Commit 84235de394 ("fs: buffer: move allocation failure loop into the
allocator") allowed __GFP_NOFAIL allocations to bypass the limit if they
fail to reclaim enough memory for the charge. But because the main test
case was on a 3.2-based system, the patch missed the fact that on newer
kernels the charge function needs to return root_mem_cgroup when
bypassing the limit, and not NULL. This will corrupt whatever memory is
at NULL + percpu pointer offset. Fix this quickly before problems are
reported.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge three fixes from Andrew Morton.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
memcg: use __this_cpu_sub() to dec stats to avoid incorrect subtrahend casting
percpu: fix this_cpu_sub() subtrahend casting for unsigneds
mm/pagewalk.c: fix walk_page_range() access of wrong PTEs
As of commit 3ea67d06e4 ("memcg: add per cgroup writeback pages
accounting") memcg counter errors are possible when moving charged
memory to a different memcg. Charge movement occurs when processing
writes to memory.force_empty, moving tasks to a memcg with
memcg.move_charge_at_immigrate=1, or memcg deletion.
An example showing error after memory.force_empty:
$ cd /sys/fs/cgroup/memory
$ mkdir x
$ rm /data/tmp/file
$ (echo $BASHPID >> x/tasks && exec mmap_writer /data/tmp/file 1M) &
[1] 13600
$ grep ^mapped x/memory.stat
mapped_file 1048576
$ echo 13600 > tasks
$ echo 1 > x/memory.force_empty
$ grep ^mapped x/memory.stat
mapped_file 4503599627370496
mapped_file should end with 0.
4503599627370496 == 0x10,0000,0000,0000 == 0x100,0000,0000 pages
1048576 == 0x10,0000 == 0x100 pages
This issue only affects the source memcg on 64 bit machines; the
destination memcg counters are correct. So the rmdir case is not too
important because such counters are soon disappearing with the entire
memcg. But the memcg.force_empty and memory.move_charge_at_immigrate=1
cases are larger problems as the bogus counters are visible for the
(possibly long) remaining life of the source memcg.
The problem is due to memcg use of __this_cpu_from(.., -nr_pages), which
is subtly wrong because it subtracts the unsigned int nr_pages (either
-1 or -512 for THP) from a signed long percpu counter. When
nr_pages=-1, -nr_pages=0xffffffff. On 64 bit machines stat->count[idx]
is signed 64 bit. So memcg's attempt to simply decrement a count (e.g.
from 1 to 0) boils down to:
long count = 1
unsigned int nr_pages = 1
count += -nr_pages /* -nr_pages == 0xffff,ffff */
count is now 0x1,0000,0000 instead of 0
The fix is to subtract the unsigned page count rather than adding its
negation. This only works once "percpu: fix this_cpu_sub() subtrahend
casting for unsigneds" is applied to fix this_cpu_sub().
Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
this_cpu_sub() is implemented as negation and addition.
This patch casts the adjustment to the counter type before negation to
sign extend the adjustment. This helps in cases where the counter type
is wider than an unsigned adjustment. An alternative to this patch is
to declare such operations unsupported, but it seemed useful to avoid
surprises.
This patch specifically helps the following example:
unsigned int delta = 1
preempt_disable()
this_cpu_write(long_counter, 0)
this_cpu_sub(long_counter, delta)
preempt_enable()
Before this change long_counter on a 64 bit machine ends with value
0xffffffff, rather than 0xffffffffffffffff. This is because
this_cpu_sub(pcp, delta) boils down to this_cpu_add(pcp, -delta),
which is basically:
long_counter = 0 + 0xffffffff
Also apply the same cast to:
__this_cpu_sub()
__this_cpu_sub_return()
this_cpu_sub_return()
All percpu_test.ko passes, especially the following cases which
previously failed:
l -= ui_one;
__this_cpu_sub(long_counter, ui_one);
CHECK(l, long_counter, -1);
l -= ui_one;
this_cpu_sub(long_counter, ui_one);
CHECK(l, long_counter, -1);
CHECK(l, long_counter, 0xffffffffffffffff);
ul -= ui_one;
__this_cpu_sub(ulong_counter, ui_one);
CHECK(ul, ulong_counter, -1);
CHECK(ul, ulong_counter, 0xffffffffffffffff);
ul = this_cpu_sub_return(ulong_counter, ui_one);
CHECK(ul, ulong_counter, 2);
ul = __this_cpu_sub_return(ulong_counter, ui_one);
CHECK(ul, ulong_counter, 1);
Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When walk_page_range walk a memory map's page tables, it'll skip
VM_PFNMAP area, then variable 'next' will to assign to vma->vm_end, it
maybe larger than 'end'. In next loop, 'addr' will be larger than
'next'. Then in /proc/XXXX/pagemap file reading procedure, the 'addr'
will growing forever in pagemap_pte_range, pte_to_pagemap_entry will
access the wrong pte.
