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2017-08-20PATCH] iio: Fix some documentation warningsJonathan Corbet
The kerneldoc description for the trig_readonly field of struct iio_dev lacked a colon, leading to this doc build warning: ./include/linux/iio/iio.h:603: warning: No description found for parameter 'trig_readonly' A similar issue for iio_trigger_set_immutable() in trigger.h yielded: ./include/linux/iio/trigger.h:151: warning: No description found for parameter 'indio_dev' ./include/linux/iio/trigger.h:151: warning: No description found for parameter 'trig' Fix the formatting and silence the warnings. Signed-off-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-08-20net/mlx5e: Add outbound PCI buffer overflow counterEran Ben Elisha
Add outbound_pci_buffer_overflow to ethtool output for monitoring the number of packets that were dropped due to lack of PCIe buffers on receive path from NIC port toward the host(s). This counter is valid only in case that tx_overflow_buffer_pkt is supported in MCAM enhanced features. Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2017-08-20net/mlx5: Add RX buffer fullness counters infrastructureGal Pressman
Add capability bit in PCAM register and counters to PPCNT register. Signed-off-by: Gal Pressman <galp@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2017-08-20net/mlx5: Add PCIe outbound stalls counters infrastructureGal Pressman
Add capability bit in MCAM register and counters to MPCNT register. Signed-off-by: Gal Pressman <galp@mellanox.com> Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
2017-08-19bpf: linux/bpf.h needs linux/numa.hDavid S. Miller
Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-19bpf: Allow selecting numa node during map creationMartin KaFai Lau
The current map creation API does not allow to provide the numa-node preference. The memory usually comes from where the map-creation-process is running. The performance is not ideal if the bpf_prog is known to always run in a numa node different from the map-creation-process. One of the use case is sharding on CPU to different LRU maps (i.e. an array of LRU maps). Here is the test result of map_perf_test on the INNER_LRU_HASH_PREALLOC test if we force the lru map used by CPU0 to be allocated from a remote numa node: [ The machine has 20 cores. CPU0-9 at node 0. CPU10-19 at node 1 ] ># taskset -c 10 ./map_perf_test 512 8 1260000 8000000 5:inner_lru_hash_map_perf pre-alloc 1628380 events per sec 4:inner_lru_hash_map_perf pre-alloc 1626396 events per sec 3:inner_lru_hash_map_perf pre-alloc 1626144 events per sec 6:inner_lru_hash_map_perf pre-alloc 1621657 events per sec 2:inner_lru_hash_map_perf pre-alloc 1621534 events per sec 1:inner_lru_hash_map_perf pre-alloc 1620292 events per sec 7:inner_lru_hash_map_perf pre-alloc 1613305 events per sec 0:inner_lru_hash_map_perf pre-alloc 1239150 events per sec #<<< After specifying numa node: ># taskset -c 10 ./map_perf_test 512 8 1260000 8000000 5:inner_lru_hash_map_perf pre-alloc 1629627 events per sec 3:inner_lru_hash_map_perf pre-alloc 1628057 events per sec 1:inner_lru_hash_map_perf pre-alloc 1623054 events per sec 6:inner_lru_hash_map_perf pre-alloc 1616033 events per sec 2:inner_lru_hash_map_perf pre-alloc 1614630 events per sec 4:inner_lru_hash_map_perf pre-alloc 1612651 events per sec 7:inner_lru_hash_map_perf pre-alloc 1609337 events per sec 0:inner_lru_hash_map_perf pre-alloc 1619340 events per sec #<<< This patch adds one field, numa_node, to the bpf_attr. Since numa node 0 is a valid node, a new flag BPF_F_NUMA_NODE is also added. The numa_node field is honored if and only if the BPF_F_NUMA_NODE flag is set. Numa node selection is not supported for percpu map. This patch does not change all the kmalloc. F.e. 'htab = kzalloc()' is not changed since the object is small enough to stay in the cache. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-18net: drop unused attribute argument from sysfs queue funcsstephen hemminger
The show and store functions don't need/use the attribute. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-18net: constify net_ns_type_operationsstephen hemminger
This can be const. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-18net: constify netdev_class_filestephen hemminger
These functions are wrapper arount class_create_file which can take a const attribute. Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-18net: ethtool: Add macro to clear a link mode settingLendacky, Thomas
There are currently macros to set and test an ETHTOOL_LINK_MODE_ setting, but not to clear one. Add a macro to clear an ETHTOOL_LINK_MODE_ setting. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-08-18mm, oom: fix potential data corruption when oom_reaper races with writerMichal Hocko
