The error handling in mem_online_node() is incorrect: hotadd_new_pgdat()
returns NULL if the new pgdat could not have been allocated and a pointer
to it otherwise.
mem_online_node() should fail if hotadd_new_pgdat() fails, not the
inverse. This fixes an issue when memoryless nodes are not onlined and
their sysfs interface is not registered when their first cpu is brought
up.
The bug was introduced by commit cf23422b9d76 ("cpu/mem hotplug: enable
CPUs online before local memory online") iow v2.6.35.
nfs_update_inode will update isize if there is no queued pages. For pNFS,
layoutcommit is supposed to change file size on server, the same effect as queued
pages. nfs_update_inode may be called when dirty pages are written back (nfsi->npages==0)
but layoutcommit is not sent, and it will change client file size according to server
file size. Then client ends up losing what it just writes back in pNFS path.
So we should skip updating client file size if file needs layoutcommit.
When 1GB hugepages are allocated on a system, free(1) reports less
available memory than what really is installed in the box. Also, if the
total size of hugepages allocated on a system is over half of the total
memory size, CommitLimit becomes a negative number.
The problem is that gigantic hugepages (order > MAX_ORDER) can only be
allocated at boot with bootmem, thus its frames are not accounted to
'totalram_pages'. However, they are accounted to hugetlb_total_pages()
What happens to turn CommitLimit into a negative number is this
calculation, in fs/proc/meminfo.c:
A similar calculation occurs in __vm_enough_memory() in mm/mmap.c.
Also, every vm statistic which depends on 'totalram_pages' will render
confusing values, as if system were 'missing' some part of its memory.
Impact of this bug:
When gigantic hugepages are allocated and sysctl_overcommit_memory ==
OVERCOMMIT_NEVER. In a such situation, __vm_enough_memory() goes through
the mentioned 'allowed' calculation and might end up mistakenly returning
-ENOMEM, thus forcing the system to start reclaiming pages earlier than it
would be ususal, and this could cause detrimental impact to overall
system's performance, depending on the workload.
Besides the aforementioned scenario, I can only think of this causing
annoyances with memory reports from /proc/meminfo and free(1).
[akpm@linux-foundation.org: standardize comment layout] Reported-by: Russ Anderson <rja@sgi.com> Signed-off-by: Rafael Aquini <aquini@linux.com> Acked-by: Russ Anderson <rja@sgi.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Commit b6147490e6aac82 ("mmc: tmio: split core functionality, DMA and
MFD glue") broke handling of the TMIO_MMC_WRPROTECT_DISABLE flag by
the tmio-mmc driver. This patch restores the original behaviour.
In some rare cases, nmis are generated immediately after the nmi
handler of the cpu was started. This causes the counter not to be
enabled. Before enabling the nmi handlers we need to set variable
ctr_running first and make sure its value is written to memory.
Also, the patch makes all existing barriers a memory barrier instead
of a compiler barrier only.
Some BIOSes will reset the Intel MISC_ENABLE MSR (specifically the
XD_DISABLE bit) when resuming from S3, which can interact poorly with ebba638ae723d8a8fc2f7abce5ec18b688b791d7. In 32bit PAE mode, this can
lead to a fault when EFER is restored by the kernel wakeup routines,
due to it setting the NX bit for a CPU that (thanks to the BIOS reset)
now incorrectly thinks it lacks the NX feature. (64bit is not affected
because it uses a common CPU bring-up that specifically handles the
XD_DISABLE bit.)
The need for MISC_ENABLE being restored so early is specific to the S3
resume path. Normally, MISC_ENABLE is saved in save_processor_state(),
but this happens after the resume header is created, so just reproduce
the logic here. (acpi_suspend_lowlevel() creates the header, calls
do_suspend_lowlevel, which calls save_processor_state(), so the saved
processor context isn't available during resume header creation.)
[ hpa: Consider for stable if OK in mainline ]
Signed-off-by: Kees Cook <kees.cook@canonical.com> Link: http://lkml.kernel.org/r/20110707011034.GA8523@outflux.net Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Because the socket buffer is freed in the completion interrupt, it is not
safe to access it after submitting it to the hardware.
Acked-by: Sachin Sanap <ssanap@marvell.com> Cc: Zhangfei Gao <zgao6@marvell.com> Cc: Philip Rakity <prakity@marvell.com> Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Disable fast channel change by default on AR2413/AR5413 due to
some bug reports (it still works for me but it's better to be safe).
Add a module parameter "fastchanswitch" in case anyone wants to enable
it and play with it.
Signed-off-by: Nick Kossifidis <mickflemm@gmail.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We would free the proper number of curves, but in the wrong
slots, due to a missing level of indirection through
the pdgain_idx table.
It's simpler just to try to free all four slots, so do that.
Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When opening /dev/snapshot device, snapshot_open() creates memory
bitmaps which are freed in snapshot_release(). But if any of the
callbacks called by pm_notifier_call_chain() returns NOTIFY_BAD, open()
fails, snapshot_release() is never called and bitmaps are not freed.
Next attempt to open /dev/snapshot then triggers BUG_ON() check in
create_basic_memory_bitmaps(). This happens e.g. when vmwatchdog module
is active on s390x.
