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2013-11-11ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHEDPeter Zijlstra4-4/+25
Since the introduction of PREEMPT_NEED_RESCHED in: f27dde8deef3 ("sched: Add NEED_RESCHED to the preempt_count") we need to be able to look at both TIF_NEED_RESCHED and PREEMPT_NEED_RESCHED to understand the full preemption behaviour. Add it to the trace output. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com> Link: http://lkml.kernel.org/r/20131004152826.GP3081@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-11stop_machine: Fix race between stop_two_cpus() and stop_cpus()Rik van Riel1-2/+13
There is a race between stop_two_cpus, and the global stop_cpus. It is possible for two CPUs to get their stopper functions queued "backwards" from one another, resulting in the stopper threads getting stuck, and the system hanging. This can happen because queuing up stoppers is not synchronized. This patch adds synchronization between stop_cpus (a rare operation), and stop_two_cpus. Reported-and-Tested-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@suse.de> Link: http://lkml.kernel.org/r/20131101104146.03d1e043@annuminas.surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-06sched: Remove unnecessary iteration over sched domains to update nr_busy_cpusPreeti U Murthy3-18/+28
nr_busy_cpus parameter is used by nohz_kick_needed() to find out the number of busy cpus in a sched domain which has SD_SHARE_PKG_RESOURCES flag set. Therefore instead of updating nr_busy_cpus at every level of sched domain, since it is irrelevant, we can update this parameter only at the parent domain of the sd which has this flag set. Introduce a per-cpu parameter sd_busy which represents this parent domain. In nohz_kick_needed() we directly query the nr_busy_cpus parameter associated with the groups of sd_busy. By associating sd_busy with the highest domain which has SD_SHARE_PKG_RESOURCES flag set, we cover all lower level domains which could have this flag set and trigger nohz_idle_balancing if any of the levels have more than one busy cpu. sd_busy is irrelevant for asymmetric load balancing. However sd_asym has been introduced to represent the highest sched domain which has SD_ASYM_PACKING flag set so that it can be queried directly when required. While we are at it, we might as well change the nohz_idle parameter to be updated at the sd_busy domain level alone and not the base domain level of a CPU. This will unify the concept of busy cpus at just one level of sched domain where it is currently used. Signed-off-by: Preeti U Murthy<preeti@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: svaidy@linux.vnet.ibm.com Cc: vincent.guittot@linaro.org Cc: bitbucket@online.de Cc: benh@kernel.crashing.org Cc: anton@samba.org Cc: Morten.Rasmussen@arm.com Cc: pjt@google.com Cc: peterz@infradead.org Cc: mikey@neuling.org Link: http://lkml.kernel.org/r/20131030031252.23426.4417.stgit@preeti.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-06sched: Fix asymmetric scheduling for POWER7Vaidyanathan Srinivasan1-1/+1
Asymmetric scheduling within a core is a scheduler loadbalancing feature that is triggered when SD_ASYM_PACKING flag is set. The goal for the load balancer is to move tasks to lower order idle SMT threads within a core on a POWER7 system. In nohz_kick_needed(), we intend to check if our sched domain (core) is completely busy or we have idle cpu. The following check for SD_ASYM_PACKING: (cpumask_first_and(nohz.idle_cpus_mask, sched_domain_span(sd)) < cpu) already covers the case of checking if the domain has an idle cpu, because cpumask_first_and() will not yield any set bits if this domain has no idle cpu. Hence, nr_busy check against group weight can be removed. Reported-by: Michael Neuling <michael.neuling@au1.ibm.com> Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Tested-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: vincent.guittot@linaro.org Cc: bitbucket@online.de Cc: benh@kernel.crashing.org Cc: anton@samba.org Cc: Morten.Rasmussen@arm.com Cc: pjt@google.com Link: http://lkml.kernel.org/r/20131030031242.23426.13019.stgit@preeti.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-06sched: Move completion code from core.c to completion.cPeter Zijlstra4-286/+301
Completions already have their own header file: linux/completion.h Move the implementation out of kernel/sched/core.c and into its own file: kernel/sched/completion.c. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-x2y49rmxu5dljt66ai2lcfuw@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-06sched: Move wait code from core.c to wait.cPeter Zijlstra2-105/+105
For some reason only the wait part of the wait api lives in kernel/sched/wait.c and the wake part still lives in kernel/sched/core.c; ammend this. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-ftycee88naznulqk7ei5mbci@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-06sched: Move wait.c into kernel/sched/Peter Zijlstra3-1/+2
Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-5q5yqvdaen0rmapwloeaotx3@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-01sched/wait: Fix __wait_event_interruptible_lock_irq_timeout()Heiko Carstens1-1/+1
