Commit Graph

9736 Commits

Author SHA1 Message Date
Linus Torvalds
907a426179 Linux v2.6.14-rc4 2005-10-10 18:19:19 -07:00
Andi Kleen
3c92c2ba33 [PATCH] i386: Don't discard upper 32bits of HWCR on K8
Need to use long long, not long when RMWing a MSR. I think
it's harmless right now, but still should be better fixed
if AMD adds any bits in the upper 32bit of HWCR.

Bug was introduced with the TLB flush filter fix for i386

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 16:34:09 -07:00
Andi Kleen
421c7ce6d0 [PATCH] x86_64: Allocate cpu local data for all possible CPUs
CPU hotplug fills up the possible map to NR_CPUs, but it did that after
setting up per CPU data. This lead to CPU data not getting allocated
for all possible CPUs, which lead to various side effects.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 16:33:25 -07:00
Linus Torvalds
af74c3a61d Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6 2005-10-10 16:32:32 -07:00
Linus Torvalds
d7dd8a72ab Use the new "kill_proc_info_as_uid()" for USB disconnect too
All the same issues - we can't just save the pointer to the thread, we
must save the pid/uid/euid combination.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 16:31:30 -07:00
Harald Welte
46113830a1 [PATCH] Fix signal sending in usbdevio on async URB completion
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: Harald Welte <laforge@gnumonks.org>
[ Fixed up types and added symbol exports ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 16:16:33 -07:00
David S. Miller
5d8e1b181c [SPARC64]: Fix Ultra5, Ultra60, et al. boot failures.
On the boot processor, we need to do the move onto the Linux trap
table a little bit differently else we'll take unhandlable faults in
the firmware address space.

Previously we would do the following:

1) Disable PSTATE_IE in %pstate.
2) Set %tba by hand to sparc64_ttable_tl0
3) Initialize alternate, mmu, and interrupt global
   trap registers.
4) Call prom_set_traptable()

That doesn't work very well actually with the way we boot the kernel
VM these days.  It worked by luck on many systems because the firmware
accesses for the prom_set_traptable() call happened to be loaded into
the TLB already, something we cannot assume.

So the new scheme is this:

1) Clear PSTATE_IE in %pstate and set %pil to 15
2) Call prom_set_traptable()
3) Initialize alternate, mmu, and interrupt global
   trap registers.

and this works quite well.  This sequence has been moved into a
callable function in assembler named setup-trap_table().  The idea is
that eventually trampoline.S can use this code as well.  That isn't
possible currently due to some complications, but eventually we should
be able to do it.

Thanks to Meelis Roos for the Ultra5 boot failure report.

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-10 16:12:13 -07:00
Andi Kleen
094804c5a1 [PATCH] x86_64: Fix change_page_attr cache flushing
Noticed by Terence Ripperda

Undo wrong change in global_flush_tlb. We need to flush the caches in all
cases, not just when pages were reverted. This was a bogus optimization
added earlier, but it was wrong.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 16:10:33 -07:00
Linus Torvalds
f96c3bbe91 Merge master.kernel.org:/home/rmk/linux-2.6-ucb 2005-10-10 10:39:26 -07:00
Linus Torvalds
ec384d297c Merge master.kernel.org:/home/rmk/linux-2.6-arm 2005-10-10 10:39:14 -07:00
Vincent Sanders
71e2b2ecc1 [ARM] 2968/1: defconfig for the ARM Collie platform
Patch from Vincent Sanders

Add a defconfig for the ARM Collie platform

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Vincent Sanders <vince@arm.linux.org.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 18:24:09 +01:00
Vincent Sanders
36e5ea6759 [ARM] 2967/1: defconfig for the ARM Corgi platform
Patch from Vincent Sanders

Add a defconfig for the ARM Corgi Zarus platform

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Vincent Sanders <vince@arm.linux.org.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 18:24:08 +01:00
Vincent Sanders
b0bdc7be78 [ARM] 2966/1: defconfig for the ARM Poodle platform
Patch from Vincent Sanders

Add a defconfig for the ARM Poodle Zarus platform

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Vincent Sanders <vince@arm.linux.org.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 18:24:07 +01:00
Vincent Sanders
86b324874f [ARM] 2965/1: defconfig for the ARM Spitz platform
Patch from Vincent Sanders

Add a defconfig for the ARM Spitz Zarus platform

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Vincent Sanders <vince@arm.linux.org.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 18:24:06 +01:00
Nicolas Pitre
585f54575d [ARM] 2956/1: fix the "Fix gcc4 build errors in ucb1x00-core.c"
Patch from Nicolas Pitre

drivers/mfd/ucb1x00-core.c: In function 'ucb1x00_probe':
drivers/mfd/ucb1x00-core.c:482: error: 'ucb1x00_class' undeclared (first use in this function)

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 18:22:17 +01:00
Markus F.X.J. Oberhumer
d347f37227 [PATCH] i386: fix stack alignment for signal handlers
This fixes the setup of the alignment of the signal frame, so that all
signal handlers are run with a properly aligned stack frame.

