1. 11 Apr, 2009 2 commits
    • Linus Torvalds's avatar
      Revert "ACPI battery: fix async boot oops" · b0cbc861
      Linus Torvalds authored
      This reverts commit 5d38258e, since the
      underlying problem got fixed properly in the previous commit ("async:
      Fix module loading async-work regression").
      
      Cc: Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>
      Cc: Vegard Nossum <vegard.nossum@gmail.com>
      Cc: Len Brown <len.brown@intel.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b0cbc861
    • Linus Torvalds's avatar
      async: Fix module loading async-work regression · d6de2c80
      Linus Torvalds authored
      Several drivers use asynchronous work to do device discovery, and we
      synchronize with them in the compiled-in case before we actually try to
      mount root filesystems etc.
      
      However, when compiled as modules, that synchronization is missing - the
      module loading completes, but the driver hasn't actually finished
      probing for devices, and that means that any user mode that expects to
      use the devices after the 'insmod' is now potentially broken.
      
      We already saw one case of a similar issue in the ACPI battery code,
      where the kernel itself expected the module to be all done, and unmapped
      the init memory - but the async device discovery was still running.
      That got hacked around by just removing the "__init" (see commit
      5d38258e "ACPI battery: fix async boot
      oops"), but the real fix is to just make the module loading wait for all
      async work to be completed.
      
      It will slow down module loading, but since common devices should be
      built in anyway, and since the bug is really annoying and hard to handle
      from user space (and caused several S3 resume regressions), the simple
      fix to wait is the right one.
      
      This fixes at least
      
      	http://bugzilla.kernel.org/show_bug.cgi?id=13063
      
      but probably a few other bugzilla entries too (12936, for example), and
      is confirmed to fix Rafael's storage driver breakage after resume bug
      report (no bugzilla entry).
      
      We should also be able to now revert that ACPI battery fix.
      Reported-and-tested-by: default avatarRafael J. Wysocki <rjw@suse.com>
      Tested-by: default avatarHeinz Diehl <htd@fancy-poultry.org>
      Acked-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d6de2c80
  2. 10 Apr, 2009 8 commits
  3. 09 Apr, 2009 29 commits
  4. 08 Apr, 2009 1 commit
    • Mikulas Patocka's avatar
      dm kcopyd: fix callback race · 340cd444
      Mikulas Patocka authored
      If the thread calling dm_kcopyd_copy is delayed due to scheduling inside
      split_job/segment_complete and the subjobs complete before the loop in
      split_job completes, the kcopyd callback could be invoked from the
      thread that called dm_kcopyd_copy instead of the kcopyd workqueue.
      
      dm_kcopyd_copy -> split_job -> segment_complete -> job->fn()
      
      Snapshots depend on the fact that callbacks are called from the singlethreaded
      kcopyd workqueue and expect that there is no racing between individual
      callbacks. The racing between callbacks can lead to corruption of exception
      store and it can also mean that exception store callbacks are called twice
      for the same exception - a likely reason for crashes reported inside
      pending_complete() / remove_exception().
      
      This patch fixes two problems:
      
      1. job->fn being called from the thread that submitted the job (see above).
      
      - Fix: hand over the completion callback to the kcopyd thread.
      
      2. job->fn(read_err, write_err, job->context); in segment_complete
      reports the error of the last subjob, not the union of all errors.
      
      - Fix: pass job->write_err to the callback to report all error bits
        (it is done already in run_complete_job)
      
      Cc: stable@kernel.org
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
      340cd444