original_kernel/Documentation
Robin Holt 34441427aa revert "procfs: provide stack information for threads" and its fixup commits
Originally, commit d899bf7b ("procfs: provide stack information for
threads") attempted to introduce a new feature for showing where the
threadstack was located and how many pages are being utilized by the
stack.

Commit c44972f1 ("procfs: disable per-task stack usage on NOMMU") was
applied to fix the NO_MMU case.

Commit 89240ba0 ("x86, fs: Fix x86 procfs stack information for threads on
64-bit") was applied to fix a bug in ia32 executables being loaded.

Commit 9ebd4eba7 ("procfs: fix /proc/<pid>/stat stack pointer for kernel
threads") was applied to fix a bug which had kernel threads printing a
userland stack address.

Commit 1306d603f ('proc: partially revert "procfs: provide stack
information for threads"') was then applied to revert the stack pages
being used to solve a significant performance regression.

This patch nearly undoes the effect of all these patches.

The reason for reverting these is it provides an unusable value in
field 28.  For x86_64, a fork will result in the task->stack_start
value being updated to the current user top of stack and not the stack
start address.  This unpredictability of the stack_start value makes
it worthless.  That includes the intended use of showing how much stack
space a thread has.

Other architectures will get different values.  As an example, ia64
gets 0.  The do_fork() and copy_process() functions appear to treat the
stack_start and stack_size parameters as architecture specific.

I only partially reverted c44972f1 ("procfs: disable per-task stack usage
on NOMMU") .  If I had completely reverted it, I would have had to change
mm/Makefile only build pagewalk.o when CONFIG_PROC_PAGE_MONITOR is
configured.  Since I could not test the builds without significant effort,
I decided to not change mm/Makefile.

I only partially reverted 89240ba0 ("x86, fs: Fix x86 procfs stack
information for threads on 64-bit") .  I left the KSTK_ESP() change in
place as that seemed worthwhile.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Stefani Seibold <stefani@seibold.net>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-11 17:33:41 -07:00
..
ABI
DocBook libata: Fix several inaccuracies in developer's guide 2010-05-05 14:48:27 -04:00
PCI
RCU
accounting
acpi
aoe
arm
auxdisplay
blackfin
block
blockdev
cdrom
cgroups cgroups: fix procs documentation 2010-04-24 11:31:25 -07:00
connector
console
cpu-freq
cpuidle
cris
crypto
development-process
device-mapper
driver-model
dvb
early-userspace
fault-injection
fb
filesystems revert "procfs: provide stack information for threads" and its fixup commits 2010-05-11 17:33:41 -07:00
firmware_class
frv
hwmon
i2c i2c-core: Erase pointer to clientdata on removal 2010-05-04 11:09:27 +02:00
i2o
ia64
ide
infiniband
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2010-05-05 07:53:18 -07:00
ioctl
isdn
ja_JP
kbuild
kdump
ko_KR
kvm
laptops
lguest
m68k
make
mips
misc-devices
mn10300
mtd
namespaces
netlabel
networking
parisc
pcmcia
power
powerpc
pps
prctl
s390
scheduler
scsi
serial
sh
sound
sparc
spi spi: spidev_test gives error upon 1-byte transfer 2010-04-29 16:40:30 -06:00
sysctl
telephony
thermal
timers
trace
uml
usb
video4linux
vm
w1
watchdog
wimax
x86
zh_CN
00-INDEX
BUG-HUNTING
Changes
CodingStyle
DMA-API-HOWTO.txt
DMA-API.txt
DMA-ISA-LPC.txt
DMA-attributes.txt
HOWTO Documentation/HOWTO: update git home URL 2010-04-22 15:24:56 -07:00
IO-mapping.txt
IPMI.txt
IRQ-affinity.txt
IRQ.txt
Intel-IOMMU.txt
Makefile
ManagementStyle
SAK.txt
SELinux.txt
SM501.txt
SecurityBugs
Smack.txt
SubmitChecklist
SubmittingDrivers
SubmittingPatches
VGA-softcursor.txt
applying-patches.txt
atomic_ops.txt
bad_memory.txt
basic_profiling.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
cachetlb.txt
circular-buffers.txt
cpu-hotplug.txt
cpu-load.txt
cputopology.txt
credentials.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt
dmaengine.txt
dontdiff
dynamic-debug-howto.txt
edac.txt
eisa.txt
email-clients.txt
feature-removal-schedule.txt V4L/DVB: feature-removal: announce videotext.h removal 2010-05-06 19:20:50 -03:00
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt
gpio.txt
highuid.txt
hw_random.txt
init.txt
initrd.txt
intel_txt.txt
io-mapping.txt
io_ordering.txt
iostats.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kernel-doc-nano-HOWTO.txt
kernel-docs.txt
kernel-parameters.txt libata: fix docs, RE port and device of libata.force ID separated by point 2010-04-22 21:52:14 -04:00
keys-request-key.txt
keys.txt
kmemcheck.txt
kmemleak.txt
kobject.txt
kprobes.txt
kref.txt
ldm.txt
leds-class.txt
leds-lp3944.txt
local_ops.txt
lockdep-design.txt
lockstat.txt
logo.gif
logo.txt
magic-number.txt
mca.txt
md.txt
memory-barriers.txt
memory-hotplug.txt
memory.txt
mono.txt
mutex-design.txt
nmi_watchdog.txt
nommu-mmap.txt
numastat.txt
oops-tracing.txt
parport-lowlevel.txt
parport.txt
pi-futex.txt
pnp.txt
preempt-locking.txt
printk-formats.txt
prio_tree.txt
rbtree.txt
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rt-mutex-design.txt
rt-mutex.txt
rtc.txt
serial-console.txt
sgi-ioc4.txt
sgi-visws.txt
slow-work.txt
sparse.txt
spinlocks.txt
stable_api_nonsense.txt
stable_kernel_rules.txt Documentation: -stable rules: upstream commit ID requirement reworded 2010-04-22 15:24:56 -07:00
svga.txt
sysfs-rules.txt
sysrq.txt
tomoyo.txt
unaligned-memory-access.txt
unicode.txt
unshare.txt
vgaarbiter.txt
video-output.txt
volatile-considered-harmful.txt
zorro.txt