The current code "over-aligns" the stack pointer so that the stack frame
is effectively always mis-aligned by 4 bytes.  But what we really want
is that on function entry ((sp + 4) & 15) == 0, which matches what would
happen if the stack were aligned before a "call" instruction.

Signed-off-by: Markus F.X.J. Oberhumer <markus@oberhumer.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:45:06 -07:00
Benjamin Herrenschmidt
867f8b4e47 [PATCH] ide: Workaround PM problem
The logic in ide_do_request() doesn't guarantee that both drives will be
serviced after a call.  It may "forget" to service one in some
circumstances, including when one of the drive is suspended (it will
eventually fail to service the slave when the master is suspended for
example).  This prevents the wakeup requests that gets queued on wakeup
from sleep from beeing serviced in some cases when 2 drives are sharing
an IDE bus.

The problem is deep enough in the way this code works (and there are
probably a few other problematic but rare corner cases) and fixing it
would require some major rethinking of the way IDE decides which channel
to service.  This is not 2.6.14 material.  However, in the meantime,
Bart has accepted this simple workaround that will fix the crash on
wakeup from sleep since this specific corner case is actually hitting
users to get into 2.6.14.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:40:47 -07:00
Tom Zanussi
1cc956e12a [PATCH] relayfs: fix bogus param value in call to vmap
The third param in this call to vmap shouldn't be GFP_KERNEL, which
makes no sense, but rather VM_MAP.  Thanks to Al Viro for spotting
this.

Signed-off-by: Tom Zanussi <zanussi@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:39:50 -07:00
Linus Torvalds
eb1b74e097 Merge master.kernel.org:/home/rmk/linux-2.6-arm 2005-10-10 08:38:52 -07:00
Jeff Dike
50f72b5794 [PATCH] uml: fix x86_64 with !CONFIG_FRAME_POINTER
UML/x86_64 doesn't run when built with frame pointers disabled.  There
was an implicit frame pointer assumption in the stub segfault handler.
With frame pointers disabled, UML dies on handling its first page fault.

The container-of part of this is from Paolo Giarrusso <blaisorblade@yahoo.it>.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:37:59 -07:00
Rafael J. Wysocki
3dd083255d [PATCH] x86_64: Set up safe page tables during resume
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: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:36:46 -07:00
Paolo 'Blaisorblade' Giarrusso
52a2d3e45e [PATCH] uml: cleanup whitespace for COW driver
Fix whitespace - I split this off the previous patch for easier review.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:36:00 -07:00
Paolo 'Blaisorblade' Giarrusso
028c0cc16e [PATCH] uml: cleanup byte order macros for COW driver
After restoring the existing code, make it work also when included in
kernelspace code (which isn't currently the case, but at least this will prevent
people from "fixing" it as just happened).
Whitespace is fixed in next patch - it cluttered the diff too much.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:36:00 -07:00
Paolo 'Blaisorblade' Giarrusso
855ec613ca [PATCH] uml: restore include breakage, breaking binary format of COW driver
Commit 44456d37b5, between 2.6.13-rc3 and -rc4,
was a "nice cleanup" which broke something. Revert the offending part.

It broke because:
a) because this part doesn't fall under the description
b) the author didn't know what he was doing here
c) the author didn't try to compile the existing code and see that it worked
   perfectly.
d) the author didn't ask us what was happening
e) you didn't either, and somebody there should have learned that UML is a bit
   different.

In fact, UML is special in linking to host libc and using its includes.

In particular, since host includes always define both __BIG_ENDIAN and
__LITTLE_ENDIAN, ntohll() macros started thinking to be in a big-endian world;
and on-disk compatibility was broken.

Many thanks go to Nix for reporting the problem and correctly diagnosing an
endianness problem.

Btw, this patch restores the previous code, which worked; but the definitions
would be uncorrect if used in kernelspace files.

Next patch addresses that.

Cc: Nix <nix@esperi.org.uk>, Olaf Hering <olh@suse.de>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:36:00 -07:00
Paolo 'Blaisorblade' Giarrusso
54a8a2220c [PATCH] uml: allow building .s/.i/.lst files from userspace files
For files which need to include glibc headers (i.e. userspace files), we
specified the correct flags only for .o, not for .s/.lst/.i. Fix this.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:36:00 -07:00
Paolo 'Blaisorblade' Giarrusso
9e3d862e5c [PATCH] uml: add mode=skas0 as a synonym of skas0
Too many people were confused by skas0 and tried using "mode=skas0". And after
all, they are right - accept this.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:36:00 -07:00
Paolo 'Blaisorblade' Giarrusso
5cd10daa0c [PATCH] Uml: hide commands when not being verbose
Add a missing $(Q) to a "ln" invocation.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:36:00 -07:00
Steven Rostedt
220ec02911 [PATCH] pcmcia: fix task state at pccard thread exit
The pccardd thread has a race in it that it can shutdown in the
TASK_INTERRUPTIBLE state.

