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  1. 30 Jul, 2014 2 commits
  3. 28 Jul, 2014 5 commits
  5. 27 Jul, 2014 5 commits
  7. 26 Jul, 2014 13 commits
    • Linus Torvalds's avatar
      Fix gcc-4.9.0 miscompilation of load_balance() in scheduler · 2062afb4
      Linus Torvalds authored 
      Michel Dänzer and a couple of other people reported inexplicable random
oopses in the scheduler, and the cause turns out to be gcc mis-compiling
the load_balance() function when debugging is enabled.  The gcc bug
apparently goes back to gcc-4.5, but slight optimization changes means
that it now showed up as a problem in 4.9.0 and 4.9.1.

The instruction scheduling problem causes gcc to schedule a spill
operation to before the stack frame has been created, which in turn can
corrupt the spilled value if an interrupt comes in.  There may be other
effects of this bug too, but that's the code generation problem seen in
Michel's case.

This is fixed in current gcc HEAD, but the workaround as suggested by
Markus Trippelsdorf is pretty simple: use -fno-var-tracking-assignments
when compiling the kernel, which disables the gcc code that causes the
problem.  This can result in slightly worse debug information for
variable accesses, but that is infinitely preferable to actual code
generation problems.

Doing this unconditionally (not just for CONFIG_DEBUG_INFO) also allows
non-debug builds to verify that the debug build would be identical: we
can do

    export GCC_COMPARE_DEBUG=1

to make gcc internally verify that the result of the build is
independent of the "-g" flag (it will make the compiler build everything
twice, toggling the debug flag, and compare the results).

Without the "-fno-var-tracking-assignments" option, the build would fail
(even with 4.8.3 that didn't show the actual stack frame bug) with a gcc
compare failure.

See also gcc bugzilla:

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61801Reported-by: default avatarMichel Dänzer <michel@daenzer.net>
Suggested-by: default avatarMarkus Trippelsdorf <markus@trippelsdorf.de>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: stable@kernel.org
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2062afb4
    • Hugh Dickins's avatar
      mm: fix direct reclaim writeback regression · 8bdd6380
      Hugh Dickins authored 
      Shortly before 3.16-rc1, Dave Jones reported:

  WARNING: CPU: 3 PID: 19721 at fs/xfs/xfs_aops.c:971
           xfs_vm_writepage+0x5ce/0x630 [xfs]()
  CPU: 3 PID: 19721 Comm: trinity-c61 Not tainted 3.15.0+ #3
  Call Trace:
    xfs_vm_writepage+0x5ce/0x630 [xfs]
    shrink_page_list+0x8f9/0xb90
    shrink_inactive_list+0x253/0x510
    shrink_lruvec+0x563/0x6c0
    shrink_zone+0x3b/0x100
    shrink_zones+0x1f1/0x3c0
    try_to_free_pages+0x164/0x380
    __alloc_pages_nodemask+0x822/0xc90
    alloc_pages_vma+0xaf/0x1c0
    handle_mm_fault+0xa31/0xc50
  etc.

 970   if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
 971                   PF_MEMALLOC))

I did not respond at the time, because a glance at the PageDirty block
in shrink_page_list() quickly shows that this is impossible: we don't do
writeback on file pages (other than tmpfs) from direct reclaim nowadays.
Dave was hallucinating, but it would have been disrespectful to say so.

However, my own /var/log/messages now shows similar complaints

  WARNING: CPU: 1 PID: 28814 at fs/ext4/inode.c:1881 ext4_writepage+0xa7/0x38b()
  WARNING: CPU: 0 PID: 27347 at fs/ext4/inode.c:1764 ext4_writepage+0xa7/0x38b()

from stressing some mmotm trees during July.

Could a dirty xfs or ext4 file page somehow get marked PageSwapBacked,
so fail shrink_page_list()'s page_is_file_cache() test, and so proceed
to mapping->a_ops->writepage()?

Yes, 3.16-rc1's commit 68711a74 ("mm, migration: add destination
page freeing callback") has provided such a way to compaction: if
migrating a SwapBacked page fails, its newpage may be put back on the
list for later use with PageSwapBacked still set, and nothing will clear
it.

Whether that can do anything worse than issue WARN_ON_ONCEs, and get
some statistics wrong, is unclear: easier to fix than to think through
the consequences.

Fixing it here, before the put_new_page(), addresses the bug directly,
but is probably the worst place to fix it.  Page migration is doing too
many parts of the job on too many levels: fixing it in
move_to_new_page() to complement its SetPageSwapBacked would be
preferable, except why is it (and newpage->mapping and newpage->index)
done there, rather than down in migrate_page_move_mapping(), once we are
sure of success? Not a cleanup to get into right now, especially not
with memcg cleanups coming in 3.17.
Reported-by: default avatarDave Jones <davej@redhat.com>
Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8bdd6380
    • Linus Torvalds's avatar
      Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux · b401796c
      Linus Torvalds authored 
      Pull drm fixes from Dave Airlie:
 "This is radeon and intel fixes, and is a small bit larger than I'm
  guessing you'd like it to be.

