28 Oct, 2016
5 commits
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On large systems, when some slab caches grow to millions of objects (and
many gigabytes), running 'cat /proc/slabinfo' can take up to 1-2
seconds. During this time, interrupts are disabled while walking the
slab lists (slabs_full, slabs_partial, and slabs_free) for each node,
and this sometimes causes timeouts in other drivers (for instance,
Infiniband).This patch optimizes 'cat /proc/slabinfo' by maintaining a counter for
total number of allocated slabs per node, per cache. This counter is
updated when a slab is created or destroyed. This enables us to skip
traversing the slabs_full list while gathering slabinfo statistics, and
since slabs_full tends to be the biggest list when the cache is large,
it results in a dramatic performance improvement. Getting slabinfo
statistics now only requires walking the slabs_free and slabs_partial
lists, and those lists are usually much smaller than slabs_full.We tested this after growing the dentry cache to 70GB, and the
performance improved from 2s to 5ms.Link: http://lkml.kernel.org/r/1472517876-26814-1-git-send-email-aruna.ramakrishna@oracle.com
Signed-off-by: Aruna Ramakrishna
Acked-by: David Rientjes
Cc: Mike Kravetz
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: David Rientjes
Cc: Joonsoo Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Recent changes to printk require KERN_CONT uses to continue logging
messages. So add KERN_CONT where necessary.[akpm@linux-foundation.org: coding-style fixes]
Fixes: 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines")
Link: http://lkml.kernel.org/r/c7df37c8665134654a17aaeb8b9f6ace1d6db58b.1476239034.git.joe@perches.com
Reported-by: Mark Rutland
Signed-off-by: Joe Perches
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
As described in https://bugzilla.kernel.org/show_bug.cgi?id=177821:
After some analysis it seems to be that the problem is in alloc_super().
In case list_lru_init_memcg() fails it goes into destroy_super(), which
calls list_lru_destroy().And in list_lru_init() we see that in case memcg_init_list_lru() fails,
lru->node is freed, but not set NULL, which then leads list_lru_destroy()
to believe it is initialized and call memcg_destroy_list_lru().
memcg_destroy_list_lru() in turn can access lru->node[i].memcg_lrus,
which is NULL.[akpm@linux-foundation.org: add comment]
Signed-off-by: Alexander Polakov
Acked-by: Vladimir Davydov
Cc: Al Viro
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
There is a bug report that SLAB makes extreme load average due to over
2000 kworker thread.https://bugzilla.kernel.org/show_bug.cgi?id=172981
This issue is caused by kmemcg feature that try to create new set of
kmem_caches for each memcg. Recently, kmem_cache creation is slowed by
synchronize_sched() and futher kmem_cache creation is also delayed since
kmem_cache creation is synchronized by a global slab_mutex lock. So,
the number of kworker that try to create kmem_cache increases quietly.synchronize_sched() is for lockless access to node's shared array but
it's not needed when a new kmem_cache is created. So, this patch rules
out that case.Fixes: 801faf0db894 ("mm/slab: lockless decision to grow cache")
Link: http://lkml.kernel.org/r/1475734855-4837-1-git-send-email-iamjoonsoo.kim@lge.com
Reported-by: Doug Smythies
Tested-by: Doug Smythies
Signed-off-by: Joonsoo Kim
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: David Rientjes
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The per-zone waitqueues exist because of a scalability issue with the
page waitqueues on some NUMA machines, but it turns out that they hurt
normal loads, and now with the vmalloced stacks they also end up
breaking gfs2 that uses a bit_wait on a stack object:wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE)
where 'gh' can be a reference to the local variable 'mount_gh' on the
stack of fill_super().The reason the per-zone hash table breaks for this case is that there is
no "zone" for virtual allocations, and trying to look up the physical
page to get at it will fail (with a BUG_ON()).It turns out that I actually complained to the mm people about the
per-zone hash table for another reason just a month ago: the zone lookup
also hurts the regular use of "unlock_page()" a lot, because the zone
lookup ends up forcing several unnecessary cache misses and generates
horrible code.As part of that earlier discussion, we had a much better solution for
the NUMA scalability issue - by just making the page lock have a
separate contention bit, the waitqueue doesn't even have to be looked at
for the normal case.Peter Zijlstra already has a patch for that, but let's see if anybody
even notices. In the meantime, let's fix the actual gfs2 breakage by
simplifying the bitlock waitqueues and removing the per-zone issue.Reported-by: Andreas Gruenbacher
Tested-by: Bob Peterson
Acked-by: Mel Gorman
Cc: Peter Zijlstra
Cc: Andy Lutomirski
Cc: Steven Whitehouse
Signed-off-by: Linus Torvalds
25 Oct, 2016
1 commit
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This patch unexports the low-level __get_user_pages() function.
