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>
perf events: repair incorrect use of copy_from_user
This makes the perf_event_period() return 0 instead of
-EFAULT on success.
Signed-off-by: John Blackwood<john.blackwood@ccur.com>
Signed-off-by: Joe Korty <joe.korty@ccur.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100928220311.GA18145@tsunami.ccur.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* '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
BugLink: https://bugs.launchpad.net/bugs/653420
Add another HP DV6 notebook (103c:363e) to use STAC_HP_DV5.
Signed-off-by: Luke Yelavich <luke.yelavich@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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>
Currently the pressure range in Cintiq 21UX2 is limited to half of the
supported. This patch fixes the problem.
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Acked-by: Ping Cheng <pingc@wacom.com>
CC: stable@kernel.org
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Commit 861b4ea4 broke oldnoconfig when removed the oldnoconfig checks on
if (input_mode == nonint_oldconfig ||
input_mode == oldnoconfig) {
if (input_mode == nonint_oldconfig &&
sym->name &&
!sym_is_choice_value(sym)) {
to avoid oldnoconfig chugging through the else stanza.
Fix that to restore expected behaviour (which I've confirmed in the
Fedora kernel build that the configs end up looking the same.)
Signed-off-by: Kyle McMartin <kyle@redhat.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
After fixing a use-after-free bug in kconfig, a 'make defconfig' or
'make allmodconfig' fills the screen with warnings that were not
detected before. Given that we are close to the release now, disable the
warnings temporarily and deal with them after 2.6.36.
Signed-off-by: Michal Marek <mmarek@suse.cz>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
ACPI: add DMI to disable AML Vista compatibility on MSI GX723 Notebook
ACPI: Handle ACPI0007 Device in acpi_early_set_pdc
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
ceph: update issue_seq on cap grant
ceph: send cap release message early on failed revoke.
ceph: Update max_len with minimum required size
ceph: Fix return value of encode_fh function
ceph: avoid null deref in osd request error path
ceph: fix list_add usage on unsafe_writes list
* 'drm-intel-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ickle/drm-intel:
drm/i915: Prevent module unload to avoid random memory corruption
* 's5p-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung:
ARM: SAMSUNG: Add a workaround for get_clock() for serial driver
ARM: S5P: Bug fix on errors of build with CONFIG_PREEMPT_NONE
ARM: SAMSUNG: Fix build warnings because of unused codes
Define an _addr_lsb field in the mips and ia64 siginfo_ts, following
the asm-generic version. This just puts the field over padding.
This fixes a compilation problem introduced with a337fda.
Cc: ralf@linux-mips.org
Cc: tony.luck@intel.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Must drop reference taken by blk_make_request().
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org # .35.x
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ATM-C6 was commented out, pending public documentation.
https://bugzilla.kernel.org/show_bug.cgi?id=19762
Tested-by: Dennis Jansen <Dennis.Jansen@...>
Signed-off-by: Len Brown <len.brown@intel.com>
Calling ETHTOOL_GRXCLSRLALL with a large rule_cnt will allocate kernel
heap without clearing it. For the one driver (niu) that implements it,
it will leave the unused portion of heap unchanged and copy the full
contents back to userspace.
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>
setup.phone and setup.eazmsn are 32 character buffers.
rcvmsg.msg_data.byte_array is a 48 character buffer.
sc_adapter[card]->channel[rcvmsg.phy_link_no - 1].dn is 50 chars.
The rcvmsg struct comes from the memcpy_fromio() in receivemessage().
I guess that means it's data off the wire. I'm not very familiar with
this code but I don't see any reason to assume these strings are NULL
terminated.
Also it's weird that "dn" in a 50 character buffer but we only seem to
use 32 characters. In drivers/isdn/sc/scioc.h, "dn" is only a 49
character buffer. So potentially there is still an issue there.
The important thing for now is to prevent the memory corruption.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This BUG is there since the first submit of the code, but only triggered
in last Kernel. It's timing related do to the asynchronous object-creation
behaviour of exofs. (Which should be investigated farther)
The bug is obvious hence the fixed.