BUG: Bad page map in process procrank pte:8437526f pmd:785de067
addr:9108d000 vm_flags:00200073 anon_vma:f0d99020 mapping: (null) index:9108d
CPU: 1 PID: 4974 Comm: procrank Tainted: G B W O 3.10.1+ #1
Call Trace:
dump_stack+0x16/0x18
print_bad_pte+0x114/0x1b0
vm_normal_page+0x56/0x60
pagemap_pte_range+0x17a/0x1d0
walk_page_range+0x19e/0x2c0
pagemap_read+0x16e/0x200
vfs_read+0x84/0x150
SyS_read+0x4a/0x80
syscall_call+0x7/0xb
Signed-off-by: Liu ShuoX <shuox.liu@intel.com>
Signed-off-by: Chen LinX <linx.z.chen@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org> [3.10.x+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I've seen a fair number of issues with kswapd and other processes
appearing to get stuck in v3.12-rc. Using sysrq-p many times seems to
indicate that it gets stuck somewhere in list_lru_walk_node(), called
from prune_icache_sb() and super_cache_scan().
I never seem to be able to trigger a calltrace for functions above that
point.
So I decided to add the following to super_cache_scan():
@@ -81,10 +81,14 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
inodes = list_lru_count_node(&sb->s_inode_lru, sc->nid);
dentries = list_lru_count_node(&sb->s_dentry_lru, sc->nid);
total_objects = dentries + inodes + fs_objects + 1;
+printk("%s:%u: %s: dentries %lu inodes %lu total %lu\n", current->comm, current->pid, __func__, dentries, inodes, total_objects);
/* proportion the scan between the caches */
dentries = mult_frac(sc->nr_to_scan, dentries, total_objects);
inodes = mult_frac(sc->nr_to_scan, inodes, total_objects);
+printk("%s:%u: %s: dentries %lu inodes %lu\n", current->comm, current->pid, __func__, dentries, inodes);
+BUG_ON(dentries == 0);
+BUG_ON(inodes == 0);
/*
* prune the dcache first as the icache is pinned by it, then
@@ -99,7 +103,7 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
freed += sb->s_op->free_cached_objects(sb, fs_objects,
sc->nid);
}
-
+printk("%s:%u: %s: dentries %lu inodes %lu freed %lu\n", current->comm, current->pid, __func__, dentries, inodes, freed);
drop_super(sb);
return freed;
}
and shortly thereafter, having applied some pressure, I got this:
update-apt-xapi:1616: super_cache_scan: dentries 25632 inodes 2 total 25635
update-apt-xapi:1616: super_cache_scan: dentries 1023 inodes 0
------------[ cut here ]------------
Kernel BUG at c0101994 [verbose debug info unavailable]
Internal error: Oops - BUG: 0 [#3] SMP ARM
Modules linked in: fuse rfcomm bnep bluetooth hid_cypress
CPU: 0 PID: 1616 Comm: update-apt-xapi Tainted: G D 3.12.0-rc7+ #154
task: daea1200 ti: c3bf8000 task.ti: c3bf8000
PC is at super_cache_scan+0x1c0/0x278
LR is at trace_hardirqs_on+0x14/0x18
Process update-apt-xapi (pid: 1616, stack limit = 0xc3bf8240)
...
Backtrace:
(super_cache_scan) from [<c00cd69c>] (shrink_slab+0x254/0x4c8)
(shrink_slab) from [<c00d09a0>] (try_to_free_pages+0x3a0/0x5e0)
(try_to_free_pages) from [<c00c59cc>] (__alloc_pages_nodemask+0x5)
(__alloc_pages_nodemask) from [<c00e07c0>] (__pte_alloc+0x2c/0x13)
(__pte_alloc) from [<c00e3a70>] (handle_mm_fault+0x84c/0x914)
(handle_mm_fault) from [<c001a4cc>] (do_page_fault+0x1f0/0x3bc)
(do_page_fault) from [<c001a7b0>] (do_translation_fault+0xac/0xb8)
(do_translation_fault) from [<c000840c>] (do_DataAbort+0x38/0xa0)
(do_DataAbort) from [<c00133f8>] (__dabt_usr+0x38/0x40)
Notice that we had a very low number of inodes, which were reduced to
zero my mult_frac().
Now, prune_icache_sb() calls list_lru_walk_node() passing that number of
inodes (0) into that as the number of objects to scan:
long prune_icache_sb(struct super_block *sb, unsigned long nr_to_scan,
int nid)
{
LIST_HEAD(freeable);
long freed;
freed = list_lru_walk_node(&sb->s_inode_lru, nid, inode_lru_isolate,
&freeable, &nr_to_scan);
which does:
unsigned long
list_lru_walk_node(struct list_lru *lru, int nid, list_lru_walk_cb isolate,
void *cb_arg, unsigned long *nr_to_walk)
{
struct list_lru_node *nlru = &lru->node[nid];
struct list_head *item, *n;
unsigned long isolated = 0;
spin_lock(&nlru->lock);
restart:
list_for_each_safe(item, n, &nlru->list) {
enum lru_status ret;
/*
* decrement nr_to_walk first so that we don't livelock if we
* get stuck on large numbesr of LRU_RETRY items
*/
if (--(*nr_to_walk) == 0)
break;
So, if *nr_to_walk was zero when this function was entered, that means
we're wanting to operate on (~0UL)+1 objects - which might as well be
infinite.
Clearly this is not correct behaviour. If we think about the behaviour
of this function when *nr_to_walk is 1, then clearly it's wrong - we
decrement first and then test for zero - which results in us doing
nothing at all. A post-decrement would give the desired behaviour -
we'd try to walk one object and one object only if *nr_to_walk were one.
It also gives the correct behaviour for zero - we exit at this point.
Fixes: 5cedf721a7 ("list_lru: fix broken LRU_RETRY behaviour")
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
[ Modified to make sure we never underflow the count: this function gets
called in a loop, so the 0 -> ~0ul transition is dangerous - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull serial fixes from Greg KH:
"Here are 3 tiny fixes that are needed for 3.12-final for some serial
drivers.
One of them is a revert of a broken patch, and two others are fixes
for reported bugs. All of these have been in linux-next for a while,
I forgot I had not sent them to you yet, my fault"
(Actually, Greg, you _had_ sent two of the three, so this pulls in just
one actual new fix)
* tag 'tty-3.12-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
tty/serial: at91: fix uart/usart selection for older products
Pull drm fixes from Dave Airlie:
"Mainly Intel regression fixes and quirks, along with a simple one
liner to fix rendernodes ioctl access (off by default, but testers
want to test it)"
* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
drm: allow DRM_IOCTL_VERSION on render-nodes
drm/i915: Fix the PPT fdi lane bifurcate state handling on ivb
drm/i915: No LVDS hardware on Intel D410PT and D425KT
drm/i915/dp: workaround BIOS eDP bpp clamping issue
drm/i915: Add HSW CRT output readout support
drm/i915: Add support for pipe_bpp readout
Pull sound fixes from Takashi Iwai:
"A few small HD-audio regression fixes, mostly for stable kernels, too"
* tag 'sound-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda - Fix silent headphone on Thinkpads with AD1984A codec
ALSA: hda - Add missing initial vmaster hook at build_controls callback
ALSA: hda - Fix unbalanced runtime PM refcount after S3/S4
Pull KVM fixes from Paolo Bonzini:
"Fixes for the 3.12 debugfs problem - removing the duplicate directory
name, and using a better the error code"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: use a more sensible error number when debugfs directory creation fails
KVM: Fix modprobe failure for kvm_intel/kvm_amd
We need to check the length parameter before doing the memcpy(). I've
actually changed it to strlcpy() as well so that it's NUL terminated.
You need CAP_NET_ADMIN to trigger these so it's not the end of the
world.
Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I don't know if this was due to cut and paste, or somebody was really
using a D20 to pick the error code for kvm_init_debugfs as suggested by
Linus (EFAULT is 14, so the possibility cannot be entirely ruled out).
In any case, this patch fixes it.