Wenwei Tao has noticed that our current assumption that the oom victim is dying and never doing any visible changes after it dies, and so the oom_reaper can tear it down, is not entirely true. __task_will_free_mem consider a task dying when SIGNAL_GROUP_EXIT is set but do_group_exit sends SIGKILL to all threads _after_ the flag is set. So there is a race window when some threads won't have fatal_signal_pending while the oom_reaper could start unmapping the address space. Moreover some paths might not check for fatal signals before each PF/g-u-p/copy_from_user. We already have a protection for oom_reaper vs. PF races by checking MMF_UNSTABLE. This has been, however, checked only for kernel threads (use_mm users) which can outlive the oom victim. A simple fix would be to extend the current check in handle_mm_fault for all tasks but that wouldn't be sufficient because the current check assumes that a kernel thread would bail out after EFAULT from get_user*/copy_from_user and never re-read the same address which would succeed because the PF path has established page tables already. This seems to be the case for the only existing use_mm user currently (virtio driver) but it is rather fragile in general. This is even more fragile in general for more complex paths such as generic_perform_write which can re-read the same address more times (e.g. iov_iter_copy_from_user_atomic to fail and then iov_iter_fault_in_readable on retry). Therefore we have to implement MMF_UNSTABLE protection in a robust way and never make a potentially corrupted content visible. That requires to hook deeper into the PF path and check for the flag _every time_ before a pte for anonymous memory is established (that means all !VM_SHARED mappings). The corruption can be triggered artificially (http://lkml.kernel.org/r/201708040646.v746kkhC024636@www262.sakura.ne.jp) but there doesn't seem to be any real life bug report. The race window should be quite tight to trigger most of the time. Link: http://lkml.kernel.org/r/20170807113839.16695-3-mhocko@kernel.org Fixes: aac453635549 ("mm, oom: introduce oom reaper") Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Wenwei Tao <wenwei.tww@alibaba-inc.com> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Andrea Argangeli <andrea@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-18mm: discard memblock data laterPavel Tatashin
There is existing use after free bug when deferred struct pages are enabled: The memblock_add() allocates memory for the memory array if more than 128 entries are needed. See comment in e820__memblock_setup(): * The bootstrap memblock region count maximum is 128 entries * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries * than that - so allow memblock resizing. This memblock memory is freed here: free_low_memory_core_early() We access the freed memblock.memory later in boot when deferred pages are initialized in this path: deferred_init_memmap() for_each_mem_pfn_range() __next_mem_pfn_range() type = &memblock.memory; One possible explanation for why this use-after-free hasn't been hit before is that the limit of INIT_MEMBLOCK_REGIONS has never been exceeded at least on systems where deferred struct pages were enabled. Tested by reducing INIT_MEMBLOCK_REGIONS down to 4 from the current 128, and verifying in qemu that this code is getting excuted and that the freed pages are sane. Link: http://lkml.kernel.org/r/1502485554-318703-2-git-send-email-pasha.tatashin@oracle.com Fixes: 7e18adb4f80b ("mm: meminit: initialise remaining struct pages in parallel with kswapd") Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Steven Sistare <steven.sistare@oracle.com> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Bob Picco <bob.picco@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-18wait: add wait_event_killable_timeout()Luis R. Rodriguez
These are the few pending fixes I have queued up for v4.13-final. One is a a generic regression fix for recursive loops on kmod and the other one is a trivial print out correction. During the v4.13 development we assumed that recursive kmod loops were no longer possible. Clearly that is not true. The regression fix makes use of a new killable wait. We use a killable wait to be paranoid in how signals might be sent to modprobe and only accept a proper SIGKILL. The signal will only be available to userspace to issue *iff* a thread has already entered a wait state, and that happens only if we've already throttled after 50 kmod threads have been hit. Note that although it may seem excessive to trigger a failure afer 5 seconds if all kmod thread remain busy, prior to the series of changes that went into v4.13 we would actually *always* fatally fail any request which came in if the limit was already reached. The new waiting implemented in v4.13 actually gives us *more* breathing room -- the wait for 5 seconds is a wait for *any* kmod thread to finish. We give up and fail *iff* no kmod thread has finished and they're *all* running straight for 5 consecutive seconds. If 50 kmod threads are running consecutively for 5 seconds something else must be really bad. Recursive loops with kmod are bad but they're also hard to implement properly as a selftest without currently fooling current userspace tools like kmod [1]. For instance kmod will complain when you run depmod if it finds a recursive loop with symbol dependency between modules as such this type of recursive loop cannot go upstream as the modules_install target will fail after running depmod. These tests already exist on userspace kmod upstream though (refer to the testsuite/module-playground/mod-loop-*.c files). The same is not true if request_module() is used though, or worst if aliases are used. Likewise the issue with 64-bit kernels booting 32-bit userspace without a binfmt handler built-in is also currently not detected and proactively avoided by userspace kmod tools, or kconfig for all architectures. Although we could complain in the kernel when some of these individual