litmus-rt.git/lib, branch wip-budget

FS-Cache: Don't delete pending pages from the page-store tracking tree

2009-11-19T18:11:29+00:00

Don't delete pending pages from the page-store tracking tree, but rather send
them for another write as they've presumably been updated.

Signed-off-by: David Howells

FS-Cache: Use radix tree preload correctly in tracking of pages to be stored

2009-11-19T18:11:14+00:00

__fscache_write_page() attempts to load the radix tree preallocation pool for
the CPU it is on before calling radix_tree_insert(), as the insertion must be
done inside a pair of spinlocks.

Use of the preallocation pool, however, is contingent on the radix tree being
initialised without __GFP_WAIT specified.  __fscache_acquire_cookie() was
passing GFP_NOFS to INIT_RADIX_TREE() - but that includes __GFP_WAIT.

The solution is to AND out __GFP_WAIT.

Additionally, the banner comment to radix_tree_preload() is altered to make
note of this prerequisite.  Possibly there should be a WARN_ON() too.

Without this fix, I have seen the following recursive deadlock caused by
radix_tree_insert() attempting to allocate memory inside the spinlocked
region, which resulted in FS-Cache being called back into to release memory -
which required the spinlock already held.

=============================================
[ INFO: possible recursive locking detected ]
2.6.32-rc6-cachefs #24
---------------------------------------------
nfsiod/7916 is trying to acquire lock:
 (&cookie->lock){+.+.-.}, at: [] __fscache_uncache_page+0xdb/0x160 [fscache]

but task is already holding lock:
 (&cookie->lock){+.+.-.}, at: [] __fscache_write_page+0x15c/0x3f3 [fscache]

other info that might help us debug this:
5 locks held by nfsiod/7916:
 #0:  (nfsiod){+.+.+.}, at: [] worker_thread+0x19a/0x2e2
 #1:  (&task->u.tk_work#2){+.+.+.}, at: [] worker_thread+0x19a/0x2e2
 #2:  (&cookie->lock){+.+.-.}, at: [] __fscache_write_page+0x15c/0x3f3 [fscache]
 #3:  (&object->lock#2){+.+.-.}, at: [] __fscache_write_page+0x197/0x3f3 [fscache]
 #4:  (&cookie->stores_lock){+.+...}, at: [] __fscache_write_page+0x19f/0x3f3 [fscache]

stack backtrace:
Pid: 7916, comm: nfsiod Not tainted 2.6.32-rc6-cachefs #24
Call Trace:
 [] __lock_acquire+0x1649/0x16e3
 [] ? __lock_acquire+0x7b7/0x16e3
 [] ? dump_trace+0x248/0x257
 [] lock_acquire+0x57/0x6d
 [] ? __fscache_uncache_page+0xdb/0x160 [fscache]
 [] _spin_lock+0x2c/0x3b
 [] ? __fscache_uncache_page+0xdb/0x160 [fscache]
 [] __fscache_uncache_page+0xdb/0x160 [fscache]
 [] ? __fscache_check_page_write+0x0/0x71 [fscache]
 [] nfs_fscache_release_page+0x86/0xc4 [nfs]
 [] nfs_release_page+0x3c/0x41 [nfs]
 [] try_to_release_page+0x32/0x3b
 [] shrink_page_list+0x316/0x4ac
 [] ? mark_held_locks+0x52/0x70
 [] ? _spin_unlock_irq+0x2b/0x31
 [] shrink_inactive_list+0x392/0x67c
 [] ? mark_held_locks+0x52/0x70
 [] shrink_list+0x8d/0x8f
 [] shrink_zone+0x278/0x33c
 [] ? ktime_get_ts+0xad/0xba
 [] try_to_free_pages+0x22e/0x392
 [] ? isolate_pages_global+0x0/0x212
 [] __alloc_pages_nodemask+0x3dc/0x5cf
 [] cache_alloc_refill+0x34d/0x6c1
 [] ? radix_tree_node_alloc+0x52/0x5c
 [] kmem_cache_alloc+0xb2/0x118
 [] radix_tree_node_alloc+0x52/0x5c
 [] radix_tree_insert+0x57/0x19c
 [] __fscache_write_page+0x1e3/0x3f3 [fscache]
 [] __nfs_readpage_to_fscache+0x58/0x11e [nfs]
 [] nfs_readpage_release+0x34/0x9b [nfs]
 [] nfs_readpage_release_full+0x32/0x4b [nfs]
 [] rpc_release_calldata+0x12/0x14 [sunrpc]
 [] rpc_free_task+0x59/0x61 [sunrpc]
 [] rpc_async_release+0x10/0x12 [sunrpc]
 [] worker_thread+0x1ef/0x2e2
 [] ? worker_thread+0x19a/0x2e2
 [] ? thread_return+0x3e/0x101
 [] ? rpc_async_release+0x0/0x12 [sunrpc]
 [] ? autoremove_wake_function+0x0/0x34
 [] ? trace_hardirqs_on+0xd/0xf
 [] ? worker_thread+0x0/0x2e2
 [] kthread+0x7a/0x82
 [] child_rip+0xa/0x20
 [] ? restore_args+0x0/0x30
 [] ? add_wait_queue+0x15/0x44
 [] ? kthread+0x0/0x82
 [] ? child_rip+0x0/0x20