Signed-off-by: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Pages isolated for migration are accounted with the vmstat counters
NR_ISOLATE_[ANON|FILE]. Callers of migrate_pages() are expected to
increment these counters when pages are isolated from the LRU. Once the
pages have been migrated, they are put back on the LRU or freed and the
isolated count is decremented.
Memory failure is not properly accounting for pages it isolates causing
the NR_ISOLATED counters to be negative. On SMP builds, this goes
unnoticed as negative counters are treated as 0 due to expected per-cpu
drift. On UP builds, the counter is treated by too_many_isolated() as a
large value causing processes to enter D state during page reclaim or
compaction. This patch accounts for pages isolated by memory failure
correctly.
appended patch adds support for the new FTDI FT232H chip. This chip is a
single channel version of the dual FT2232H/quad FT4232H, coming with it's
own default PID 0x6014 (FT2232H uses the same PID 0x6010 like FT2232C,
FT4232H has also it's own PID).
The patch was checked on an UM232H module and a terminal program with TX/RX
shorted to that typing in the terminal reproduced the characters.
Tanya ran into an issue when trying to switch a UAS device from the BOT
configuration to the UAS configuration via the bConfigurationValue sysfs
file. Before installing the UAS configuration, set_bConfigurationValue()
calls usb_disable_device(). That function is supposed to remove all host
controller resources associated with that device, but it leaves some state
in the xHCI host controller.
Commit 0791971ba8fbc44e4f476079f856335ed45e6324
usb: allow drivers to use allocated bandwidth until unbound
added a call to usb_disable_device() in usb_set_configuration(), before
the xHCI bandwidth functions were invoked. That commit fixed a bug, but
also introduced a bug that is triggered when a configured device is
switched to a new configuration.
usb_disable_device() goes through all the motions of unbinding the drivers
attached to active interfaces and removing the USB core structures
associated with those interfaces, but it doesn't actually remove the
endpoints from the internal xHCI host controller bandwidth structures.
When usb_disable_device() calls usb_disable_endpoint() with reset_hardware
set to true, the entries in udev->ep_out and udev->ep_in will be set to
NULL. Usually, when the USB core installs a new configuration,
usb_hcd_alloc_bandwidth() will drop all non-NULL endpoints in udev->ep_out
and udev->ep_in before adding any new endpoints. However, when the new
UAS configuration was added, all those entries were null, so none of the
old endpoints in the BOT configuration were dropped.
The xHCI driver blindly added the UAS configuration endpoints, and some of
the endpoint addresses overlapped with the old BOT configuration
endpoints. This caused the xHCI host to reject the Configure Endpoint
command. Now that the xHCI driver code is cleaned up to reject a
double-add of active endpoints, we need to fix the USB core to properly
drop old endpoints in usb_disable_device().
If the host controller driver needs bandwidth checking support, make
usb_disable_device() call usb_disable_endpoint() with
reset_hardware set to false, drop the endpoints from the xHCI host
controller, and then call usb_disable_endpoint() again with
reset_hardware set to true.
The first call to usb_disable_endpoint() will cancel any pending URBs and
wait on them to be freed in usb_hcd_disable_endpoint(), but will keep the
pointers in udev->ep_out and udev->ep in intact. Then
usb_hcd_alloc_bandwidth() will use those pointers to know which endpoints
to drop.
The final call to usb_disable_endpoint() will do two things:
1. It will call usb_hcd_disable_endpoint() again, which should be harmless
since the ep->urb_list should be empty after the first call to
usb_disable_endpoint() returns.
2. It will set the entries in udev->ep_out and udev->ep in to NULL, and call
usb_hcd_disable_endpoint(). That call will have no effect, since the xHCI
driver doesn't set the endpoint_disable function pointer.
Note that usb_disable_device() will now need to be called with
hcd->bandwidth_mutex held.
This should be backported to kernels as old as 2.6.32.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Reported-by: Tanya Brokhman <tlinder@codeaurora.org> Cc: ablay@codeaurora.org Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When the xHCI driver encounters a Missed Service Interval event for an
isochronous endpoint ring, it means the host controller skipped over
one or more isochronous TDs. For TD that is skipped, skip_isoc_td() is
called. This sets the frame descriptor status to -EXDEV, and also sets
the value stored in the int pointed to by status to -EXDEV.
If the isochronous TD happens to be the last TD in an URB,
handle_tx_event() will use the status variable to give back the URB to
the USB core. That means drivers will see urb->status as -EXDEV.
It turns out that EHCI, UHCI, and OHCI always set urb->status to zero for
an isochronous urb, regardless of what the frame status is. See
itd_complete() in ehci-sched.c:
} else {
/* URB was too late */
desc->status = -EXDEV;
}
}
/* ASSERT: it's really the last itd for this urb
list_for_each_entry (itd, &stream->td_list, itd_list)
BUG_ON (itd->urb == urb);
*/
/* give urb back to the driver; completion often (re)submits */
dev = urb->dev;
ehci_urb_done(ehci, urb, 0);
ehci_urb_done() completes the URB with the status of the third argument, which
is always zero in this case.
It turns out that many USB webcam drivers, such as uvcvideo, cannot
handle urb->status set to a non-zero value. They will not resubmit
their isochronous URBs in that case, and userspace will see a frozen
video.
Change the xHCI driver to be consistent with the EHCI and UHCI driver,
and always set urb->status to 0 for isochronous URBs.
