1. 07 Jul, 2015 1 commit
    • Shreyas B. Prabhu's avatar
      powerpc/powernv: Fix race in updating core_idle_state · b32aadc1
      Shreyas B. Prabhu authored
      core_idle_state is maintained for each core. It uses 0-7 bits to track
      whether a thread in the core has entered fastsleep or winkle. 8th bit is
      used as a lock bit.
      The lock bit is set in these 2 scenarios-
       - The thread is first in subcore to wakeup from sleep/winkle.
       - If its the last thread in the core about to enter sleep/winkle
      
      While the lock bit is set, if any other thread in the core wakes up, it
      loops until the lock bit is cleared before proceeding in the wakeup
      path. This helps prevent race conditions w.r.t fastsleep workaround and
      prevents threads from switching to process context before core/subcore
      resources are restored.
      
      But, in the path to sleep/winkle entry, we currently don't check for
      lock-bit. This exposes us to following race when running with subcore
      on-
      
      First thread in the subcorea		Another thread in the same
      waking up		   		core entering sleep/winkle
      
      lwarx   r15,0,r14
      ori     r15,r15,PNV_CORE_IDLE_LOCK_BIT
      stwcx.  r15,0,r14
      [Code to restore subcore state]
      
      						lwarx   r15,0,r14
      						[clear thread bit]
      						stwcx.  r15,0,r14
      
      andi.   r15,r15,PNV_CORE_IDLE_THREAD_BITS
      stw     r15,0(r14)
      
      Here, after the thread entering sleep clears its thread bit in
      core_idle_state, the value is overwritten by the thread waking up.
      In such cases when the core enters fastsleep, code mistakes an idle
      thread as running. Because of this, the first thread waking up from
      fastsleep which is supposed to resync timebase skips it. So we can
      end up having a core with stale timebase value.
      
      This patch fixes the above race by looping on the lock bit even while
      entering the idle states.
      Signed-off-by: default avatarShreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
      Fixes: 7b54e9f213f76 'powernv/powerpc: Add winkle support for offline cpus'
      Cc: stable@vger.kernel.org # 3.19+
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      b32aadc1
  2. 06 Jul, 2015 7 commits
  3. 05 Jul, 2015 4 commits
    • Linus Torvalds's avatar
      Linux 4.2-rc1 · d770e558
      Linus Torvalds authored
      d770e558
    • Linus Torvalds's avatar
      Merge tag 'platform-drivers-x86-v4.2-2' of... · a585d2b7
      Linus Torvalds authored
      Merge tag 'platform-drivers-x86-v4.2-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86
      
      Pull late x86 platform driver updates from Darren Hart:
       "The following came in a bit later and I wanted them to bake in next a
        few more days before submitting, thus the second pull.
      
        A new intel_pmc_ipc driver, a symmetrical allocation and free fix in
        dell-laptop, a couple minor fixes, and some updated documentation in
        the dell-laptop comments.
      
        intel_pmc_ipc:
         - Add Intel Apollo Lake PMC IPC driver
      
        tc1100-wmi:
         - Delete an unnecessary check before the function call "kfree"
      
        dell-laptop:
         - Fix allocating & freeing SMI buffer page
         - Show info about WiGig and UWB in debugfs
         - Update information about wireless control"
      
      * tag 'platform-drivers-x86-v4.2-2' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
        intel_pmc_ipc: Add Intel Apollo Lake PMC IPC driver
        tc1100-wmi: Delete an unnecessary check before the function call "kfree"
        dell-laptop: Fix allocating & freeing SMI buffer page
        dell-laptop: Show info about WiGig and UWB in debugfs
        dell-laptop: Update information about wireless control
      a585d2b7
    • Linus Torvalds's avatar
      Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs · 1dc51b82
      Linus Torvalds authored
      Pull more vfs updates from Al Viro:
       "Assorted VFS fixes and related cleanups (IMO the most interesting in
        that part are f_path-related things and Eric's descriptor-related
        stuff).  UFS regression fixes (it got broken last cycle).  9P fixes.
        fs-cache series, DAX patches, Jan's file_remove_suid() work"
      
      [ I'd say this is much more than "fixes and related cleanups".  The
        file_table locking rule change by Eric Dumazet is a rather big and
        fundamental update even if the patch isn't huge.   - Linus ]
      
      * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits)
        9p: cope with bogus responses from server in p9_client_{read,write}
        p9_client_write(): avoid double p9_free_req()
        9p: forgetting to cancel request on interrupted zero-copy RPC
        dax: bdev_direct_access() may sleep
        block: Add support for DAX reads/writes to block devices
        dax: Use copy_from_iter_nocache
        dax: Add block size note to documentation
        fs/file.c: __fget() and dup2() atomicity rules
        fs/file.c: don't acquire files->file_lock in fd_install()
        fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation
        vfs: avoid creation of inode number 0 in get_next_ino
        namei: make set_root_rcu() return void
        make simple_positive() public
        ufs: use dir_pages instead of ufs_dir_pages()
        pagemap.h: move dir_pages() over there
        remove the pointless include of lglock.h
        fs: cleanup slight list_entry abuse
        xfs: Correctly lock inode when removing suid and file capabilities
        fs: Call security_ops->inode_killpriv on truncate
        fs: Provide function telling whether file_remove_privs() will do anything
        ...
      1dc51b82
    • Linus Torvalds's avatar
      bluetooth: fix list handling · 9b284cbd
      Linus Torvalds authored
      Commit 835a6a2f ("Bluetooth: Stop sabotaging list poisoning")
      thought that the code was sabotaging the list poisoning when NULL'ing
      out the list pointers and removed it.
      
      But what was going on was that the bluetooth code was using NULL
      pointers for the list as a way to mark it empty, and that commit just
      broke it (and replaced the test with NULL with a "list_empty()" test on
      a uninitialized list instead, breaking things even further).
      
      So fix it all up to use the regular and real list_empty() handling
      (which does not use NULL, but a pointer to itself), also making sure to
      initialize the list properly (the previous NULL case was initialized
      implicitly by the session being allocated with kzalloc())
      
      This is a combination of patches by Marcel Holtmann and Tedd Ho-Jeong
      An.
      
      [ I would normally expect to get this through the bt tree, but I'm going
        to release -rc1, so I'm just committing this directly   - Linus ]
      Reported-and-tested-by: default avatarJörg Otte <jrg.otte@gmail.com>
      Cc: Alexey Dobriyan <adobriyan@gmail.com>
      Original-by: default avatarTedd Ho-Jeong An <tedd.an@intel.com>
      Original-by: Marcel Holtmann <marcel@holtmann.org>:
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9b284cbd
  4. 04 Jul, 2015 28 commits