Make sure we mark ourselves runnable again as we remove ourselves from
the wait queue.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10 08:33:27 -07:00
Ben Dooks
7dead80cbe [ARM] 2964/1: S3C2410 - serial: add .owner to driver
Patch from Ben Dooks

Initialise the driver's .owner field so that
the device driver can be referenced to the
module that owns it

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 10:20:07 +01:00
Ben Dooks
cdfc8f5079 [ARM] 2963/1: S3C2410 - add .owner field to device_driver
Patch from Ben Dooks

Add initialisation of .owner field so that
the device driver can be referenced to the
module that owns it.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 10:20:06 +01:00
Richard Purdie
7c3989885c [ARM] 2962/1: scoop: Allow GPIO pin suspend state to be specified
Patch from Richard Purdie

Allow the GPIO pin suspend states to be specified for SCOOP devices.
This is needed for correct operation on the spitz platform.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 10:20:06 +01:00
Richard Purdie
1036260e93 [ARM] 2961/1: corgi: Add missing include
Patch from Richard Purdie

Add a missing include from corgi.c

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 10:17:45 +01:00
Richard Purdie
97b8e00e85 [ARM] 2960/1: collie: Add missing scoop call parameters
Patch from Richard Purdie

Add some missing parameters from the scoop calls on collie.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 10:17:44 +01:00
George G. Davis
19da83f632 [ARM] 2959/1: Add test for invalid LDRD/STRD Rd cases in ARM alignment handler
Patch from George G. Davis

Add test for invalid LDRD/STRD Rd cases in ARM alignment handler
and restore SWP printk KERN_ERR.

Signed-off-by: Steve Longerbeam <slongerbeam@mvista.com>
Signed-off-by: George G. Davis <gdavis@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 10:17:44 +01:00
Sascha Hauer
79d13b62ef [ARM] 2958/1: fix definition in imx-regs.h
Patch from Sascha Hauer

Fix PD7_AF_UART2_DTR definition

Signed-off-by: Giancarlo Formicuccia <gformicuccia@atinno.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 10:17:43 +01:00
Sascha Hauer
86371d071b [ARM] 2957/1: imx UART Error handling
Patch from Sascha Hauer

Fix error path in imx_startup.

Signed-off-by: Giancarlo Formicuccia <gformicuccia@atinno.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 10:17:42 +01:00
Russell King
ce80cc1481 [ARM] Update mach-types
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-10-10 09:48:10 +01:00
Sven Hartge
2e457ef667 [SPARC64]: Fix compile error in irq.c
irq.c is missing the inclusion of asm/io.h, which causes
readb() and writeb() the be undefined.

Signed-off-by: Sven Hartge <hartge@ds9.argh.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-10-08 21:12:04 -07:00
Al Viro
dd0fc66fb3 [PATCH] gfp flags annotations - part 1
- 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: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 15:00:57 -07:00
Jens Axboe
3b0e77bd14 [PATCH] scsi_ioctl: only warn for rejected commands
We should not be warning about commands that we allow, even if they are
unknown. So move the if-root-allow check up a notch.

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 15:00:57 -07:00
Linus Torvalds
8aa19ad84c Merge master.kernel.org:/pub/scm/linux/kernel/git/perex/alsa 2005-10-08 14:59:13 -07:00
Linus Torvalds
58a2c3221e Merge master.kernel.org:/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog 2005-10-08 14:58:25 -07:00
Linus Torvalds
dcbd39a1f1 Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2005-10-08 14:57:46 -07:00
Linus Torvalds
582fd48761 Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6 2005-10-08 14:57:20 -07:00
David Howells
7ab501db8c [PATCH] Keys: Possessor permissions should be additive
This patch makes the possessor permissions on a key additive with
user/group/other permissions on the same key.

This permits extra rights to be granted to the possessor of a key without
taking away any rights conferred by them owning the key or having common group
membership.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 14:54:48 -07:00
David Howells
468ed2b0c8 [PATCH] Keys: Split key permissions checking into a .c file
The attached patch splits key permissions checking out of key-ui.h and
moves it into a .c file.  It's quite large and called quite a lot, and
it's about to get bigger with the addition of LSM support for keys...

key_any_permission() is also discarded as it's no longer used.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 14:53:31 -07:00
David Howells
f1a9badcf6 [PATCH] Keys: Add request-key process documentation
The attached patch adds documentation for the process by which request-key
works, including how it permits helper processes to gain access to the
requestor's keyrings.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 14:53:31 -07:00
David Howells
74fd92c511 [PATCH] key: plug request_key_auth memleak
Plug request_key_auth memleak.  This can be triggered by unprivileged
users, so is local DoS.

Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 14:53:31 -07:00
David Vrabel
c2059b2e0b [PATCH] yenta: fix build if YENTA && !CARDBUS
(struct pcmcia_socket).tune_bridge only exists if CONFIG_CARDBUS is set
but building yenta_socket without CardBus is valid.

Signed-off-by: David Vrabel <dvrabel@arcom.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 14:53:31 -07:00
Oleg Nesterov
788e05a67c [PATCH] fix do_coredump() vs SIGSTOP race
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: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 14:53:31 -07:00