This patch should be backported to kernels as old as 2.6.36
While trying to switch a UAS device from the BOT configuration to the UAS
configuration via the bConfigurationValue file, Tanya ran into an issue in
the USB core. usb_disable_device() sets entries in udev->ep_out and
udev->ep_out to NULL, but doesn't call into the xHCI bandwidth management
functions to remove the BOT configuration endpoints from the xHCI host's
internal structures.
The USB core would then attempt to add endpoints for the UAS
configuration, and some of the endpoints had the same address as endpoints
in the BOT configuration. The xHCI driver blindly added the endpoints
again, but the xHCI host controller rejected the Configure Endpoint
command because active endpoints were added without being dropped.
Make the xHCI driver reject calls to xhci_add_endpoint() that attempt to
add active endpoints without first calling xhci_drop_endpoint().
This should be backported to kernels as old as 2.6.31.
The recent changes to the connector code introduced this bug where even
when a callback was invoked, we would return an error resulting in
double freeing of the skb. This patch fixes this bug.
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We restored tty_ldisc_wait_idle in 100eeae2c5c (TTY: restore
tty_ldisc_wait_idle). We used it in the ldisc changing path to fix the
case where there are tasks in n_tty_read waiting for data and somebody
tries to change ldisc.
Similar to the case above, there may be also tasks waiting in
n_tty_read while hangup is performed. As 65b770468e98 (tty-ldisc: turn
ldisc user count into a proper refcount) removed the wait-until-idle
from all paths, hangup path won't wait for them to disappear either
now. So add it back even to the hangup path.
There is a difference, we need uninterruptible sleep as there is
obviously HUP signal pending. So tty_ldisc_wait_idle now sleeps
without possibility to be interrupted. This is what original
tty_ldisc_wait_idle did. After the wait idle reintroduction
(100eeae2c5c), we have had interruptible sleeps for the ldisc changing
path. But as there is a 5s timeout anyway, we don't allow it to be
interrupted from now on. It's not worth the added complexity of
deciding what kind of sleep we want.
Before 65b770468e98 tty_ldisc_release was called also from
tty_ldisc_release. It is called from tty_release, so I don't think we
need to restore that one.
This is nicely reproducible after constifying the timing when
drivers/tty/n_tty.c is patched as follows ("TTY: ntty, add one more
sanity check" patch is needed to actually see it explode):
%% -1548,6 +1549,7 @@ static int n_tty_open(struct tty_struct *tty)
/* These are ugly. Currently a malloc failure here can panic */
if (!tty->read_buf) {
+ msleep(100);
tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
if (!tty->read_buf)
return -ENOMEM;
%% -1785,6 +1788,7 @@ do_it_again:
break;
}
timeout = schedule_timeout(timeout);
+ msleep(20);
continue;
}
__set_current_state(TASK_RUNNING);
===== With a process: =====
while (1) {
int fd = open(argv[1], O_RDWR);
read(fd, buf, sizeof(buf));
close(fd);
}
===== and its child: =====
setsid();
while (1) {
int fd = open(tty, O_RDWR|O_NOCTTY);
ioctl(fd, TIOCSCTTY, 1);
vhangup();
close(fd);
usleep(100 * (10 + random() % 1000));
}
===== EOF =====
This patch fixes the way of comparison for handling of two or more
clock sources for UART.
For example, if just only one clock source is defined even though
there are two clock sources for UART, the serial driver does not
set proper clock up. Of course, it is problem.
So this patch changes the condition of comparison to avoid useless
setup clock and adds a flag 'NO_NEED_CHECK_CLKSRC' which means
selection of source clock is not required.
In addition, since the Exynos4210 has only one clock source for UART
this patch adds the flag into its common_init_uarts().
Signed-off-by: Boojin Kim <boojin.kim@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The clocksource watchdog code is interruptible and it has been
observed that this can trigger false positives which disable the TSC.
The reason is that an interrupt storm or a long running interrupt
handler between the read of the watchdog source and the read of the
TSC brings the two far enough apart that the delta is larger than the
unstable treshold. Move both reads into a short interrupt disabled
region to avoid that.
Reported-and-tested-by: Vernon Mauery <vernux@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Previously we would check for acpi_sci_override_gsi == gsi every time
a PCI device was enabled. That works during early bootup, but later
on it could lead to triggering unnecessarily the acpi_gsi_to_irq(..) lookup.
The reason is that acpi_sci_override_gsi was declared in __initdata and
after early bootup could contain bogus values.
This patch moves the check for acpi_sci_override_gsi to the
site where the ACPI SCI is preset.
Reported-by: Raghavendra D Prabhu <rprabhu@wnohang.net> Tested-by: Raghavendra D Prabhu <rprabhu@wnohang.net>
[http://lists.xensource.com/archives/html/xen-devel/2011-07/msg00154.html] Suggested-by: Ian Campbell <ijc@hellion.org.uk> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
which means that GSI 20 (or pin 20) is to be overriden for IRQ 9.
Our code that presets the interrupt for ACPI SCI however would
use the GSI 20 instead of IRQ 9 ending up with:
as the ACPI interpreter made a call to 'acpi_gsi_to_irq' which got nine.
It used that value to request an IRQ (request_irq) and since that was not
present it failed.
