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  1. 28 6月, 2006 2 次提交
  3. 27 6月, 2006 2 次提交
  5. 26 6月, 2006 1 次提交
    • K
      [PATCH] pacct: add pacct_struct to fix some pacct bugs. · 0e464814
      由 KaiGai Kohei 提交于 
      The pacct facility need an i/o operation when an accounting record is
generated.  There is a possibility to wake OOM killer up.  If OOM killer is
activated, it kills some processes to make them release process memory
regions.

But acct_process() is called in the killed processes context before calling
exit_mm(), so those processes cannot release own memory.  In the results, any
processes stop in this point and it finally cause a system stall.
      0e464814
  7. 23 6月, 2006 2 次提交
  9. 01 5月, 2006 1 次提交
  11. 20 4月, 2006 2 次提交
  13. 15 4月, 2006 1 次提交
  15. 01 4月, 2006 3 次提交
    • K
      [PATCH] wrong error path in dup_fd() leading to oopses in RCU · 42862298
      由 Kirill Korotaev 提交于 
      Wrong error path in dup_fd() - it should return NULL on error,
not an address of already freed memory :/

Triggered by OpenVZ stress test suite.

What is interesting is that it was causing different oopses in RCU like
below:
Call Trace:
   [<c013492c>] rcu_do_batch+0x2c/0x80
   [<c0134bdd>] rcu_process_callbacks+0x3d/0x70
   [<c0126cf3>] tasklet_action+0x73/0xe0
   [<c01269aa>] __do_softirq+0x10a/0x130
   [<c01058ff>] do_softirq+0x4f/0x60
   =======================
   [<c0113817>] smp_apic_timer_interrupt+0x77/0x110
   [<c0103b54>] apic_timer_interrupt+0x1c/0x24
  Code:  Bad EIP value.
   <0>Kernel panic - not syncing: Fatal exception in interrupt
Signed-Off-By: NPavel Emelianov <xemul@sw.ru>
Signed-Off-By: NDmitry Mishin <dim@openvz.org>
Signed-Off-By: NKirill Korotaev <dev@openvz.org>
Signed-Off-By: NLinus Torvalds <torvalds@osdl.org>
      42862298
    • E
      [PATCH] pidhash: Refactor the pid hash table · 92476d7f
      由 Eric W. Biederman 提交于 
      Simplifies the code, reduces the need for 4 pid hash tables, and makes the
code more capable.

In the discussions I had with Oleg it was felt that to a large extent the
cleanup itself justified the work.  With struct pid being dynamically
allocated meant we could create the hash table entry when the pid was
allocated and free the hash table entry when the pid was freed.  Instead of
playing with the hash lists when ever a process would attach or detach to a
process.

For myself the fact that it gave what my previous task_ref patch gave for free
with simpler code was a big win.  The problem is that if you hold a reference
to struct task_struct you lock in 10K of low memory.  If you do that in a user
controllable way like /proc does, with an unprivileged but hostile user space
application with typical resource limits of 1000 fds and 100 processes I can
trigger the OOM killer by consuming all of low memory with task structs, on a
machine wight 1GB of low memory.

If I instead hold a reference to struct pid which holds a pointer to my
task_struct, I don't suffer from that problem because struct pid is 2 orders
of magnitude smaller.  In fact struct pid is small enough that most other
kernel data structures dwarf it, so simply limiting the number of referring
data structures is enough to prevent exhaustion of low memory.

This splits the current struct pid into two structures, struct pid and struct
pid_link, and reduces our number of hash tables from PIDTYPE_MAX to just one.
struct pid_link is the per process linkage into the hash tables and lives in
struct task_struct.  struct pid is given an indepedent lifetime, and holds
pointers to each of the pid types.

The independent life of struct pid simplifies attach_pid, and detach_pid,
because we are always manipulating the list of pids and not the hash table.
In addition in giving struct pid an indpendent life it makes the concept much
more powerful.

Kernel data structures can now embed a struct pid * instead of a pid_t and
not suffer from pid wrap around problems or from keeping unnecessarily
large amounts of memory allocated.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      92476d7f
    • A
      [PATCH] resurrect __put_task_struct · 158d9ebd
      由 Andrew Morton 提交于 
      This just got nuked in mainline.  Bring it back because Eric's patches use it.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      158d9ebd
  17. 29 3月, 2006 9 次提交
  19. 28 3月, 2006 1 次提交
  21. 27 3月, 2006 2 次提交
  23. 24 3月, 2006 2 次提交
    • P
      [PATCH] cpuset memory spread slab cache optimizations · c61afb18
      由 Paul Jackson 提交于 
      The hooks in the slab cache allocator code path for support of NUMA
mempolicies and cpuset memory spreading are in an important code path.  Many
systems will use neither feature.

This patch optimizes those hooks down to a single check of some bits in the
current tasks task_struct flags.  For non NUMA systems, this hook and related
code is already ifdef'd out.

The optimization is done by using another task flag, set if the task is using
a non-default NUMA mempolicy.  Taking this flag bit along with the
PF_SPREAD_PAGE and PF_SPREAD_SLAB flag bits added earlier in this 'cpuset
memory spreading' patch set, one can check for the combination of any of these
special case memory placement mechanisms with a single test of the current
tasks task_struct flags.

