Skip to content
Snippets Groups Projects
Select Git revision
  • llvm_v4.8
  • dev_smp_nullb
  • dev_smp
  • dev_nullb
  • lcd_v4.8 default
  • dev_foobar
  • dev_ixgbe
  • dev_netdummy
  • depriv
  • dev_idl_4.8_no_channels
  • dev_idl_4.8
  • dev_idl
  • temp_lcd_v4.8
  • idl_fixes
  • lcd
  • lcd_stack_protector
  • irq
  • pmfs
  • dev_nvme
  • async
  • sosp-19
  • v3.11.3
  • v3.10.14
  • v3.4.64
  • v3.0.98
  • v3.12-rc3
  • v3.11.2
  • v3.10.13
  • v3.4.63
  • v3.0.97
  • v3.12-rc2
  • v3.12-rc1
  • v3.11.1
  • v3.10.12
  • v3.4.62
  • v3.0.96
  • v3.2.51
  • v3.10.11
  • v3.4.61
  • v3.0.95
40 results
Search by author
  • Any Author
  • Abhiram Balasubramanian Abhiram Balasubramanian abhiram
  • Anton Burtsev Anton Burtsev aburtsev
  • Charlie Jacobsen Charlie Jacobsen cjacobsen
  • David Detweiler David Detweiler ddetweiler
  • David Johnson David Johnson johnsond
  • Michael Quigley Michael Quigley MichaelQuigley
  • Mike Hibler Mike Hibler hibler
  • Robert Ricci Robert Ricci ricci
  • Sarah Spall Sarah Spall spall
  • Scotty Bauer Scotty Bauer ScottyB
  • Vikram Narayanan Vikram Narayanan vikram
11 authors
  1. Oct 17, 2005
  3. Oct 14, 2005
  5. Oct 10, 2005
    • Harald Welte's avatar
      [PATCH] Fix signal sending in usbdevio on async URB completion · 46113830
      Harald Welte authored 
      
If a process issues an URB from userspace and (starts to) terminate
before the URB comes back, we run into the issue described above.  This
is because the urb saves a pointer to "current" when it is posted to the
device, but there's no guarantee that this pointer is still valid
afterwards.

In fact, there are three separate issues:

1) the pointer to "current" can become invalid, since the task could be
   completely gone when the URB completion comes back from the device.

2) Even if the saved task pointer is still pointing to a valid task_struct,
   task_struct->sighand could have gone meanwhile.

3) Even if the process is perfectly fine, permissions may have changed,
   and we can no longer send it a signal.

So what we do instead, is to save the PID and uid's of the process, and
introduce a new kill_proc_info_as_uid() function.

Signed-off-by: default avatarHarald Welte <laforge@gnumonks.org>
[ Fixed up types and added symbol exports ]
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      46113830
    • Rafael J. Wysocki's avatar
      [PATCH] x86_64: Set up safe page tables during resume · 3dd08325
      Rafael J. Wysocki authored 
      
The following patch makes swsusp avoid the possible temporary corruption
of page translation tables during resume on x86-64.  This is achieved by
creating a copy of the relevant page tables that will not be modified by
swsusp and can be safely used by it on resume.

The problem is that during resume on x86-64 swsusp may temporarily
corrupt the page tables used for the direct mapping of RAM.  If that
happens, a page fault occurs and cannot be handled properly, which leads
to the solid hang of the affected system.  This leads to the loss of the
system's state from before suspend and may result in the loss of data or
the corruption of filesystems, so it is a serious issue.  Also, it
appears to happen quite often (for me, as often as 50% of the time).

The problem is related to the fact that (at least) one of the PMD
entries used in the direct memory mapping (starting at PAGE_OFFSET)
points to a page table the physical address of which is much greater
than the physical address of the PMD entry itself.  Moreover,
unfortunately, the physical address of the page table before suspend
(i.e.  the one stored in the suspend image) happens to be different to
the physical address of the corresponding page table used during resume
(i.e.  the one that is valid right before swsusp_arch_resume() in
arch/x86_64/kernel/suspend_asm.S is executed).  Thus while the image is
restored, the "offending" PMD entry gets overwritten, so it does not
point to the right physical address any more (i.e.  there's no page
table at the address pointed to by it, because it points to the address
the page table has been at during suspend).  Consequently, if the PMD
entry is used later on, and it _is_ used in the process of copying the
image pages, a page fault occurs, but it cannot be handled in the normal
way and the system hangs.

In principle we can call create_resume_mapping() from
swsusp_arch_resume() (ie.  from suspend_asm.S), but then the memory
allocations in create_resume_mapping(), resume_pud_mapping(), and
resume_pmd_mapping() must be made carefully so that we use _only_
NosaveFree pages in them (the other pages are overwritten by the loop in
swsusp_arch_resume()).  Additionally, we are in atomic context at that
time, so we cannot use GFP_KERNEL.  Moreover, if one of the allocations
fails, we should free all of the allocated pages, so we need to trace
them somehow.