__wait_event_interruptible_lock_irq_timeout() needs the timeout parameter passed instead of "ret". This magically compiled since the only user has a local ret variable. Luckily we got a build warning: CC drivers/s390/scsi/zfcp_qdio.o drivers/s390/scsi/zfcp_qdio.c: In function 'zfcp_qdio_sbal_get': include/linux/wait.h:780:15: warning: 'ret' may be used uninitialized Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20131031114814.GB5551@osiris Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-01Merge branch 'linus' into sched/coreIngo Molnar506-2851/+4225
Resolve cherry-picking conflicts: Conflicts: mm/huge_memory.c mm/memory.c mm/mprotect.c See this upstream merge commit for more details: 52469b4fcd4f Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-11-01Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds4-63/+81
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull NUMA balancing memory corruption fixes from Ingo Molnar: "So these fixes are definitely not something I'd like to sit on, but as I said to Mel at the KS the timing is quite tight, with Linus planning v3.12-final within a week. Fedora-19 is affected: comet:~> grep NUMA_BALANCING /boot/config-3.11.3-201.fc19.x86_64 CONFIG_ARCH_SUPPORTS_NUMA_BALANCING=y CONFIG_NUMA_BALANCING_DEFAULT_ENABLED=y CONFIG_NUMA_BALANCING=y AFAICS Ubuntu will be affected as well, once it updates the kernel: hubble:~> grep NUMA_BALANCING /boot/config-3.8.0-32-generic CONFIG_ARCH_SUPPORTS_NUMA_BALANCING=y CONFIG_NUMA_BALANCING_DEFAULT_ENABLED=y CONFIG_NUMA_BALANCING=y These 6 commits are a minimalized set of cherry-picks needed to fix the memory corruption bugs. All commits are fixes, except "mm: numa: Sanitize task_numa_fault() callsites" which is a cleanup that made two followup fixes simpler. I've done targeted testing with just this SHA1 to try to make sure there are no cherry-picking artifacts. The original non-cherry-picked set of fixes were exposed to linux-next for a couple of weeks" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: mm: Account for a THP NUMA hinting update as one PTE update mm: Close races between THP migration and PMD numa clearing mm: numa: Sanitize task_numa_fault() callsites mm: Prevent parallel splits during THP migration mm: Wait for THP migrations to complete during NUMA hinting faults mm: numa: Do not account for a hinting fault if we raced
2013-10-31Merge branch 'for-linus' of ↵Linus Torvalds7-20/+51
git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input Pull input updates from Dmitry Torokhov: "A bit later than I would want, but the changes are very minor - a few new device IDs for new hardware in existing drivers, fix for battery in Wacom devices not be considered system battery and cause emergency hibernations, and a couple of other bug fixes" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: Input: ALPS - add support for model found on Dell XT2 Input: wacom - add support for ISDv4 0x10E sensor Input: wacom - add support for ISDv4 0x10F sensor Input: wacom - export battery scope Input: cm109 - convert high volume dev_err() to dev_err_ratelimited() Input: move name/timer init to input_alloc_dev() Input: i8042 - i8042_flush fix for a full 8042 buffer Input: pxa27x_keypad - fix NULL pointer dereference
2013-10-31Merge tag 'pm+acpi-3.12-late' of ↵Linus Torvalds3-10/+3
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull ACPI and power management fixes from Rafael J Wysocki: "Last-minute ACPI and power management fixes for 3.12 - Revert epoll and select commits related to the freezer, introduced during the 3.11 cycle, that cause mysterious user space breakage to occur during resume from suspend to RAM for multiple users of 32-bit x86 systems. Material for 3.11.y stable kernels. - Revert a recent ACPI-based PCI hotplug (ACPIPHP) commit that was part of boot problem fixes for one machine, but turns out to cause issues with hotplug on Thunderbolt chains with multiple devices. It also turns out to be unnecessary after another fix in the same area that went in later. From Mika Westerberg" * tag 'pm+acpi-3.12-late' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: Revert "ACPI / hotplug / PCI: Avoid doing too much for spurious notifies" Revert "select: use freezable blocking call" Revert "epoll: use freezable blocking call"
2013-10-31Input: ALPS - add support for model found on Dell XT2Yunkang Tang1-0/+1
This patch adds support for touchpad found on Dell XT2. It's a dual device with device ID: 73, 00, 14, that comply with "ALPS_PROTO_V2". Signed-off-by: Yunkang Tang <yunkang.tang@cn.alps.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2013-10-31Merge branch 'drm-fixes-3.12' of git://people.freedesktop.org/~agd5f/linux ↵Dave Airlie3-3/+4
into drm-fixes Just a few small fixes for radeon (audio regression fix, stability fix, and an endian bug noticed by coverity). * 'drm-fixes-3.12' of git://people.freedesktop.org/~agd5f/linux: drm/radeon/dpm: fix incompatible casting on big endian drm/radeon: disable bapm on KB drm/radeon: use sw CTS/N values for audio on DCE4+