recursive issues creep up, proactively avoiding these situations in userspace at build time is what we should keep striving for. Lastly, since recursive loops could happen with kmod it may mean recursive loops may also be possible with other kernel usermode helpers, this should be investigated and long term if we can come up with a more sensible generic solution even better! [0] https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git/log/?h=20170809-kmod-for-v4.13-final [1] https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git This patch (of 3): This wait is similar to wait_event_interruptible_timeout() but only accepts SIGKILL interrupt signal. Other signals are ignored. Link: http://lkml.kernel.org/r/20170809234635.13443-2-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Jessica Yu <jeyu@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Michal Marek <mmarek@suse.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Daniel Mentz <danielmentz@google.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Matt Redfearn <matt.redfearn@imgetc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-18mm: memcontrol: fix NULL pointer crash in test_clear_page_writeback()Johannes Weiner
Jaegeuk and Brad report a NULL pointer crash when writeback ending tries to update the memcg stats: BUG: unable to handle kernel NULL pointer dereference at 00000000000003b0 IP: test_clear_page_writeback+0x12e/0x2c0 [...] RIP: 0010:test_clear_page_writeback+0x12e/0x2c0 Call Trace: <IRQ> end_page_writeback+0x47/0x70 f2fs_write_end_io+0x76/0x180 [f2fs] bio_endio+0x9f/0x120 blk_update_request+0xa8/0x2f0 scsi_end_request+0x39/0x1d0 scsi_io_completion+0x211/0x690 scsi_finish_command+0xd9/0x120 scsi_softirq_done+0x127/0x150 __blk_mq_complete_request_remote+0x13/0x20 flush_smp_call_function_queue+0x56/0x110 generic_smp_call_function_single_interrupt+0x13/0x30 smp_call_function_single_interrupt+0x27/0x40 call_function_single_interrupt+0x89/0x90 RIP: 0010:native_safe_halt+0x6/0x10 (gdb) l *(test_clear_page_writeback+0x12e) 0xffffffff811bae3e is in test_clear_page_writeback (./include/linux/memcontrol.h:619). 614 mod_node_page_state(page_pgdat(page), idx, val); 615 if (mem_cgroup_disabled() || !page->mem_cgroup) 616 return; 617 mod_memcg_state(page->mem_cgroup, idx, val); 618 pn = page->mem_cgroup->nodeinfo[page_to_nid(page)]; 619 this_cpu_add(pn->lruvec_stat->count[idx], val); 620 } 621 622 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, 623 gfp_t gfp_mask, The issue is that writeback doesn't hold a page reference and the page might get freed after PG_writeback is cleared (and the mapping is unlocked) in test_clear_page_writeback(). The stat functions looking up the page's node or zone are safe, as those attributes are static across allocation and free cycles. But page->mem_cgroup is not, and it will get cleared if we race with truncation or migration. It appears this race window has been around for a while, but less likely to trigger when the memcg stats were updated first thing after PG_writeback is cleared. Recent changes reshuffled this code to update the global node stats before the memcg ones, though, stretching the race window out to an extent where people can reproduce the problem. Update test_clear_page_writeback() to look up and pin page->mem_cgroup before clearing PG_writeback, then not use that pointer afterward. It is a partial revert of 62cccb8c8e7a ("mm: simplify lock_page_memcg()") but leaves the pageref-holding callsites that aren't affected alone. Link: http://lkml.kernel.org/r/20170809183825.GA26387@cmpxchg.org Fixes: 62cccb8c8e7a ("mm: simplify lock_page_memcg()") Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Jaegeuk Kim <jaegeuk@kernel.org> Tested-by: Jaegeuk Kim <jaegeuk@kernel.org> Reported-by: Bradley Bolen <bradleybolen@gmail.com> Tested-by: Brad Bolen <bradleybolen@gmail.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: <stable@vger.kernel.org> [4.6+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-19Merge tag 'reset-for-4.14' of git://git.pengutronix.de/git/pza/linux into ↵Arnd Bergmann
next/drivers Pull "Reset controller changes for v4.14" from Philipp Zabel: - constify zx2967 reset_ops - add a convenience API to manage an array of resets - let deassert report success and let assert report success for shared resets if the reset controller driver does not implement (de)assert. - add HSDKv1 reset driver - remove Gemini reset controller, the driver is made obsolete by a combined clock/reset driver in drivers/clk - fix the total number of reset lines in the sunxi driver - various uniphier updates and fixes: - remove sLD3 SoC support - simplify system reset register and bit definitions - add audio systems, video input subsystem, and analog amplifiers reset controls * tag 'reset-for-4.14' of git://git.pengutronix.de/git/pza/linux: reset: uniphier: add analog amplifiers reset control reset: uniphier: add video input subsystem reset control reset: uniphier: add audio systems reset control reset: sunxi: fix number of reset lines reset: uniphier: do not use per-SoC macro for system reset block reset: uniphier: remove sLD3 SoC support Revert "reset: Add a Gemini reset controller" ARC: reset: introduce HSDKv1 reset driver reset: make (de)assert report success for self-deasserting reset drivers reset: Add APIs to manage array of resets reset: zx2967: constify zx2967_reset_ops.