All of this is done in the appended patch, except that the functions
populating the page tables are located in arch/x86_64/kernel/suspend.c
rather than in init.c.  It may be done in a more elegan way in the
future, with the help of some swsusp patches that are in the works now.

[AK: move some externs into headers, renamed a function]

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      3dd08325
  7. Oct 08, 2005
    • Al Viro's avatar
      [PATCH] gfp flags annotations - part 1 · dd0fc66f
      Al Viro authored 
      
 - added typedef unsigned int __nocast gfp_t;

 - replaced __nocast uses for gfp flags with gfp_t - it gives exactly
   the same warnings as far as sparse is concerned, doesn't change
   generated code (from gcc point of view we replaced unsigned int with
   typedef) and documents what's going on far better.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      dd0fc66f
    • Oleg Nesterov's avatar
      [PATCH] fix do_coredump() vs SIGSTOP race · 788e05a6
      Oleg Nesterov authored 
      
Let's suppose we have 2 threads in thread group:
	A - does coredump
	B - has pending SIGSTOP

thread A						thread B

do_coredump:						get_signal_to_deliver:

  lock(->sighand)
  ->signal->flags = SIGNAL_GROUP_EXIT
  unlock(->sighand)

							lock(->sighand)
							signr = dequeue_signal()
								->signal->flags |= SIGNAL_STOP_DEQUEUED
								return SIGSTOP;

							do_signal_stop:
							    unlock(->sighand)

  coredump_wait:

      zap_threads:
          lock(tasklist_lock)
          send SIGKILL to B
              // signal_wake_up() does nothing
          unlock(tasklist_lock)

							    lock(tasklist_lock)
							    lock(->sighand)
							    re-check sig->flags & SIGNAL_STOP_DEQUEUED, yes
							    set_current_state(TASK_STOPPED);
							    finish_stop:
							        schedule();
							            // ->state == TASK_STOPPED

      wait_for_completion(&startup_done)
         // waits for complete() from B,
         // ->state == TASK_UNINTERRUPTIBLE

We can't wake up 'B' in any way:

	SIGCONT will be ignored because handle_stop_signal() sees
	->signal->flags & SIGNAL_GROUP_EXIT.

	sys_kill(SIGKILL)->__group_complete_signal() will choose
	uninterruptible 'A', so it can't help.

	sys_tkill(B, SIGKILL) will be ignored by specific_send_sig_info()
	because B already has pending SIGKILL.

This scenario is not possbile if 'A' does do_group_exit(), because
it sets sig->flags = SIGNAL_GROUP_EXIT and delivers SIGKILL to
subthreads atomically, holding both tasklist_lock and sighand->lock.
That means that do_signal_stop() will notice !SIGNAL_STOP_DEQUEUED
after re-locking ->sighand. And it is not possible to any other
thread to re-add SIGNAL_STOP_DEQUEUED later, because dequeue_signal()
can only return SIGKILL.

I think it is better to change do_coredump() to do sigaddset(SIGKILL)
and signal_wake_up() under sighand->lock, but this patch is much
simpler.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      788e05a6
  9. Oct 01, 2005
    • Linus Torvalds's avatar
      Fix inequality comparison against "task->state" · 14bf01bb
      Linus Torvalds authored 
      
We should always use bitmask ops, rather than depend on some ordering of
the different states.  With the TASK_NONINTERACTIVE flag, the inequality
doesn't really work.

Oleg Nesterov argues (likely correctly) that this test is unnecessary in
the first place.  However, the minimal fix for now is to at least make
it work in the presense of TASK_NONINTERACTIVE.  Waiting for consensus
from Roland & co on potential bigger cleanups.

Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      14bf01bb
  11. Sep 30, 2005
  13. Sep 29, 2005
  15. Sep 28, 2005
  17. Sep 23, 2005
    • Linus Torvalds's avatar
      Make sure SIGKILL gets proper respect · 188a1eaf
      Linus Torvalds authored 
      
Bhavesh P. Davda <bhavesh@avaya.com> noticed that SIGKILL wouldn't
properly kill a process under just the right cicumstances: a stopped
task that already had another signal queued would get the SIGKILL
queued onto the shared queue, and there it would remain until SIGCONT.

This simplifies the signal acceptance logic, and fixes the bug in the
process.

Losely based on an earlier patch by Bhavesh.

Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      188a1eaf
  19. Sep 22, 2005
  21. Sep 21, 2005
    • Andrew Morton's avatar
      [PATCH] Add printk_clock() · 31f6d9d6
      Andrew Morton authored 
      
ia64's sched_clock() accesses per-cpu data which isn't set up at boot time.
Hence ia64 cannot use printk timestamping, because printk() will crash in
sched_clock().

So make printk() use printk_clock(), defaulting to sched_clock(), overrideable
by the architecture via attribute(weak).

Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      31f6d9d6
  23. Sep 17, 2005
  25. Sep 13, 2005
  27. Sep 12, 2005
  29. Sep 11, 2005
  31. Sep 10, 2005