2013-10-31Merge branch 'akpm' (fixes from Andrew Morton)Linus Torvalds4-7/+8
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
2013-10-31memcg: use __this_cpu_sub() to dec stats to avoid incorrect subtrahend castingGreg Thelen1-1/+1
As of commit 3ea67d06e467 ("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>
2013-10-31percpu: fix this_cpu_sub() subtrahend casting for unsignedsGreg Thelen2-5/+6
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>
2013-10-31mm/pagewalk.c: fix walk_page_range() access of wrong PTEsChen LinX1-1/+1
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>
2013-10-30mm: list_lru: fix almost infinite loop causing effective livelockRussell King1-1/+2
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: 5cedf721a7cd ("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>
2013-10-30Merge tag 'tty-3.12-rc8' of ↵Linus Torvalds1-7/+2
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty 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
2013-10-30Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linuxLinus Torvalds7-54/+168
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
2013-10-30Merge tag 'sound-3.12' of ↵Linus Torvalds3-4/+22
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound 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
2013-10-30Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2-2/+2
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
2013-10-30Staging: sb105x: info leak in mp_get_count()Dan Carpenter1-1/+1
The icount.reserved[] array isn't initialized so it leaks stack information to userspace. 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>
2013-10-30Staging: bcm: info leak in ioctlDan Carpenter1-0/+1
The DevInfo.u32Reserved[] array isn't initialized so it leaks kernel information to user space. 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>
2013-10-30staging: wlags49_h2: buffer overflow setting station nameDan Carpenter1-3/+6
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>
2013-10-30aacraid: missing capable() check in compat ioctlDan Carpenter1-0/+2
In commit d496f94d22d1 ('[SCSI] aacraid: fix security weakness') we added a check on CAP_SYS_RAWIO to the ioctl. The compat ioctls need the check as well. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-10-30staging: ozwpan: prevent overflow in oz_cdev_write()Dan Carpenter1-0/+3
We need to check "count" so we don't overflow the ei->data buffer. 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>
2013-10-30uml: check length in exitcode_proc_write()Dan Carpenter1-1/+3
We don't cap the size of buffer from the user so we could write past the end of the array here. Only root can write to this file. 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>
2013-10-30Revert "ACPI / hotplug / PCI: Avoid doing too much for spurious notifies"Mika Westerberg1-5/+1
Commit 2dc4128 (ACPI / hotplug / PCI: Avoid doing too much for spurious notifies) changed the enable_slot() to check return value of pci_scan_slot() and if it is zero return early from the function. It means that there were no new devices in this particular slot. However, if a device appeared deeper in the hierarchy the code now ignores it causing things like Thunderbolt chaining fail to recognize new devices. The problem with Alex Williamson's machine was solved with commit a47d8c8 (ACPI / hotplug / PCI: Avoid parent bus rescans on spurious device checks) and hence we should be able to restore the original functionality that we always rescan on bus check notification. On a device check notification we still check what acpiphp_rescan_slot() returns and on zero bail out early. Fixes: 2dc41281b1d1 (ACPI / hotplug / PCI: Avoid doing too much for spurious notifies) Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Tested-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-30Revert "select: use freezable blocking call"Rafael J. Wysocki1-2/+1
This reverts commit 9745cdb36da8 (select: use freezable blocking call) that triggers problems during resume from suspend to RAM on Paul Bolle's 32-bit x86 machines. Paul says: Ever since I tried running (release candidates of) v3.11 on the two working i686s I still have lying around I ran into issues on resuming from suspend. Reverting 9745cdb36da8 (select: use freezable blocking call) resolves those issues. Resuming from suspend on i686 on (release candidates of) v3.11 and later triggers issues like: traps: systemd[1] general protection ip:b738e490 sp:bf882fc0 error:0 in libc-2.16.so[b731c000+1b0000] and traps: rtkit-daemon[552] general protection ip:804d6e5 sp:b6cb32f0 error:0 in rtkit-daemon[8048000+d000] Once I hit the systemd error I can only get out of the mess that the system is at that point by power cycling it. Since we are reverting another freezer-related change causing similar problems to happen, this one should be reverted as well. References: https://lkml.org/lkml/2013/10/29/583 Reported-by: Paul Bolle <pebolle@tiscali.nl> Fixes: 9745cdb36da8 (select: use freezable blocking call) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: 3.11+ <stable@vger.kernel.org> # 3.11+
2013-10-30Revert "epoll: use freezable blocking call"Rafael J. Wysocki1-3/+1
