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  1. Jan 05, 2018
  3. Dec 23, 2017
    • Jens Axboe's avatar
      blk-mq: improve heavily contended tag case · 4e5dff41
      Jens Axboe authored 
      

Even with a number of waitqueues, we can get into a situation where we
are heavily contended on the waitqueue lock. I got a report on spc1
where we're spending seconds doing this. Arguably the use case is nasty,
I reproduce it with one device and 1000 threads banging on the device.
But that doesn't mean we shouldn't be handling it better.

What ends up happening is that a thread will fail to get a tag, add
itself to the waitqueue, and subsequently get woken up when a tag is
freed - only to find itself going back to sleep on the waitqueue.

Instead of waking all threads, use an exclusive wait and wake up our
sbitmap batch count instead. This seems to work well for me (massive
improvement for this use case), and it survives basic testing. But I
haven't fully verified it yet.

An additional improvement is running the queue and checking for a new
tag BEFORE needing to add ourselves to the waitqueue.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      4e5dff41
  5. Dec 18, 2017
  7. Dec 17, 2017
  9. Dec 16, 2017
    • Linus Torvalds's avatar
      Revert "mm: replace p??_write with pte_access_permitted in fault + gup paths" · f6f37321
      Linus Torvalds authored 
      This reverts commits 5c9d2d5c, c7da82b8, and e7fe7b5c.

We'll probably need to revisit this, but basically we should not
complicate the get_user_pages_fast() case, and checking the actual page
table protection key bits will require more care anyway, since the
protection keys depend on the exact state of the VM in question.

Particularly when doing a "remote" page lookup (ie in somebody elses VM,
not your own), you need to be much more careful than this was.  Dave
Hansen says:

 "So, the underlying bug here is that we now a get_user_pages_remote()
  and then go ahead and do the p*_access_permitted() checks against the
  current PKRU. This was introduced recently with the addition of the
  new p??_access_permitted() calls.

  We have checks in the VMA path for the "remote" gups and we avoid
  consulting PKRU for them. This got missed in the pkeys selftests
  because I did a ptrace read, but not a *write*. I also didn't...
      f6f37321
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net · 7a3c296a
      Linus Torvalds authored 
      Pull networking fixes from David Miller:

 1) Clamp timeouts to INT_MAX in conntrack, from Jay Elliot.

 2) Fix broken UAPI for BPF_PROG_TYPE_PERF_EVENT, from Hendrik
    Brueckner.

 3) Fix locking in ieee80211_sta_tear_down_BA_sessions, from Johannes
    Berg.

 4) Add missing barriers to ptr_ring, from Michael S. Tsirkin.

 5) Don't advertise gigabit in sh_eth when not available, from Thomas
    Petazzoni.

 6) Check network namespace when delivering to netlink taps, from Kevin
    Cernekee.

 7) Kill a race in raw_sendmsg(), from Mohamed Ghannam.

 8) Use correct address in TCP md5 lookups when replying to an incoming
    segment, from Christoph Paasch.

 9) Add schedule points to BPF map alloc/free, from Eric Dumazet.

10) Don't allow silly mtu values to be used in ipv4/ipv6 multicast, also
    from Eric Dumazet.

11) Fix SKB leak in tipc, from Jon Maloy.

12) Disable MAC learning on OVS ports of mlxsw, from Yuval Mintz.

13) SKB leak fix ...
      7a3c296a
    • Linus Torvalds's avatar
      Merge tag 'usb-4.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb · c36c7a7c
      Linus Torvalds authored 
      Pull USB fixes from Greg KH:
 "Here are some USB fixes for 4.15-rc4.

  There is the usual handful gadget/dwc2/dwc3 fixes as always, for
  reported issues. But the most important things in here is the core fix
  from Alan Stern to resolve a nasty security bug (my first attempt is
  reverted, Alan's was much cleaner), as well as a number of usbip fixes
  from Shuah Khan to resolve those reported security issues.

  All of these have been in linux-next with no reported issues"

* tag 'usb-4.15-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: core: prevent malicious bNumInterfaces overflow
  Revert "USB: core: only clean up what we allocated"
  USB: core: only clean up what we allocated
  Revert "usb: gadget: allow to enable legacy drivers without USB_ETH"
  usb: gadget: webcam: fix V4L2 Kconfig dependency
  usb: dwc2: Fix TxFIFOn sizes and total TxFIFO size issues
  usb: dwc3: gadget: Fix PCM1 for ISOC EP with ep->mult less than 3
  usb: dwc3: of-simple: set dev_pm_ops
  usb: dwc3: of-simple: fix missing clk_disable_unprepare
  usb: dwc3: gadget: Wait longer for controller to end command processing
  usb: xhci: fix TDS for MTK xHCI1.1
  xhci: Don't add a virt_dev to the devs array before it's fully allocated
  usbip: fix stub_send_ret_submit() vulnerability to null transfer_buffer
  usbip: prevent vhci_hcd driver from leaking a socket pointer address
  usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input
  usbip: fix stub_rx: get_pipe() to validate endpoint number
  tools/usbip: fixes potential (minor) "buffer overflow" (detected on recent gcc with -Werror)
  USB: uas and storage: Add US_FL_BROKEN_FUA for another JMicron JMS567 ID
  usb: musb: da8xx: fix babble condition handling
      c36c7a7c