2017-08-18Merge tag 'v4.13-next-soc' of https://github.com/mbgg/linux-mediatek into ↵Arnd Bergmann
next/drivers Pull "arm: mediatek: soc updates for v4.14" from Matthias Brugger: - add mt7623a smp support - scpsys: reduce code duplication - scpsys: add mt7622 support - pmic wrapper: make of_device_ids constant * tag 'v4.13-next-soc' of https://github.com/mbgg/linux-mediatek: soc: mediatek: add SCPSYS power domain driver for MediaTek MT7622 SoC soc: mediatek: add header files required for MT7622 SCPSYS dt-binding soc: mediatek: reduce code duplication of scpsys_probe across all SoCs dt-bindings: soc: update the binding document for SCPSYS on MediaTek MT7622 SoC soc: mtk-pmic-wrap: make of_device_ids const. ARM: mediatek: add MT7623a smp bringup code
2017-08-18SUNRPC: Add a separate spinlock to protect the RPC request receive listTrond Myklebust
This further reduces contention with the transport_lock, and allows us to convert to using a non-bh-safe spinlock, since the list is now never accessed from a bh context. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2017-08-18Merge branch 'misc' into k.o/for-nextDoug Ledford
Conflicts: drivers/infiniband/core/iwcm.c - The rdma_netlink patches in HEAD and the iwarp cm workqueue fix (don't use WQ_MEM_RECLAIM, we aren't safe for that context) touched the same code. Signed-off-by: Doug Ledford <dledford@redhat.com>
2017-08-18PCI/IB: add support for pci driver attribute groupsGreg Kroah-Hartman
Some drivers (specifically the nes IB driver), want to create a lot of sysfs driver attributes. Instead of open-coding the creation and removal of these files (and getting it wrong btw), it's a better idea to let the driver core handle all of this logic for us. So add a new field to the pci driver structure, **groups, that allows pci drivers to specify an attribute group list it wishes to have created when it is registered with the driver core. Big bonus is now the driver doesn't race with userspace when the sysfs files are created vs. when the kobject is announced, so any script/tool that actually wanted to use these files will not have to poll waiting for them to show up. Cc: Faisal Latif <faisal.latif@intel.com> Cc: Doug Ledford <dledford@redhat.com> Cc: Sean Hefty <sean.hefty@intel.com> Cc: Hal Rosenstock <hal.rosenstock@gmail.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
2017-08-18PCI: endpoint: Add an API to get matching "pci_epf_device_id"Kishon Vijay Abraham I
Add an API to get "pci_epf_device_id" matching the EPF name. This can be used by the EPF driver to get the driver data corresponding to the EPF device name. Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com> [bhelgaas: folded in "while" loop termination fix from Colin Ian King <colin.king@canonical.com>] Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2017-08-18cgroup: Add mount flag to enable cpuset to use v2 behavior in v1 cgroupWaiman Long
A new mount option "cpuset_v2_mode" is added to the v1 cgroupfs filesystem to enable cpuset controller to use v2 behavior in a v1 cgroup. This mount option applies only to cpuset controller and have no effect on other controllers. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2017-08-18blk-mq: Make blk_mq_reinit_tagset() calls easier to readBart Van Assche
Since blk_mq_ops.reinit_request is only called from inside blk_mq_reinit_tagset(), make this function pointer an argument of blk_mq_reinit_tagset() instead of a member of struct blk_mq_ops. This patch does not change any functionality but makes blk_mq_reinit_tagset() calls easier to read and to analyze. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: James Smart <james.smart@broadcom.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-18kernel/watchdog: Prevent false positives with turbo modesThomas Gleixner
The hardlockup detector on x86 uses a performance counter based on unhalted CPU cycles and a periodic hrtimer. The hrtimer period is about 2/5 of the performance counter period, so the hrtimer should fire 2-3 times before the performance counter NMI fires. The NMI code checks whether the hrtimer fired since the last invocation. If not, it assumess a hard lockup. The calculation of those periods is based on the nominal CPU frequency. Turbo modes increase the CPU clock frequency and therefore shorten the period of the perf/NMI watchdog. With extreme Turbo-modes (3x nominal frequency) the perf/NMI period is shorter than the hrtimer period which leads to false positives. A simple fix would be to shorten the hrtimer period, but that comes with the side effect of more frequent hrtimer and softlockup thread wakeups, which is not desired. Implement a low pass filter, which checks the perf/NMI period against kernel time. If the perf/NMI fires before 4/5 of the watchdog period has elapsed then the event is ignored and postponed to the next perf/NMI. That solves the problem and avoids the overhead of shorter hrtimer periods and more frequent softlockup thread wakeups. Fixes: 58687acba592 ("lockup_detector: Combine nmi_watchdog and softlockup detector") Reported-and-tested-by: Kan Liang <Kan.liang@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: dzickus@redhat.com Cc: prarit@redhat.com Cc: ak@linux.intel.com Cc: babu.moger@oracle.com Cc: peterz@infradead.org Cc: eranian@google.com Cc: acme@redhat.com Cc: stable@vger.kernel.org Cc: atomlin@redhat.com Cc: akpm@linux-foundation.org Cc: torvalds@linux-foundation.org Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1708150931310.1886@nanos
2017-08-18Merge branch 'irq/for-gpio' into irq/coreThomas Gleixner
Merge the flow handlers and irq domain extensions which are in a separate branch so they can be consumed by the gpio folks.