This reverts commit 1c441e921201 (epoll: use freezable blocking call) which is reported to cause user space memory corruption to happen after suspend to RAM. Since it appears to be extremely difficult to root cause this problem, it is best to revert the offending commit and try to address the original issue in a better way later. References: https://bugzilla.kernel.org/show_bug.cgi?id=61781 Reported-by: Natrio <natrio@list.ru> Reported-by: Jeff Pohlmeyer <yetanothergeek@gmail.com> Bisected-by: Leo Wolf <jclw@ymail.com> Fixes: 1c441e921201 (epoll: use freezable blocking call) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: 3.11+ <stable@vger.kernel.org> # 3.11+
2013-10-30KVM: use a more sensible error number when debugfs directory creation failsPaolo Bonzini1-1/+1
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>
2013-10-30KVM: Fix modprobe failure for kvm_intel/kvm_amdTim Gardner1-1/+1
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>
2013-10-30drm: allow DRM_IOCTL_VERSION on render-nodesDavid Herrmann1-1/+1
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>
2013-10-30Merge tag 'drm-intel-fixes-2013-10-29' of ↵Dave Airlie6-53/+167
git://people.freedesktop.org/~danvet/drm-intel into drm-fixes 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
2013-10-29Fix a few incorrectly checked [io_]remap_pfn_range() callsLinus Torvalds3-49/+17
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.
2013-10-29Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds22-81/+176
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 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
2013-10-29Kconfig: make KOBJECT_RELEASE debugging require timer debuggingLinus Torvalds1-1/+1
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>
2013-10-29drm/i915: Fix the PPT fdi lane bifurcate state handling on ivbDaniel Vetter1-47/+48
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>
2013-10-29sched: Avoid throttle_cfs_rq() racing with period_timer stoppingBen Segall2-0/+10
throttle_cfs_rq() doesn't check to make sure that period_timer is running, and while update_curr/assign_cfs_runtime does, a concurrently running period_timer on another cpu could cancel itself between this cpu's update_curr and throttle_cfs_rq(). If there are no other cfs_rqs running in the tg to restart the timer, this causes the cfs_rq to be stranded forever. Fix this by calling __start_cfs_bandwidth() in throttle if the timer is inactive. (Also add some sched_debug lines for cfs_bandwidth.) Tested: make a run/sleep task in a cgroup, loop switching the cgroup between 1ms/100ms quota and unlimited, checking for timer_active=0 and throttled=1 as a failure. With the throttle_cfs_rq() change commented out this fails, with the full patch it passes. Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: pjt@google.com Link: http://lkml.kernel.org/r/20131016181632.22647.84174.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29sched: Guarantee new group-entities always have weightPaul Turner1-1/+2
Currently, group entity load-weights are initialized to zero. This admits some races with respect to the first time they are re-weighted in earlty use. ( Let g[x] denote the se for "g" on cpu "x". ) Suppose that we have root->a and that a enters a throttled state, immediately followed by a[0]->t1 (the only task running on cpu[0]) blocking: put_prev_task(group_cfs_rq(a[0]), t1) put_prev_entity(..., t1) check_cfs_rq_runtime(group_cfs_rq(a[0])) throttle_cfs_rq(group_cfs_rq(a[0])) Then, before unthrottling occurs, let a[0]->b[0]->t2 wake for the first time: enqueue_task_fair(rq[0], t2) enqueue_entity(group_cfs_rq(b[0]), t2) enqueue_entity_load_avg(group_cfs_rq(b[0]), t2) account_entity_enqueue(group_cfs_ra(b[0]), t2) update_cfs_shares(group_cfs_rq(b[0])) < skipped because b is part of a throttled hierarchy > enqueue_entity(group_cfs_rq(a[0]), b[0]) ... We now have b[0] enqueued, yet group_cfs_rq(a[0])->load.weight == 0 which violates invariants in several code-paths. Eliminate the possibility of this by initializing group entity weight. Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131016181627.22647.47543.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29sched: Fix hrtimer_cancel()/rq->lock deadlockBen Segall1-4/+11
__start_cfs_bandwidth calls hrtimer_cancel while holding rq->lock, waiting for the hrtimer to finish. However, if sched_cfs_period_timer runs for another loop iteration, the hrtimer can attempt to take rq->lock, resulting in deadlock. Fix this by ensuring that cfs_b->timer_active is cleared only if the _latest_ call to do_sched_cfs_period_timer is returning as idle. Then __start_cfs_bandwidth can just call hrtimer_try_to_cancel and wait for that to succeed or timer_active == 1. Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: pjt@google.com Link: http://lkml.kernel.org/r/20131016181622.22647.16643.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29sched: Fix cfs_bandwidth misuse of hrtimer_expires_remainingBen Segall1-3/+11
hrtimer_expires_remaining does not take internal hrtimer locks and thus must be guarded against concurrent __hrtimer_start_range_ns (but returning HRTIMER_RESTART is safe). Use cfs_b->lock to make it safe. Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: pjt@google.com Link: http://lkml.kernel.org/r/20131016181617.22647.73829.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29sched: Fix race on toggling cfs_bandwidth_usedBen Segall3-9/+19