The fix is to recognize that for interrupts that are overriden (in our
case we only care about the ACPI SCI) we should use the IRQ number
to present the IRQ instead of the using GSI. End result is that we get:
We only need to set max_pfn_mapped to the last pfn mapped on x86_64 to
make sure that cleanup_highmap doesn't remove important mappings at
_end.
We don't need to do this on x86_32 because cleanup_highmap is not called
on x86_32. Besides lowering max_pfn_mapped on x86_32 has the unwanted
side effect of limiting the amount of memory available for the 1:1
kernel pagetable allocation.
This patch reverts the x86_32 part of the original patch.
The MAXSMP config option requires CPUMASK_OFFSTACK, which in turn
requires we init the memory for the maps while we bring up the cpus.
MAXSMP also increases NR_CPUS to 4096. This increase in size exposed an
issue in the argument construction for multicalls from
xen_flush_tlb_others. The args should only need space for the actual
number of cpus.
Signed-off-by: Andrew Jones <drjones@redhat.com>
[v2: Updated to compile on 3.0]
[v3: Updated to compile when CONFIG_SMP is not defined] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Commit 8410ea (drm: rework PCI/platform driver interface) implemented
drm_pci_irq_by_busid() but forgot to make it available in the
drm_pci_bus-struct.
This caused a freeze on my Radeon9600-equipped laptop when executing glxgears.
Thanks to Michel for noticing the flaw.
[airlied: made function static also]
Reported-by: Michel Dänzer <daenzer@vmware.com> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
[drm:i915_hangcheck_ring_idle] *ERROR* Hangcheck timer elapsed... blt
ring idle [waiting on 35064155, at 35064155], missed IRQ?
This works around that problem on by making the blitter command
streamer write interrupt state to the Hardware Status Page when a
MI_USER_INTERRUPT command is decoded, which appears to force the seqno
out to memory before the interrupt happens.
v1->v2: Moved to prior interrupt handler installation and RMW flags as
per feedback.
v2->v3: Removed RMW of flags (by anholt)
Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com> Signed-off-by: Eric Anholt <eric@anholt.net> Tested-by: Chris Wilson <chris@chris-wilson.co.uk> [v1] Tested-by: Eric Anholt <eric@anholt.net> [v1,v3]
(incidence of the bug with a testcase went from avg 2/1000 to
0/12651 in the latest test run (plus more for v1)) Tested-by: Kenneth Graunke <kenneth@whitecape.org> [v1] Tested-by: Robert Hooker <robert.hooker@canonical.com> [v1]
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=33394 Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Certain revisions of the vbios on DCE3.2 cards have a bug
in the transmitter control table which prevents duallink from
being enabled properly on some cards. The action switch statement
jumps to the wrong offset for the OUTPUT_ENABLE action. The fix
is to use the ENABLE action rather than the OUTPUT_ENABLE action
on the affected cards. In fixed version of the vbios, both
actions jump to the same offset, so the change should be safe.
Reported-and-tested-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Alex Deucher <alexdeucher@gmail.com> Signed-off-by: Dave Airlie <airlied@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Revert commit 8f9a3f9b63b8cd3f03be9dc53533f90bd4120e5f. This fixes a
hang when loading the eeprom driver (see bug #35572.) GMBUS will be
re-enabled later, differently.
Signed-off-by: Jean Delvare <khali@linux-fr.org> Reported-by: Marek Otahal <markotahal@gmail.com> Tested-by: Yermandu Patapitafious <yermandu.dev@gmail.com> Tested-by: Andrew Lutomirski <luto@mit.edu> Acked-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Dave Airlie <airlied@redhat.com> Cc: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Initialize dynamically allocated sysfs attributes before device_create_file()
call to suppress lockdep_init_map() warning if lockdep debugging is enabled.
Initialize dynamically allocated sysfs attributes before device_create_file()
call to suppress lockdep_init_map() warning if lockdep debugging is enabled.
Initialize dynamically allocated sysfs attributes before device_create_file()
call to suppress lockdep_init_map() warning if lockdep debugging is enabled.
Andrea Righi reported a case where an exiting task can race against
ksmd::scan_get_next_rmap_item (http://lkml.org/lkml/2011/6/1/742) easily
triggering a NULL pointer dereference in ksmd.
ksm_scan.mm_slot == &ksm_mm_head with only one registered mm
CPU 1 (__ksm_exit) CPU 2 (scan_get_next_rmap_item)
list_empty() is false
lock slot == &ksm_mm_head
list_del(slot->mm_list)
(list now empty)
unlock
lock
slot = list_entry(slot->mm_list.next)
(list is empty, so slot is still ksm_mm_head)
unlock
slot->mm == NULL ... Oops
Close this race by revalidating that the new slot is not simply the list
head again.
Consider this scenario: When the size of the first received udp packet
is bigger than the receive buffer, MSG_TRUNC bit is set in msg->msg_flags.
However, if checksum error happens and this is a blocking socket, it will
goto try_again loop to receive the next packet. But if the size of the
next udp packet is smaller than receive buffer, MSG_TRUNC flag should not
be set, but because MSG_TRUNC bit is not cleared in msg->msg_flags before
receive the next packet, MSG_TRUNC is still set, which is wrong.
Fix this problem by clearing MSG_TRUNC flag when starting over for a
new packet.
Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
udpv6_recvmsg() function is not using the correct variable to determine
whether or not the socket is in non-blocking operation, this will lead
to unexpected behavior when a UDP checksum error occurs.
Consider a non-blocking udp receive scenario: when udpv6_recvmsg() is
called by sock_common_recvmsg(), MSG_DONTWAIT bit of flags variable in
udpv6_recvmsg() is cleared by "flags & ~MSG_DONTWAIT" in this call:
But it will always go to try_again as MSG_DONTWAIT has been cleared
from flags at call time -- only noblock contains the original value
of MSG_DONTWAIT, so the test should be:
if (noblock)
return -EAGAIN;
This is also consistent with what the ipv4/udp code does.
Signed-off-by: Xufeng Zhang <xufeng.zhang@windriver.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Check against mistakenly passing in IPv6 addresses (which would result
in an INADDR_ANY bind) or similar incompatible sockaddrs.
Signed-off-by: Marcus Meissner <meissner@suse.de> Cc: Reinhard Max <max@suse.de> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
A malicious user or buggy application can inject code and trigger an
infinite loop in inet_diag_bc_audit()
Also make sure each instruction is aligned on 4 bytes boundary, to avoid
unaligned accesses.
Reported-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In 2.6.27, commit 393e52e33c6c2 (packet: deliver VLAN TCI to userspace)
added a small information leak.
Add padding field and make sure its zeroed before copy to user.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Like in commit 0972ddb237 (provide cow_metrics() methods to blackhole
dst_ops), we must provide a cow_metrics for bridges fake_dst_ops as
well.
This fixes a regression coming from commits 62fa8a846d7d (net: Implement
read-only protection and COW'ing of metrics.) and 33eb9873a28 (bridge:
initialize fake_rtable metrics)
Signed-off-by: Alexander Holler <holler@ahsoftware.de> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Several crashes in cleanup_once() were reported in recent kernels.
Commit d6cc1d642de9 (inetpeer: various changes) added a race in
unlink_from_unused().
One way to avoid taking unused_peers.lock before doing the list_empty()
test is to catch 0->1 refcnt transitions, using full barrier atomic
operations variants (atomic_cmpxchg() and atomic_inc_return()) instead
of previous atomic_inc() and atomic_add_unless() variants.
We then call unlink_from_unused() only for the owner of the 0->1
transition.
Add a new atomic_add_unless_return() static helper
When ip_vs was adapted to netns the ftp application was not adapted
in a correct way.
However this is a fix to avoid kernel errors. In the long term another solution
might be chosen. I.e the ports that the ftp appl, uses should be per netns.
Signed-off-by: Hans Schillstrom <hans.schillstrom@ericsson.com> Acked-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
As reported by Ingo Molnar, we still have configuration combinations
where use of the WARN_RATELIMIT interfaces break the build because
dependencies don't get met.
Instead of going down the long road of trying to make it so that
ratelimit.h can get included by kernel.h or asm-generic/bug.h,
just move the interface into ratelimit.h and make users have
to include that.
Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Reported-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
A mis-configured filter can spam the logs with lots of stack traces.
Rate-limit the warnings and add printout of the bogus filter information.
Original-patch-by: Ben Greear <greearb@candelatech.com> Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We use priv->mutex to avoid race conditions between chswitch_done()
and mac_channel_switch(), when marking channel switch in
progress. But chswitch_done() can be called in atomic context
from rx_csa() or with mutex already taken from commit_rxon().
To fix remove mutex from chswitch_done() and use atomic bitops
for marking channel switch pending.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We use priv->mutex to avoid race conditions between iwl_chswitch_done()
and iwlagn_mac_channel_switch(), when marking channel switch in
progress. But iwl_chswitch_done() can be called in atomic context
from iwl_rx_csa() or with mutex already taken from iwlagn_commit_rxon().
During channge channel, tx power will not send to uCode, the tx power command
should send after scan complete. but should also can send after RXON command.
Stable fix identified by Stanislaw Gruszka <sgruszka@redhat.com>.
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Commit e9c7469bb4f5 ("md: implment REQ_FLUSH/FUA support")
introduced R5_WantFUA flag and set rw to WRITE_FUA in that case.
However remaining code still checks whether rw is exactly same
as WRITE or not, so FUAed-write ends up with being treated as
READ. Fix it.
This bug has been present since 2.6.37 and the fix is suitable for any
-stable kernel since then. It is not clear why this has not caused
more problems.
The @bio->bi_phys_segments consists of active stripes count in the
lower 16 bits and processed stripes count in the upper 16 bits. So
logical-OR operator should be bitwise one.
This bug has been present since 2.6.27 and the fix is suitable for any
-stable kernel since then. Fortunately the bad code is only used on
error paths and is relatively unlikely to be hit.
Check pers->hot_remove_disk instead of pers->hot_add_disk in slot_store()
during disk removal. The linear personality only has ->hot_add_disk and
no ->hot_remove_disk, so that removing disk in the array resulted to
following kernel bug:
In tomoyo_mount_acl() since 2.6.36, kern_path() was called without checking
dev_name != NULL. As a result, an unprivileged user can trigger oops by issuing
mount(NULL, "/", "ext3", 0, NULL) request.
Fix this by checking dev_name != NULL before calling kern_path(dev_name).
cpufreq_stats leaves behind its sysfs entries, which causes a panic
when something stumbled across them.