2017-08-18irqdomain: Add irq_domain_{push,pop}_irq() functionsDavid Daney
For an already existing irqdomain hierarchy, as might be obtained via a call to pci_enable_msix_range(), a PCI driver wishing to add an additional irqdomain to the hierarchy needs to be able to insert the irqdomain to that already initialized hierarchy. Calling irq_domain_create_hierarchy() allows the new irqdomain to be created, but no existing code allows for initializing the associated irq_data. Add a couple of helper functions (irq_domain_push_irq() and irq_domain_pop_irq()) to initialize the irq_data for the new irqdomain added to an existing hierarchy. Signed-off-by: David Daney <david.daney@cavium.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexandre Courbot <gnurou@gmail.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: linux-gpio@vger.kernel.org Link: http://lkml.kernel.org/r/1503017616-3252-6-git-send-email-david.daney@cavium.com
2017-08-18genirq: Add handle_fasteoi_{level,edge}_irq flow handlersDavid Daney
Follow-on patch for gpio-thunderx uses a irqdomain hierarchy which requires slightly different flow handlers, add them to chip.c which contains most of the other flow handlers. Make these conditionally compiled based on CONFIG_IRQ_FASTEOI_HIERARCHY_HANDLERS. Signed-off-by: David Daney <david.daney@cavium.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexandre Courbot <gnurou@gmail.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: linux-gpio@vger.kernel.org Link: http://lkml.kernel.org/r/1503017616-3252-3-git-send-email-david.daney@cavium.com
2017-08-18genirq: Restrict effective affinity to interrupts actually using itMarc Zyngier
Just because CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK is selected doesn't mean that all the interrupts are using the effective affinity mask. For a number of them, this mask is likely to be empty. In order to deal with this, let's restrict the use of the effective affinity mask to these interrupts that have a non empty effective affinity. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Lunn <andrew@lunn.ch> Cc: James Hogan <james.hogan@imgtec.com> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Chris Zankel <chris@zankel.net> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Wei Xu <xuwei5@hisilicon.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Gregory Clement <gregory.clement@free-electrons.com> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> Link: http://lkml.kernel.org/r/20170818083925.10108-2-marc.zyngier@arm.com
2017-08-18Merge branch 'x86/asm' into locking/coreIngo Molnar
We need the ASM_UNREACHABLE() macro for a dependent patch. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-18ACPI / PM: Check low power idle constraints for debug onlySrinivas Pandruvada
For SoC to achieve its lowest power platform idle state a set of hardware preconditions must be met. These preconditions or constraints can be obtained by issuing a device specific method (_DSM) with function "1". Refer to the document provided in the link below. Here during initialization (from attach() callback of LPS0 device), invoke function 1 to get the device constraints. Each enabled constraint is stored in a table. The devices in this table are used to check whether they were in required minimum state, while entering suspend. This check is done from platform freeze wake() callback, only when /sys/power/pm_debug_messages attribute is non zero. If any constraint is not met and device is ACPI power managed then it prints the device information to kernel logs. Also if debug is enabled in acpi/sleep.c, the constraint table and state of each device on wake is dumped in kernel logs. Since pm_debug_messages_on setting is used as condition to check constraints outside kernel/power/main.c, pm_debug_messages_on is changed to a global variable. Link: http://www.uefi.org/sites/default/files/resources/Intel_ACPI_Low_Power_S0_Idle.pdf Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-08-17Revert "pstore: Honor dmesg_restrict sysctl on dmesg dumps"Kees Cook
This reverts commit 68c4a4f8abc60c9440ede9cd123d48b78325f7a3, with various conflict clean-ups. The capability check required too much privilege compared to simple DAC controls. A system builder was forced to have crash handler processes run with CAP_SYSLOG which would give it the ability to read (and wipe) the _current_ dmesg, which is much more access than being given access only to the historical log stored in pstorefs. With the prior commit to make the root directory 0750, the files are protected by default but a system builder can now opt to give access to a specific group (via chgrp on the pstorefs root directory) without being forced to also give away CAP_SYSLOG. Suggested-by: Nick Kralevich <nnk@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Petr Mladek <pmladek@suse.cz> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
2017-08-17quota: Reduce contention on dq_data_lockJan Kara
dq_data_lock is currently used to protect all modifications of quota accounting information, consistency of quota accounting on the inode, and dquot pointers from inode. As a result contention on the lock can be pretty heavy. Reduce the contention on the lock by protecting quota accounting information by a new dquot->dq_dqb_lock and consistency of quota accounting with inode usage by inode->i_lock. This change reduces time to create 500000 files on ext4 on ramdisk by 50 different processes in separate directories by 6% when user quota is turned on. When those 50 processes belong to 50 different users, the improvement is about 9%. Signed-off-by: Jan Kara <jack@suse.cz>
2017-08-17fs: Provide __inode_get_bytes()Jan Kara
