25 Jun, 2015
1 commit
-
Change the default behavior of watchdog so it only runs on the
housekeeping cores when nohz_full is enabled at build and boot time.
Allow modifying the set of cores the watchdog is currently running on
with a new kernel.watchdog_cpumask sysctl.In the current system, the watchdog subsystem runs a periodic timer that
schedules the watchdog kthread to run. However, nohz_full cores are
designed to allow userspace application code running on those cores to
have 100% access to the CPU. So the watchdog system prevents the
nohz_full application code from being able to run the way it wants to,
thus the motivation to suppress the watchdog on nohz_full cores, which
this patchset provides by default.However, if we disable the watchdog globally, then the housekeeping
cores can't benefit from the watchdog functionality. So we allow
disabling it only on some cores. See Documentation/lockup-watchdogs.txt
for more information.[jhubbard@nvidia.com: fix a watchdog crash in some configurations]
Signed-off-by: Chris Metcalf
Acked-by: Don Zickus
Cc: Ingo Molnar
Cc: Ulrich Obergfell
Cc: Thomas Gleixner
Cc: Peter Zijlstra
Cc: Frederic Weisbecker
Signed-off-by: John Hubbard
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Jun, 2015
1 commit
-
Eric reported that the timer_migration sysctl is not really nice
performance wise as it needs to check at every timer insertion whether
the feature is enabled or not. Further the check does not live in the
timer code, so we have an extra function call which checks an extra
cache line to figure out that it is disabled.We can do better and store that information in the per cpu (hr)timer
bases. I pondered to use a static key, but that's a nightmare to
update from the nohz code and the timer base cache line is hot anyway
when we select a timer base.The old logic enabled the timer migration unconditionally if
CONFIG_NO_HZ was set even if nohz was disabled on the kernel command
line.With this modification, we start off with migration disabled. The user
visible sysctl is still set to enabled. If the kernel switches to NOHZ
migration is enabled, if the user did not disable it via the sysctl
prior to the switch. If nohz=off is on the kernel command line,
migration stays disabled no matter what.Before:
47.76% hog [.] main
14.84% [kernel] [k] _raw_spin_lock_irqsave
9.55% [kernel] [k] _raw_spin_unlock_irqrestore
6.71% [kernel] [k] mod_timer
6.24% [kernel] [k] lock_timer_base.isra.38
3.76% [kernel] [k] detach_if_pending
3.71% [kernel] [k] del_timer
2.50% [kernel] [k] internal_add_timer
1.51% [kernel] [k] get_nohz_timer_target
1.28% [kernel] [k] __internal_add_timer
0.78% [kernel] [k] timerfn
0.48% [kernel] [k] wake_up_nohz_cpuAfter:
48.10% hog [.] main
15.25% [kernel] [k] _raw_spin_lock_irqsave
9.76% [kernel] [k] _raw_spin_unlock_irqrestore
6.50% [kernel] [k] mod_timer
6.44% [kernel] [k] lock_timer_base.isra.38
3.87% [kernel] [k] detach_if_pending
3.80% [kernel] [k] del_timer
2.67% [kernel] [k] internal_add_timer
1.33% [kernel] [k] __internal_add_timer
0.73% [kernel] [k] timerfn
0.54% [kernel] [k] wake_up_nohz_cpuReported-by: Eric Dumazet
Signed-off-by: Thomas Gleixner
Cc: Peter Zijlstra
Cc: Paul McKenney
Cc: Frederic Weisbecker
Cc: Viresh Kumar
Cc: John Stultz
Cc: Joonwoo Park
Cc: Wenbo Wang
Link: http://lkml.kernel.org/r/20150526224512.127050787@linutronix.de
Signed-off-by: Thomas Gleixner
17 Apr, 2015
2 commits
-
When converting unsigned long to int overflows may occur. These currently
are not detected when writing to the sysctl file system.E.g. on a system where int has 32 bits and long has 64 bits
echo 0x800001234 > /proc/sys/kernel/threads-max
has the same effect as
echo 0x1234 > /proc/sys/kernel/threads-maxThe patch adds the missing check in do_proc_dointvec_conv.
With the patch an overflow will result in an error EINVAL when writing to
the the sysctl file system.Signed-off-by: Heinrich Schuchardt
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Users can change the maximum number of threads by writing to
/proc/sys/kernel/threads-max.With the patch the value entered is checked against the same limits that
apply when fork_init is called.Signed-off-by: Heinrich Schuchardt
Cc: Oleg Nesterov
Cc: Ingo Molnar
Cc: Guenter Roeck
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Apr, 2015
1 commit
-
Currently, pages which are marked as unevictable are protected from
compaction, but not from other types of migration. The POSIX real time
extension explicitly states that mlock() will prevent a major page
fault, but the spirit of this is that mlock() should give a process the
ability to control sources of latency, including minor page faults.
