Joe Perches [Thu, 23 Jan 2014 23:54:46 +0000 (15:54 -0800)]
checkpatch: improve space before tab --fix option
This test should remove all the spaces before a tab not just one space.
Substitute a tab for each 8 space block before a tab and remove less than
8 spaces before a tab.
This SPACE_BEFORE_TAB test is done after CODE_INDENT.
If there are spaces used at the beginning of a line that should be
converted to tabs, please make sure that the CODE_INDENT test and
conversion is done before this SPACE_BEFORE_TAB test and conversion.
Reported-by: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Joe Perches <joe@perches.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Andy Whitcroft <apw@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
case blocks should end in a break/return/goto/continue.
If a fall-through is used, it should have a comment showing that it is
intentional. Ideally that comment should be something like:
"/* fall-through */"
Add a test to look for missing break statements.
This looks only at the context lines before an inserted case so it's
possible to have false positives when the context contains a close brace
and the break is before the brace and not part of the patch context.
Looking at recent patches, this is a pretty rare occurrence. The normal
kernel style uses a break as the last line of the previous block.
Signed-off-by: Joe Perches <joe@perche.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com> Cc: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joe Perches [Thu, 23 Jan 2014 23:54:40 +0000 (15:54 -0800)]
checkpatch: more comprehensive split strings warning
The current checkpatch test for split strings does not find several
cases that should be found.
For instance:
/* Else poor success; go back to mode in "active" table */
} else {
IWL_DEBUG_RATE(mvm,
- "LQ: GOING BACK TO THE OLD TABLE suc=%d cur-tpt=%d old-tpt=%d\n",
+ "GOING BACK TO THE OLD TABLE: SR %d "
+ "cur-tpt %d old-tpt %d\n",
window->success_ratio,
window->average_tpt,
lq_sta->last_tpt);
does not currently emit a warning.
Improve the test to find these cases.
Add more exceptions to reduce false positives for assembly and octal/hex
string constants.
Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ard Biesheuvel [Thu, 23 Jan 2014 23:54:39 +0000 (15:54 -0800)]
firmware/dmi_scan: generalize for use by other archs
This patch makes a couple of changes to the SMBIOS/DMI scanning
code so it can be used on other archs (such as ARM and arm64):
(a) wrap the calls to ioremap()/iounmap(), this allows the use of a
flavor of ioremap() more suitable for random unaligned access;
(b) allow the non-EFI fallback probe into hardcoded physical address
0xF0000 to be disabled.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Grant Likely <grant.likely@linaro.org> Cc: Ingo Molnar <mingo@elte.hu>
Cc "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kees Cook [Thu, 23 Jan 2014 23:54:38 +0000 (15:54 -0800)]
test: check copy_to/from_user boundary validation
To help avoid an architecture failing to correctly check kernel/user
boundaries when handling copy_to_user, copy_from_user, put_user, or
get_user, perform some simple tests and fail to load if any of them
behave unexpectedly.
Specifically, this is to make sure there is a way to notice if things
like what was fixed in commit 8404663f81d2 ("ARM: 7527/1: uaccess:
explicitly check __user pointer when !CPU_USE_DOMAINS") ever regresses
again, for any architecture.
Additionally, adds new "user" selftest target, which loads this module.
Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kees Cook [Thu, 23 Jan 2014 23:54:37 +0000 (15:54 -0800)]
test: add minimal module for verification testing
This is a pair of test modules I'd like to see in the tree. Instead of
putting these in lkdtm, where I've been adding various tests that trigger
crashes, these don't make sense there since they need to be either
distinctly separate, or their pass/fail state don't need to crash the
machine.
These live in lib/ for now, along with a few other in-kernel test modules,
and use the slightly more common "test_" naming convention, instead of
"test-". We should likely standardize on the former:
The first is entirely a no-op module, designed to allow simple testing of
the module loading and verification interface. It's useful to have a
module that has no other uses or dependencies so it can be reliably used
for just testing module loading and verification.
The second is a module that exercises the user memory access functions, in
an effort to make sure that we can quickly catch any regressions in
boundary checking (e.g. like what was recently fixed on ARM).
This patch (of 2):
When doing module loading verification tests (for example, with module
signing, or LSM hooks), it is very handy to have a module that can be
built on all systems under test, isn't auto-loaded at boot, and has no
device or similar dependencies. This creates the "test_module.ko" module
for that purpose, which only reports its load and unload to printk.
Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jingoo Han [Thu, 23 Jan 2014 23:54:31 +0000 (15:54 -0800)]
backlight: kb3886_bl: fix incorrect placement of __initdata marker
The __initdata marker can be virtually anywhere on the line, EXCEPT right
after "struct". The preferred location is before the "=" sign if there is
one, or before the trailing ";" otherwise. It also fixes the following
chechpatch warning.
WARNING: __initdata should be placed after kb3886bl_device_table[]
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove unnecessary pattern for Exynos DP header from MAINTAINERS file.
After commit f9b1e013f1c6 ("video: exynos_dp: remove non-DT support for
Exynos Display Port"), 'exynos_dp.h' has not been used.
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joe Perches [Thu, 23 Jan 2014 23:54:20 +0000 (15:54 -0800)]
get_maintainer: add commit author information to --rolestats
get_maintainer currently uses "Signed-off-by" style lines to find
interested parties to send patches to when the MAINTAINERS file does not
have a specific section entry with a matching file pattern.
Add statistics for commit authors and lines added and deleted to the
information provided by --rolestats.
These statistics are also emitted whenever --rolestats and --git are
selected even when there is a specified maintainer.
