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  1. 24 Nov, 2016 24 commits
  3. 19 Nov, 2016 1 commit
    • Eric Dumazet's avatar
      udp: properly support MSG_PEEK with truncated buffers · 69335972
      Eric Dumazet authored 
      [ Upstream commit 197c949e ]

Backport of this upstream commit into stable kernels :
89c22d8c ("net: Fix skb csum races when peeking")
exposed a bug in udp stack vs MSG_PEEK support, when user provides
a buffer smaller than skb payload.

In this case,
skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr),
                                 msg->msg_iov);
returns -EFAULT.

This bug does not happen in upstream kernels since Al Viro did a great
job to replace this into :
skb_copy_and_csum_datagram_msg(skb, sizeof(struct udphdr), msg);
This variant is safe vs short buffers.

For the time being, instead reverting Herbert Xu patch and add back
skb->ip_summed invalid changes, simply store the result of
udp_lib_checksum_complete() so that we avoid computing the checksum a
second time, and avoid the problematic
skb_copy_and_csum_datagram_iovec() call.

This patch can be applied on recent kernels as it avoids a double
checksumming, then backported to stable kernels as a bug fix.
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
      69335972
  5. 22 Oct, 2016 4 commits
    • Sasha Levin's avatar
      Linux 3.18.44 · a6846cfd
      Sasha Levin authored 
      Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
      a6846cfd
    • Mathias Nyman's avatar
      xhci: fix usb2 resume timing and races. · c003797a
      Mathias Nyman authored 
      [ Upstream commit f69115fd ]

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: default avatarDaniel J Blueman <daniel@quora.org>
Tested-by: default avatarDaniel J Blueman <daniel@quora.org>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
      c003797a
    • Andrew Cooper's avatar
      x86/cpu: Fix SMAP check in PVOPS environments · bb2f5ed8
      Andrew Cooper authored 
      [ Upstream commit 581b7f15 ]

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: default avatarAndrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Tested-by: default avatarRusty 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.comSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
      bb2f5ed8
    • Linus Torvalds's avatar
      mm: remove gup_flags FOLL_WRITE games from __get_user_pages() · e45a502b
      Linus Torvalds authored 
      [ Upstream commit 19be0eaf ]

This is an ancient bug that was actually attempted to be fixed once
(badly) by me eleven years ago in commit 4ceb5db9 ("Fix
get_user_pages() race for write access") but that was then undone due to
problems on s390 by commit f33ea7f4 ("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 abf09bed ("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: default avatarPhil "not Paul" Oester <kernel@linuxace.com>
Acked-by: default avatarHugh Dickins <hughd@google.com>
Reviewed-by: default avatarMichal 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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
      e45a502b
  7. 10 Oct, 2016 5 commits
  9. 07 Oct, 2016 1 commit
  11. 06 Oct, 2016 5 commits
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