84>] (die) from [<c01169f0>] (__do_kernel_fault.part.0+0x5c/0x7c) > [<c0116994>] (__do_kernel_fault.part.0) from [<c0116784>] (do_page_fault+0x2cc/0x37c) > [<c01164b8>] (do_page_fault) from [<c0116970>] (do_translation_fault+0xb0/0xbc) > [<c01168c0>] (do_translation_fault) from [<c010138c>] (do_DataAbort+0x3c/0xbc) > [<c0101350>] (do_DataAbort) from [<c010d944>] (__dabt_svc+0x64/0xa0) > Exception stack(0xec08bdf8 to 0xec08be40) > bde0: 00000000 ec08be10 > be00: 00000000 00000000 00000000 00000001 00000063 00000000 00000007 ec08a000 > be20: 00000000 ec08be5c ec08be48 ec08be48 c04c46b8 c04c46b8 60060013 ffffffff > [<c04c4668>] (sysrq_handle_crash) from [<c04c4900>] (__handle_sysrq+0xe0/0x254) > [<c04c4820>] (__handle_sysrq) from [<c04c4aec>] (write_sysrq_trigger+0x78/0x90) > [<c04c4a74>] (write_sysrq_trigger) from [<c029148c>] (proc_reg_write+0x68/0x90) > [<c0291424>] (proc_reg_write) from [<c0229ef8>] (__vfs_write+0x34/0x12c) > [<c0229ec4>] (__vfs_write) from [<c022a16c>] (vfs_write+0xa8/0x16c) > [<c022a0c4>] (vfs_write) from [<c022a340>] (SyS_write+0x44/0x90) > [<c022a2fc>] (SyS_write) from [<c0108220>] (ret_fast_syscall+0x0/0x28) > > Signed-off-by: Zou Cao <cao.zou@windriver.com> > --- > drivers/pci/dwc/pcie-designware-host.c | 24 ++++++++++++++++++++---- > 1 file changed, 20 insertions(+), 4 deletions(-) > > diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c > index 81e2157..485c4df 100644 > --- a/drivers/pci/dwc/pcie-designware-host.c > +++ b/drivers/pci/dwc/pcie-designware-host.c > @@ -45,12 +45,28 @@ static int dw_pcie_wr_own_conf(struct pcie_port *pp, int where, int size, > return dw_pcie_write(pci->dbi_base + where, size, val); > } > > +static void dwc_pci_msi_mask_irq(struct irq_data *data) > +{ > + struct msi_desc *desc = irq_data_get_msi_desc(data); > + > + if (desc) > + pci_msi_mask_irq(data); > +} > + > +static void dwc_pci_msi_unmask_irq(struct irq_data *data) > +{ > + struct msi_desc *desc = irq_data_get_msi_desc(data); > + > + if (desc) > + pci_msi_unmask_irq(data); > +} > + > static struct irq_chip dw_msi_irq_chip = { > .name = "PCI-MSI", > - .irq_enable = pci_msi_unmask_irq, > - .irq_disable = pci_msi_mask_irq, > - .irq_mask = pci_msi_mask_irq, > - .irq_unmask = pci_msi_unmask_irq, > + .irq_enable = dwc_pci_msi_unmask_irq, > + .irq_disable = dwc_pci_msi_mask_irq, > + .irq_mask = dwc_pci_msi_mask_irq, > + .irq_unmask = dwc_pci_msi_unmask_irq, > }; You have to CC me next time please. CC'ed Marc since he knows this code ways better than me and will help us find the right way of fixing it. I do not think that's a DWC-only problem - I see no reason why this would not affect other host bridges still relying on struct msi_controller (that we have to remove from the kernel). I do not think that this code is an actual fix but a plaster to paper over the issue - I will have a look into this as soon as possible to come up with an actual fix. Thanks, Lorenzo
diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c index 81e2157..485c4df 100644 --- a/drivers/pci/dwc/pcie-designware-host.c +++ b/drivers/pci/dwc/pcie-designware-host.c @@ -45,12 +45,28 @@ static int dw_pcie_wr_own_conf(struct pcie_port *pp, int where, int size, return dw_pcie_write(pci->dbi_base + where, size, val); } +static void dwc_pci_msi_mask_irq(struct irq_data *data) +{ + struct msi_desc *desc = irq_data_get_msi_desc(data); + + if (desc) + pci_msi_mask_irq(data); +} + +static void dwc_pci_msi_unmask_irq(struct irq_data *data) +{ + struct msi_desc *desc = irq_data_get_msi_desc(data); + + if (desc) + pci_msi_unmask_irq(data); +} + static struct irq_chip dw_msi_irq_chip = { .name = "PCI-MSI", - .irq_enable = pci_msi_unmask_irq, - .irq_disable = pci_msi_mask_irq, - .irq_mask = pci_msi_mask_irq, - .irq_unmask = pci_msi_unmask_irq, + .irq_enable = dwc_pci_msi_unmask_irq, + .irq_disable = dwc_pci_msi_mask_irq, + .irq_mask = dwc_pci_msi_mask_irq, + .irq_unmask = dwc_pci_msi_unmask_irq, }; /* MSI int handler */