(Discovered by unloading cpufreq_stats while powertop was loaded).
Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
After a newly plugged CPU sets the cpu_online bit it enables
interrupts and goes idle. The cpu which brought up the new cpu waits
for the cpu_online bit and when it observes it, it sets the cpu_active
bit for this cpu. The cpu_active bit is the relevant one for the
scheduler to consider the cpu as a viable target.
With forced threaded interrupt handlers which imply forced threaded
softirqs we observed the following race:
When an interrupt happens before the cpu_active bit is set by the cpu
which brought up the newly onlined cpu, then the scheduler refuses to
enqueue the woken thread which is bound to that newly onlined cpu on
that newly onlined cpu due to the not yet set cpu_active bit and
selects a fallback runqueue. Not really an expected and desirable
behaviour.
So far this has only been observed with forced hard/softirq threading,
but in theory this could happen without forced threaded hard/softirqs
as well. It's probably unobservable as it would take a massive
interrupt storm on the newly onlined cpu which causes the softirq loop
to wake up the softirq thread and an even longer delay of the cpu
which waits for the cpu_online bit.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/built-in.o: In function `early_init_dt_check_for_initrd':
/home/florian/dev/kernel/x86/linux-2.6-x86/drivers/of/fdt.c:571:
undefined reference to `early_init_dt_setup_initrd_arch'
make: *** [.tmp_vmlinux1] Error 1
which happens as soon as we enable initrd support on a x86 devicetree
platform such as Intel CE4100.
Signed-off-by: Florian Fainelli <ffainelli@freebox.fr> Acked-by: Grant Likely <grant.likely@secretlab.ca> Cc: Maxime Bizon <mbizon@freebox.fr> Acked-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Link: http://lkml.kernel.org/r/201106061015.50039.ffainelli@freebox.fr Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Ignacy reports that sometimes after leaving an IBSS
joining a new one didn't work because there still
were stations on the list. He fixed it by flushing
stations when attempting to join a new IBSS, but
this shouldn't be happening in the first case. When
I looked into it I saw a race condition in teardown
that could cause stations to be added after flush,
and thus cause this situation. Ignacy confirms that
after applying my patch he hasn't seen this happen
again.
Reported-by: Ignacy Gawedzki <i@lri.fr> Debugged-by: Ignacy Gawedzki <i@lri.fr> Tested-by: Ignacy Gawedzki <i@lri.fr> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When SR-IOV is enabled, i350 devices fail to pass traffic. This is due to
the driver attempting to enable RSS on the PF device, which is not
supported by the i350.
When max_vfs is specified on an i350 adapter, set the number of RSS queues
to 1.
This issue affects 2.6.39 as well.
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com> Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Setting tx power can be deferred during scan or changing channel.
If after that correct tx power settings will not be sent to device,
we can observe transmission problems and timeouts. Force to send
tx power settings also after partial rxon change, to assure device
always be configured with up-to-date settings.
This patch fixes 802.11n stability and performance regression we have
since 2.6.35. It boost performance on my 5GHz N-only network from about
5MB/s to 8MB/s. Similar percentage boost can be observed on 2.4 GHz.
These are test results of 5x downloading of approximately 700MB iso
image:
This was achieved with NetworkManager configured to do not perform
periodical scans, by configuring constant BSSID. With periodical scans,
after some time, performance downgrade to unpatched driver level, like
in example below:
However patch still make better here, since similar test on unpatched
driver make link disconnects with below messages after some time:
wlan1: authenticate with 00:23:69:35:d1:3f (try 1)
wlan1: authenticate with 00:23:69:35:d1:3f (try 2)
wlan1: authenticate with 00:23:69:35:d1:3f (try 3)
wlan1: authentication with 00:23:69:35:d1:3f timed out
On 2.6.35 kernel patch helps against connection hangs with messages:
iwlagn 0000:20:00.0: queue 10 stuck 3 time. Fw reload.
iwlagn 0000:20:00.0: On demand firmware reload
iwlagn 0000:20:00.0: Stopping AGG while state not ON or starting
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The lockdep warning below detects a possible A->B/B->A locking
dependency of mm->mmap_sem and dcookie_mutex. The order in
sync_buffer() is mm->mmap_sem/dcookie_mutex, while in
sys_lookup_dcookie() it is vice versa.
Fixing it in sys_lookup_dcookie() by unlocking dcookie_mutex before
copy_to_user().
oprofiled/4432 is trying to acquire lock:
(&mm->mmap_sem){++++++}, at: [<ffffffff810b444b>] might_fault+0x53/0xa3
but task is already holding lock:
(dcookie_mutex){+.+.+.}, at: [<ffffffff81124d28>] sys_lookup_dcookie+0x45/0x149
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
This fixes the A->B/B->A locking dependency, see the warning below.
The function task_exit_notify() is called with (task_exit_notifier)
.rwsem set and then calls sync_buffer() which locks buffer_mutex. In
sync_start() the buffer_mutex was set to prevent notifier functions to
be started before sync_start() is finished. But when registering the
notifier, (task_exit_notifier).rwsem is locked too, but now in
different order than in sync_buffer(). In theory this causes a locking
dependency, what does not occur in practice since task_exit_notify()
is always called after the notifier is registered which means the lock
is already released.