This can have the effect of expanding the number of people that are shown
as possible "maintainers" of a particular file because "authors",
"added_lines", and "removed_lines" are also used as criterion for the
--max-maintainers option separate from the "commit_signers".
The first "--git-max-maintainers" values of each criterion
are emitted. Any "ties" are not shown.
For example: (forcedeth does not have a named maintainer)
Old output:
$ ./scripts/get_maintainer.pl -f drivers/net/ethernet/nvidia/forcedeth.c
"David S. Miller" <davem@davemloft.net> (commit_signer:8/10=80%)
Jiri Pirko <jiri@resnulli.us> (commit_signer:2/10=20%)
Patrick McHardy <kaber@trash.net> (commit_signer:2/10=20%)
Larry Finger <Larry.Finger@lwfinger.net> (commit_signer:1/10=10%)
Peter Zijlstra <peterz@infradead.org> (commit_signer:1/10=10%)
netdev@vger.kernel.org (open list:NETWORKING DRIVERS)
linux-kernel@vger.kernel.org (open list)
New output:
$ ./scripts/get_maintainer.pl -f drivers/net/ethernet/nvidia/forcedeth.c
"David S. Miller" <davem@davemloft.net> (commit_signer:8/10=80%)
Jiri Pirko <jiri@resnulli.us> (commit_signer:2/10=20%,authored:2/10=20%,removed_lines:3/33=9%)
Patrick McHardy <kaber@trash.net> (commit_signer:2/10=20%,authored:2/10=20%,added_lines:12/95=13%,removed_lines:10/33=30%)
Larry Finger <Larry.Finger@lwfinger.net> (commit_signer:1/10=10%,authored:1/10=10%,added_lines:35/95=37%)
Peter Zijlstra <peterz@infradead.org> (commit_signer:1/10=10%)
"Peter Hüwe" <PeterHuewe@gmx.de> (authored:1/10=10%,removed_lines:15/33=45%)
Joe Perches <joe@perches.com> (authored:1/10=10%)
Neil Horman <nhorman@tuxdriver.com> (added_lines:40/95=42%)
Bill Pemberton <wfp5p@virginia.edu> (removed_lines:3/33=9%)
netdev@vger.kernel.org (open list:NETWORKING DRIVERS)
linux-kernel@vger.kernel.org (open list)
Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Du, Changbin [Thu, 23 Jan 2014 23:54:15 +0000 (15:54 -0800)]
dynamic-debug-howto.txt: update since new wildcard support
Add the usage of using new feature wildcard support.
Signed-off-by: Du, Changbin <changbin.du@gmail.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Du, Changbin [Thu, 23 Jan 2014 23:54:14 +0000 (15:54 -0800)]
dynamic_debug: add wildcard support to filter files/functions/modules
Add wildcard '*'(matches zero or more characters) and '?' (matches one
character) support when qurying debug flags.
Now we can open debug messages using keywords. eg:
1. open debug logs in all usb drivers
echo "file drivers/usb/* +p" > <debugfs>/dynamic_debug/control
2. open debug logs for usb xhci code
echo "file *xhci* +p" > <debugfs>/dynamic_debug/control
Signed-off-by: Du, Changbin <changbin.du@gmail.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Du, Changbin [Thu, 23 Jan 2014 23:54:12 +0000 (15:54 -0800)]
lib/parser.c: add match_wildcard() function
match_wildcard function is a simple implementation of wildcard
matching algorithm. It only supports two usual wildcardes:
'*' - matches zero or more characters
'?' - matches one character
This algorithm is safe since it is non-recursive.
Signed-off-by: Du, Changbin <changbin.du@gmail.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Frysinger [Thu, 23 Jan 2014 23:54:10 +0000 (15:54 -0800)]
include/uapi/linux/dn.h: pull in ioctl.h header
This header uses _IOW/_IOR defines but doesn't include ioctl.h for it.
If you try to use this w/out including ioctl.h yourself, it can fail to
build, so add the explicit include.
Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Frysinger [Thu, 23 Jan 2014 23:54:09 +0000 (15:54 -0800)]
include/uapi/linux/ppp-ioctl.h: pull in ppp_defs.h
This header uses enum NPmode but doesn't include ppp_defs.h. If you try
to use this header w/out including the defs header first, it leads to a
build failure. So add the explicit include to fix it.
Don't know of any packages directly impacted, but noticed while building
some ppp code by hand.
Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: Paul Mackerras <paulus@samba.org> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Paul Bolle [Thu, 23 Jan 2014 23:54:08 +0000 (15:54 -0800)]
headers_check: special case seqbuf_dump()
"make headers_check" warns about soundcard.h for (at least) five years
now:
[...]/usr/include/linux/soundcard.h:1054: userspace cannot reference function or variable defined in the kernel
We're apparently stuck with providing OSSlib-3.8 compatibility, so let's
special case this declaration just to silence it.
Notes:
0) Support for OSSlib post 3.8 was already removed in commit 43a990765a
("sound: Remove OSSlib stuff from linux/soundcard.h"). Five years have
passed since that commit: do people still care about OSSlib-3.8? If
not, quite a bit of code could be remove from soundcard.h (and probably
ultrasound.h).
2) By the way, what is actually meant by:
It is no longer possible to actually link against OSSlib with this
header, but we still provide these macros for programs using them.
Doesn't that mean compatibility to OSSlib isn't even useful?
3) Anyhow, a previous discussion soundcard.h, which led to that commit,
starts at https://lkml.org/lkml/2009/1/20/349 .