   - i915: fixes 32-bit highmem i915 blank screen, semaphore hang and
     runtime pm fix

   - radeon: gpuvm stability fix for hangs since 3.15, and hang/reboot
     regression on TN/RL devices,

  The only slightly controversial one is the change to use GB for the
  vm_size, which I'm letting through as its a new interface we defined
  in this merge window, and I'd prefer to have the released kernel have
  the final interface rather than changing it later"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/radeon: fix cut and paste issue for hawaii.
  drm/radeon: fix irq ring buffer overflow handling
  drm/i915: Simplify i915_gem_release_all_mmaps()
  drm/radeon: fix error handling in radeon_vm_bo_set_addr
  drm/i915: fix freeze with blank screen booting highmem
  drm/i915: Reorder the semaphore deadlock check, again
  drm/radeon/TN: only enable bapm on MSI systems
  drm/radeon: fix VM IB handling
  drm/radeon: fix handling of radeon_vm_bo_rmv v3
  drm/radeon: let's use GB for vm_size (v2)
      b401796c
    • Linus Torvalds's avatar
      Merge tag 'sound-3.16-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound · 9c550218
      Linus Torvalds authored 
      Pull sound fixes from Takashi Iwai:
 "Here contains only the fixes for the new FireWire bebob driver.  All
  fairly trivial and local fixes, so safe to apply"

* tag 'sound-3.16-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: bebob: Correction for return value of special_clk_ctl_put() in error
  ALSA: bebob: Correction for return value of .put callback
  ALSA: bebob: Use different labels for digital input/output
  ALSA: bebob: Fix a missing to unlock mutex in error handling case
      9c550218
    • Linus Torvalds's avatar
      Merge tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging · 051c2a9f
      Linus Torvalds authored 
      Pull hwmon fix from Guenter Roeck:
 "Fixes to temperature limit and vrm write operations in smsc47m192
  driver"

* tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (smsc47m192) Fix temperature limit and vrm write operations
      051c2a9f
    • Randy Dunlap's avatar
      parport: fix menu breakage · edffe1b6
      Randy Dunlap authored 
      Do not split the PARPORT-related symbols with the new kconfig
symbol ARCH_MIGHT_HAVE_PC_PARPORT. The split was causing incorrect
display of these symbols -- they were not being displayed together
as they should be.

Fixes: d90c3eb3 "Kconfig cleanup (PARPORT_PC dependencies)"
Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: stable@vger.kernel.org # for 3.13, 3.14, 3.15
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      edffe1b6
    • Linus Torvalds's avatar
      Merge tag 'blackfin-3.16-fixes' of... · 32e6e5c3
      Linus Torvalds authored 
      Merge tag 'blackfin-3.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/realmz6/blackfin-linux

Pull blackfin fixes from Steven Miao:
 "smc nor flash PM fix, pinctrl group fix, update defconfig, and build
  fixes"

* tag 'blackfin-3.16-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/realmz6/blackfin-linux:
  blackfin: vmlinux.lds.S: reserve 32 bytes space at the end of data section for XIP kernel
  defconfig: BF609: update spi config name
  irq: blackfin sec: drop duplicated sec priority set
  blackfin: bind different groups of one pinmux function to different state name
  blackfin: fix some bf5xx boards build for missing <linux/gpio.h>
  pm: bf609: cleanup smc nor flash
      32e6e5c3
    • Steven Miao's avatar
      blackfin: vmlinux.lds.S: reserve 32 bytes space at the end of data section for XIP kernel · b76f9823
      Steven Miao authored 
      to collect some undefined section to the end of the data section and avoid section overlap
Signed-off-by: default avatarSteven Miao <realmz6@gmail.com>
      b76f9823
    • Steven Miao's avatar
      defconfig: BF609: update spi config name · ac425b61
      Steven Miao authored 
      Signed-off-by: default avatarSteven Miao <realmz6@gmail.com>
      ac425b61
    • Steven Miao's avatar
      irq: blackfin sec: drop duplicated sec priority set · 814ecd0d
      Steven Miao authored 
      Signed-off-by: default avatarSteven Miao <realmz6@gmail.com>
      814ecd0d
    • Sonic Zhang's avatar
      blackfin: bind different groups of one pinmux function to different state name · 3f68e175
      Sonic Zhang authored 
      Signed-off-by: default avatarSonic Zhang <sonic.zhang@analog.com>
Signed-off-by: default avatarSteven Miao <realmz6@gmail.com>
      3f68e175
    • Steven Miao's avatar
      blackfin: fix some bf5xx boards build for missing <linux/gpio.h> · 4ba7b5f0
      Steven Miao authored 
      Signed-off-by: default avatarSteven Miao <realmz6@gmail.com>
      4ba7b5f0
    • Steven Miao's avatar
      pm: bf609: cleanup smc nor flash · c6a26ce9
      Steven Miao authored 
      drop smc pin state change code, pin state will be saved in pinctrl-adi2 driver
cleanup nor flash init/exit for pm suspend/resume
Signed-off-by: default avatarSteven Miao <realmz6@gmail.com>
      c6a26ce9
  9. 25 Jul, 2014 6 commits
  11. 24 Jul, 2014 9 commits
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