This patch also tightens up the code, to save a few bytes of kernel text
space, and moves some of it out of line.  Due to the nested inlines called
from multiple places, we were ending up with three copies of this code, which
once we get off the main code path (for local node allocation) seems a bit
wasteful of instruction memory.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      c61afb18
    • J
      [PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23 · 2056a782
      由 Jens Axboe 提交于 
      Signed-off-by: NJens Axboe <axboe@suse.de>
      2056a782
  25. 23 3月, 2006 1 次提交
    • E
      [PATCH] Shrinks sizeof(files_struct) and better layout · 0c9e63fd
      由 Eric Dumazet 提交于 
      1) Reduce the size of (struct fdtable) to exactly 64 bytes on 32bits
   platforms, lowering kmalloc() allocated space by 50%.

2) Reduce the size of (files_struct), using a special 32 bits (or
   64bits) embedded_fd_set, instead of a 1024 bits fd_set for the
   close_on_exec_init and open_fds_init fields.  This save some ram (248
   bytes per task) as most tasks dont open more than 32 files.  D-Cache
   footprint for such tasks is also reduced to the minimum.

3) Reduce size of allocated fdset.  Currently two full pages are
   allocated, that is 32768 bits on x86 for example, and way too much.  The
   minimum is now L1_CACHE_BYTES.

UP and SMP should benefit from this patch, because most tasks will touch
only one cache line when open()/close() stdin/stdout/stderr (0/1/2),
(next_fd, close_on_exec_init, open_fds_init, fd_array[0 ..  2] being in the
same cache line)
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      0c9e63fd
  27. 22 3月, 2006 1 次提交
  29. 19 3月, 2006 1 次提交
  31. 17 3月, 2006 1 次提交
  33. 14 3月, 2006 1 次提交
    • G
      [PATCH] Fix sigaltstack corruption among cloned threads · f9a3879a
      由 GOTO Masanori 提交于 
      This patch fixes alternate signal stack corruption among cloned threads
with CLONE_SIGHAND (and CLONE_VM) for linux-2.6.16-rc6.

The value of alternate signal stack is currently inherited after a call of
clone(...  CLONE_SIGHAND | CLONE_VM).  But if sigaltstack is set by a
parent thread, and then if multiple cloned child threads (+ parent threads)
call signal handler at the same time, some threads may be conflicted -
because they share to use the same alternative signal stack region.
Finally they get sigsegv.  It's an undesirable race condition.  Note that
child threads created from NPTL pthread_create() also hit this conflict
when the parent thread uses sigaltstack, without my patch.

To fix this problem, this patch clears the child threads' sigaltstack
information like exec().  This behavior follows the SUSv3 specification.
In SUSv3, pthread_create() says "The alternate stack shall not be inherited
(when new threads are initialized)".  It means that sigaltstack should be
cleared when sigaltstack memory space is shared by cloned threads with
CLONE_SIGHAND.

Note that I chose "if (clone_flags & CLONE_SIGHAND)" line because:
  - If clone_flags line is not existed, fork() does not inherit sigaltstack.
  - CLONE_VM is another choice, but vfork() does not inherit sigaltstack.
  - CLONE_SIGHAND implies CLONE_VM, and it looks suitable.
  - CLONE_THREAD is another candidate, and includes CLONE_SIGHAND + CLONE_VM,
    but this flag has a bit different semantics.
I decided to use CLONE_SIGHAND.

[ Changed to test for CLONE_VM && !CLONE_VFORK after discussion --Linus ]
Signed-off-by: NGOTO Masanori <gotom@sanori.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: NLinus Torvalds <torvalds@osdl.org>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      f9a3879a
  35. 12 3月, 2006 1 次提交
  37. 16 2月, 2006 2 次提交
    • O
      [PATCH] fix kill_proc_info() vs fork() theoretical race · dadac81b
      由 Oleg Nesterov 提交于 
      copy_process:

	attach_pid(p, PIDTYPE_PID, p->pid);
	attach_pid(p, PIDTYPE_TGID, p->tgid);

What if kill_proc_info(p->pid) happens in between?

copy_process() holds current->sighand.siglock, so we are safe
in CLONE_THREAD case, because current->sighand == p->sighand.

Otherwise, p->sighand is unlocked, the new process is already
visible to the find_task_by_pid(), but have a copy of parent's
'struct pid' in ->pids[PIDTYPE_TGID].

This means that __group_complete_signal() may hang while doing

	do ... while (next_thread() != p)

We can solve this problem if we reverse these 2 attach_pid()s:

	attach_pid() does wmb()

	group_send_sig_info() calls spin_lock(), which
	provides a read barrier. // Yes ?

I don't think we can hit this race in practice, but still.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      dadac81b
    • O
      [PATCH] fix kill_proc_info() vs CLONE_THREAD race · 3f17da69
      由 Oleg Nesterov 提交于 
      There is a window after copy_process() unlocks ->sighand.siglock
and before it adds the new thread to the thread list.

In that window __group_complete_signal(SIGKILL) will not see the
new thread yet, so this thread will start running while the whole
thread group was supposed to exit.

I beleive we have another good reason to place attach_pid(PID/TGID)
under ->sighand.siglock. We can do the same for

	release_task()->__unhash_process()

	de_thread()->switch_exec_pids()

After that we don't need tasklist_lock to iterate over the thread
list, and we can simplify things, see for example do_sigaction()
or sys_times().
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      3f17da69
  39. 08 2月, 2006 4 次提交