commit a6846cfd266b48af1ee7c3c19d5cb60477ca4469
Author: Sasha Levin <alexander.levin@verizon.com>
Date: Sat Oct 22 16:45:02 2016 -0400
Linux 3.18.44
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
commit c003797af3bc3b267a262b4d28ca06efc80390d4
Author: Mathias Nyman <mathias.nyman@linux.intel.com>
Date: Fri Dec 11 14:38:06 2015 +0200
xhci: fix usb2 resume timing and races.
[ Upstream commit f69115fdbc1ac0718e7d19ad3caa3da2ecfe1c96 ]
According to USB 2 specs ports need to signal resume for at least 20ms,
in practice even longer, before moving to U0 state.
Both host and devices can initiate resume.
On device initiated resume, a port status interrupt with the port in resume
state in issued. The interrupt handler tags a resume_done[port]
timestamp with current time + USB_RESUME_TIMEOUT, and kick roothub timer.
Root hub timer requests for port status, finds the port in resume state,
checks if resume_done[port] timestamp passed, and set port to U0 state.
On host initiated resume, current code sets the port to resume state,
sleep 20ms, and finally sets the port to U0 state. This should also
be changed to work in a similar way as the device initiated resume, with
timestamp tagging, but that is not yet tested and will be a separate
fix later.
There are a few issues with this approach
1. A host initiated resume will also generate a resume event. The event
handler will find the port in resume state, believe it's a device
initiated resume, and act accordingly.
2. A port status request might cut the resume signalling short if a
get_port_status request is handled during the host resume signalling.
The port will be found in resume state. The timestamp is not set leading
to time_after_eq(jiffies, timestamp) returning true, as timestamp = 0.
get_port_status will proceed with moving the port to U0.
3. If an error, or anything else happens to the port during device
initiated resume signalling it will leave all the device resume
parameters hanging uncleared, preventing further suspend, returning
-EBUSY, and cause the pm thread to busyloop trying to enter suspend.
Fix this by using the existing resuming_ports bitfield to indicate that
resume signalling timing is taken care of.
Check if the resume_done[port] is set before using it for timestamp
comparison, and also clear out any resume signalling related variables
if port is not in U0 or Resume state
This issue was discovered when a PM thread busylooped, trying to runtime
suspend the xhci USB 2 roothub on a Dell XPS
Cc: stable <stable@vger.kernel.org>
Reported-by: Daniel J Blueman <daniel@quora.org>
Tested-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
commit bb2f5ed8935a47f78a70ac48e58e993de46430e0
Author: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Wed Jun 3 10:31:14 2015 +0100
x86/cpu: Fix SMAP check in PVOPS environments
[ Upstream commit 581b7f158fe0383b492acd1ce3fb4e99d4e57808 ]
There appears to be no formal statement of what pv_irq_ops.save_fl() is
supposed to return precisely. Native returns the full flags, while lguest and
Xen only return the Interrupt Flag, and both have comments by the
implementations stating that only the Interrupt Flag is looked at. This may
have been true when initially implemented, but no longer is.
To make matters worse, the Xen PVOP leaves the upper bits undefined, making
the BUG_ON() undefined behaviour. Experimentally, this now trips for 32bit PV
guests on Broadwell hardware. The BUG_ON() is consistent for an individual
build, but not consistent for all builds. It has also been a sitting timebomb
since SMAP support was introduced.
Use native_save_fl() instead, which will obtain an accurate view of the AC
flag.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Tested-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: <lguest@lists.ozlabs.org>
Cc: Xen-devel <xen-devel@lists.xen.org>
CC: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1433323874-6927-1-git-send-email-andrew.cooper3@citrix.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
commit e45a502bdeae5a075257c4f061d1ff4ff0821354
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu Oct 13 13:07:36 2016 -0700
mm: remove gup_flags FOLL_WRITE games from __get_user_pages()
[ Upstream commit 19be0eaffa3ac7d8eb6784ad9bdbc7d67ed8e619 ]
This is an ancient bug that was actually attempted to be fixed once
(badly) by me eleven years ago in commit 4ceb5db9757a ("Fix
get_user_pages() race for write access") but that was then undone due to
problems on s390 by commit f33ea7f404e5 ("fix get_user_pages bug").
In the meantime, the s390 situation has long been fixed, and we can now
fix it by checking the pte_dirty() bit properly (and do it better). The
s390 dirty bit was implemented in abf09bed3cce ("s390/mm: implement
software dirty bits") which made it into v3.9. Earlier kernels will
have to look at the page state itself.
Also, the VM has become more scalable, and what used a purely
theoretical race back then has become easier to trigger.
To fix it, we introduce a new internal FOLL_COW flag to mark the "yes,
we already did a COW" rather than play racy games with FOLL_WRITE that
is very fundamental, and then use the pte dirty flag to validate that
the FOLL_COW flag is still valid.
Reported-and-tested-by: Phil "not Paul" Oester <kernel@linuxace.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Michal Hocko <mhocko@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>