Signed-off-by: Boaz Harrosh <Boaz Harrosh bharrosh@panasas.com>
The i915 driver has quite a few module unload bugs, the known ones at
least have fixes that are targeting 2.6.37. However, in order to
maintain a stable kernel, we should prevent this known random memory
corruption following driver unload. This should have very low impact on
normal users who are unlikely to need to unload the i915 driver.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@kernel.org
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Serial drivers call get_clock() very early, before platform bus
has been set up, this requires a special check to let them get
a proper clock. Without this patch, a serial console is broken
on S5PV310 and S5PC210 boards.
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
[kgene.kim@samsung.com: fix coding-style]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
This patch adds header <linux/sched.h> into the below files for build with
CONFIG_PREEMPT_NONE.
arch/arm/mach-s5p6440/cpu.c
arch/arm/mach-s5p6442/cpu.c
arch/arm/mach-s5pc100/cpu.c
arch/arm/mach-s5pv210/cpu.c
Following is error message of in case of s5pv210_defconfig with CONFIG_PREEMPT_NONE.
arch/arm/mach-s5pv210/cpu.c:91: error: implicit declaration of function 'need_resched'
Signed-off-by: SeungChull Suh <sc.suh@samsung.com>
[kgene.kim@samsung.com: removed mach-s5p64x0/cpu.c]
[kgene.kim@samsung.com: added fix mach-s5p6440/cpu.c]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
This patch removes following unused codes for removing build warnings.
arch/arm/plat-samsung/adc.c:438: warning: unused variable 'flags'
arch/arm/mach-s5pv210/clock.c:176: warning: 's5pv210_clk_ip4_ctrl' defined but not used
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
* 'hwpoison-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6:
HWPOISON: Stop shrinking at right page count
HWPOISON: Report correct address granuality for AO huge page errors
HWPOISON: Copy si_addr_lsb to user
page-types.c: fix name of unpoison interface
* 'for-linus' of git://neil.brown.name/md:
md: check return code of read_sb_page
md/raid1: minor bio initialisation improvements.
md/raid1: avoid overflow in raid1 resync when bitmap is in use.
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm: don't drop handle reference on unload
drm/ttm: Fix two race conditions + fix busy codepaths
* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
of/i2c: Fix module load order issue caused by of_i2c.c
i2c: Fix checks which cause legacy suspend to never get called
i2c-pca: Fix waitforcompletion() return value
i2c: Fix for suspend/resume issue
i2c: Remove obsolete cleanup for clientdata
When proc_doulongvec_minmax() is used with an array of longs, and no
min/max check requested (.extra1 or .extra2 being NULL), we dereference a
NULL pointer for the second element of the array.
Noticed while doing some changes in network stack for the "16TB problem"
Fix is to not change min & max pointers in __do_proc_doulongvec_minmax(),
so that all elements of the vector share an unique min/max limit, like
proc_dointvec_minmax().
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need to check parent's thresholds if parent has use_hierarchy == 1 to
be sure that parent's threshold events will be triggered even if parent
itself is not active (no MEM_CGROUP_EVENTS).
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During boot of a 16TB system, the following is printed:
Dentry cache hash table entries: -2147483648 (order: 22, 17179869184 bytes)
Signed-off-by: Robin Holt <holt@sgi.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 5ed3bc7288.
It turns-out that not all drivers are calling ieee80211_tx_status from a
compatible context. Revert this for now and try again later...
Signed-off-by: John W. Linville <linville@tuxdriver.com>
We need to update the issue_seq on any grant operation, be it via an MDS
reply or a separate grant message. The update in the grant path was
missing. This broke cap release for inodes in which the MDS sent an
explicit grant message that was not soon after followed by a successful
MDS reply on the same inode.
Also fix the signedness on seq locals.
Signed-off-by: Sage Weil <sage@newdream.net>
If an MDS tries to revoke caps that we don't have, we want to send
releases early since they probably contain the caps message the MDS
is looking for.
Previously, we only sent the messages if we didn't have the inode either. But
in a multi-mds system we can retain the inode after dropping all caps for
a single MDS.
Signed-off-by: Greg Farnum <gregf@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
encode_fh on error should update max_len with minimum required
size, so that caller can redo the call with the reallocated buffer.
This is required with open by handle patch series
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Sage Weil <sage@newdream.net>