However, the mlock manpage only explicitly says that a locked page will
not be written to swap and this can cause some confusion. The
compaction code today does not give a developer who wants to avoid swap
but wants to have large contiguous areas available any method to achieve
this state. This patch introduces a sysctl for controlling compaction
behavior with respect to the unevictable lru. Users who demand no page
faults after a page is present can set compact_unevictable_allowed to 0
and users who need the large contiguous areas can enable compaction on
locked memory by leaving the default value of 1.To illustrate this problem I wrote a quick test program that mmaps a
large number of 1MB files filled with random data. These maps are
created locked and read only. Then every other mmap is unmapped and I
attempt to allocate huge pages to the static huge page pool. When the
compact_unevictable_allowed sysctl is 0, I cannot allocate hugepages
after fragmenting memory. When the value is set to 1, allocations
succeed.Signed-off-by: Eric B Munson
Acked-by: Michal Hocko
Acked-by: Vlastimil Babka
Acked-by: Christoph Lameter
Acked-by: David Rientjes
Acked-by: Rik van Riel
Cc: Vlastimil Babka
Cc: Thomas Gleixner
Cc: Christoph Lameter
Cc: Peter Zijlstra
Cc: Mel Gorman
Cc: David Rientjes
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
15 Apr, 2015
3 commits
-
Merge first patchbomb from Andrew Morton:
- arch/sh updates
- ocfs2 updates
- kernel/watchdog feature
- about half of mm/
* emailed patches from Andrew Morton : (122 commits)
Documentation: update arch list in the 'memtest' entry
Kconfig: memtest: update number of test patterns up to 17
arm: add support for memtest
arm64: add support for memtest
memtest: use phys_addr_t for physical addresses
mm: move memtest under mm
mm, hugetlb: abort __get_user_pages if current has been oom killed
mm, mempool: do not allow atomic resizing
memcg: print cgroup information when system panics due to panic_on_oom
mm: numa: remove migrate_ratelimited
mm: fold arch_randomize_brk into ARCH_HAS_ELF_RANDOMIZE
mm: split ET_DYN ASLR from mmap ASLR
s390: redefine randomize_et_dyn for ELF_ET_DYN_BASE
mm: expose arch_mmap_rnd when available
s390: standardize mmap_rnd() usage
powerpc: standardize mmap_rnd() usage
mips: extract logic for mmap_rnd()
arm64: standardize mmap_rnd() usage
x86: standardize mmap_rnd() usage
arm: factor out mmap ASLR into mmap_rnd
... -
With the current user interface of the watchdog mechanism it is only
possible to disable or enable both lockup detectors at the same time.
This series introduces new kernel parameters and changes the semantics of
some existing kernel parameters, so that the hard lockup detector and the
soft lockup detector can be disabled or enabled individually. With this
series applied, the user interface is as follows.- parameters in /proc/sys/kernel
. soft_watchdog
This is a new parameter to control and examine the run state of
the soft lockup detector.. nmi_watchdog
The semantics of this parameter have changed. It can now be used
to control and examine the run state of the hard lockup detector.. watchdog
This parameter is still available to control the run state of both
lockup detectors at the same time. If this parameter is examined,
it shows the logical OR of soft_watchdog and nmi_watchdog.. watchdog_thresh
The semantics of this parameter are not affected by the patch.- kernel command line parameters
. nosoftlockup
The semantics of this parameter have changed. It can now be used
to disable the soft lockup detector at boot time.. nmi_watchdog=0 or nmi_watchdog=1
Disable or enable the hard lockup detector at boot time. The patch
introduces '=1' as a new option.. nowatchdog
The semantics of this parameter are not affected by the patch. It
is still available to disable both lockup detectors at boot time.Also, remove the proc_dowatchdog() function which is no longer needed.
[dzickus@redhat.com: wrote changelog]
[dzickus@redhat.com: update documentation for kernel params and sysctl]
Signed-off-by: Ulrich Obergfell
Signed-off-by: Don Zickus
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Pull vfs update from Al Viro:
"Part one:- struct filename-related cleanups
- saner iov_iter_init() replacements (and switching the syscalls to
use of those)- ntfs switch to ->write_iter() (Anton)
- aio cleanups and splitting iocb into common and async parts
(Christoph)- assorted fixes (me, bfields, Andrew Elble)
There's a lot more, including the completion of switchover to
->{read,write}_iter(), d_inode/d_backing_inode annotations, f_flags
race fixes, etc, but that goes after #for-davem merge. David has
pulled it, and once it's in I'll send the next vfs pull request"* 'for-linus-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (35 commits)
sg_start_req(): use import_iovec()
sg_start_req(): make sure that there's not too many elements in iovec
blk_rq_map_user(): use import_single_range()
sg_io(): use import_iovec()
process_vm_access: switch to {compat_,}import_iovec()
switch keyctl_instantiate_key_common() to iov_iter
switch {compat_,}do_readv_writev() to {compat_,}import_iovec()
aio_setup_vectored_rw(): switch to {compat_,}import_iovec()
vmsplice_to_user(): switch to import_iovec()
kill aio_setup_single_vector()
aio: simplify arguments of aio_setup_..._rw()
aio: lift iov_iter_init() into aio_setup_..._rw()
lift iov_iter into {compat_,}do_readv_writev()
NFS: fix BUG() crash in notify_change() with patch to chown_common()
dcache: return -ESTALE not -EBUSY on distributed fs race
NTFS: Version 2.1.32 - Update file write from aio_write to write_iter.