Recent refactoring of the get_user_pages* functions allow flags to be
passed through get_user_pages() which eliminates the need for access to
this function from its one user, kvm.We can see that the two calls to get_user_pages() which replace
__get_user_pages() in kvm_main.c are equivalent by examining their call
stacks:get_user_page_nowait():
get_user_pages(start, 1, flags, page, NULL)
__get_user_pages_locked(current, current->mm, start, 1, page, NULL, NULL,
false, flags | FOLL_TOUCH)
__get_user_pages(current, current->mm, start, 1,
flags | FOLL_TOUCH | FOLL_GET, page, NULL, NULL)check_user_page_hwpoison():
get_user_pages(addr, 1, flags, NULL, NULL)
__get_user_pages_locked(current, current->mm, addr, 1, NULL, NULL, NULL,
false, flags | FOLL_TOUCH)
__get_user_pages(current, current->mm, addr, 1, flags | FOLL_TOUCH, NULL,
NULL, NULL)Signed-off-by: Lorenzo Stoakes
Acked-by: Paolo Bonzini
Acked-by: Michal Hocko
Signed-off-by: Linus Torvalds
23 Oct, 2016
1 commit
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Pull vmap stack fixes from Ingo Molnar:
"This is fallout from CONFIG_HAVE_ARCH_VMAP_STACK=y on x86: stack
accesses that used to be just somewhat questionable are now totally
buggy.These changes try to do it without breaking the ABI: the fields are
left there, they are just reporting zero, or reporting narrower
information (the maps file change)"* 'mm-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
mm: Change vm_is_stack_for_task() to vm_is_stack_for_current()
fs/proc: Stop trying to report thread stacks
fs/proc: Stop reporting eip and esp in /proc/PID/stat
mm/numa: Remove duplicated include from mprotect.c
20 Oct, 2016
1 commit
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Asking for a non-current task's stack can't be done without races
unless the task is frozen in kernel mode. As far as I know,
vm_is_stack_for_task() never had a safe non-current use case.The __unused annotation is because some KSTK_ESP implementations
ignore their parameter, which IMO is further justification for this
patch.Signed-off-by: Andy Lutomirski
Acked-by: Thomas Gleixner
Cc: Al Viro
Cc: Andrew Morton
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Jann Horn
Cc: Kees Cook
Cc: Linus Torvalds
Cc: Linux API
Cc: Peter Zijlstra
Cc: Tycho Andersen
Link: http://lkml.kernel.org/r/4c3f68f426e6c061ca98b4fc7ef85ffbb0a25b0c.1475257877.git.luto@kernel.org
Signed-off-by: Ingo Molnar
19 Oct, 2016
13 commits
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Merge the gup_flags cleanups from Lorenzo Stoakes:
"This patch series adjusts functions in the get_user_pages* family such
that desired FOLL_* flags are passed as an argument rather than
implied by flags.The purpose of this change is to make the use of FOLL_FORCE explicit
so it is easier to grep for and clearer to callers that this flag is
being used. The use of FOLL_FORCE is an issue as it overrides missing
VM_READ/VM_WRITE flags for the VMA whose pages we are reading
from/writing to, which can result in surprising behaviour.The patch series came out of the discussion around commit 38e088546522
("mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing"),
which addressed a BUG_ON() being triggered when a page was faulted in
with PROT_NONE set but having been overridden by FOLL_FORCE.
do_numa_page() was run on the assumption the page _must_ be one marked
for NUMA node migration as an actual PROT_NONE page would have been
dealt with prior to this code path, however FOLL_FORCE introduced a
situation where this assumption did not hold.See
https://marc.info/?l=linux-mm&m=147585445805166
for the patch proposal"
Additionally, there's a fix for an ancient bug related to FOLL_FORCE and
FOLL_WRITE by me.[ This branch was rebased recently to add a few more acked-by's and
reviewed-by's ]* gup_flag-cleanups:
mm: replace access_process_vm() write parameter with gup_flags
mm: replace access_remote_vm() write parameter with gup_flags
mm: replace __access_remote_vm() write parameter with gup_flags
mm: replace get_user_pages_remote() write/force parameters with gup_flags
mm: replace get_user_pages() write/force parameters with gup_flags
mm: replace get_vaddr_frames() write/force parameters with gup_flags
mm: replace get_user_pages_locked() write/force parameters with gup_flags
mm: replace get_user_pages_unlocked() write/force parameters with gup_flags
mm: remove write/force parameters from __get_user_pages_unlocked()
mm: remove write/force parameters from __get_user_pages_locked()
mm: remove gup_flags FOLL_WRITE games from __get_user_pages() -
This removes the 'write' argument from access_process_vm() and replaces
it with 'gup_flags' as use of this function previously silently implied
FOLL_FORCE, whereas after this patch callers explicitly pass this flag.We make this explicit as use of FOLL_FORCE can result in surprising
behaviour (and hence bugs) within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Acked-by: Jesper Nilsson
Acked-by: Michal Hocko
Acked-by: Michael Ellerman
Signed-off-by: Linus Torvalds -
Signed-off-by: Wei Yongjun
Cc: Dave Hansen
Cc: linux-mm@kvack.org
Cc: Andrew Morton
Cc: Mel Gorman
Cc: "Kirill A. Shutemov"
Link: http://lkml.kernel.org/r/1476719259-6214-1-git-send-email-weiyj.lk@gmail.com
Signed-off-by: Thomas Gleixner -
This removes the 'write' argument from access_remote_vm() and replaces
it with 'gup_flags' as use of this function previously silently implied
FOLL_FORCE, whereas after this patch callers explicitly pass this flag.We make this explicit as use of FOLL_FORCE can result in surprising
behaviour (and hence bugs) within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Acked-by: Michal Hocko
Signed-off-by: Linus Torvalds -
This removes the 'write' argument from __access_remote_vm() and replaces
it with 'gup_flags' as use of this function previously silently implied
FOLL_FORCE, whereas after this patch callers explicitly pass this flag.We make this explicit as use of FOLL_FORCE can result in surprising
behaviour (and hence bugs) within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Acked-by: Michal Hocko
Signed-off-by: Linus Torvalds -
This removes the 'write' and 'force' from get_user_pages_remote() and
replaces them with 'gup_flags' to make the use of FOLL_FORCE explicit in
callers as use of this flag can result in surprising behaviour (and
hence bugs) within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Acked-by: Michal Hocko
Reviewed-by: Jan Kara
Signed-off-by: Linus Torvalds -
This removes the 'write' and 'force' from get_user_pages() and replaces
them with 'gup_flags' to make the use of FOLL_FORCE explicit in callers
as use of this flag can result in surprising behaviour (and hence bugs)
within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Acked-by: Christian König
Acked-by: Jesper Nilsson
Acked-by: Michal Hocko
Reviewed-by: Jan Kara
Signed-off-by: Linus Torvalds -
This removes the 'write' and 'force' from get_vaddr_frames() and
replaces them with 'gup_flags' to make the use of FOLL_FORCE explicit in
callers as use of this flag can result in surprising behaviour (and
hence bugs) within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Acked-by: Michal Hocko
Reviewed-by: Jan Kara
Signed-off-by: Linus Torvalds -
This removes the 'write' and 'force' use from get_user_pages_locked()
and replaces them with 'gup_flags' to make the use of FOLL_FORCE
explicit in callers as use of this flag can result in surprising
behaviour (and hence bugs) within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Acked-by: Michal Hocko
Reviewed-by: Jan Kara
Signed-off-by: Linus Torvalds -
This removes the 'write' and 'force' use from get_user_pages_unlocked()
and replaces them with 'gup_flags' to make the use of FOLL_FORCE
explicit in callers as use of this flag can result in surprising
behaviour (and hence bugs) within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Reviewed-by: Jan Kara
Acked-by: Michal Hocko
Signed-off-by: Linus Torvalds -
This removes the redundant 'write' and 'force' parameters from
__get_user_pages_unlocked() to make the use of FOLL_FORCE explicit in
callers as use of this flag can result in surprising behaviour (and
hence bugs) within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Acked-by: Paolo Bonzini
Reviewed-by: Jan Kara
Acked-by: Michal Hocko
Signed-off-by: Linus Torvalds -
This removes the redundant 'write' and 'force' parameters from
__get_user_pages_locked() to make the use of FOLL_FORCE explicit in
callers as use of this flag can result in surprising behaviour (and
hence bugs) within the mm subsystem.Signed-off-by: Lorenzo Stoakes
Reviewed-by: Jan Kara
Acked-by: Michal Hocko
Signed-off-by: Linus Torvalds -
This is an ancient bug that was actually attempted to be fixed once
(badly) by me eleven years ago in commit 4ceb5db9757a ("Fix
get_user_pages() race for write access") but that was then undone due to
problems on s390 by commit f33ea7f404e5 ("fix get_user_pages bug").In the meantime, the s390 situation has long been fixed, and we can now
fix it by checking the pte_dirty() bit properly (and do it better). The
s390 dirty bit was implemented in abf09bed3cce ("s390/mm: implement
software dirty bits") which made it into v3.9. Earlier kernels will
have to look at the page state itself.Also, the VM has become more scalable, and what used a purely
theoretical race back then has become easier to trigger.To fix it, we introduce a new internal FOLL_COW flag to mark the "yes,
we already did a COW" rather than play racy games with FOLL_WRITE that
is very fundamental, and then use the pte dirty flag to validate that
the FOLL_COW flag is still valid.Reported-and-tested-by: Phil "not Paul" Oester
Acked-by: Hugh Dickins
Reviewed-by: Michal Hocko
Cc: Andy Lutomirski
Cc: Kees Cook
Cc: Oleg Nesterov
Cc: Willy Tarreau
Cc: Nick Piggin
Cc: Greg Thelen
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds
16 Oct, 2016
2 commits
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I observed false KSAN positives in the sctp code, when
sctp uses jprobe_return() in jsctp_sf_eat_sack().The stray 0xf4 in shadow memory are stack redzones:
[ ] ==================================================================
[ ] BUG: KASAN: stack-out-of-bounds in memcmp+0xe9/0x150 at addr ffff88005e48f480
[ ] Read of size 1 by task syz-executor/18535
[ ] page:ffffea00017923c0 count:0 mapcount:0 mapping: (null) index:0x0
[ ] flags: 0x1fffc0000000000()
[ ] page dumped because: kasan: bad access detected
[ ] CPU: 1 PID: 18535 Comm: syz-executor Not tainted 4.8.0+ #28
[ ] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
[ ] ffff88005e48f2d0 ffffffff82d2b849 ffffffff0bc91e90 fffffbfff10971e8
[ ] ffffed000bc91e90 ffffed000bc91e90 0000000000000001 0000000000000000
[ ] ffff88005e48f480 ffff88005e48f350 ffffffff817d3169 ffff88005e48f370
[ ] Call Trace:
[ ] [] dump_stack+0x12e/0x185
[ ] [] kasan_report+0x489/0x4b0
[ ] [] __asan_report_load1_noabort+0x19/0x20
[ ] [] memcmp+0xe9/0x150
[ ] [] depot_save_stack+0x176/0x5c0
[ ] [] save_stack+0xb1/0xd0
[ ] [] kasan_slab_free+0x72/0xc0
[ ] [] kfree+0xc8/0x2a0
[ ] [] skb_free_head+0x79/0xb0
[ ] [] skb_release_data+0x37a/0x420
[ ] [] skb_release_all+0x4f/0x60
[ ] [] consume_skb+0x138/0x370
[ ] [] sctp_chunk_put+0xcb/0x180
[ ] [] sctp_chunk_free+0x58/0x70
[ ] [] sctp_inq_pop+0x68f/0xef0
[ ] [] sctp_assoc_bh_rcv+0xd6/0x4b0
[ ] [] sctp_inq_push+0x131/0x190
[ ] [] sctp_backlog_rcv+0xe9/0xa20
[ ... ]
[ ] Memory state around the buggy address:
[ ] ffff88005e48f380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ ] ffff88005e48f400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ ] >ffff88005e48f480: f4 f4 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ ] ^
[ ] ffff88005e48f500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ ] ffff88005e48f580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ ] ==================================================================KASAN stack instrumentation poisons stack redzones on function entry
and unpoisons them on function exit. If a function exits abnormally
(e.g. with a longjmp like jprobe_return()), stack redzones are left
poisoned. Later this leads to random KASAN false reports.Unpoison stack redzones in the frames we are going to jump over
before doing actual longjmp in jprobe_return().Signed-off-by: Dmitry Vyukov
Acked-by: Masami Hiramatsu
Reviewed-by: Mark Rutland
Cc: Mark Rutland
Cc: Catalin Marinas
Cc: Andrey Ryabinin
Cc: Lorenzo Pieralisi
Cc: Alexander Potapenko
Cc: Will Deacon
Cc: Andrew Morton
Cc: Ananth N Mavinakayanahalli
Cc: Anil S Keshavamurthy
Cc: "David S. Miller"
Cc: Masami Hiramatsu
Cc: kasan-dev@googlegroups.com
Cc: surovegin@google.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/1476454043-101898-1-git-send-email-dvyukov@google.com
Signed-off-by: Ingo Molnar -
Pull gcc plugins update from Kees Cook:
"This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot
time as possible, hoping to capitalize on any possible variation in
CPU operation (due to runtime data differences, hardware differences,
SMP ordering, thermal timing variation, cache behavior, etc).At the very least, this plugin is a much more comprehensive example
for how to manipulate kernel code using the gcc plugin internals"* tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
latent_entropy: Mark functions with __latent_entropy
gcc-plugins: Add latent_entropy plugin
15 Oct, 2016
1 commit
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Pull percpu updates from Tejun Heo:
- Nick improved generic implementations of percpu operations which
modify the variable and return so that they calculate the physical
address only once.- percpu_ref percpu atomic mode switching improvements. The
patchset was originally posted about a year ago but fell through the
crack.- misc non-critical fixes.
* 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
mm/percpu.c: fix potential memory leakage for pcpu_embed_first_chunk()
mm/percpu.c: correct max_distance calculation for pcpu_embed_first_chunk()
percpu: eliminate two sparse warnings
percpu: improve generic percpu modify-return implementation
percpu-refcount: init ->confirm_switch member properly
percpu_ref: allow operation mode switching operations to be called concurrently
percpu_ref: restructure operation mode switching
percpu_ref: unify staggered atomic switching wait behavior
percpu_ref: reorganize __percpu_ref_switch_to_atomic() and relocate percpu_ref_switch_to_atomic()
percpu_ref: remove unnecessary RCU grace period for staggered atomic switching confirmation
13 Oct, 2016
1 commit
-
This affectively reverts commit 377ccbb48373 ("Makefile: Mute warning
for __builtin_return_address(>0) for tracing only") because it turns out
that it really isn't tracing only - it's all over the tree.We already also had the warning disabled separately for mm/usercopy.c
(which this commit also removes), and it turns out that we will also
want to disable it for get_lock_parent_ip(), that is used for at least
TRACE_IRQFLAGS. Which (when enabled) ends up being all over the tree.Steven Rostedt had a patch that tried to limit it to just the config
options that actually triggered this, but quite frankly, the extra
complexity and abstraction just isn't worth it. We have never actually
had a case where the warning is actually useful, so let's just disable
it globally and not worry about it.Acked-by: Steven Rostedt
Cc: Thomas Gleixner
Cc: Andrew Morton
Cc: Ingo Molnar
Cc: Peter Anvin
Signed-off-by: Linus Torvalds
12 Oct, 2016
1 commit
-
Some of the kmemleak_*() callbacks in memblock, bootmem, CMA convert a
physical address to a virtual one using __va(). However, such physical
addresses may sometimes be located in highmem and using __va() is
incorrect, leading to inconsistent object tracking in kmemleak.The following functions have been added to the kmemleak API and they take
a physical address as the object pointer. They only perform the
corresponding action if the address has a lowmem mapping:kmemleak_alloc_phys
kmemleak_free_part_phys
kmemleak_not_leak_phys
kmemleak_ignore_physThe affected calling places have been updated to use the new kmemleak
API.Link: http://lkml.kernel.org/r/1471531432-16503-1-git-send-email-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas
Reported-by: Vignesh R
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Oct, 2016
9 commits
-
Pull more vfs updates from Al Viro:
">rename2() work from Miklos + current_time() from Deepa"* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: Replace current_fs_time() with current_time()
fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
fs: Replace CURRENT_TIME with current_time() for inode timestamps
fs: proc: Delete inode time initializations in proc_alloc_inode()
vfs: Add current_time() api
vfs: add note about i_op->rename changes to porting
fs: rename "rename2" i_op to "rename"
vfs: remove unused i_op->rename
fs: make remaining filesystems use .rename2
libfs: support RENAME_NOREPLACE in simple_rename()
fs: support RENAME_NOREPLACE for local filesystems
ncpfs: fix unused variable warning -
Pull vfs xattr updates from Al Viro:
"xattr stuff from AndreasThis completes the switch to xattr_handler ->get()/->set() from
->getxattr/->setxattr/->removexattr"* 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: Remove {get,set,remove}xattr inode operations
xattr: Stop calling {get,set,remove}xattr inode operations
vfs: Check for the IOP_XATTR flag in listxattr
xattr: Add __vfs_{get,set,remove}xattr helpers
libfs: Use IOP_XATTR flag for empty directory handling
vfs: Use IOP_XATTR flag for bad-inode handling
vfs: Add IOP_XATTR inode operations flag
vfs: Move xattr_resolve_name to the front of fs/xattr.c
ecryptfs: Switch to generic xattr handlers
sockfs: Get rid of getxattr iop
sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names
kernfs: Switch to generic xattr handlers
hfs: Switch to generic xattr handlers
jffs2: Remove jffs2_{get,set,remove}xattr macros
xattr: Remove unnecessary NULL attribute name check -
The __latent_entropy gcc attribute can be used only on functions and
variables. If it is on a function then the plugin will instrument it for
gathering control-flow entropy. If the attribute is on a variable then
the plugin will initialize it with random contents. The variable must
be an integer, an integer array type or a structure with integer fields.These specific functions have been selected because they are init
functions (to help gather boot-time entropy), are called at unpredictable
times, or they have variable loops, each of which provide some level of
latent entropy.Signed-off-by: Emese Revfy
[kees: expanded commit message]
Signed-off-by: Kees Cook -
This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.The need for very-early boot entropy tends to be very architecture or
system design specific, so this plugin is more suited for those sorts
of special cases. The existing kernel RNG already attempts to extract
entropy from reliable runtime variation, but this plugin takes the idea to
a logical extreme by permuting a global variable based on any variation
in code execution (e.g. a different value (and permutation function)
is used to permute the global based on loop count, case statement,
if/then/else branching, etc).To do this, the plugin starts by inserting a local variable in every
marked function. The plugin then adds logic so that the value of this
variable is modified by randomly chosen operations (add, xor and rol) and
random values (gcc generates separate static values for each location at
compile time and also injects the stack pointer at runtime). The resulting
value depends on the control flow path (e.g., loops and branches taken).Before the function returns, the plugin mixes this local variable into
the latent_entropy global variable. The value of this global variable
is added to the kernel entropy pool in do_one_initcall() and _do_fork(),
though it does not credit any bytes of entropy to the pool; the contents
of the global are just used to mix the pool.Additionally, the plugin can pre-initialize arrays with build-time
random contents, so that two different kernel builds running on identical
hardware will not have the same starting values.Signed-off-by: Emese Revfy
[kees: expanded commit message and code comments]
Signed-off-by: Kees Cook -
Pull splice fixups from Al Viro:
"A couple of fixups for interaction of pipe-backed iov_iter with
O_DIRECT reads + constification of a couple of primitives in uio.h
missed by previous rounds.Kudos to davej - his fuzzing has caught those bugs"
* 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
[btrfs] fix check_direct_IO() for non-iovec iterators
constify iov_iter_count() and iter_is_iovec()
fix ITER_PIPE interaction with direct_IO -
Pull misc vfs updates from Al Viro:
"Assorted misc bits and pieces.There are several single-topic branches left after this (rename2
series from Miklos, current_time series from Deepa Dinamani, xattr
series from Andreas, uaccess stuff from from me) and I'd prefer to
send those separately"* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (39 commits)
proc: switch auxv to use of __mem_open()
hpfs: support FIEMAP
cifs: get rid of unused arguments of CIFSSMBWrite()
posix_acl: uapi header split
posix_acl: xattr representation cleanups
fs/aio.c: eliminate redundant loads in put_aio_ring_file
fs/internal.h: add const to ns_dentry_operations declaration
compat: remove compat_printk()
fs/buffer.c: make __getblk_slow() static
proc: unsigned file descriptors
fs/file: more unsigned file descriptors
fs: compat: remove redundant check of nr_segs
cachefiles: Fix attempt to read i_blocks after deleting file [ver #2]
cifs: don't use memcpy() to copy struct iov_iter
get rid of separate multipage fault-in primitives
fs: Avoid premature clearing of capabilities
fs: Give dentry to inode_change_ok() instead of inode
fuse: Propagate dentry down to inode_change_ok()
ceph: Propagate dentry down to inode_change_ok()
xfs: Propagate dentry down to inode_change_ok()
... -
Pull protection keys syscall interface from Thomas Gleixner:
"This is the final step of Protection Keys support which adds the
syscalls so user space can actually allocate keys and protect memory
areas with them. Details and usage examples can be found in the
documentation.The mm side of this has been acked by Mel"
* 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/pkeys: Update documentation
x86/mm/pkeys: Do not skip PKRU register if debug registers are not used
x86/pkeys: Fix pkeys build breakage for some non-x86 arches
x86/pkeys: Add self-tests
x86/pkeys: Allow configuration of init_pkru
x86/pkeys: Default to a restrictive init PKRU
pkeys: Add details of system call use to Documentation/
generic syscalls: Wire up memory protection keys syscalls
x86: Wire up protection keys system calls
x86/pkeys: Allocation/free syscalls
x86/pkeys: Make mprotect_key() mask off additional vm_flags
mm: Implement new pkey_mprotect() system call
x86/pkeys: Add fault handling for PF_PK page fault bit -
by making sure we call iov_iter_advance() on original
iov_iter even if direct_IO (done on its copy) has returned 0.
It's a no-op for old iov_iter flavours and does the right thing
(== truncation of the stuff we'd allocated, but not filled) in
ITER_PIPE case. Failures (e.g. -EIO) get caught and dealt with
by cleanup in generic_file_read_iter().Signed-off-by: Al Viro
08 Oct, 2016
5 commits
-
Merge updates from Andrew Morton:
- fsnotify updates
- ocfs2 updates
- all of MM
* emailed patches from Andrew Morton : (127 commits)
console: don't prefer first registered if DT specifies stdout-path
cred: simpler, 1D supplementary groups
CREDITS: update Pavel's information, add GPG key, remove snail mail address
mailmap: add Johan Hovold
.gitattributes: set git diff driver for C source code files
uprobes: remove function declarations from arch/{mips,s390}
spelling.txt: "modeled" is spelt correctly
nmi_backtrace: generate one-line reports for idle cpus
arch/tile: adopt the new nmi_backtrace framework
nmi_backtrace: do a local dump_stack() instead of a self-NMI
nmi_backtrace: add more trigger_*_cpu_backtrace() methods
min/max: remove sparse warnings when they're nested
Documentation/filesystems/proc.txt: add more description for maps/smaps
mm, proc: fix region lost in /proc/self/smaps
proc: fix timerslack_ns CAP_SYS_NICE check when adjusting self
proc: add LSM hook checks to /proc//timerslack_ns
proc: relax /proc//timerslack_ns capability requirements
meminfo: break apart a very long seq_printf with #ifdefs
seq/proc: modify seq_put_decimal_[u]ll to take a const char *, not char
proc: faster /proc/*/status
... -
These inode operations are no longer used; remove them.
Signed-off-by: Andreas Gruenbacher
Signed-off-by: Al Viro -
Allow some seq_puts removals by taking a string instead of a single
char.[akpm@linux-foundation.org: update vmstat_show(), per Joe]
Link: http://lkml.kernel.org/r/667e1cf3d436de91a5698170a1e98d882905e956.1470704995.git.joe@perches.com
Signed-off-by: Joe Perches
Cc: Joe Perches
Cc: Andi Kleen
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Every current KDE system has process named ksysguardd polling files
below once in several seconds:$ strace -e trace=open -p $(pidof ksysguardd)
Process 1812 attached
open("/etc/mtab", O_RDONLY|O_CLOEXEC) = 8
open("/etc/mtab", O_RDONLY|O_CLOEXEC) = 8
open("/proc/net/dev", O_RDONLY) = 8
open("/proc/net/wireless", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/proc/stat", O_RDONLY) = 8
open("/proc/vmstat", O_RDONLY) = 8Hell knows what it is doing but speed up reading /proc/vmstat by 33%!
Benchmark is open+read+close 1.000.000 times.
BEFORE
$ perf stat -r 10 taskset -c 3 ./proc-vmstatPerformance counter stats for 'taskset -c 3 ./proc-vmstat' (10 runs):
13146.768464 task-clock (msec) # 0.960 CPUs utilized ( +- 0.60% )
15 context-switches # 0.001 K/sec ( +- 1.41% )
1 cpu-migrations # 0.000 K/sec ( +- 11.11% )
104 page-faults # 0.008 K/sec ( +- 0.57% )
45,489,799,349 cycles # 3.460 GHz ( +- 0.03% )
9,970,175,743 stalled-cycles-frontend # 21.92% frontend cycles idle ( +- 0.10% )
2,800,298,015 stalled-cycles-backend # 6.16% backend cycles idle ( +- 0.32% )
79,241,190,850 instructions # 1.74 insn per cycle
# 0.13 stalled cycles per insn ( +- 0.00% )
17,616,096,146 branches # 1339.956 M/sec ( +- 0.00% )
176,106,232 branch-misses # 1.00% of all branches ( +- 0.18% )13.691078109 seconds time elapsed ( +- 0.03% )
^^^^^^^^^^^^AFTER
$ perf stat -r 10 taskset -c 3 ./proc-vmstatPerformance counter stats for 'taskset -c 3 ./proc-vmstat' (10 runs):
8688.353749 task-clock (msec) # 0.950 CPUs utilized ( +- 1.25% )
10 context-switches # 0.001 K/sec ( +- 2.13% )
1 cpu-migrations # 0.000 K/sec
104 page-faults # 0.012 K/sec ( +- 0.56% )
30,384,010,730 cycles # 3.497 GHz ( +- 0.07% )
12,296,259,407 stalled-cycles-frontend # 40.47% frontend cycles idle ( +- 0.13% )
3,370,668,651 stalled-cycles-backend # 11.09% backend cycles idle ( +- 0.69% )
28,969,052,879 instructions # 0.95 insn per cycle
# 0.42 stalled cycles per insn ( +- 0.01% )
6,308,245,891 branches # 726.058 M/sec ( +- 0.00% )
214,685,502 branch-misses # 3.40% of all branches ( +- 0.26% )9.146081052 seconds time elapsed ( +- 0.07% )
^^^^^^^^^^^vsnprintf() is slow because:
1. format_decode() is busy looking for format specifier: 2 branches
per character (not in this case, but in others)2. approximately million branches while parsing format mini language
and everywhere3. just look at what string() does /proc/vmstat is good case because
most of its content are stringsLink: http://lkml.kernel.org/r/20160806125455.GA1187@p183.telecom.by
Signed-off-by: Alexey Dobriyan
Cc: Joe Perches
Cc: Andi Kleen
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