Provide helper __inode_get_bytes() which assumes i_lock is already acquired. Quota code will need this to be able to use i_lock to protect consistency of quota accounting information and inode usage. Signed-off-by: Jan Kara <jack@suse.cz>
2017-08-17quota: Inline functions into their callsitesJan Kara
inode_add_rsv_space() and inode_sub_rsv_space() had only one callsite. Inline them there directly. inode_claim_rsv_space() and inode_reclaim_rsv_space() had two callsites so inline them there as well. This will simplify further locking changes. Signed-off-by: Jan Kara <jack@suse.cz>
2017-08-17quota: Allow disabling tracking of dirty dquots in a listJan Kara
Filesystems that are journalling quotas generally don't need tracking of dirty dquots in a list since forcing a transaction commit flushes all quotas anyway. Allow filesystem to say it doesn't want dquots to be tracked as it reduces contention on the dq_list_lock. Signed-off-by: Jan Kara <jack@suse.cz>
2017-08-17quota: Remove dq_wait_unused from dquotJan Kara
Currently every dquot carries a wait_queue_head_t used only when we are turning quotas off to wait for last users to drop dquot references. Since such rare case is not performance sensitive in any means, just use a global waitqueue for this and save space in struct dquot. Also convert the logic to use wait_event() instead of open-coding it. Signed-off-by: Jan Kara <jack@suse.cz>
2017-08-18Merge tag 'omapdrm-4.14' of ↵Dave Airlie
git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux into drm-next omapdrm changes for v4.14 * HDMI hot plug IRQ support (instead of polling) * Big driver cleanup from Laurent (no functional changes) * OMAP5 DSI support (only the pinmuxing was missing) * tag 'omapdrm-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux: (60 commits) drm/omap: Potential NULL deref in omap_crtc_duplicate_state() drm/omap: remove no-op cleanup code drm/omap: rename omapdrm device back drm: omapdrm: Remove omapdrm platform data ARM: OMAP2+: Don't register omapdss device for omapdrm ARM: OMAP2+: Remove unused omapdrm platform device drm: omapdrm: Remove the omapdss driver drm: omapdrm: Register omapdrm platform device in omapdss driver drm: omapdrm: hdmi: Don't allocate PHY features dynamically drm: omapdrm: hdmi: Configure the PHY from the HDMI core version drm: omapdrm: hdmi: Configure the PLL from the HDMI core version drm: omapdrm: hdmi: Pass HDMI core version as integer to HDMI audio drm: omapdrm: hdmi: Replace OMAP SoC model check with HDMI xmit version drm: omapdrm: hdmi: Rename functions and structures to use hdmi_ prefix drm/omap: add OMAP5 DSIPHY lane-enable support drm/omap: use regmap_update_bit() when muxing DSI pads drm: omapdrm: Remove dss_features.h drm: omapdrm: Move supported outputs feature to dss driver drm: omapdrm: Move DSS_FCK feature to dss driver drm: omapdrm: Move PCD, LINEWIDTH and DOWNSCALE features to dispc driver ...
2017-08-17lsm_audit: update my email addressStephen Smalley
Update my email address since epoch.ncsc.mil no longer exists. MAINTAINERS and CREDITS are already correct. Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Signed-off-by: Paul Moore <paul@paul-moore.com>
2017-08-17quota: Convert dqio_mutex to rwsemJan Kara
Convert dqio_mutex to rwsem and call it dqio_sem. No functional changes yet. Signed-off-by: Jan Kara <jack@suse.cz>
2017-08-17pty: fix the cached path of the pty slave file descriptor in the masterLinus Torvalds
Christian Brauner reported that if you use the TIOCGPTPEER ioctl() to get a slave pty file descriptor, the resulting file descriptor doesn't look right in /proc/<pid>/fd/<fd>. In particular, he wanted to use readlink() on /proc/self/fd/<fd> to get the pathname of the slave pty (basically implementing "ptsname{_r}()"). The reason for that was that we had generated the wrong 'struct path' when we create the pty in ptmx_open(). In particular, the dentry was correct, but the vfsmount pointed to the mount of the ptmx node. That _can_ be correct - in case you use "/dev/pts/ptmx" to open the master - but usually is not. The normal case is to use /dev/ptmx, which then looks up the pts/ directory, and then the vfsmount of the ptmx node is obviously the /dev directory, not the /dev/pts/ directory. We actually did have the right vfsmount available, but in the wrong place (it gets looked up in 'devpts_acquire()' when we get a reference to the pts filesystem), and so ptmx_open() used the wrong mnt pointer. The end result of this confusion was that the pty worked fine, but when if you did TIOCGPTPEER to get the slave side of the pty, end end result would also work, but have that dodgy 'struct path'. And then when doing "d_path()" on to get the pathname, the vfsmount would not match the root of the pts directory, and d_path() would return an empty pathname thinking that the entry had escaped a bind mount into another mount. This fixes the problem by making devpts_acquire() return the vfsmount for the pts filesystem, allowing ptmx_open() to trivially just use the right mount for the pts dentry, and create the proper 'struct path'. Reported-by: Christian Brauner <christian.brauner@ubuntu.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-17Merge branches 'doc.2017.08.17a', 'fixes.2017.08.17a', ↵Paul E. McKenney
'hotplug.2017.07.25b', 'misc.2017.08.17a', 'spin_unlock_wait_no.2017.08.17a', 'srcu.2017.07.27c' and 'torture.2017.07.24c' into HEAD doc.2017.08.17a: Documentation updates. fixes.2017.08.17a: RCU fixes. hotplug.2017.07.25b: CPU-hotplug updates. misc.2017.08.17a: Miscellaneous fixes outside of RCU (give or take conflicts). spin_unlock_wait_no.2017.08.17a: Remove spin_unlock_wait(). srcu.2017.07.27c: SRCU updates. torture.2017.07.24c: Torture-test updates.