Signed-off-by: David Howells

strcmp: fix overflow and possibly signedness error

2009-11-19T01:18:13+00:00

Doing the strcmp return value as

	signed char __res = *cs - *ct;

is wrong for two reasons.  The subtraction can overflow because __res
doesn't use a type big enough.  Moreover the compared bytes should be
interpreted as unsigned char as specified by POSIX.

The same problem is fixed in strncmp.

Signed-off-by: Uwe Kleine-König 
Cc: Michael Buesch 
Cc: Andreas Schwab 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-11-05T18:54:08+00:00

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, fs: Fix x86 procfs stack information for threads on 64-bit
  x86: Add reboot quirk for 3 series Mac mini
  x86: Fix printk message typo in mtrr cleanup code
  dma-debug: Fix compile warning with PAE enabled
  x86/amd-iommu: Un__init function required on shutdown
  x86/amd-iommu: Workaround for erratum 63

dma-debug: Fix compile warning with PAE enabled

2009-10-29T15:25:50+00:00

When PAE is enabled in the kernel configuration the size of
phys_addr_t differs from the size of a void pointer. The gcc
prints a warning about that in dma-debug code.
This patch fixes the warning by converting the output to
unsigned long long instead of a pointer.

Signed-off-by: Joerg Roedel

powerpc: Minor cleanup to lib/Kconfig.debug

2009-10-27T05:42:42+00:00

We don't need an explicit PPC64 in the DEBUG_PREEMPT dependancies as all
PPC platforms now support TRACE_IRQFLAGS_SUPPORT.

Signed-off-by: Kumar Gala 
Signed-off-by: Benjamin Herrenschmidt

Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6

2009-10-11T18:34:50+00:00

* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6: (21 commits)
  [S390] dasd: fix race condition in resume code
  [S390] Add EX_TABLE for addressing exception in usercopy functions.
  [S390] 64-bit register support for 31-bit processes
  [S390] hibernate: Use correct place for CPU address in lowcore
  [S390] pm: ignore time spend in suspended state
  [S390] zcrypt: Improve some comments
  [S390] zcrypt: Fix sparse warning.
  [S390] perf_counter: fix vdso detection
  [S390] ftrace: drop nmi protection
  [S390] compat: fix truncate system call wrapper
  [S390] Provide arch specific mdelay implementation.
  [S390] Fix enabled udelay for short delays.
  [S390] cio: allow setting boxed devices offline
  [S390] cio: make not operational handling consistent
  [S390] cio: make disconnected handling consistent
  [S390] Fix memory leak in /proc/cio_ignore
  [S390] cio: channel path memory leak
  [S390] module: fix memory leak in s390 module loader
  [S390] Enable kmemleak on s390.
  [S390] 3270 console build fix
  ...

headers: remove sched.h from interrupt.h

2009-10-11T18:20:58+00:00

After m68k's task_thread_info() doesn't refer to current,
it's possible to remove sched.h from interrupt.h and not break m68k!
Many thanks to Heiko Carstens for allowing this.

Signed-off-by: Alexey Dobriyan

[S390] Enable kmemleak on s390.

2009-10-06T08:35:06+00:00

Also increase the maximum possible kmemleak early log entries since
2000 are not sufficient on s390.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky

sscanf(): fix %*s%n

2009-10-01T23:11:16+00:00

When using %*s, sscanf should honor conversion specifiers immediately
following the %*s.  For example, the following code should find the
position of the end of the string "hello".

  int end;
  char buf[] = "hello    world";
  sscanf(buf, "%*s%n", &end);
  printf("%d\n", end);

Ideally, sscanf would advance the fmt and str pointers the same as it
would without the *, but the code for that is rather complicated and is
not included in the patch.

Signed-off-by: Andy Spencer 
Acked-by: WANG Cong 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds