30 Jan, 2015
1 commit
-
The core VM already knows about VM_FAULT_SIGBUS, but cannot return a
"you should SIGSEGV" error, because the SIGSEGV case was generally
handled by the caller - usually the architecture fault handler.That results in lots of duplication - all the architecture fault
handlers end up doing very similar "look up vma, check permissions, do
retries etc" - but it generally works. However, there are cases where
the VM actually wants to SIGSEGV, and applications _expect_ SIGSEGV.In particular, when accessing the stack guard page, libsigsegv expects a
SIGSEGV. And it usually got one, because the stack growth is handled by
that duplicated architecture fault handler.However, when the generic VM layer started propagating the error return
from the stack expansion in commit fee7e49d4514 ("mm: propagate error
from stack expansion even for guard page"), that now exposed the
existing VM_FAULT_SIGBUS result to user space. And user space really
expected SIGSEGV, not SIGBUS.To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach all those
duplicate architecture fault handlers about it. They all already have
the code to handle SIGSEGV, so it's about just tying that new return
value to the existing code, but it's all a bit annoying.This is the mindless minimal patch to do this. A more extensive patch
would be to try to gather up the mostly shared fault handling logic into
one generic helper routine, and long-term we really should do that
cleanup.Just from this patch, you can generally see that most architectures just
copied (directly or indirectly) the old x86 way of doing things, but in
the meantime that original x86 model has been improved to hold the VM
semaphore for shorter times etc and to handle VM_FAULT_RETRY and other
"newer" things, so it would be a good idea to bring all those
improvements to the generic case and teach other architectures about
them too.Reported-and-tested-by: Takashi Iwai
Tested-by: Jan Engelhardt
Acked-by: Heiko Carstens # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds
13 Sep, 2013
1 commit
-
Unlike global OOM handling, memory cgroup code will invoke the OOM killer
in any OOM situation because it has no way of telling faults occuring in
kernel context - which could be handled more gracefully - from
user-triggered faults.Pass a flag that identifies faults originating in user space from the
architecture-specific fault handlers to generic code so that memcg OOM
handling can be improved.Signed-off-by: Johannes Weiner
Reviewed-by: Michal Hocko
Cc: David Rientjes
Cc: KAMEZAWA Hiroyuki
Cc: azurIt
Cc: KOSAKI Motohiro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 Jul, 2013
1 commit
-
A few remaining architectures directly kill the page faulting task in an
out of memory situation. This is usually not a good idea since that
task might not even use a significant amount of memory and so may not be
the optimal victim to resolve the situation.Since 2.6.29's 1c0fe6e ("mm: invoke oom-killer from page fault") there
is a hook that architecture page fault handlers are supposed to call to
invoke the OOM killer and let it pick the right task to kill. Convert
the remaining architectures over to this hook.To have the previous behavior of simply taking out the faulting task the
vm.oom_kill_allocating_task sysctl can be set to 1.Signed-off-by: Johannes Weiner
Reviewed-by: Michal Hocko
Cc: KAMEZAWA Hiroyuki
Acked-by: David Rientjes
Acked-by: Vineet Gupta [arch/arc bits]
Cc: James Hogan
Cc: David Howells
Cc: Jonas Bonn
Cc: Chen Liqin
Cc: Lennox Wu
Cc: Chris Metcalf
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Jul, 2013
4 commits
-
Prepare for removing num_physpages and simplify mem_init().
Signed-off-by: Jiang Liu
Acked-by: Jonas Bonn
Cc: David Howells
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Concentrate code to modify totalram_pages into the mm core, so the arch
memory initialized code doesn't need to take care of it. With these
changes applied, only following functions from mm core modify global
variable totalram_pages: free_bootmem_late(), free_all_bootmem(),
free_all_bootmem_node(), adjust_managed_page_count().With this patch applied, it will be much more easier for us to keep
totalram_pages and zone->managed_pages in consistence.Signed-off-by: Jiang Liu
Acked-by: David Howells
Cc: "H. Peter Anvin"
Cc: "Michael S. Tsirkin"
Cc:
Cc: Arnd Bergmann
Cc: Catalin Marinas
Cc: Chris Metcalf
Cc: Geert Uytterhoeven
Cc: Ingo Molnar
Cc: Jeremy Fitzhardinge
Cc: Jianguo Wu
Cc: Joonsoo Kim
Cc: Kamezawa Hiroyuki
Cc: Konrad Rzeszutek Wilk
Cc: Marek Szyprowski
Cc: Mel Gorman
Cc: Michel Lespinasse
Cc: Minchan Kim
Cc: Rik van Riel
Cc: Rusty Russell
Cc: Tang Chen
Cc: Tejun Heo
Cc: Thomas Gleixner
Cc: Wen Congyang
Cc: Will Deacon
Cc: Yasuaki Ishimatsu
Cc: Yinghai Lu
Cc: Russell King
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Address more review comments from last round of code review.
1) Enhance free_reserved_area() to support poisoning freed memory with
pattern '0'. This could be used to get rid of poison_init_mem()
on ARM64.
2) A previous patch has disabled memory poison for initmem on s390
by mistake, so restore to the original behavior.
3) Remove redundant PAGE_ALIGN() when calling free_reserved_area().Signed-off-by: Jiang Liu
Cc: Geert Uytterhoeven
Cc: "H. Peter Anvin"
Cc: "Michael S. Tsirkin"
Cc:
Cc: Arnd Bergmann
Cc: Catalin Marinas
Cc: Chris Metcalf
Cc: David Howells
Cc: Ingo Molnar
Cc: Jeremy Fitzhardinge
Cc: Jianguo Wu
Cc: Joonsoo Kim
Cc: Kamezawa Hiroyuki
Cc: Konrad Rzeszutek Wilk
Cc: Marek Szyprowski
Cc: Mel Gorman
Cc: Michel Lespinasse
Cc: Minchan Kim
Cc: Rik van Riel
Cc: Rusty Russell
Cc: Tang Chen
Cc: Tejun Heo
Cc: Thomas Gleixner
Cc: Wen Congyang
Cc: Will Deacon
Cc: Yasuaki Ishimatsu
Cc: Yinghai Lu
Cc: Russell King
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Change signature of free_reserved_area() according to Russell King's
suggestion to fix following build warnings:arch/arm/mm/init.c: In function 'mem_init':
arch/arm/mm/init.c:603:2: warning: passing argument 1 of 'free_reserved_area' makes integer from pointer without a cast [enabled by default]
free_reserved_area(__va(PHYS_PFN_OFFSET), swapper_pg_dir, 0, NULL);
^
In file included from include/linux/mman.h:4:0,
from arch/arm/mm/init.c:15:
include/linux/mm.h:1301:22: note: expected 'long unsigned int' but argument is of type 'void *'
extern unsigned long free_reserved_area(unsigned long start, unsigned long end,mm/page_alloc.c: In function 'free_reserved_area':
>> mm/page_alloc.c:5134:3: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast [enabled by default]
In file included from arch/mips/include/asm/page.h:49:0,
from include/linux/mmzone.h:20,
from include/linux/gfp.h:4,
from include/linux/mm.h:8,
from mm/page_alloc.c:18:
arch/mips/include/asm/io.h:119:29: note: expected 'const volatile void *' but argument is of type 'long unsigned int'
mm/page_alloc.c: In function 'free_area_init_nodes':
mm/page_alloc.c:5030:34: warning: array subscript is below array bounds [-Warray-bounds]Also address some minor code review comments.
Signed-off-by: Jiang Liu
Reported-by: Arnd Bergmann
Cc: "H. Peter Anvin"
Cc: "Michael S. Tsirkin"
Cc:
Cc: Catalin Marinas
Cc: Chris Metcalf
Cc: David Howells
Cc: Geert Uytterhoeven
Cc: Ingo Molnar
Cc: Jeremy Fitzhardinge
Cc: Jianguo Wu
Cc: Joonsoo Kim
Cc: Kamezawa Hiroyuki
Cc: Konrad Rzeszutek Wilk
Cc: Marek Szyprowski
Cc: Mel Gorman
Cc: Michel Lespinasse
Cc: Minchan Kim
Cc: Rik van Riel
Cc: Rusty Russell
Cc: Tang Chen
Cc: Tejun Heo
Cc: Thomas Gleixner
Cc: Wen Congyang
Cc: Will Deacon
Cc: Yasuaki Ishimatsu
Cc: Yinghai Lu
Cc: Russell King
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
30 Apr, 2013
1 commit
-
Use common help functions to free reserved pages.
Also include to avoid local declarations.Signed-off-by: Jiang Liu
Cc: Jonas Bonn
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Feb, 2013
1 commit
-
The self-modifying code that updates the TLB handler at start-up has
a subtle ordering requirement: the DTLB handler must be the last thing
changed.What I was seeing was the following:
i) The DTLB handler was updated
ii) The following printk caused a TLB miss and the look-up resulted
in the page containing itlb_vector (0xc0000a00) being bounced from
the TLB.
iii) The subsequent access to itlb_vector caused a TLB miss and reload
of the page containing itlb_vector from the page tables.
iv) But this reload of the page in iii) was being done by the "new"
DTLB-miss handler which resulted (correctly) in the page flags being
set to read-only; the subsequent write-access to itlb_vector thus
resulted in a page (access) fault.This is easily remedied if we ensure that the boot-time DTLB-miss handler
continues running until the very last bit of self-modifying code has been
executed. This patch should ensure that the very last thing updated is the
DTLB-handler itself.Signed-off-by: Jonas Bonn
Acked-by: Julius Baxter
Tested-by: Sebastian Macke
09 Oct, 2012
1 commit
-
.fault now can retry. The retry can break state machine of .fault. In
filemap_fault, if page is miss, ra->mmap_miss is increased. In the second
try, since the page is in page cache now, ra->mmap_miss is decreased. And
these are done in one fault, so we can't detect random mmap file access.Add a new flag to indicate .fault is tried once. In the second try, skip
ra->mmap_miss decreasing. The filemap_fault state machine is ok with it.I only tested x86, didn't test other archs, but looks the change for other
archs is obvious, but who knows :)Signed-off-by: Shaohua Li
Cc: Rik van Riel
Cc: Wu Fengguang
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
08 May, 2012
1 commit
-
Commit d065bd810b6deb67d4897a14bfe21f8eb526ba99
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e0525d393d48a7d59f870b3bc061a30ccdb
(x86,mm: make pagefault killable)The above commits introduced changes into the x86 pagefault handler
for making the page fault handler retryable as well as killable.These changes reduce the mmap_sem hold time, which is crucial
during OOM killer invocation.Port these changes to openrisc.
Signed-off-by: Mohd. Faris
Signed-off-by: Kautuk Consul
Signed-off-by: Jonas Bonn
29 Mar, 2012
2 commits
-
…m/linux/kernel/git/dhowells/linux-asm_system
Pull "Disintegrate and delete asm/system.h" from David Howells:
"Here are a bunch of patches to disintegrate asm/system.h into a set of
separate bits to relieve the problem of circular inclusion
dependencies.I've built all the working defconfigs from all the arches that I can
and made sure that they don't break.The reason for these patches is that I recently encountered a circular
dependency problem that came about when I produced some patches to
optimise get_order() by rewriting it to use ilog2().This uses bitops - and on the SH arch asm/bitops.h drags in
asm-generic/get_order.h by a circuituous route involving asm/system.h.The main difficulty seems to be asm/system.h. It holds a number of
low level bits with no/few dependencies that are commonly used (eg.
memory barriers) and a number of bits with more dependencies that
aren't used in many places (eg. switch_to()).These patches break asm/system.h up into the following core pieces:
(1) asm/barrier.h
Move memory barriers here. This already done for MIPS and Alpha.
(2) asm/switch_to.h
Move switch_to() and related stuff here.
(3) asm/exec.h
Move arch_align_stack() here. Other process execution related bits
could perhaps go here from asm/processor.h.(4) asm/cmpxchg.h
Move xchg() and cmpxchg() here as they're full word atomic ops and
frequently used by atomic_xchg() and atomic_cmpxchg().(5) asm/bug.h
Move die() and related bits.
(6) asm/auxvec.h
Move AT_VECTOR_SIZE_ARCH here.
Other arch headers are created as needed on a per-arch basis."
Fixed up some conflicts from other header file cleanups and moving code
around that has happened in the meantime, so David's testing is somewhat
weakened by that. We'll find out anything that got broken and fix it..* tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits)
Delete all instances of asm/system.h
Remove all #inclusions of asm/system.h
Add #includes needed to permit the removal of asm/system.h
Move all declarations of free_initmem() to linux/mm.h
Disintegrate asm/system.h for OpenRISC
Split arch_align_stack() out from asm-generic/system.h
Split the switch_to() wrapper out of asm-generic/system.h
Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h
Create asm-generic/barrier.h
Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h
Disintegrate asm/system.h for Xtensa
Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt]
Disintegrate asm/system.h for Tile
Disintegrate asm/system.h for Sparc
Disintegrate asm/system.h for SH
Disintegrate asm/system.h for Score
Disintegrate asm/system.h for S390
Disintegrate asm/system.h for PowerPC
Disintegrate asm/system.h for PA-RISC
Disintegrate asm/system.h for MN10300
... -
Disintegrate asm/system.h for OpenRISC. Not compiled.
Signed-off-by: David Howells
Acked-by: Arnd Bergmann
cc: linux@lists.openrisc.net
17 Feb, 2012
1 commit
-
Use BUG_ON(x) rather than if(x) BUG();
The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)//
@@ identifier x; @@
-if (x) BUG();
+BUG_ON(x);@@ identifier x; @@
-if (!x) BUG();
+BUG_ON(!x);
//Signed-off-by: Julia Lawall
Signed-off-by: Jonas Bonn
23 Jul, 2011
2 commits
-
Signed-off-by: Jonas Bonn
Reviewed-by: Arnd Bergmann -
Signed-off-by: Jonas Bonn
Reviewed-by: Arnd Bergmann