4) And, yes, I sneaked in a whitespace fix.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Cc: Takashi Iwai <tiwai@suse.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dan Carpenter [Thu, 23 Jan 2014 23:54:07 +0000 (15:54 -0800)]
drivers/vlynq/vlynq.c: fix another resource size off by 1 error
We fixed the call to request_mem_region() in commit 3354f73b24c6
("drivers/vlynq/vlynq.c: fix resource size off by 1 error"). But we
need to fix the call the release_mem_region() as well.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Florian Fainelli <florian@openwrt.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Howells [Thu, 23 Jan 2014 23:54:05 +0000 (15:54 -0800)]
drivers/mfd/tps65217.c: fix pointer-integer size mismatch warning in tps65217_probe()
Fix up the following pointer-integer size mismatch warning in
tps65217_probe():
drivers/mfd/tps65217.c: In function 'tps65217_probe':
drivers/mfd/tps65217.c:173:13: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
chip_id = (unsigned int)match->data;
^
Signed-off-by: David Howells <dhowells@redhat.com> Cc: AnilKumar Ch <anilkumar@ti.com> Cc: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Howells [Thu, 23 Jan 2014 23:54:04 +0000 (15:54 -0800)]
drivers/mfd/max8998.c: fix pointer-integer size mismatch warning in max8998_i2c_get_driver_data()
Fix up the following pointer-integer size mismatch warning in
max8998_i2c_get_driver_data():
drivers/mfd/max8998.c: In function 'max8998_i2c_get_driver_data':
drivers/mfd/max8998.c:178:10: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
return (int)match->data;
^
Signed-off-by: David Howells <dhowells@redhat.com> Cc: Tomasz Figa <t.figa@samsung.com> Cc: Mark Brown <broonie@linaro.org> Cc: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Rob Herring <robh+dt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alex Elder [Thu, 23 Jan 2014 23:54:01 +0000 (15:54 -0800)]
remove extra definitions of U32_MAX
Now that the definition is centralized in <linux/kernel.h>, the
definitions of U32_MAX (and related) elsewhere in the kernel can be
removed.
Signed-off-by: Alex Elder <elder@linaro.org> Acked-by: Sage Weil <sage@inktank.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alex Elder [Thu, 23 Jan 2014 23:54:00 +0000 (15:54 -0800)]
kernel.h: define u8, s8, u32, etc. limits
Create constants that define the maximum and minimum values
representable by the kernel types u8, s8, u16, s16, and so on.
Signed-off-by: Alex Elder <elder@linaro.org> Cc: Sage Weil <sage@inktank.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alex Elder [Thu, 23 Jan 2014 23:53:59 +0000 (15:53 -0800)]
conditionally define U32_MAX
The symbol U32_MAX is defined in several spots. Change these
definitions to be conditional. This is in preparation for the next
patch, which centralizes the definition in <linux/kernel.h>.
Signed-off-by: Alex Elder <elder@linaro.org> Cc: Sage Weil <sage@inktank.com> Cc: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mark Salter [Thu, 23 Jan 2014 23:53:58 +0000 (15:53 -0800)]
um: use generic fixmap.h
Signed-off-by: Mark Salter <msalter@redhat.com> Acked-by: Richard Weinberger <richard@nod.at> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mark Salter [Thu, 23 Jan 2014 23:53:55 +0000 (15:53 -0800)]
powerpc: use generic fixmap.h
Signed-off-by: Mark Salter <msalter@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mark Salter [Thu, 23 Jan 2014 23:53:51 +0000 (15:53 -0800)]
hexagon: use generic fixmap.h
Signed-off-by: Mark Salter <msalter@redhat.com> Acked-by: Richard Kuo <rkuo@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mark Salter [Thu, 23 Jan 2014 23:53:48 +0000 (15:53 -0800)]
add generic fixmap.h
Many architectures provide an asm/fixmap.h which defines support for
compile-time 'special' virtual mappings which need to be made before
paging_init() has run. This support is also used for early ioremap on
x86. Much of this support is identical across the architectures. This
patch consolidates all of the common bits into asm-generic/fixmap.h
which is intended to be included from arch/*/include/asm/fixmap.h.
Signed-off-by: Mark Salter <msalter@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: James Hogan <james.hogan@imgtec.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jonas Bonn <jonas.bonn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fabian Frederick [Thu, 23 Jan 2014 23:53:46 +0000 (15:53 -0800)]
drivers/block/Kconfig: update RAM block device module name
RAM block device support module name changed to brd.ko some years ago
with an "rd" alias to match previous module implementation. This patch
updates its Kconfig definition.
Signed-off-by: Fabian Frederick <fabf@skynet.be> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now all 64-bit architectures have been converted to int-ll64.h, we can
remove int-l64.h in kernelspace.
For backwards compatibility, alpha, ia64, mips64, and powerpc64 still
use int-l64.h in userspace.
This is the (reworked for UAPI) non-documentation part of more than two
year old "asm/types.h: All architectures use int-ll64.h in kernelspace"
(https://lkml.org/lkml/2011/8/13/104)
Since <asm/types.h> (from include/uapi/asm-generic/types.h) is used for
both kernel and user space, include/asm-generic/int-ll64.h cannot just
become include/asm-generic/types.h, as Arnd suggested.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cyrill Gorcunov [Thu, 23 Jan 2014 23:53:42 +0000 (15:53 -0800)]
mm: ignore VM_SOFTDIRTY on VMA merging
The VM_SOFTDIRTY bit affects vma merge routine: if two VMAs has all bits
in vm_flags matched except dirty bit the kernel can't longer merge them
and this forces the kernel to generate new VMAs instead.
It finally may lead to the situation when userspace application reaches
vm.max_map_count limit and get crashed in worse case
| (gimp:11768): GLib-ERROR **: gmem.c:110: failed to allocate 4096 bytes
|
| (file-tiff-load:12038): LibGimpBase-WARNING **: file-tiff-load: gimp_wire_read(): error
| xinit: connection to X server lost
|
| waiting for X server to shut down
| /usr/lib64/gimp/2.0/plug-ins/file-tiff-load terminated: Hangup
| /usr/lib64/gimp/2.0/plug-ins/script-fu terminated: Hangup
| /usr/lib64/gimp/2.0/plug-ins/script-fu terminated: Hangup
Initial problem came from missed VM_SOFTDIRTY in do_brk() routine but
even if we would set up VM_SOFTDIRTY here, there is still a way to
prevent VMAs from merging: one can call
| echo 4 > /proc/$PID/clear_refs
and clear all VM_SOFTDIRTY over all VMAs presented in memory map, then
new do_brk() will try to extend old VMA and finds that dirty bit doesn't
match thus new VMA will be generated.
As discussed with Pavel, the right approach should be to ignore
VM_SOFTDIRTY bit when we're trying to merge VMAs and if merge successed
we mark extended VMA with dirty bit where needed.
Jamie Liu [Thu, 23 Jan 2014 23:53:40 +0000 (15:53 -0800)]
mm/swapfile.c: do not skip lowest_bit in scan_swap_map() scan loop
In the second half of scan_swap_map()'s scan loop, offset is set to
si->lowest_bit and then incremented before entering the loop for the
first time, causing si->swap_map[si->lowest_bit] to be skipped.
Signed-off-by: Jamie Liu <jamieliu@google.com> Cc: Shaohua Li <shli@fusionio.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:53:39 +0000 (15:53 -0800)]
memcg: remove unused code from kmem_cache_destroy_work_func
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mel Gorman [Thu, 23 Jan 2014 23:53:38 +0000 (15:53 -0800)]
mm: improve documentation of page_order
Developers occasionally try and optimise PFN scanners by using
page_order but miss that in general it requires zone->lock. This has
happened twice for compaction.c and rejected both times. This patch
clarifies the documentation of page_order and adds a note to
compaction.c why page_order is not used.
[akpm@linux-foundation.org: tweaks]
[lauraa@codeaurora.org: Corrected a page_zone(page)->lock reference] Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rafael Aquini <aquini@redhat.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Laura Abbott <lauraa@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Thu, 23 Jan 2014 23:53:37 +0000 (15:53 -0800)]
memcg: fix css reference leak and endless loop in mem_cgroup_iter
Commit 19f39402864e ("memcg: simplify mem_cgroup_iter") has reorganized
mem_cgroup_iter code in order to simplify it. A part of that change was
dropping an optimization which didn't call css_tryget on the root of the
walked tree. The patch however didn't change the css_put part in
mem_cgroup_iter which excludes root.
This wasn't an issue at the time because __mem_cgroup_iter_next bailed
out for root early without taking a reference as cgroup iterators
(css_next_descendant_pre) didn't visit root themselves.
Nevertheless cgroup iterators have been reworked to visit root by commit bd8815a6d802 ("cgroup: make css_for_each_descendant() and friends
include the origin css in the iteration") when the root bypass have been
dropped in __mem_cgroup_iter_next. This means that css_put is not
called for root and so css along with mem_cgroup and other cgroup
internal object tied by css lifetime are never freed.
Fix the issue by reintroducing root check in __mem_cgroup_iter_next and
do not take css reference for it.
This reference counting magic protects us also from another issue, an
endless loop reported by Hugh Dickins when reclaim races with root
removal and css_tryget called by iterator internally would fail. There
would be no other nodes to visit so __mem_cgroup_iter_next would return
NULL and mem_cgroup_iter would interpret it as "start looping from root
again" and so mem_cgroup_iter would loop forever internally.
Michal Hocko [Thu, 23 Jan 2014 23:53:35 +0000 (15:53 -0800)]
memcg: fix endless loop caused by mem_cgroup_iter
Hugh has reported an endless loop when the hardlimit reclaim sees the
same group all the time. This might happen when the reclaim races with
the memcg removal.
The issue seemed to be introduced by commit 5f5781619718 ("memcg: relax
memcg iter caching") which has replaced unconditional css_get/css_put by
css_tryget/css_put for the cached iterator.
This patch fixes the issue by skipping css_tryget on the root of the
tree walk in mem_cgroup_iter_load and symmetrically doesn't release it
in mem_cgroup_iter_update.
David Rientjes [Thu, 23 Jan 2014 23:53:34 +0000 (15:53 -0800)]
mm, oom: prefer thread group leaders for display purposes
When two threads have the same badness score, it's preferable to kill
the thread group leader so that the actual process name is printed to
the kernel log rather than the thread group name which may be shared
amongst several processes.
This was the behavior when select_bad_process() used to do
for_each_process(), but it now iterates threads instead and leads to
ambiguity.
Signed-off-by: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Thu, 23 Jan 2014 23:53:32 +0000 (15:53 -0800)]
mm/memcg: iteration skip memcgs not yet fully initialized
It is surprising that the mem_cgroup iterator can return memcgs which
have not yet been fully initialized. By accident (or trial and error?)
this appears not to present an actual problem; but it may be better to
prevent such surprises, by skipping memcgs not yet online.
Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> [3.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hugh Dickins [Thu, 23 Jan 2014 23:53:30 +0000 (15:53 -0800)]
mm/memcg: fix last_dead_count memory wastage
Shorten mem_cgroup_reclaim_iter.last_dead_count from unsigned long to
int: it's assigned from an int and compared with an int, and adjacent to
an unsigned int: so there's no point to it being unsigned long, which
wasted 104 bytes in every mem_cgroup_per_zone.
Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Paul Gortmaker [Thu, 23 Jan 2014 23:53:30 +0000 (15:53 -0800)]
mm: audit/fix non-modular users of module_init in core code
Code that is obj-y (always built-in) or dependent on a bool Kconfig
(built-in or absent) can never be modular. So using module_init as an
alias for __initcall can be somewhat misleading.
Fix these up now, so that we can relocate module_init from init.h into
module.h in the future. If we don't do this, we'd have to add module.h
to obviously non-modular code, and that would be a worse thing.
The audit targets the following module_init users for change:
mm/ksm.c bool KSM
mm/mmap.c bool MMU
mm/huge_memory.c bool TRANSPARENT_HUGEPAGE
mm/mmu_notifier.c bool MMU_NOTIFIER
Note that direct use of __initcall is discouraged, vs. one of the
priority categorized subgroups. As __initcall gets mapped onto
device_initcall, our use of subsys_initcall (which makes sense for these
files) will thus change this registration from level 6-device to level
4-subsys (i.e. slightly earlier).
However no observable impact of that difference has been observed during
testing.
One might think that core_initcall (l2) or postcore_initcall (l3) would
be more appropriate for anything in mm/ but if we look at some actual
init functions themselves, we see things like:
and hence the choice of subsys_initcall (l4) seems reasonable, and at
the same time minimizes the risk of changing the priority too
drastically all at once. We can adjust further in the future.
Also, several instances of missing ";" at EOL are fixed.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the interim, all __initcall are mapped onto device_initcall, which as
can be seen above, comes quite late in the ordering.
Currently the mm_kobj is created with __initcall in mm_sysfs_init().
This means that any other initcalls that want to reference the mm_kobj
have to be device_initcall (or later), otherwise we will for example,
trip the BUG_ON(!kobj) in sysfs's internal_create_group(). This
unfairly restricts those users; for example something that clearly makes
sense to be an arch_initcall will not be able to choose that.
However, upon examination, it is only this way for historical reasons
(i.e. simply not reprioritized yet). We see that sysfs is ready quite
earlier in init/main.c via:
vfs_caches_init
|_ mnt_init
|_ sysfs_init
well ahead of the processing of the prioritized calls listed above.
So we can recategorize mm_sysfs_init to be a pure_initcall, which in
turn allows any mm_kobj initcall users a wider range (1 --> 7) of
initcall priorities to choose from.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Han Pingtian [Thu, 23 Jan 2014 23:53:28 +0000 (15:53 -0800)]
mm: show message when updating min_free_kbytes in thp
min_free_kbytes may be raised during THP's initialization. Sometimes,
this will change the value which was set by the user. Showing this
message will clarify this confusion.
Only show this message when changing a value which was set by the user
according to Michal Hocko's suggestion.
Show the old value of min_free_kbytes according to Dave Hansen's
suggestion. This will give user the chance to restore old value of
min_free_kbytes.
Signed-off-by: Han Pingtian <hanpt@linux.vnet.ibm.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nathan Zimmer [Thu, 23 Jan 2014 23:53:26 +0000 (15:53 -0800)]
mm/memory_hotplug.c: move register_memory_resource out of the lock_memory_hotplug
We don't need to do register_memory_resource() under
lock_memory_hotplug() since it has its own lock and doesn't make any
callbacks.
Also register_memory_resource return NULL on failure so we don't have
anything to cleanup at this point.
The reason for this rfc is I was doing some experiments with hotplugging
of memory on some of our larger systems. While it seems to work, it can
be quite slow. With some preliminary digging I found that
lock_memory_hotplug is clearly ripe for breakup.
It could be broken up per nid or something but it also covers the
online_page_callback. The online_page_callback shouldn't be very hard
to break out.
Also there is the issue of various structures(wmarks come to mind) that
are only updated under the lock_memory_hotplug that would need to be
dealt with.
get_allocated_memblock_reserved_regions_info() should work if it is
compiled in. Extended the ifdef around
get_allocated_memblock_memory_regions_info() to include
get_allocated_memblock_reserved_regions_info() as well. Similar changes
in nobootmem.c/free_low_memory_core_early() where the two functions are
called.
[akpm@linux-foundation.org: cleanup] Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com> Cc: qiuxishi <qiuxishi@huawei.com> Cc: David Howells <dhowells@redhat.com> Cc: Daeseok Youn <daeseok.youn@gmail.com> Cc: Jiang Liu <liuj97@gmail.com> Acked-by: Yinghai Lu <yinghai@kernel.org> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Grygorii Strashko <grygorii.strashko@ti.com> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:53:23 +0000 (15:53 -0800)]
mm: vmscan: call NUMA-unaware shrinkers irrespective of nodemask
If a shrinker is not NUMA-aware, shrink_slab() should call it exactly
once with nid=0, but currently it is not true: if node 0 is not set in
the nodemask or if it is not online, we will not call such shrinkers at
all. As a result some slabs will be left untouched under some
circumstances. Let us fix it.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reported-by: Dave Chinner <dchinner@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Glauber Costa <glommer@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If there are only a few shrinkers available, such a behavior won't cause
any problems, because the batch_size is usually small, but if we have a
lot of slab shrinkers, which is perfectly possible since FS shrinkers
are now per-superblock, we can end up with hundreds of megabytes of
practically unreclaimable kmem objects. For instance, mounting a
thousand of ext2 FS images with a hundred of files in each and iterating
over all the files using du(1) will result in about 200 Mb of FS caches
that cannot be dropped even with the aid of the vm.drop_caches sysctl!
This problem was initially pointed out by Glauber Costa [*]. Glauber
proposed to fix it by making the shrink_slab() always take at least one
pass, to put it simply, turning the scan loop above to a do{}while()
loop. However, this proposal was rejected, because it could result in
more aggressive and frequent slab shrinking even under low memory
pressure when total_scan is naturally very small.
This patch is a slightly modified version of Glauber's approach.
Similarly to Glauber's patch, it makes shrink_slab() scan less than
batch_size objects, but only if the total number of objects we want to
scan (total_scan) is greater than the total number of objects available
(max_pass). Since total_scan is biased as half max_pass if the current
delta change is small:
this is only possible if we are scanning at high prio. That said, this
patch shouldn't change the vmscan behaviour if the memory pressure is
low, but if we are tight on memory, we will do our best by trying to
reclaim all available objects, which sounds reasonable.
Wanpeng Li [Thu, 23 Jan 2014 23:53:21 +0000 (15:53 -0800)]
sched/numa: fix setting of cpupid on page migration twice
Commit 7851a45cd3f6 ("mm: numa: Copy cpupid on page migration") copiess
over the cpupid at page migration time. It is unnecessary to set it
again in migrate_misplaced_transhuge_page().
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jianguo Wu [Thu, 23 Jan 2014 23:53:19 +0000 (15:53 -0800)]
mm: do_mincore() cleanup
Two cleanups:
1. remove redundant codes for hugetlb pages.
2. end = pmd_addr_end(addr, end) restricts [addr, end) within PMD_SIZE,
this may increase do_mincore() calls, remove it.
Signed-off-by: Jianguo Wu <wujianguo@huawei.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: qiuxishi <qiuxishi@huawei.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Han Pingtian [Thu, 23 Jan 2014 23:53:17 +0000 (15:53 -0800)]
mm: prevent setting of a value less than 0 to min_free_kbytes
If echo -1 > /proc/vm/sys/min_free_kbytes, the system will hang. Changing
proc_dointvec() to proc_dointvec_minmax() in the
min_free_kbytes_sysctl_handler() can prevent this to happen.
mhocko said:
: You can still do echo $BIG_VALUE > /proc/vm/sys/min_free_kbytes and make
: your machine unusable but I agree that proc_dointvec_minmax is more
: suitable here as we already have:
:
: .proc_handler = min_free_kbytes_sysctl_handler,
: .extra1 = &zero,
:
: It used to work properly but then 6fce56ec91b5 ("sysctl: Remove references
: to ctl_name and strategy from the generic sysctl table") has removed
: sysctl_intvec strategy and so extra1 is ignored.
Signed-off-by: Han Pingtian <hanpt@linux.vnet.ibm.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Thu, 23 Jan 2014 23:53:15 +0000 (15:53 -0800)]
mm: new_vma_page() cannot see NULL vma for hugetlb pages
Commit 11c731e81bb0 ("mm/mempolicy: fix !vma in new_vma_page()") has
removed BUG_ON(!vma) from new_vma_page which is partially correct
because page_address_in_vma will return EFAULT for non-linear mappings
and at least shared shmem might be mapped this way.
The patch also tried to prevent NULL ptr for hugetlb pages which is not
correct AFAICS because hugetlb pages cannot be mapped as VM_NONLINEAR
and other conditions in page_address_in_vma seem to be legit and catch
real bugs.
This patch restores BUG_ON for PageHuge to catch potential issues when
the to-be-migrated page is not setup properly.
Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Bob Liu <bob.liu@oracle.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Naoya Horiguchi [Thu, 23 Jan 2014 23:53:14 +0000 (15:53 -0800)]
mm/memory-failure.c: shift page lock from head page to tail page after thp split
After thp split in hwpoison_user_mappings(), we hold page lock on the
raw error page only between try_to_unmap, hence we are in danger of race
condition.
I found in the RHEL7 MCE-relay testing that we have "bad page" error
when a memory error happens on a thp tail page used by qemu-kvm:
Triggering MCE exception on CPU 10
mce: [Hardware Error]: Machine check events logged
MCE exception done on CPU 10
MCE 0x38c535: Killing qemu-kvm:8418 due to hardware memory corruption
MCE 0x38c535: dirty LRU page recovery: Recovered
qemu-kvm[8418]: segfault at 20 ip 00007ffb0f0f229a sp 00007fffd6bc5240 error 4 in qemu-kvm[7ffb0ef14000+420000]
BUG: Bad page state in process qemu-kvm pfn:38c400
page:ffffea000e310000 count:0 mapcount:0 mapping: (null) index:0x7ffae3c00
page flags: 0x2fffff0008001d(locked|referenced|uptodate|dirty|swapbacked)
Modules linked in: hwpoison_inject mce_inject vhost_net macvtap macvlan ...
CPU: 0 PID: 8418 Comm: qemu-kvm Tainted: G M -------------- 3.10.0-54.0.1.el7.mce_test_fixed.x86_64 #1
Hardware name: NEC NEC Express5800/R120b-1 [N8100-1719F]/MS-91E7-001, BIOS 4.6.3C19 02/10/2011
Call Trace:
dump_stack+0x19/0x1b
bad_page.part.59+0xcf/0xe8
free_pages_prepare+0x148/0x160
free_hot_cold_page+0x31/0x140
free_hot_cold_page_list+0x46/0xa0
release_pages+0x1c1/0x200
free_pages_and_swap_cache+0xad/0xd0
tlb_flush_mmu.part.46+0x4c/0x90
tlb_finish_mmu+0x55/0x60
exit_mmap+0xcb/0x170
mmput+0x67/0xf0
vhost_dev_cleanup+0x231/0x260 [vhost_net]
vhost_net_release+0x3f/0x90 [vhost_net]
__fput+0xe9/0x270
____fput+0xe/0x10
task_work_run+0xc4/0xe0
do_exit+0x2bb/0xa40
do_group_exit+0x3f/0xa0
get_signal_to_deliver+0x1d0/0x6e0
do_signal+0x48/0x5e0
do_notify_resume+0x71/0xc0
retint_signal+0x48/0x8c
The reason of this bug is that a page fault happens before unlocking the
head page at the end of memory_failure(). This strange page fault is
trying to access to address 0x20 and I'm not sure why qemu-kvm does
this, but anyway as a result the SIGSEGV makes qemu-kvm exit and on the
way we catch the bad page bug/warning because we try to free a locked
page (which was the former head page.)