VFS: Add iov_iter_fault_in_multipages_readable()
drop bogus check in file_open_root()
switch security_inode_getattr() to struct path *
constify tomoyo_realpath_from_path()
...
26 Mar, 2015
1 commit
-
struct kiocb now is a generic I/O container, so move it to fs.h.
Also do a #include diet for aio.h while we're at it.Signed-off-by: Christoph Hellwig
Signed-off-by: Al Viro
18 Mar, 2015
1 commit
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Add a tuning knob so we can adjust the dirtytime expiration timeout,
which is very useful for testing lazytime.Signed-off-by: Theodore Ts'o
Reviewed-by: Jan Kara
11 Feb, 2015
1 commit
-
Commit ed4d4902ebdd ("mm, hugetlb: remove hugetlb_zero and
hugetlb_infinity") replaced 'unsigned long hugetlb_zero' with 'int zero'
leading to out-of-bounds access in proc_doulongvec_minmax(). Use
'.extra1 = NULL' instead of '.extra1 = &zero'. Passing NULL is
equivalent to passing minimal value, which is 0 for unsigned types.Fixes: ed4d4902ebdd ("mm, hugetlb: remove hugetlb_zero and hugetlb_infinity")
Signed-off-by: Andrey Ryabinin
Reported-by: Dmitry Vyukov
Suggested-by: Manfred Spraul
Acked-by: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Dec, 2014
1 commit
-
Pull tracing updates from Steven Rostedt:
"As the merge window is still open, and this code was not as complex as
I thought it might be. I'm pushing this in now.This will allow Thomas to debug his irq work for 3.20.
This adds two new features:
1) Allow traceopoints to be enabled right after mm_init().
By passing in the trace_event= kernel command line parameter,
tracepoints can be enabled at boot up. For debugging things like
the initialization of interrupts, it is needed to have tracepoints
enabled very early. People have asked about this before and this
has been on my todo list. As it can be helpful for Thomas to debug
his upcoming 3.20 IRQ work, I'm pushing this now. This way he can
add tracepoints into the IRQ set up and have users enable them when
things go wrong.2) Have the tracepoints printed via printk() (the console) when they
are triggered.If the irq code locks up or reboots the box, having the tracepoint
output go into the kernel ring buffer is useless for debugging.
But being able to add the tp_printk kernel command line option
along with the trace_event= option will have these tracepoints
printed as they occur, and that can be really useful for debugging
early lock up or reboot problems.This code is not that intrusive and it passed all my tests. Thomas
tried them out too and it works for his needs.Link: http://lkml.kernel.org/r/20141214201609.126831471@goodmis.org"
* tag 'trace-3.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Add tp_printk cmdline to have tracepoints go to printk()
tracing: Move enabling tracepoints to just after rcu_init()
15 Dec, 2014
1 commit
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Add the kernel command line tp_printk option that will have tracepoints
that are active sent to printk() as well as to the trace buffer.Passing "tp_printk" will activate this. To turn it off, the sysctl
/proc/sys/kernel/tracepoint_printk can have '0' echoed into it. Note,
this only works if the cmdline option is used. Echoing 1 into the sysctl
file without the cmdline option will have no affect.Note, this is a dangerous option. Having high frequency tracepoints send
their data to printk() can possibly cause a live lock. This is another
reason why this is only active if the command line option is used.Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1412121539300.16494@nanos
Suggested-by: Thomas Gleixner
Tested-by: Thomas Gleixner
Acked-by: Thomas Gleixner
Signed-off-by: Steven Rostedt
11 Dec, 2014
1 commit
-
There have been several times where I have had to rebuild a kernel to
cause a panic when hitting a WARN() in the code in order to get a crash
dump from a system. Sometimes this is easy to do, other times (such as
in the case of a remote admin) it is not trivial to send new images to
the user.A much easier method would be a switch to change the WARN() over to a
panic. This makes debugging easier in that I can now test the actual
image the WARN() was seen on and I do not have to engage in remote
debugging.This patch adds a panic_on_warn kernel parameter and
/proc/sys/kernel/panic_on_warn calls panic() in the
warn_slowpath_common() path. The function will still print out the
location of the warning.An example of the panic_on_warn output:
The first line below is from the WARN_ON() to output the WARN_ON()'s
location. After that the panic() output is displayed.WARNING: CPU: 30 PID: 11698 at /home/prarit/dummy_module/dummy-module.c:25 init_dummy+0x1f/0x30 [dummy_module]()
Kernel panic - not syncing: panic_on_warn set ...CPU: 30 PID: 11698 Comm: insmod Tainted: G W OE 3.17.0+ #57
Hardware name: Intel Corporation S2600CP/S2600CP, BIOS RMLSDP.86I.00.29.D696.1311111329 11/11/2013
0000000000000000 000000008e3f87df ffff88080f093c38 ffffffff81665190
0000000000000000 ffffffff818aea3d ffff88080f093cb8 ffffffff8165e2ec
ffffffff00000008 ffff88080f093cc8 ffff88080f093c68 000000008e3f87df
Call Trace:
[] dump_stack+0x46/0x58
[] panic+0xd0/0x204
[] ? init_dummy+0x1f/0x30 [dummy_module]
[] warn_slowpath_common+0xd0/0xd0
[] ? dummy_greetings+0x40/0x40 [dummy_module]
[] warn_slowpath_null+0x1a/0x20
[] init_dummy+0x1f/0x30 [dummy_module]
[] do_one_initcall+0xd4/0x210
[] ? __vunmap+0xc2/0x110
[] load_module+0x16a9/0x1b30
[] ? store_uevent+0x70/0x70
[] ? copy_module_from_fd.isra.44+0x129/0x180
[] SyS_finit_module+0xa6/0xd0
[] system_call_fastpath+0x12/0x17Successfully tested by me.
hpa said: There is another very valid use for this: many operators would
rather a machine shuts down than being potentially compromised either
functionally or security-wise.Signed-off-by: Prarit Bhargava
Cc: Jonathan Corbet
Cc: Rusty Russell
Cc: "H. Peter Anvin"
Cc: Andi Kleen
Cc: Masami Hiramatsu
Acked-by: Yasuaki Ishimatsu
Cc: Fabian Frederick
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
28 Oct, 2014
1 commit
-
File /proc/sys/kernel/numa_balancing_scan_size_mb allows writing of zero.
This bash command reproduces problem:
$ while :; do echo 0 > /proc/sys/kernel/numa_balancing_scan_size_mb; \
echo 256 > /proc/sys/kernel/numa_balancing_scan_size_mb; donedivide error: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 24112 Comm: bash Not tainted 3.17.0+ #8
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88013c852600 ti: ffff880037a68000 task.ti: ffff880037a68000
RIP: 0010:[] [] task_scan_min+0x21/0x50
RSP: 0000:ffff880037a6bce0 EFLAGS: 00010246
RAX: 0000000000000a00 RBX: 00000000000003e8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88013c852600
RBP: ffff880037a6bcf0 R08: 0000000000000001 R09: 0000000000015c90
R10: ffff880239bf6c00 R11: 0000000000000016 R12: 0000000000003fff
R13: ffff88013c852600 R14: ffffea0008d1b000 R15: 0000000000000003
FS: 00007f12bb048700(0000) GS:ffff88007da00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000001505678 CR3: 0000000234770000 CR4: 00000000000006f0
Stack:
ffff88013c852600 0000000000003fff ffff880037a6bd18 ffffffff810741d1
ffff88013c852600 0000000000003fff 000000000002bfff ffff880037a6bda8
ffffffff81077ef7 ffffea0008a56d40 0000000000000001 0000000000000001
Call Trace:
[] task_scan_max+0x11/0x40
[] task_numa_fault+0x1f7/0xae0
[] ? migrate_misplaced_page+0x276/0x300
[] handle_mm_fault+0x62d/0xba0
[] __do_page_fault+0x191/0x510
[] ? native_smp_send_reschedule+0x42/0x60
[] ? check_preempt_curr+0x80/0xa0
[] ? wake_up_new_task+0x11c/0x1a0
[] ? do_fork+0x14d/0x340
[] ? get_unused_fd_flags+0x2b/0x30
[] ? __fd_install+0x1f/0x60
[] do_page_fault+0xc/0x10
[] page_fault+0x22/0x30
RIP [] task_scan_min+0x21/0x50
RSP
---[ end trace 9a826d16936c04de ]---Also fix race in task_scan_min (it depends on compiler behaviour).
Signed-off-by: Kirill Tkhai
Signed-off-by: Peter Zijlstra (Intel)
Cc: Aaron Tomlin
Cc: Andrew Morton
Cc: Dario Faggioli
Cc: David Rientjes
Cc: Jens Axboe
Cc: Kees Cook
Cc: Linus Torvalds
Cc: Paul E. McKenney
Cc: Rik van Riel
Link: http://lkml.kernel.org/r/1413455977.24793.78.camel@tkhai
Signed-off-by: Ingo Molnar
13 Oct, 2014
1 commit
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Pull RCU updates from Ingo Molnar:
"The main changes in this cycle were:- changes related to No-CBs CPUs and NO_HZ_FULL
- RCU-tasks implementation
- torture-test updates
- miscellaneous fixes
- locktorture updates
- RCU documentation updates"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits)
workqueue: Use cond_resched_rcu_qs macro
workqueue: Add quiescent state between work items
locktorture: Cleanup header usage
locktorture: Cannot hold read and write lock
locktorture: Fix __acquire annotation for spinlock irq
locktorture: Support rwlocks
rcu: Eliminate deadlock between CPU hotplug and expedited grace periods
locktorture: Document boot/module parameters
rcutorture: Rename rcutorture_runnable parameter
locktorture: Add test scenario for rwsem_lock
locktorture: Add test scenario for mutex_lock
locktorture: Make torture scripting account for new _runnable name
locktorture: Introduce torture context
locktorture: Support rwsems
locktorture: Add infrastructure for torturing read locks
torture: Address race in module cleanup
locktorture: Make statistics generic
locktorture: Teach about lock debugging
locktorture: Support mutexes
locktorture: Add documentation
...
10 Oct, 2014
1 commit
-
The deprecation warnings for the scan_unevictable interface triggers by
scripts doing `sysctl -a | grep something else'. This is annoying and not
helpful.The interface has been defunct since 264e56d8247e ("mm: disable user
interface to manually rescue unevictable pages"), which was in 2011, and
there haven't been any reports of usecases for it, only reports that the
deprecation warnings are annying. It's unlikely that anybody is using
this interface specifically at this point, so remove it.Signed-off-by: Johannes Weiner
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Sep, 2014
1 commit
-
This commit changes rcutorture_runnable to torture_runnable, which is
consistent with the names of the other parameters and is a bit shorter
as well.Signed-off-by: Paul E. McKenney
07 Aug, 2014
1 commit
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They are unnecessary: "zero" can be used in place of "hugetlb_zero" and
passing extra2 == NULL is equivalent to infinity.Signed-off-by: David Rientjes
Cc: Joonsoo Kim
Reviewed-by: Naoya Horiguchi
Reviewed-by: Luiz Capitulino
Cc: "Kirill A. Shutemov"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
24 Jun, 2014
2 commits
-
A 'softlockup' is defined as a bug that causes the kernel to loop in
kernel mode for more than a predefined period to time, without giving
other tasks a chance to run.Currently, upon detection of this condition by the per-cpu watchdog
task, debug information (including a stack trace) is sent to the system
log.On some occasions, we have observed that the "victim" rather than the
actual "culprit" (i.e. the owner/holder of the contended resource) is
reported to the user. Often this information has proven to be
insufficient to assist debugging efforts.To avoid loss of useful debug information, for architectures which
support NMI, this patch makes it possible to improve soft lockup
reporting. This is accomplished by issuing an NMI to each cpu to obtain
a stack trace.If NMI is not supported we just revert back to the old method. A sysctl
and boot-time parameter is available to toggle this feature.[dzickus@redhat.com: add CONFIG_SMP in certain areas]
[akpm@linux-foundation.org: additional CONFIG_SMP=n optimisations]
[mq@suse.cz: fix warning]
Signed-off-by: Aaron Tomlin
Signed-off-by: Don Zickus
Cc: David S. Miller
Cc: Mateusz Guzik
Cc: Oleg Nesterov
Signed-off-by: Jan Moskyto Matejka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Oleg reports a division by zero error on zero-length write() to the
percpu_pagelist_fraction sysctl:divide error: 0000 [#1] SMP DEBUG_PAGEALLOC
CPU: 1 PID: 9142 Comm: badarea_io Not tainted 3.15.0-rc2-vm-nfs+ #19
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
task: ffff8800d5aeb6e0 ti: ffff8800d87a2000 task.ti: ffff8800d87a2000
RIP: 0010: percpu_pagelist_fraction_sysctl_handler+0x84/0x120
RSP: 0018:ffff8800d87a3e78 EFLAGS: 00010246
RAX: 0000000000000f89 RBX: ffff88011f7fd000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000010
RBP: ffff8800d87a3e98 R08: ffffffff81d002c8 R09: ffff8800d87a3f50
R10: 000000000000000b R11: 0000000000000246 R12: 0000000000000060
R13: ffffffff81c3c3e0 R14: ffffffff81cfddf8 R15: ffff8801193b0800
FS: 00007f614f1e9740(0000) GS:ffff88011f440000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f614f1fa000 CR3: 00000000d9291000 CR4: 00000000000006e0
Call Trace:
proc_sys_call_handler+0xb3/0xc0
proc_sys_write+0x14/0x20
vfs_write+0xba/0x1e0
SyS_write+0x46/0xb0
tracesys+0xe1/0xe6However, if the percpu_pagelist_fraction sysctl is set by the user, it
is also impossible to restore it to the kernel default since the user
cannot write 0 to the sysctl.This patch allows the user to write 0 to restore the default behavior.
It still requires a fraction equal to or larger than 8, however, as
stated by the documentation for sanity. If a value in the range [1, 7]
is written, the sysctl will return EINVAL.This successfully solves the divide by zero issue at the same time.
Signed-off-by: David Rientjes
Reported-by: Oleg Drokin
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 Jun, 2014
1 commit
-
Pull sparc fixes from David Miller:
"Sparc sparse fixes from Sam Ravnborg"* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next: (67 commits)
sparc64: fix sparse warnings in int_64.c
sparc64: fix sparse warning in ftrace.c
sparc64: fix sparse warning in kprobes.c
sparc64: fix sparse warning in kgdb_64.c
sparc64: fix sparse warnings in compat_audit.c
sparc64: fix sparse warnings in init_64.c
sparc64: fix sparse warnings in aes_glue.c
sparc: fix sparse warnings in smp_32.c + smp_64.c
sparc64: fix sparse warnings in perf_event.c
sparc64: fix sparse warnings in kprobes.c
sparc64: fix sparse warning in tsb.c
sparc64: clean up compat_sigset_t.seta handling
sparc64: fix sparse "Should it be static?" warnings in signal32.c
sparc64: fix sparse warnings in sys_sparc32.c
sparc64: fix sparse warning in pci.c
sparc64: fix sparse warnings in smp_64.c
sparc64: fix sparse warning in prom_64.c
sparc64: fix sparse warning in btext.c
sparc64: fix sparse warnings in sys_sparc_64.c + unaligned_64.c
sparc64: fix sparse warning in process_64.c
...Conflicts:
arch/sparc/include/asm/pgtable_64.h
13 Jun, 2014
1 commit
-
Pull networking updates from David Miller:
1) Seccomp BPF filters can now be JIT'd, from Alexei Starovoitov.
2) Multiqueue support in xen-netback and xen-netfront, from Andrew J
Benniston.3) Allow tweaking of aggregation settings in cdc_ncm driver, from Bjørn
Mork.4) BPF now has a "random" opcode, from Chema Gonzalez.
5) Add more BPF documentation and improve test framework, from Daniel
Borkmann.6) Support TCP fastopen over ipv6, from Daniel Lee.
7) Add software TSO helper functions and use them to support software
TSO in mvneta and mv643xx_eth drivers. From Ezequiel Garcia.8) Support software TSO in fec driver too, from Nimrod Andy.
9) Add Broadcom SYSTEMPORT driver, from Florian Fainelli.
10) Handle broadcasts more gracefully over macvlan when there are large
numbers of interfaces configured, from Herbert Xu.11) Allow more control over fwmark used for non-socket based responses,
from Lorenzo Colitti.12) Do TCP congestion window limiting based upon measurements, from Neal
Cardwell.13) Support busy polling in SCTP, from Neal Horman.
14) Allow RSS key to be configured via ethtool, from Venkata Duvvuru.
15) Bridge promisc mode handling improvements from Vlad Yasevich.
16) Don't use inetpeer entries to implement ID generation any more, it
performs poorly, from Eric Dumazet.* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1522 commits)
rtnetlink: fix userspace API breakage for iproute2 < v3.9.0
tcp: fixing TLP's FIN recovery
net: fec: Add software TSO support
net: fec: Add Scatter/gather support
net: fec: Increase buffer descriptor entry number
net: fec: Factorize feature setting
net: fec: Enable IP header hardware checksum
net: fec: Factorize the .xmit transmit function
bridge: fix compile error when compiling without IPv6 support
bridge: fix smatch warning / potential null pointer dereference
via-rhine: fix full-duplex with autoneg disable
bnx2x: Enlarge the dorq threshold for VFs
bnx2x: Check for UNDI in uncommon branch
bnx2x: Fix 1G-baseT link
bnx2x: Fix link for KR with swapped polarity lane
sctp: Fix sk_ack_backlog wrap-around problem
net/core: Add VF link state control policy
net/fsl: xgmac_mdio is dependent on OF_MDIO
net/fsl: Make xgmac_mdio read error message useful
net_sched: drr: warn when qdisc is not work conserving
...
07 Jun, 2014
4 commits
-
This typedef is unnecessary and should just be removed.
Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When writing to a sysctl string, each write, regardless of VFS position,
begins writing the string from the start. This means the contents of
the last write to the sysctl controls the string contents instead of the
first:open("/proc/sys/kernel/modprobe", O_WRONLY) = 1
write(1, "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"..., 4096) = 4096
write(1, "/bin/true", 9) = 9
close(1) = 0$ cat /proc/sys/kernel/modprobe
/bin/trueExpected behaviour would be to have the sysctl be "AAAA..." capped at
maxlen (in this case KMOD_PATH_LEN: 256), instead of truncating to the
contents of the second write. Similarly, multiple short writes would
not append to the sysctl.The old behavior is unlike regular POSIX files enough that doing audits
of software that interact with sysctls can end up in unexpected or
dangerous situations. For example, "as long as the input starts with a
trusted path" turns out to be an insufficient filter, as what must also
happen is for the input to be entirely contained in a single write
syscall -- not a common consideration, especially for high level tools.This provides kernel.sysctl_writes_strict as a way to make this behavior
act in a less surprising manner for strings, and disallows non-zero file
position when writing numeric sysctls (similar to what is already done
when reading from non-zero file positions). For now, the default (0) is
to warn about non-zero file position use, but retain the legacy
behavior. Setting this to -1 disables the warning, and setting this to
1 enables the file position respecting behavior.[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: move misplaced hunk, per Randy]
Signed-off-by: Kees Cook
Cc: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Consolidate buffer length checking with new-line/end-of-line checking.
Additionally, instead of reading user memory twice, just do the
assignment during the loop.This change doesn't affect the potential races here. It was already
possible to read a sysctl that was in the middle of a write. In both
cases, the string will always be NULL terminated. The pre-existing race
remains a problem to be solved.Signed-off-by: Kees Cook
Cc: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When writing to a sysctl string, each write, regardless of VFS position,
began writing the string from the start. This meant the contents of the
last write to the sysctl controlled the string contents instead of the
first.This misbehavior was featured in an exploit against Chrome OS. While
it's not in itself a vulnerability, it's a weirdness that isn't on the
mind of most auditors: "This filter looks correct, the first line
written would not be meaningful to sysctl" doesn't apply here, since the
size of the write and the contents of the final write are what matter
when writing to sysctls.This adds the sysctl kernel.sysctl_writes_strict to control the write
behavior. The default (0) reports when VFS position is non-0 on a
write, but retains legacy behavior, -1 disables the warning, and 1
enables the position-respecting behavior.The long-term plan here is to wait for userspace to be fixed in response
to the new warning and to then switch the default kernel behavior to the
new position-respecting behavior.This patch (of 4):
The char buffer arguments are needlessly cast in weird places. Clean it
up so things are easier to read.Signed-off-by: Kees Cook
Cc: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Jun, 2014
1 commit
-
Pull x86 cdso updates from Peter Anvin:
"Vdso cleanups and improvements largely from Andy Lutomirski. This
makes the vdso a lot less ''special''"* 'x86/vdso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso, build: Make LE access macros clearer, host-safe
x86/vdso, build: Fix cross-compilation from big-endian architectures
x86/vdso, build: When vdso2c fails, unlink the output
x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET
x86, mm: Replace arch_vma_name with vm_ops->name for vsyscalls
x86, mm: Improve _install_special_mapping and fix x86 vdso naming
mm, fs: Add vm_ops->name as an alternative to arch_vma_name
x86, vdso: Fix an OOPS accessing the HPET mapping w/o an HPET
x86, vdso: Remove vestiges of VDSO_PRELINK and some outdated comments
x86, vdso: Move the vvar and hpet mappings next to the 64-bit vDSO
x86, vdso: Move the 32-bit vdso special pages after the text
x86, vdso: Reimplement vdso.so preparation in build-time C
x86, vdso: Move syscall and sysenter setup into kernel/cpu/common.c
x86, vdso: Clean up 32-bit vs 64-bit vdso params
x86, mm: Ensure correct alignment of the fixmap
19 May, 2014
1 commit
-
Fix following warning:
tsb.c:290:5: warning: symbol 'sysctl_tsb_ratio' was not declared. Should it be static?Add extern declaration in asm/setup.h and remove local declaration
in kernel/sysctl.cSigned-off-by: Sam Ravnborg
Signed-off-by: David S. Miller
15 May, 2014
1 commit
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ip_local_port_range is already per netns, so should ip_local_reserved_ports
be. And since it is none by default we don't actually need it when we don't
enable CONFIG_SYSCTL.By the way, rename inet_is_reserved_local_port() to inet_is_local_reserved_port()
Cc: "David S. Miller"
Signed-off-by: Cong Wang
Signed-off-by: David S. Miller
06 May, 2014
1 commit
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Rather than using 'vdso_enabled' and an awful #define, just call the
parameters vdso32_enabled and vdso64_enabled.Signed-off-by: Andy Lutomirski
Link: http://lkml.kernel.org/r/87913de56bdcbae3d93917938302fc369b05caee.1399317206.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin
26 Apr, 2014
1 commit
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Support for uevent_helper, aka hotplug, is not required on many systems
these days but it can still be enabled via sysfs or sysctl.Reported-by: Darren Shepherd
Signed-off-by: Michael Marineau
Signed-off-by: Greg Kroah-Hartman
08 Apr, 2014
1 commit
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As sysctl_hung_task_timeout_sec is unsigned long, when this value is
larger then LONG_MAX/HZ, the function schedule_timeout_interruptible in
watchdog will return immediately without sleep and with print :schedule_timeout: wrong timeout value ffffffffffffff83
and then the funtion watchdog will call schedule_timeout_interruptible
again and again. The screen will be filled with"schedule_timeout: wrong timeout value ffffffffffffff83"
This patch does some check and correction in sysctl, to let the function
schedule_timeout_interruptible allways get the valid parameter.Signed-off-by: Liu Hua
Tested-by: Satoru Takeuchi
Cc: [3.4+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Apr, 2014
1 commit
-
There is plenty of anecdotal evidence and a load of blog posts
suggesting that using "drop_caches" periodically keeps your system
running in "tip top shape". Perhaps adding some kernel documentation
will increase the amount of accurate data on its use.If we are not shrinking caches effectively, then we have real bugs.
