Time stamps for the ring buffer are created by the difference between
two events. Each page of the ring buffer holds a full 64 bit timestamp.
Each event has a 27 bit delta stamp from the last event. The unit of time
is nanoseconds, so 27 bits can hold ~134 milliseconds. If two events
happen more than 134 milliseconds apart, a time extend is inserted
to add more bits for the delta. The time extend has 59 bits, which
is good for ~18 years.
Currently the time extend is committed separately from the event.
If an event is discarded before it is committed, due to filtering,
the time extend still exists. If all events are being filtered, then
after ~134 milliseconds a new time extend will be added to the buffer.
This can only happen till the end of the page. Since each page holds
a full timestamp, there is no reason to add a time extend to the
beginning of a page. Time extends can only fill a page that has actual
data at the beginning, so there is no fear that time extends will fill
more than a page without any data.
When reading an event, a loop is made to skip over time extends
since they are only used to maintain the time stamp and are never
given to the caller. As a paranoid check to prevent the loop running
forever, with the knowledge that time extends may only fill a page,
a check is made that tests the iteration of the loop, and if the
iteration is more than the number of time extends that can fit in a page
a warning is printed and the ring buffer is disabled (all of ftrace
is also disabled with it).
There is another event type that is called a TIMESTAMP which can
hold 64 bits of data in the theoretical case that two events happen
18 years apart. This code has not been implemented, but the name
of this event exists, as well as the structure for it. The
size of a TIMESTAMP is 16 bytes, where as a time extend is only
8 bytes. The macro used to calculate how many time extends can fit on
a page used the TIMESTAMP size instead of the time extend size
cutting the amount in half.
The following test case can easily trigger the warning since we only
need to have half the page filled with time extends to trigger the
warning:
# cd /sys/kernel/debug/tracing/
# echo function > current_tracer
# echo 'common_pid < 0' > events/ftrace/function/filter
# echo > trace
# echo 1 > trace_marker
# sleep 120
# cat trace
Enabling the function tracer and then setting the filter to only trace
functions where the process id is negative (no events), then clearing
the trace buffer to ensure that we have nothing in the buffer,
then write to trace_marker to add an event to the beginning of a page,
sleep for 2 minutes (only 35 seconds is probably needed, but this
guarantees the bug), and then finally reading the trace which will
trigger the bug.
This patch fixes the typo and prevents the false positive of that warning.
Reported-by: Hans J. Koch <hjk@linutronix.de>
Tested-by: Hans J. Koch <hjk@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stable Kernel <stable@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
I see the following error message in my kernel log from time to time:
radeon 0000:07:00.0: ffff88007c334000 reserve failed for wait
radeon 0000:07:00.0: ffff88007c334000 reserve failed for wait
After investigation, it turns out that there's nothing to be afraid of
and everything works as intended. So remove the spurious log message.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
These bits are used for internal communication and should
be left enabled. This may fix s/r issues on some systems.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
We should not allocate any object into unmappable vram if we
have no means to access them which on all GPU means having the
CP running and on newer GPU having the blit utility working.
This patch limit the vram allocation to visible vram until
we have acceleration up and running.
Note that it's more than unlikely that we run into any issue
related to that as when acceleration is not woring userspace
should allocate any object in vram beside front buffer which
should fit in visible vram.
V2 use real_vram_size as mc_vram_size could be bigger than
the actual amount of vram
[airlied: fixup r700_cp_stop case]
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This patch disables the fanotify syscalls by just not building them and
letting the cond_syscall() statements in kernel/sys_ni.c redirect them
to sys_ni_syscall().
It was pointed out by Tvrtko Ursulin that the fanotify interface did not
include an explicit prioritization between groups. This is necessary
for fanotify to be usable for hierarchical storage management software,
as they must get first access to the file, before inotify-like notifiers
see the file.
This feature can be added in an ABI compatible way in the next release
(by using a number of bits in the flags field to carry the info) but it
was suggested by Alan that maybe we should just hold off and do it in
the next cycle, likely with an (new) explicit argument to the syscall.
I don't like this approach best as I know people are already starting to
use the current interface, but Alan is all wise and noone on list backed
me up with just using what we have. I feel this is needlessly ripping
the rug out from under people at the last minute, but if others think it
needs to be a new argument it might be the best way forward.
Three choices:
Go with what we got (and implement the new feature next cycle). Add a
new field right now (and implement the new feature next cycle). Wait
till next cycle to release the ABI (and implement the new feature next
cycle). This is number 3.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
commit 511d22247b (tg3: 64 bit stats on all arches), overlooked the
rx_dropped accounting.