To fix this, this patch suggests to shift page lock from head page to
tail page just after thp split. SIGSEGV still happens, but it affects
only error affected VMs, not a whole system.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> [3.9+] # a3e0f9e47d5ef "mm/memory-failure.c: transfer page count from head page to tail page after split thp" Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When calling free_all_bootmem() the free areas under memblock's control
are released to the buddy allocator. Additionally the reserved list is
freed if it was reallocated by memblock. The same should apply for the
memory list.
Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/nobootmem.c: add return value check in __alloc_memory_core_early()
When memblock_reserve() fails because memblock.reserved.regions cannot
be resized, the caller (e.g. alloc_bootmem()) is not informed of the
failed allocation. Therefore alloc_bootmem() silently returns the same
pointer again and again.
This patch adds a check for the return value of memblock_reserve() in
__alloc_memory_core().
Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we take both the memcg_create_mutex and the set_limit_mutex
when we enable kmem accounting for a memory cgroup, which makes kmem
activation events serialize with both memcg creations and other memcg
limit updates (memory.limit, memory.memsw.limit). However, there is no
point in such strict synchronization rules there.
First, the set_limit_mutex was introduced to keep the memory.limit and
memory.memsw.limit values in sync. Since memory.kmem.limit can be set
independently of them, it is better to introduce a separate mutex to
synchronize against concurrent kmem limit updates.
Second, we take the memcg_create_mutex in order to make sure all
children of this memcg will be kmem-active as well. For achieving that,
it is enough to hold this mutex only while checking if
memcg_has_children() though. This guarantees that if a child is added
after we checked that the memcg has no children, the newly added cgroup
will see its parent kmem-active (of course if the latter succeeded), and
call kmem activation for itself.
This patch simplifies the locking rules of memcg_update_kmem_limit()
according to these considerations.
[vdavydov@parallels.com: fix unintialized var warning] Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:53:08 +0000 (15:53 -0800)]
memcg: remove KMEM_ACCOUNTED_ACTIVATED flag
Currently we have two state bits in mem_cgroup::kmem_account_flags
regarding kmem accounting activation, ACTIVATED and ACTIVE. We start
kmem accounting only if both flags are set (memcg_can_account_kmem()),
plus throughout the code there are several places where we check only
the ACTIVE flag, but we never check the ACTIVATED flag alone. These
flags are both set from memcg_update_kmem_limit() under the
set_limit_mutex, the ACTIVE flag always being set after ACTIVATED, and
they never get cleared. That said checking if both flags are set is
equivalent to checking only for the ACTIVE flag, and since there is no
ACTIVATED flag checks, we can safely remove the ACTIVATED flag, and
nothing will change.
Let's try to understand what was the reason for introducing these flags.
The purpose of the ACTIVE flag is clear - it states that kmem should be
accounting to the cgroup. The only requirement for it is that it should
be set after we have fully initialized kmem accounting bits for the
cgroup and patched all static branches relating to kmem accounting.
Since we always check if static branch is enabled before actually
considering if we should account (otherwise we wouldn't benefit from
static branching), this guarantees us that we won't skip a commit or
uncharge after a charge due to an unpatched static branch.
Now let's move on to the ACTIVATED bit. As I proved in the beginning of
this message, it is absolutely useless, and removing it will change
nothing. So what was the reason introducing it?
The ACTIVATED flag was introduced by commit a8964b9b84f9 ("memcg: use
static branches when code not in use") in order to guarantee that
static_key_slow_inc(&memcg_kmem_enabled_key) would be called only once
for each memory cgroup when its kmem accounting was activated. The
point was that at that time the memcg_update_kmem_limit() function's
work-flow looked like this:
bool must_inc_static_branch = false;
cgroup_lock();
mutex_lock(&set_limit_mutex);
if (!memcg->kmem_account_flags && val != RESOURCE_MAX) {
/* The kmem limit is set for the first time */
ret = res_counter_set_limit(&memcg->kmem, val);
if (must_inc_static_branch) {
/* We can't do this under cgroup_lock */
static_key_slow_inc(&memcg_kmem_enabled_key);
memcg_kmem_set_active(memcg);
}
So that without the ACTIVATED flag we could race with other threads
trying to set the limit and increment the static branching ref-counter
more than once. Today we call the whole memcg_update_kmem_limit()
function under the set_limit_mutex and this race is impossible.
As now we understand why the ACTIVATED bit was introduced and why we
don't need it now, and know that removing it will change nothing anyway,
let's get rid of it.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:53:06 +0000 (15:53 -0800)]
memcg, slab: RCU protect memcg_params for root caches
We relocate root cache's memcg_params whenever we need to grow the
memcg_caches array to accommodate all kmem-active memory cgroups.