However, after checking the notifier functions it turned out the
buffer_mutex in sync_start() is unnecessary. This is because
sync_buffer() may be called from the notifiers even if sync_start()
did not finish yet, the buffers are already allocated but empty. No
need to protect this with the mutex.
So we fix this theoretical locking dependency by removing buffer_mutex
in sync_start(). This is similar to the implementation before commit:
750d857 oprofile: fix crash when accessing freed task structs
which introduced the locking dependency.
Lockdep warning:
oprofiled/4447 is trying to acquire lock:
(buffer_mutex){+.+...}, at: [<ffffffffa0000e55>] sync_buffer+0x31/0x3ec [oprofile]
but task is already holding lock:
((task_exit_notifier).rwsem){++++..}, at: [<ffffffff81058026>] __blocking_notifier_call_chain+0x39/0x67
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
Reported-by: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Carl Love <carll@us.ibm.com> Signed-off-by: Robert Richter <robert.richter@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
After registering the task free notifier we possibly have tasks in our
dying_tasks list. Free them after unregistering the notifier in case
of an error.
Signed-off-by: Robert Richter <robert.richter@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
BugLink: https://launchpad.net/bugs/792712
The original reporter states that sound from the internal speakers is
inaudible until using the model=auto quirk. This symptom is due to an
existing quirk mask for 0x102802b* that uses the model=dell quirk. To
limit the possible regressions, leave the existing quirk mask but add
a higher priority specific mask for the reporter's PCI SSID.
Reported-and-tested-by: rodni hipp Signed-off-by: Daniel T Chen <crimsun@ubuntu.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Currently it is possible that snd_soc_new_{mixer,mux,pga} is called with a
DAPM context not matching the widgets context. This can lead to a wrong
prefix_len calculation, which will result in undefined behaviour. To avoid
this always use the DAPM context from the widget itself.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Liam Girdwood <lrg@ti.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
It's possible for the following set of events to happen:
cifsd calls cifs_reconnect which reconnects the socket. A userspace
process then calls cifs_negotiate_protocol to handle the NEGOTIATE and
gets a reply. But, while processing the reply, cifsd calls
cifs_reconnect again. Eventually the GlobalMid_Lock is dropped and the
reply from the earlier NEGOTIATE completes and the tcpStatus is set to
CifsGood. cifs_reconnect then goes through and closes the socket and sets the
pointer to zero, but because the status is now CifsGood, the new socket
is not created and cifs_reconnect exits with the socket pointer set to
NULL.
Fix this by only setting the tcpStatus to CifsGood if the tcpStatus is
CifsNeedNegotiate, and by making sure that generic_ip_connect is always
called at least once in cifs_reconnect.
Note that this is not a perfect fix for this issue. It's still possible
that the NEGOTIATE reply is handled after the socket has been closed and
reconnected. In that case, the socket state will look correct but it no
NEGOTIATE was performed on it be for the wrong socket. In that situation
though the server should just shut down the socket on the next attempted
send, rather than causing the oops that occurs today.
Reported-and-Tested-by: Ben Greear <greearb@candelatech.com> Signed-off-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
AppArmor may do a GFP_KERNEL memory allocation with task_lock(tsk->group_leader);
held when called from security_task_setrlimit. This will only occur when the
task's current policy has been replaced, and the task's creds have not been
updated before entering the LSM security_task_setrlimit() hook.
BUG: sleeping function called from invalid context at mm/slub.c:847
in_atomic(): 1, irqs_disabled(): 0, pid: 1583, name: cupsd
2 locks held by cupsd/1583:
#0: (tasklist_lock){.+.+.+}, at: [<ffffffff8104dafa>] do_prlimit+0x61/0x189
#1: (&(&p->alloc_lock)->rlock){+.+.+.}, at: [<ffffffff8104db2d>]
do_prlimit+0x94/0x189
Pid: 1583, comm: cupsd Not tainted 3.0.0-rc2-git1 #7
Call Trace:
[<ffffffff8102ebf2>] __might_sleep+0x10d/0x112
[<ffffffff810e6f46>] slab_pre_alloc_hook.isra.49+0x2d/0x33
[<ffffffff810e7bc4>] kmem_cache_alloc+0x22/0x132
[<ffffffff8105b6e6>] prepare_creds+0x35/0xe4
[<ffffffff811c0675>] aa_replace_current_profile+0x35/0xb2
[<ffffffff811c4d2d>] aa_current_profile+0x45/0x4c
[<ffffffff811c4d4d>] apparmor_task_setrlimit+0x19/0x3a
[<ffffffff811beaa5>] security_task_setrlimit+0x11/0x13
[<ffffffff8104db6b>] do_prlimit+0xd2/0x189
[<ffffffff8104dea9>] sys_setrlimit+0x3b/0x48
[<ffffffff814062bb>] system_call_fastpath+0x16/0x1b
Signed-off-by: John Johansen <john.johansen@canonical.com> Reported-by: Miles Lane <miles.lane@gmail.com> Signed-off-by: James Morris <jmorris@namei.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Full-speed isoc endpoints specify interval in exponent based form in
frames, not microframes, so we need to adjust accordingly.