When we transition cfs_bandwidth_used to false, any currently throttled groups will incorrectly return false from cfs_rq_throttled. While tg_set_cfs_bandwidth will unthrottle them eventually, currently running code (including at least dequeue_task_fair and distribute_cfs_runtime) will cause errors. Fix this by turning off cfs_bandwidth_used only after unthrottling all cfs_rqs. Tested: toggle bandwidth back and forth on a loaded cgroup. Caused crashes in minutes without the patch, hasn't crashed with it. Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: pjt@google.com Link: http://lkml.kernel.org/r/20131016181611.22647.80365.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29mm: Account for a THP NUMA hinting update as one PTE updateMel Gorman1-1/+1
A THP PMD update is accounted for as 512 pages updated in vmstat. This is large difference when estimating the cost of automatic NUMA balancing and can be misleading when comparing results that had collapsed versus split THP. This patch addresses the accounting issue. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-10-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29mm: Close races between THP migration and PMD numa clearingMel Gorman2-26/+26
THP migration uses the page lock to guard against parallel allocations but there are cases like this still open Task A Task B --------------------- --------------------- do_huge_pmd_numa_page do_huge_pmd_numa_page lock_page mpol_misplaced == -1 unlock_page goto clear_pmdnuma lock_page mpol_misplaced == 2 migrate_misplaced_transhuge pmd = pmd_mknonnuma set_pmd_at During hours of testing, one crashed with weird errors and while I have no direct evidence, I suspect something like the race above happened. This patch extends the page lock to being held until the pmd_numa is cleared to prevent migration starting in parallel while the pmd_numa is being cleared. It also flushes the old pmd entry and orders pagetable insertion before rmap insertion. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-9-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29mm: numa: Sanitize task_numa_fault() callsitesMel Gorman2-44/+34
There are three callers of task_numa_fault(): - do_huge_pmd_numa_page(): Accounts against the current node, not the node where the page resides, unless we migrated, in which case it accounts against the node we migrated to. - do_numa_page(): Accounts against the current node, not the node where the page resides, unless we migrated, in which case it accounts against the node we migrated to. - do_pmd_numa_page(): Accounts not at all when the page isn't migrated, otherwise accounts against the node we migrated towards. This seems wrong to me; all three sites should have the same sementaics, furthermore we should accounts against where the page really is, we already know where the task is. So modify all three sites to always account; we did after all receive the fault; and always account to where the page is after migration, regardless of success. They all still differ on when they clear the PTE/PMD; ideally that would get sorted too. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-8-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29mm: Prevent parallel splits during THP migrationMel Gorman1-14/+30
THP migrations are serialised by the page lock but on its own that does not prevent THP splits. If the page is split during THP migration then the pmd_same checks will prevent page table corruption but the unlock page and other fix-ups potentially will cause corruption. This patch takes the anon_vma lock to prevent parallel splits during migration. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-7-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29mm: Wait for THP migrations to complete during NUMA hinting faultsMel Gorman1-7/+16
The locking for migrating THP is unusual. While normal page migration prevents parallel accesses using a migration PTE, THP migration relies on a combination of the page_table_lock, the page lock and the existance of the NUMA hinting PTE to guarantee safety but there is a bug in the scheme. If a THP page is currently being migrated and another thread traps a fault on the same page it checks if the page is misplaced. If it is not, then pmd_numa is cleared. The problem is that it checks if the page is misplaced without holding the page lock meaning that the racing thread can be migrating the THP when the second thread clears the NUMA bit and faults a stale page. This patch checks if the page is potentially being migrated and stalls using the lock_page if it is potentially being migrated before checking if the page is misplaced or not. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-6-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
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