Messages in this thread | | | Date | Thu, 21 Feb 2019 12:49:26 +0100 | From | Greg KH <> | Subject | Re: Patch "PCI: Fix __initdata issue with "pci=disable_acs_redir" parameter" has been added to the 4.20-stable tree |
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On Thu, Feb 21, 2019 at 12:43:20AM -0500, Sasha Levin wrote: > This is a note to let you know that I've just added the patch titled > > PCI: Fix __initdata issue with "pci=disable_acs_redir" parameter > > to the 4.20-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > pci-fix-__initdata-issue-with-pci-disable_acs_redir-.patch > and it can be found in the queue-4.20 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@vger.kernel.org> know about it. > > > > commit 44557eb5390967bb678394cfbcef5df39bfa751e > Author: Logan Gunthorpe <logang@deltatee.com> > Date: Thu Jan 17 08:46:34 2019 -0600 > > PCI: Fix __initdata issue with "pci=disable_acs_redir" parameter > > [ Upstream commit d2fd6e81912a665993b24dcdc1c1384a42a54f7e ] > > The disable_acs_redir parameter stores a pointer to the string passed to > pci_setup(). However, the string passed to PCI setup is actually a > temporary copy allocated in static __initdata memory. After init, once the > memory is freed, it is no longer valid to reference this pointer. > > This bug was noticed in v5.0-rc1 after a change in commit c5eb1190074c > ("PCI / PM: Allow runtime PM without callback functions") caused > pci_disable_acs_redir() to be called during shutdown which manifested > as an unable to handle kernel paging request at: > > RIP: 0010:pci_enable_acs+0x3f/0x1e0 > Call Trace: > pci_restore_state.part.44+0x159/0x3c0 > pci_restore_standard_config+0x33/0x40 > pci_pm_runtime_resume+0x2b/0xd0 > ? pci_restore_standard_config+0x40/0x40 > __rpm_callback+0xbc/0x1b0 > rpm_callback+0x1f/0x70 > ? pci_restore_standard_config+0x40/0x40 > rpm_resume+0x4f9/0x710 > ? pci_conf1_read+0xb6/0xf0 > ? pci_conf1_write+0xb2/0xe0 > __pm_runtime_resume+0x47/0x70 > pci_device_shutdown+0x1e/0x60 > device_shutdown+0x14a/0x1f0 > kernel_restart+0xe/0x50 > __do_sys_reboot+0x1ee/0x210 > ? __fput+0x144/0x1d0 > do_writev+0x5e/0xf0 > ? do_writev+0x5e/0xf0 > do_syscall_64+0x48/0xf0 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > It was also likely possible to trigger this bug when hotplugging PCI > devices. > > To fix this, instead of storing a pointer, we use kstrdup() to copy the > disable_acs_redir_param to its own buffer which will never be freed. > > Fixes: aaca43fda742 ("PCI: Add "pci=disable_acs_redir=" parameter for peer-to-peer support")
According to this tag it is needed in 4.19.y as well...
now added there.
greg k-h
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