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  1. 10 1月, 2008 1 次提交
  3. 09 1月, 2008 8 次提交
  5. 07 1月, 2008 2 次提交
    • I
      CPU hotplug: fix cpu_is_offline() on !CONFIG_HOTPLUG_CPU · a263898f
      由 Ingo Molnar 提交于 
      make randconfig bootup testing found that the cpufreq code
crashes on bootup, if the powernow-k8 driver is enabled and
if maxcpus=1 passed on the boot line to a !CONFIG_HOTPLUG_CPU
kernel.

First lockdep found out that there's an inconsistent unlock
sequence:

 =====================================
 [ BUG: bad unlock balance detected! ]
 -------------------------------------
 swapper/1 is trying to release lock (&per_cpu(cpu_policy_rwsem, cpu)) at:
 [<ffffffff806ffd8e>] unlock_policy_rwsem_write+0x3c/0x42
 but there are no more locks to release!

Call Trace:
 [<ffffffff806ffd8e>] unlock_policy_rwsem_write+0x3c/0x42
 [<ffffffff80251c29>] print_unlock_inbalance_bug+0x104/0x12c
 [<ffffffff80252f3a>] mark_held_locks+0x56/0x94
 [<ffffffff806ffd8e>] unlock_policy_rwsem_write+0x3c/0x42
 [<ffffffff807008b6>] cpufreq_add_dev+0x2a8/0x5c4
 ...

then shortly afterwards the cpufreq code crashed on an assert:

 ------------[ cut here ]------------
 kernel BUG at drivers/cpufreq/cpufreq.c:1068!
 invalid opcode: 0000 [1] SMP
 [...]
 Call Trace:
  [<ffffffff805145d6>] sysdev_driver_unregister+0x5b/0x91
  [<ffffffff806ff520>] cpufreq_register_driver+0x15d/0x1a2
  [<ffffffff80cc0596>] powernowk8_init+0x86/0x94
 [...]
 ---[ end trace 1e9219be2b4431de ]---

the bug was caused by maxcpus=1 bootup, which brought up the
secondary core as !cpu_online() but !cpu_is_offline() either,
which on on !CONFIG_HOTPLUG_CPU is always 0 (include/linux/cpu.h):

  /* CPUs don't go offline once they're online w/o CONFIG_HOTPLUG_CPU */
  static inline int cpu_is_offline(int cpu) { return 0; }

but the cpufreq code uses cpu_online() and cpu_is_offline() in
a mixed way - the low-level drivers use cpu_online(), while
the cpufreq core uses cpu_is_offline(). This opened up the
possibility to add the non-initialized sysdev device of the
secondary core:

 cpufreq-core: trying to register driver powernow-k8
 cpufreq-core: adding CPU 0
 powernow-k8: BIOS error - no PSB or ACPI _PSS objects
 cpufreq-core: initialization failed
 cpufreq-core: adding CPU 1
 cpufreq-core: initialization failed

which then blew up. The fix is to make cpu_is_offline() always
the negation of cpu_online(). With that fix applied the kernel
boots up fine without crashing:

 Calling initcall 0xffffffff80cc0510: powernowk8_init+0x0/0x94()
 powernow-k8: Found 1 AMD Athlon(tm) 64 X2 Dual Core Processor 3800+ processors (1 cpu cores) (version 2.20.00)
 powernow-k8: BIOS error - no PSB or ACPI _PSS objects
 initcall 0xffffffff80cc0510: powernowk8_init+0x0/0x94() returned -19.
 initcall 0xffffffff80cc0510 ran for 19 msecs: powernowk8_init+0x0/0x94()
 Calling initcall 0xffffffff80cc328f: init_lapic_nmi_sysfs+0x0/0x39()

We could fix this by making CPU enumeration aware of max_cpus, but that
would be more fragile IMO, and the cpu_online(cpu) != cpu_is_offline(cpu)
possibility was quite confusing and a continuous source of bugs too.

Most distributions have kernels with CPU hotplug enabled, so this bug
remained hidden for a long time.

Bug forensics:

The broken cpu_is_offline() API variant was introduced via:

 commit a59d2e4e6977e7b94e003c96a41f07e96cddc340
 Author: Rusty Russell <rusty@rustcorp.com.au>
 Date:   Mon Mar 8 06:06:03 2004 -0800

     [PATCH] minor cleanups for hotplug CPUs

( this predates linux-2.6.git, this commit is available from Thomas's
  historic git tree. )

Then 1.5 years later the cpufreq code made use of it:

 commit c32b6b8e
 Author: Ashok Raj <ashok.raj@intel.com>
 Date:   Sun Oct 30 14:59:54 2005 -0800

     [PATCH] create and destroy cpufreq sysfs entries based on cpu notifiers

 +       if (cpu_is_offline(cpu))
 +               return 0;

which is a correct use of the subtly broken new API. v2.6.15 then
shipped with this bug included.

then it took two more years for random-kernel qa to hit it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a263898f
    • L
      Revert "scsi: revert "[SCSI] Get rid of scsi_cmnd->done"" · 7b3d9545
      由 Linus Torvalds 提交于 
      This reverts commit ac40532e, which gets
us back the original cleanup of 6f5391c2.

It turns out that the bug that was triggered by that commit was
apparently not actually triggered by that commit at all, and just the
testing conditions had changed enough to make it appear to be due to it.

The real problem seems to have been found by Peter Osterlund:

  "pktcdvd sets it [block device size] when opening the /dev/pktcdvd
   device, but when the drive is later opened as /dev/scd0, there is
   nothing that sets it back.  (Btw, 40944 is possible if the disk is a
   CDRW that was formatted with "cdrwtool -m 10236".)