2017-08-17locking: Remove spin_unlock_wait() generic definitionsPaul E. McKenney
There is no agreed-upon definition of spin_unlock_wait()'s semantics, and it appears that all callers could do just as well with a lock/unlock pair. This commit therefore removes spin_unlock_wait() and related definitions from core code. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Andrea Parri <parri.andrea@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-17Merge branch 'core' into arm/tegraJoerg Roedel
2017-08-17swait: Add idle variants which don't contribute to load averageLuis R. Rodriguez
There are cases where folks are using an interruptible swait when using kthreads. This is rather confusing given you'd expect interruptible waits to be -- interruptible, but kthreads are not interruptible ! The reason for such practice though is to avoid having these kthreads contribute to the system load average. When systems are idle some kthreads may spend a lot of time blocking if using swait_event_timeout(). This would contribute to the system load average. On systems without preemption this would mean the load average of an idle system is bumped to 2 instead of 0. On systems with PREEMPT=y this would mean the load average of an idle system is bumped to 3 instead of 0. This adds proper API using TASK_IDLE to make such goals explicit and avoid confusion. Suggested-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-08-17rcu: Create reasonable API for do_exit() TASKS_RCU processingPaul E. McKenney
Currently, the exit-time support for TASKS_RCU is open-coded in do_exit(). This commit creates exit_tasks_rcu_start() and exit_tasks_rcu_finish() APIs for do_exit() use. This has the benefit of confining the use of the tasks_rcu_exit_srcu variable to one file, allowing it to become static. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-08-17rcu: Drive TASKS_RCU directly off of PREEMPTPaul E. McKenney
The actual use of TASKS_RCU is only when PREEMPT, otherwise RCU-sched is used instead. This commit therefore makes synchronize_rcu_tasks() and call_rcu_tasks() available always, but mapped to synchronize_sched() and call_rcu_sched(), respectively, when !PREEMPT. This approach also allows some #ifdefs to be removed from rcutorture. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Ingo Molnar <mingo@kernel.org>
2017-08-17locking/lockdep: Explicitly initialize wq_barrier::done::mapBoqun Feng
With the new lockdep crossrelease feature, which checks completions usage, a false positive is reported in the workqueue code: > Worker A : acquired of wfc.work -> wait for cpu_hotplug_lock to be released > Task B : acquired of cpu_hotplug_lock -> wait for lock#3 to be released > Task C : acquired of lock#3 -> wait for completion of barr->done > (Task C is in lru_add_drain_all_cpuslocked()) > Worker D : wait for wfc.work to be released -> will complete barr->done Such a dead lock can not happen because Task C's barr->done and Worker D's barr->done can not be the same instance. The reason of this false positive is we initialize all wq_barrier::done at insert_wq_barrier() via init_completion(), which makes them belong to the same lock class, therefore, impossible circles are reported. To fix this, explicitly initialize the lockdep map for wq_barrier::done in insert_wq_barrier(), so that the lock class key of wq_barrier::done is a subkey of the corresponding work_struct, as a result we won't build a dependency between a wq_barrier with a unrelated work, and we can differ wq barriers based on the related works, so the false positive above is avoided. Also define the empty lockdep_init_map_crosslock() for !CROSSRELEASE to make the code simple and away from unnecessary #ifdefs. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170817094622.12915-1-boqun.feng@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17locking/lockdep: Rename CONFIG_LOCKDEP_COMPLETE to CONFIG_LOCKDEP_COMPLETIONSByungchul Park
'complete' is an adjective and LOCKDEP_COMPLETE sounds like 'lockdep is complete', so pick a better name that uses a noun. Signed-off-by: Byungchul Park <byungchul.park@lge.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-team@lge.com Link: http://lkml.kernel.org/r/1502960261-16206-3-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17efi: Introduce efi_early_memdesc_ptr to get pointer to memmap descriptorBaoquan He
The existing map iteration helper for_each_efi_memory_desc_in_map can only be used after the kernel initializes the EFI subsystem to set up struct efi_memory_map. Before that we also need iterate map descriptors which are stored in several intermediate structures, like struct efi_boot_memmap for arch independent usage and struct efi_info for x86 arch only. Introduce efi_early_memdesc_ptr() to get pointer to a map descriptor, and replace several places where that primitive is open coded. Signed-off-by: Baoquan He <bhe@redhat.com> [ Various improvements to the text. ] Acked-by: Matt Fleming <matt@codeblueprint.co.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: ard.biesheuvel@linaro.org Cc: fanc.fnst@cn.fujitsu.com Cc: izumi.taku@jp.fujitsu.com Cc: keescook@chromium.org Cc: linux-efi@vger.kernel.org Cc: n-horiguchi@ah.jp.nec.com Cc: thgarnie@google.com Link: http://lkml.kernel.org/r/20170816134651.GF21273@x1 Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17locking/refcounts, x86/asm: Implement fast refcount overflow protectionKees Cook