Currently on relocation we free the old version immediately, which can
lead to use-after-free, because the memcg_caches array is accessed
lock-free (see cache_from_memcg_idx()). This patch fixes this by making
memcg_params RCU-protected for root caches.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:53:05 +0000 (15:53 -0800)]
slab: do not panic if we fail to create memcg cache
There is no point in flooding logs with warnings or especially crashing
the system if we fail to create a cache for a memcg. In this case we
will be accounting the memcg allocation to the root cgroup until we
succeed to create its own cache, but it isn't that critical.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:53:03 +0000 (15:53 -0800)]
memcg: get rid of kmem_cache_dup()
kmem_cache_dup() is only called from memcg_create_kmem_cache(). The
latter, in fact, does nothing besides this, so let's fold
kmem_cache_dup() into memcg_create_kmem_cache().
This patch also makes the memcg_cache_mutex private to
memcg_create_kmem_cache(), because it is not used anywhere else.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:53:02 +0000 (15:53 -0800)]
memcg, slab: fix races in per-memcg cache creation/destruction
We obtain a per-memcg cache from a root kmem_cache by dereferencing an
entry of the root cache's memcg_params::memcg_caches array. If we find
no cache for a memcg there on allocation, we initiate the memcg cache
creation (see memcg_kmem_get_cache()). The cache creation proceeds
asynchronously in memcg_create_kmem_cache() in order to avoid lock
clashes, so there can be several threads trying to create the same
kmem_cache concurrently, but only one of them may succeed. However, due
to a race in the code, it is not always true. The point is that the
memcg_caches array can be relocated when we activate kmem accounting for
a memcg (see memcg_update_all_caches(), memcg_update_cache_size()). If
memcg_update_cache_size() and memcg_create_kmem_cache() proceed
concurrently as described below, we can leak a kmem_cache.
Asume two threads schedule creation of the same kmem_cache. One of them
successfully creates it. Another one should fail then, but if
memcg_create_kmem_cache() interleaves with memcg_update_cache_size() as
follows, it won't:
// kmem_cache_create_memcg takes slab_mutex
// so we will hang around until
// memcg_update_cache_size finishes, but
// nothing will prevent it from succeeding so
// memcg_caches[idx] will be overwritten in
// memcg_register_cache!
Let's fix this by moving the check for existence of the memcg cache to
kmem_cache_create_memcg() to be called under the slab_mutex and make it
return NULL if so.
A similar race is possible when destroying a memcg cache (see
kmem_cache_destroy()). Since memcg_unregister_cache(), which clears the
pointer in the memcg_caches array, is called w/o protection, we can race
with memcg_update_cache_size() and omit clearing the pointer. Therefore
memcg_unregister_cache() should be moved before we release the
slab_mutex.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:53:01 +0000 (15:53 -0800)]
memcg: fix possible NULL deref while traversing memcg_slab_caches list
All caches of the same memory cgroup are linked in the memcg_slab_caches
list via kmem_cache::memcg_params::list. This list is traversed, for
example, when we read memory.kmem.slabinfo.
Since the list actually consists of memcg_cache_params objects, we have
to convert an element of the list to a kmem_cache object using
memcg_params_to_cache(), which obtains the pointer to the cache from the
memcg_params::memcg_caches array of the corresponding root cache. That
said the pointer to a kmem_cache in its parent's memcg_params must be
initialized before adding the cache to the list, and cleared only after
it has been unlinked. Currently it is vice-versa, which can result in a
NULL ptr dereference while traversing the memcg_slab_caches list. This
patch restores the correct order.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:52:59 +0000 (15:52 -0800)]
memcg, slab: fix barrier usage when accessing memcg_caches
Each root kmem_cache has pointers to per-memcg caches stored in its
memcg_params::memcg_caches array. Whenever we want to allocate a slab
for a memcg, we access this array to get per-memcg cache to allocate
from (see memcg_kmem_get_cache()). The access must be lock-free for
performance reasons, so we should use barriers to assert the kmem_cache
is up-to-date.
First, we should place a write barrier immediately before setting the
pointer to it in the memcg_caches array in order to make sure nobody
will see a partially initialized object. Second, we should issue a read
barrier before dereferencing the pointer to conform to the write
barrier.
However, currently the barrier usage looks rather strange. We have a
write barrier *after* setting the pointer and a read barrier *before*
reading the pointer, which is incorrect. This patch fixes this.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vladimir Davydov [Thu, 23 Jan 2014 23:52:58 +0000 (15:52 -0800)]
memcg, slab: clean up memcg cache initialization/destruction
Currently, we have rather a messy function set relating to per-memcg
kmem cache initialization/destruction.
Per-memcg caches are created in memcg_create_kmem_cache(). This
function calls kmem_cache_create_memcg() to allocate and initialize a
kmem cache and then "registers" the new cache in the
memcg_params::memcg_caches array of the parent cache.
During its work-flow, kmem_cache_create_memcg() executes the following
memcg-related functions:
- memcg_alloc_cache_params(), to initialize memcg_params of the newly
created cache;
- memcg_cache_list_add(), to add the new cache to the memcg_slab_caches
list.
On the other hand, kmem_cache_destroy() called on a cache destruction
only calls memcg_release_cache(), which does all the work: it cleans the
reference to the cache in its parent's memcg_params::memcg_caches,
removes the cache from the memcg_slab_caches list, and frees
memcg_params.
Such an inconsistency between destruction and initialization paths make
the code difficult to read, so let's clean this up a bit.
This patch moves all the code relating to registration of per-memcg
caches (adding to memcg list, setting the pointer to a cache from its
parent) to the newly created memcg_register_cache() and
memcg_unregister_cache() functions making the initialization and
destruction paths look symmetrical.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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