   The problem is that pktcdvd opens the cd device in non-blocking mode
   when pktsetup is run, and doesn't close it again until pktsetup -d is
   run.  The effect is that if you meanwhile open the cd device,
   blkdev.c:do_open() doesn't call bd_set_size() because
   bdev->bd_openers is non-zero."

In particular, to repeat the bug (regardless of whether commit
6f5391c2 is applied or not):

  " 1. Start with an empty drive.
    2. pktsetup 0 /dev/scd0
    3. Insert a CD containing an isofs filesystem.
    4. mount /dev/pktcdvd/0 /mnt/tmp
    5. umount /mnt/tmp
    6. Press the eject button.
    7. Insert a DVD containing a non-writable filesystem.
    8. mount /dev/scd0 /mnt/tmp
    9. find /mnt/tmp -type f -print0 | xargs -0 sha1sum >/dev/null
    10. If the DVD contains data beyond the physical size of a CD, you
        get I/O errors in the terminal, and dmesg reports lots of
        "attempt to access beyond end of device" errors."

which in turn is because the nested open after the media change won't
cause the size to be set properly (because the original open still holds
the block device, and we only do the bd_set_size() when we don't have
other people holding the device open).

The proper fix for that is probably to just do something like

	bdev->bd_inode->i_size = (loff_t)get_capacity(disk)<<9;

in fs/block_dev.c:do_open() even for the cases where we're not the
original opener (but *not* call bd_set_size(), since that will also
change the block size of the device).

Cc: Peter Osterlund <petero2@telia.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7b3d9545
  7. 04 1月, 2008 1 次提交
  9. 03 1月, 2008 3 次提交
  11. 02 1月, 2008 3 次提交
  13. 28 12月, 2007 1 次提交
  15. 27 12月, 2007 5 次提交
  17. 24 12月, 2007 1 次提交
  19. 21 12月, 2007 2 次提交
  21. 20 12月, 2007 3 次提交
  23. 19 12月, 2007 5 次提交
  25. 18 12月, 2007 5 次提交
    • A
      block: let elv_register() return void · 2fdd82bd
      由 Adrian Bunk 提交于 
      elv_register() always returns 0, and there isn't anything it does where
it should return an error (the only error condition is so grave that
it's handled with a BUG_ON).
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
      2fdd82bd
    • C
      quicklist: Set tlb->need_flush if pages are remaining in quicklist 0 · 421d9919
      由 Christoph Lameter 提交于 
      This ensures that the quicklists are drained. Otherwise draining may only
occur when the processor reaches an idle state.

Fixes fatal leakage of pgd_t's on 2.6.22 and later.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Reported-by: NDhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      421d9919
    • N
      Revert "hugetlb: Add hugetlb_dynamic_pool sysctl" · 368d2c63
      由 Nishanth Aravamudan 提交于 
      This reverts commit 54f9f80d ("hugetlb:
Add hugetlb_dynamic_pool sysctl")

Given the new sysctl nr_overcommit_hugepages, the boolean dynamic pool
sysctl is not needed, as its semantics can be expressed by 0 in the
overcommit sysctl (no dynamic pool) and non-0 in the overcommit sysctl
(pool enabled).

(Needed in 2.6.24 since it reverts a post-2.6.23 userspace-visible change)
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Acked-by: NAdam Litke <agl@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      368d2c63
    • N
      hugetlb: introduce nr_overcommit_hugepages sysctl · d1c3fb1f
      由 Nishanth Aravamudan 提交于 
      hugetlb: introduce nr_overcommit_hugepages sysctl

While examining the code to support /proc/sys/vm/hugetlb_dynamic_pool, I
became convinced that having a boolean sysctl was insufficient:

1) To support per-node control of hugepages, I have previously submitted
patches to add a sysfs attribute related to nr_hugepages. However, with
a boolean global value and per-mount quota enforcement constraining the
dynamic pool, adding corresponding control of the dynamic pool on a
per-node basis seems inconsistent to me.

2) Administration of the hugetlb dynamic pool with multiple hugetlbfs
mount points is, arguably, more arduous than it needs to be. Each quota
would need to be set separately, and the sum would need to be monitored.

To ease the administration, and to help make the way for per-node
control of the static & dynamic hugepage pool, I added a separate
sysctl, nr_overcommit_hugepages. This value serves as a high watermark
for the overall hugepage pool, while nr_hugepages serves as a low
watermark. The boolean sysctl can then be removed, as the condition

	nr_overcommit_hugepages > 0

indicates the same administrative setting as

	hugetlb_dynamic_pool == 1

Quotas still serve as local enforcement of the size of the pool on a
per-mount basis.

A few caveats:

1) There is a race whereby the global surplus huge page counter is
incremented before a hugepage has allocated. Another process could then
try grow the pool, and fail to convert a surplus huge page to a normal
huge page and instead allocate a fresh huge page. I believe this is
benign, as no memory is leaked (the actual pages are still tracked
correctly) and the counters won't go out of sync.

2) Shrinking the static pool while a surplus is in effect will allow the
number of surplus huge pages to exceed the overcommit value. As long as
this condition holds, however, no more surplus huge pages will be
allowed on the system until one of the two sysctls are increased
sufficiently, or the surplus huge pages go out of use and are freed.

Successfully tested on x86_64 with the current libhugetlbfs snapshot,
modified to use the new sysctl.
Signed-off-by: NNishanth Aravamudan <nacc@us.ibm.com>
Acked-by: NAdam Litke <agl@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d1c3fb1f
    • A
      apm_event{,info}_t are userspace types · 8d936626
      由 Adam Jackson 提交于 
      These types define the size of data read from /dev/apm_bios.  They should
not be hidden behind #ifdef __KERNEL__.

This is killing my xserver compile, apm_event_t is used in the xserver
source.
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8d936626