Using drop_caches will simply mask the bugs and make them harder to
find, but certainly does not fix them, nor is it an appropriate
"workaround" to limit the size of the caches. On the contrary, there
have been bug reports on issues that turned out to be misguided use of
cache dropping.Dropping caches is a very drastic and disruptive operation that is good
for debugging and running tests, but if it creates bug reports from
production use, kernel developers should be aware of its use.Add a bit more documentation about it, a syslog message to track down
abusers, and vmstat drop counters to help analyze problem reports.[akpm@linux-foundation.org: checkpatch fixes]
[hannes@cmpxchg.org: add runtime suppression control]
Signed-off-by: Dave Hansen
Signed-off-by: Michal Hocko
Acked-by: KOSAKI Motohiro
Acked-by: KAMEZAWA Hiroyuki
Signed-off-by: Johannes Weiner
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
02 Apr, 2014
1 commit
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Pull core block layer updates from Jens Axboe:
"This is the pull request for the core block IO bits for the 3.15
kernel. It's a smaller round this time, it contains:- Various little blk-mq fixes and additions from Christoph and
myself.- Cleanup of the IPI usage from the block layer, and associated
helper code. From Frederic Weisbecker and Jan Kara.- Duplicate code cleanup in bio-integrity from Gu Zheng. This will
give you a merge conflict, but that should be easy to resolve.- blk-mq notify spinlock fix for RT from Mike Galbraith.
- A blktrace partial accounting bug fix from Roman Pen.
- Missing REQ_SYNC detection fix for blk-mq from Shaohua Li"
* 'for-3.15/core' of git://git.kernel.dk/linux-block: (25 commits)
blk-mq: add REQ_SYNC early
rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlock
blk-mq: support partial I/O completions
blk-mq: merge blk_mq_insert_request and blk_mq_run_request
blk-mq: remove blk_mq_alloc_rq
blk-mq: don't dump CPU -> hw queue map on driver load
blk-mq: fix wrong usage of hctx->state vs hctx->flags
blk-mq: allow blk_mq_init_commands() to return failure
block: remove old blk_iopoll_enabled variable
blktrace: fix accounting of partially completed requests
smp: Rename __smp_call_function_single() to smp_call_function_single_async()
smp: Remove wait argument from __smp_call_function_single()
watchdog: Simplify a little the IPI call
smp: Move __smp_call_function_single() below its safe version
smp: Consolidate the various smp_call_function_single() declensions
smp: Teach __smp_call_function_single() to check for offline cpus
smp: Remove unused list_head from csd
smp: Iterate functions through llist_for_each_entry_safe()
block: Stop abusing rq->csd.list in blk-softirq
block: Remove useless IPI struct initialization
...
13 Mar, 2014
1 commit
-
This was a debugging measure to toggle enabled/disabled
when testing. But for real production setups, it's not
safe to toggle this setting without either reloading
drivers of quiescing IO first. Neither of which the toggle
enforces.Additionally, it makes drivers deal with the conditional
state.Remove it completely. It's up to the driver whether iopoll
is enabled or not.Signed-off-by: Jens Axboe
02 Feb, 2014
1 commit
-
Conflicts:
kernel/sysctl.cSigned-off-by: Ingo Molnar
01 Feb, 2014
1 commit
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Pull core debug changes from Ingo Molnar:
"This contains mostly kernel debugging related updates:- make hung_task detection more configurable to distros
- add final bits for x86 UV NMI debugging, with related KGDB changes
- update the mailing-list of MAINTAINERS entries I'm involved with"* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
hung_task: Display every hung task warning
sysctl: Add neg_one as a standard constraint
x86/uv/nmi, kgdb/kdb: Fix UV NMI handler when KDB not configured
x86/uv/nmi: Fix Sparse warnings
kgdb/kdb: Fix no KDB config problem
MAINTAINERS: Restore "L: linux-kernel@vger.kernel.org" entries
28 Jan, 2014
1 commit
-
Excessive migration of pages can hurt the performance of workloads
that span multiple NUMA nodes. However, it turns out that the
p->numa_migrate_deferred knob is a really big hammer, which does
reduce migration rates, but does not actually help performance.Now that the second stage of the automatic numa balancing code
has stabilized, it is time to replace the simplistic migration
deferral code with something smarter.Signed-off-by: Rik van Riel
Acked-by: Mel Gorman
Signed-off-by: Peter Zijlstra
Cc: Chegu Vinod
Link: http://lkml.kernel.org/r/1390860228-21539-2-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar
25 Jan, 2014
1 commit
-
When khungtaskd detects hung tasks, it prints out
backtraces from a number of those tasks.Limiting the number of backtraces being printed
out can result in the user not seeing the information
necessary to debug the issue. The hung_task_warnings
sysctl controls this feature.This patch makes it possible for hung_task_warnings
to accept a special value to print an unlimited
number of backtraces when khungtaskd detects hung
tasks.The special value is -1. To use this value it is
necessary to change types from ulong to int.Signed-off-by: Aaron Tomlin
Reviewed-by: Rik van Riel
Acked-by: David Rientjes
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/1390239253-24030-3-git-send-email-atomlin@redhat.com
[ Build warning fix. ]
Signed-off-by: Ingo Molnar