Reported-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The x86 specific kvm init creates a new conflicting
debugfs directory which causes modprobe issues
with kvm_intel and kvm_amd. For example,
sudo modprobe kvm_amd
modprobe: ERROR: could not insert 'kvm_amd': Bad address
The simplest fix is to just rename the directory. The following
KVM config options are set:
CONFIG_KVM_GUEST=y
CONFIG_KVM_DEBUG_FS=y
CONFIG_HAVE_KVM=y
CONFIG_HAVE_KVM_IRQCHIP=y
CONFIG_HAVE_KVM_IRQ_ROUTING=y
CONFIG_HAVE_KVM_EVENTFD=y
CONFIG_KVM_APIC_ARCHITECTURE=y
CONFIG_KVM_MMIO=y
CONFIG_KVM_ASYNC_PF=y
CONFIG_HAVE_KVM_MSI=y
CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT=y
CONFIG_KVM=m
CONFIG_KVM_INTEL=m
CONFIG_KVM_AMD=m
CONFIG_KVM_DEVICE_ASSIGNMENT=y
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
[Change debugfs directory name. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
DRM_IOCTL_VERSION is a reliable way to get the driver-name and version
information. It's not related to the interface-version (SET_VERSION ioctl)
so we can safely enable it on render-nodes.
Note that gbm uses udev-BUSID to load the correct mesa driver. However,
the VERSION ioctl should be the more reliable way to do this (in case we
add new DRM-bus drivers which have no BUSID or similar).
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Regression and warn fixes for i915.
* tag 'drm-intel-fixes-2013-10-29' of git://people.freedesktop.org/~danvet/drm-intel:
drm/i915: Fix the PPT fdi lane bifurcate state handling on ivb
drm/i915: No LVDS hardware on Intel D410PT and D425KT
drm/i915/dp: workaround BIOS eDP bpp clamping issue
drm/i915: Add HSW CRT output readout support
drm/i915: Add support for pipe_bpp readout
Nico Golde reports a few straggling uses of [io_]remap_pfn_range() that
really should use the vm_iomap_memory() helper. This trivially converts
two of them to the helper, and comments about why the third one really
needs to continue to use remap_pfn_range(), and adds the missing size
check.
Reported-by: Nico Golde <nico@ngolde.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org.
Pull perf tooling fixes from Ingo Molnar:
"This contains five tooling fixes:
- fix a remaining mmap2 assumption which resulted in perf top output
breakage
- fix mmap ring-buffer processing bug that corrupts data
- fix for a severe python scripting memory leak
- fix broken (and user-visible) -g option handling
- fix stdio output
The diffstat size is larger than what we'd like to see this late :-/"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf tools: Fixup mmap event consumption
perf top: Split -G and --call-graph
perf record: Split -g and --call-graph
perf hists: Add color overhead for stdio output buffer
perf tools: Fix up /proc/PID/maps parsing
perf script python: Fix mem leak due to missing Py_DECREFs on dict entries
Without the timer debugging, the delayed kobject release will just
result in undebuggable oopses if it triggers any latent bugs. That
doesn't actually help debugging at all.
So make DEBUG_KOBJECT_RELEASE depend on DEBUG_OBJECTS_TIMERS to avoid
having people enable one without the other.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Originally I've thought that this is leftover hw state dirt from the
BIOS. But after way too much helpless flailing around on my part I've
noticed that the actual bug is when we change the state of an already
active pipe.
For example when we change the fdi lines from 2 to 3 without switching
off outputs in-between we'll never see the crucial on->off transition
in the ->modeset_global_resources hook the current logic relies on.
Patch version 2 got this right by instead also checking whether the
pipe is indeed active. But that in turn broke things when pipes have
been turned off through dpms since the bifurcate enabling is done in
the ->crtc_mode_set callback.
To address this issues discussed with Ville in the patch review move
the setting of the bifurcate bit into the ->crtc_enable hook. That way
we won't wreak havoc with this state when userspace puts all other
outputs into dpms off state. This also moves us forward with our
overall goal to unify the modeset and dpms on paths (which we need to
have to allow runtime pm in the dpms off state).
Unfortunately this requires us to move the bifurcate helpers around a
bit.
Also update the commit message, I've misanalyzed the bug rather badly.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70507
Tested-by: Jan-Michael Brummer <jan.brummer@tabos.org>
Cc: stable@vger.kernel.org
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Johannes Weiner
Linus Torvalds
Greg Thelen
Chen LinX
Russell King
Dan Carpenter
Paolo Bonzini
Tim Gardner
David Herrmann
Dave Airlie
Daniel Vetter