NEC xHCI host controllers will return an error code of 0x11 if a full
speed isochronous endpoint is added with the Interval field set to
something less than 3 (2^3 = 8 microframes, or one frame). It is
impossible for a full speed device to have an interval smaller than one
frame.
This was always an issue in the xHCI driver, but commit dfa49c4ad120a784ef1ff0717168aa79f55a483a "USB: xhci - fix math in
xhci_get_endpoint_interval()" removed the clamping of the minimum value
in the Interval field, which revealed this bug.
This needs to be backported to stable kernels back to 2.6.31.
Reported-by: Matt Evans <matt@ozlabs.org> Signed-off-by: Dmitry Torokhov <dtor@vmware.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some Fresco Logic hosts, including those found in the AUAU N533V laptop,
advertise MSI, but fail to actually generate MSI interrupts. Add a new
xHCI quirk to skip MSI enabling for the Fresco Logic host controllers.
Fresco Logic confirms that all chips with PCI vendor ID 0x1b73 and device
ID 0x1000, regardless of PCI revision ID, do not support MSI.
This should be backported to stable kernels as far back as 2.6.36, which
was the first kernel to support MSI on xHCI hosts.
xHCI controllers respond to a Reset Device command when the Slot is in the
Enabled/Disabled state by returning an error. This is fine on other host
controllers, but the Etron xHCI host controller returns a vendor-specific
error code that the xHCI driver doesn't understand. The xHCI driver then
gives up on device enumeration.
Instead of issuing a command that will fail, just return. This fixes the
issue with the xhci driver not working on ASRock P67 Pro/Extreme boards.
This should be backported to stable kernels as far back as 2.6.34.
It breaks some people's machines, so this will all get worked out in the
3.0 kernel release, it's not quite ready for 2.6.39 just yet.
Thanks to Maarten Lankhorst <m.b.lankhorst@gmail.com> for reporting the
issue.
Cc: Maarten Lankhorst <m.b.lankhorst@gmail.com> Cc: Jim Bos <jim876@xs4all.nl> Cc: Matthew Garrett <mjg@redhat.com> Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some USB mass-storage devices have bugs that cause them not to handle
the first READ(10) command they receive correctly. The Corsair
Padlock v2 returns completely bogus data for its first read (possibly
it returns the data in encrypted form even though the device is
supposed to be unlocked). The Feiya SD/SDHC card reader fails to
complete the first READ(10) command after it is plugged in or after a
new card is inserted, returning a status code that indicates it thinks
the command was invalid, which prevents the kernel from retrying the
read.
Since the first read of a new device or a new medium is for the
partition sector, the kernel is unable to retrieve the device's
partition table. Users have to manually issue an "hdparm -z" or
"blockdev --rereadpt" command before they can access the device.
This patch (as1470) works around the problem. It adds a new quirk
flag, US_FL_INVALID_READ10, indicating that the first READ(10) should
always be retried immediately, as should any failing READ(10) commands
(provided the preceding READ(10) command succeeded, to avoid getting
stuck in a loop). The patch also adds appropriate unusual_devs
entries containing the new flag.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Sven Geggus <sven-usbst@geggus.net> Tested-by: Paul Hartman <paul.hartman+linux@gmail.com> CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Protocol stall should not be fatal while reading port or hub status as it is
transient state. Currently hub EP0 STALL during port status read results in
failed device enumeration. This has been observed with ST-Ericsson (formerly
Philips) USB 2.0 Hub (04cc:1521) after connecting keyboard.
The funtion option_send_status times out when sending USB messages
to the interfaces 0, 1, and 2 of this UMTS stick. This results in a
5s timeout in the function causing other tty operations to feel very
sluggish.
This patch adds a blacklist entry for these 3 interfaces on the ZTE
K3765-Z device.
I was also able to reproduce the problem with v2.6.38 and v2.6.39.
This modem really wants sendsetup blacklisted for interfaces 0 and 1,
otherwise the kernel hardlocks for about 10 seconds while waiting for
the modem's firmware to respond, which it of course doesn't do.
A slight complication here is that TCT (who owns the Alcatel brand) used
the same USB IDs for the X200 as the X060s despite the devices having
completely different firmware and AT command sets, so we end up adding
the X060s to the blacklist at the same time. PSA to OEMs: don't use the
same USB IDs for different devices. Really. It makes your kittens cry.
Signed-off-by: Dan Williams <dcbw@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Unconditionally changing the address limit to USER_DS and not restoring
it to its old value in the error path is wrong because it prevents us
using kernel memory on repeated calls to this function. This, in fact,
breaks the fallback of hard coded paths to the init program from being
ever successful if the first candidate fails to load.
With this patch applied switching to USER_DS is delayed until the point
of no return is reached which makes it possible to have a multi-arch
rootfs with one arch specific init binary for each of the (hard coded)
probed paths.
Since the address limit is already set to USER_DS when start_thread()
will be invoked, this redundancy can be safely removed.
Many Linux distributions would enable vesafb in order to display
early stage boot splash. In this case, we will get garbled X
Window screen if running X fbdev on psbfb.
This is because fb0 is occupied by vesafb while psbfb is on fb1.
They tried to drive the same pieces of hardware at the same
time. With unmodified X start-up, it would try to use default
fb0 framebuffer device and unfortunately it is now broken
becaues fb1 supersedes it.
We should let psbfb takeover framebuffer control from vesafb
to get around this problem.