We use a full "struct rtnl_link_stats64" to hold rx_dropped value, but
forgot to report it in tg3_get_stats64().
Use an "unsigned long" instead to shrink "struct tg3" by 176 bytes, and
report this value to stats readers.
Increment rx_dropped counter for oversized frames.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Michael Chan <mchan@broadcom.com>
CC: Matt Carlson <mcarlson@broadcom.com>
Acked-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For carrier detection to work properly when binding the driver with a cable
unplugged, netif_carrier_off() should be called after register_netdev(),
not before.
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Russ reported SGI UV is broken recently. He said:
| The SRAT table shows that memory range is spread over two nodes.
|
| SRAT: Node 0 PXM 0 100000000-800000000
| SRAT: Node 1 PXM 1 800000000-1000000000
| SRAT: Node 0 PXM 0 1000000000-1080000000
|
|Previously, the kernel early_node_map[] would show three entries
|with the proper node.
|
|[ 0.000000] 0: 0x00100000 -> 0x00800000
|[ 0.000000] 1: 0x00800000 -> 0x01000000
|[ 0.000000] 0: 0x01000000 -> 0x01080000
|
|The problem is recent community kernel early_node_map[] shows
|only two entries with the node 0 entry overlapping the node 1
|entry.
|
| 0: 0x00100000 -> 0x01080000
| 1: 0x00800000 -> 0x01000000
After looking at the changelog, Found out that it has been broken for a while by
following commit
|commit 8716273cae
|Author: David Rientjes <rientjes@google.com>
|Date: Fri Sep 25 15:20:04 2009 -0700
|
| x86: Export srat physical topology
Before that commit, register_active_regions() is called for every SRAT memory
entry right away.
Use nodememblk_range[] instead of nodes[] in order to make sure we
capture the actual memory blocks registered with each node. nodes[]
contains an extended range which spans all memory regions associated
with a node, but that does not mean that all the memory in between are
included.
Reported-by: Russ Anderson <rja@sgi.com>
Tested-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4CB27BDF.5000800@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: <stable@kernel.org> 2.6.33 .34 .35 .36
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Several other ethtool functions leave heap uncleared (potentially) by
drivers. Some interfaces appear safe (eeprom, etc), in that the sizes
are well controlled. In some situations (e.g. unchecked error conditions),
the heap will remain unchanged in areas before copying back to userspace.
Note that these are less of an issue since these all require CAP_NET_ADMIN.
Cc: stable@kernel.org
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stanse found that i2400m_rx frees skb, but still uses skb->len even
though it has skb_len defined. So use skb_len properly in the code.
And also define it unsinged int rather than size_t to solve
compilation warnings.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Cc: linux-wimax@intel.com
Acked-by: Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stanse found that ia_init_one locks a spinlock and inside of that it
calls ia_start which calls:
* request_irq
* tx_init which does kmalloc(GFP_KERNEL)
Both of them can thus sleep and result in a deadlock. I don't see a
reason to have a per-device spinlock there which is used only there
and inited right before the lock location. So remove it completely.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Chas Williams <chas@cmf.nrl.navy.mil>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stanse found we do in console_show:
kfree_skb(skb);
return skb->len;
which is not good. Fix that by remembering the len and use it in the
function instead.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Chas Williams <chas@cmf.nrl.navy.mil>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
kbuild: fix oldnoconfig to do the right thing
kconfig: Temporarily disable dependency warnings
kconfig: delay symbol direct dependency initialization
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mjg59/platform-drivers-x86:
IPS driver: Fix limit clamping when reducing CPU power
[PATCH 2/2] IPS driver: disable CPU turbo
IPS driver: apply BIOS provided CPU limit if different from default
intel_ips -- ensure we do not enable gpu turbo mode without driver linkage
intel_ips: Print MCP limit exceeded values.
IPS driver: verify BIOS provided limits
IPS driver: don't toggle CPU turbo on unsupported CPUs
NULL pointer might be used in ips_monitor()
Release symbol on error-handling path of ips_get_i915_syms()
old_cpu_power is wrongly divided by 65535 in ips_monitor()
seqno mask of THM_ITV register is 16bit
We shouldn't return directly here because we're still holding the
&soundcard_mutex.
This bug goes all the way back to the start of git. It's strange that
no one has complained about it as a runtime bug.
CC: stable@kernel.org
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Steven Rostedt
Deng-Cheng Zhu
Jean Delvare
Alex Deucher
Jerome Glisse
John Blackwood
Pierre BAILLY
Eric Paris
Eric Dumazet
Paul Fertser
Yinghai Lu
Kees Cook
Jiri Slaby
Linus Torvalds
Takashi Iwai
Luke Yelavich
Dan Carpenter