This implements refcount_t overflow protection on x86 without a noticeable performance impact, though without the fuller checking of REFCOUNT_FULL. This is done by duplicating the existing atomic_t refcount implementation but with normally a single instruction added to detect if the refcount has gone negative (e.g. wrapped past INT_MAX or below zero). When detected, the handler saturates the refcount_t to INT_MIN / 2. With this overflow protection, the erroneous reference release that would follow a wrap back to zero is blocked from happening, avoiding the class of refcount-overflow use-after-free vulnerabilities entirely. Only the overflow case of refcounting can be perfectly protected, since it can be detected and stopped before the reference is freed and left to be abused by an attacker. There isn't a way to block early decrements, and while REFCOUNT_FULL stops increment-from-zero cases (which would be the state _after_ an early decrement and stops potential double-free conditions), this fast implementation does not, since it would require the more expensive cmpxchg loops. Since the overflow case is much more common (e.g. missing a "put" during an error path), this protection provides real-world protection. For example, the two public refcount overflow use-after-free exploits published in 2016 would have been rendered unexploitable: http://perception-point.io/2016/01/14/analysis-and-exploitation-of-a-linux-kernel-vulnerability-cve-2016-0728/ http://cyseclabs.com/page?n=02012016 This implementation does, however, notice an unchecked decrement to zero (i.e. caller used refcount_dec() instead of refcount_dec_and_test() and it resulted in a zero). Decrements under zero are noticed (since they will have resulted in a negative value), though this only indicates that a use-after-free may have already happened. Such notifications are likely avoidable by an attacker that has already exploited a use-after-free vulnerability, but it's better to have them reported than allow such conditions to remain universally silent. On first overflow detection, the refcount value is reset to INT_MIN / 2 (which serves as a saturation value) and a report and stack trace are produced. When operations detect only negative value results (such as changing an already saturated value), saturation still happens but no notification is performed (since the value was already saturated). On the matter of races, since the entire range beyond INT_MAX but before 0 is negative, every operation at INT_MIN / 2 will trap, leaving no overflow-only race condition. As for performance, this implementation adds a single "js" instruction to the regular execution flow of a copy of the standard atomic_t refcount operations. (The non-"and_test" refcount_dec() function, which is uncommon in regular refcount design patterns, has an additional "jz" instruction to detect reaching exactly zero.) Since this is a forward jump, it is by default the non-predicted path, which will be reinforced by dynamic branch prediction. The result is this protection having virtually no measurable change in performance over standard atomic_t operations. The error path, located in .text.unlikely, saves the refcount location and then uses UD0 to fire a refcount exception handler, which resets the refcount, handles reporting, and returns to regular execution. This keeps the changes to .text size minimal, avoiding return jumps and open-coded calls to the error reporting routine. Example assembly comparison: refcount_inc() before: .text: ffffffff81546149: f0 ff 45 f4 lock incl -0xc(%rbp) refcount_inc() after: .text: ffffffff81546149: f0 ff 45 f4 lock incl -0xc(%rbp) ffffffff8154614d: 0f 88 80 d5 17 00 js ffffffff816c36d3 ... .text.unlikely: ffffffff816c36d3: 48 8d 4d f4 lea -0xc(%rbp),%rcx ffffffff816c36d7: 0f ff (bad) These are the cycle counts comparing a loop of refcount_inc() from 1 to INT_MAX and back down to 0 (via refcount_dec_and_test()), between unprotected refcount_t (atomic_t), fully protected REFCOUNT_FULL (refcount_t-full), and this overflow-protected refcount (refcount_t-fast): 2147483646 refcount_inc()s and 2147483647 refcount_dec_and_test()s: cycles protections atomic_t 82249267387 none refcount_t-fast 82211446892 overflow, untested dec-to-zero refcount_t-full 144814735193 overflow, untested dec-to-zero, inc-from-zero This code is a modified version of the x86 PAX_REFCOUNT atomic_t overflow defense from the last public patch of PaX/grsecurity, based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Thanks to PaX Team for various suggestions for improvement for repurposing this code to be a refcount-only protection. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: David S. Miller <davem@davemloft.net> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Elena Reshetova <elena.reshetova@intel.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Hans Liljestrand <ishkamiel@gmail.com> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: Jann Horn <jannh@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Manfred Spraul <manfred@colorfullife.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Serge E. Hallyn <serge@hallyn.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: arozansk@redhat.com Cc: axboe@kernel.dk Cc: kernel-hardening@lists.openwall.com Cc: linux-arch <linux-arch@vger.kernel.org> Link: http://lkml.kernel.org/r/20170815161924.GA133115@beast Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-17x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pagesTony Luck
Speculative processor accesses may reference any memory that has a valid page table entry. While a speculative access won't generate a machine check, it will log the error in a machine check bank. That could cause escalation of a subsequent error since the overflow bit will be then set in the machine check bank status register. Code has to be double-plus-tricky to avoid mentioning the 1:1 virtual address of the page we want to map out otherwise we may trigger the very problem we are trying to avoid. We use a non-canonical address that passes through the usual Linux table walking code to get to the same "pte". Thanks to Dave Hansen for reviewing several iterations of this. Also see: http://marc.info/?l=linux-mm&m=149860136413338&w=2 Signed-off-by: Tony Luck <tony.luck@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Elliott, Robert (Persistent Memory) <elliott@hpe.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20170816171803.28342-1-tony.luck@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>