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2016-03-03cgroup: separate out interface file creation from css creationTejun Heo1-29/+43
Currently, interface files are created when a css is created depending on whether @visible is set. This patch separates out the two into separate steps to help code refactoring and eventually allow cgroups which aren't visible through cgroup fs. Move css_populate_dir() out of create_css() and drop @visible. While at it, rename the function to css_create() for consistency. Signed-off-by: Tejun Heo <[email protected]> Acked-by: Zefan Li <[email protected]>
2016-03-03cgroup: suppress spurious de-populated eventsTejun Heo1-2/+3
During task migration, tasks may transfer between two css_sets which are associated with the same cgroup. If those tasks are the only tasks in the cgroup, this currently triggers a spurious de-populated event on the cgroup. Fix it by bumping up populated count before bumping it down during migration to ensure that it doesn't reach zero spuriously. Signed-off-by: Tejun Heo <[email protected]> Acked-by: Zefan Li <[email protected]>
2016-03-03cgroup: re-hash init_css_set after subsystems are initializedTejun Heo1-4/+11
css_sets are hashed by their subsys[] contents and in cgroup_init() init_css_set is hashed early, before subsystem inits, when all entries in its subsys[] are NULL, so that cgroup_dfl_root initialization can find and link to it. As subsystems are initialized, init_css_set.subsys[] is filled up but the hashing is never updated making init_css_set hashed in the wrong place. While incorrect, this doesn't cause a critical failure as css_set management code would create an identical css_set dynamically. Fix it by rehashing init_css_set after subsystems are initialized. While at it, drop unnecessary @key local variable. Signed-off-by: Tejun Heo <[email protected]> Acked-by: Zefan Li <[email protected]>
2016-03-01cgroup: reset css on destructionVladimir Davydov1-0/+3
An associated css can be around for quite a while after a cgroup directory has been removed. In general, it makes sense to reset it to defaults so as not to worry about any remnants. For instance, memory cgroup needs to reset memory.low, otherwise pages charged to a dead cgroup might never get reclaimed. There's ->css_reset callback, which would fit perfectly for the purpose. Currently, it's only called when a subsystem is disabled in the unified hierarchy and there are other subsystems dependant on it. Let's call it on css destruction as well. Suggested-by: Johannes Weiner <[email protected]> Signed-off-by: Vladimir Davydov <[email protected]> Signed-off-by: Tejun Heo <[email protected]>
2016-02-27cgroup: fix a mistake in warning messageXiubo Li1-1/+1
There is a mistake about the print format name:id <--> %d:%s, which the name is 'char *' type and id is 'int' type. Change "name:id" to "id:name" instead to be consistent with "cgroup_subsys %d:%s". Signed-off-by: Xiubo Li <[email protected]> Acked-by: Zefan Li <[email protected]> Signed-off-by: Tejun Heo <[email protected]>
2016-02-23cgroup: use ->subtree_control when testing no internal process ruleTejun Heo1-2/+2
No internal process rule is enforced by cgroup_migrate_prepare_dst() during process migration. It tests whether the target cgroup's ->child_subsys_mask is zero which is different from "subtree_control" write path which tests ->subtree_control. This hasn't mattered because up until now, both ->child_subsys_mask and ->subtree_control are zero or non-zero at the same time. However, with the planned addition of implicit controllers, this will no longer be true. This patch prepares for the change by making cgorup_migrate_prepare_dst() test ->subtree_control instead. Signed-off-by: Tejun Heo <[email protected]>
2016-02-23cgroup: make css_tryget_online_from_dir() also recognize cgroup2 fsTejun Heo1-2/+3
The function currently returns -EBADF for a directory on the default hierarchy. Make it also recognize cgroup2_fs_type. This will be used for perf_event cgroup2 support. Signed-off-by: Tejun Heo <[email protected]>
2016-02-23cgroup: convert cgroup_subsys flag fields to bool bitfieldsTejun Heo3-3/+3
Signed-off-by: Tejun Heo <[email protected]> Cc: Li Zefan <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]>
2016-02-23cgroup: s/cgrp_dfl_root_/cgrp_dfl_/Tejun Heo1-9/+9
These var names are unnecessarily unwiedly and another similar variable will be added. Let's shorten them. Signed-off-by: Tejun Heo <[email protected]>
2016-02-22cgroup: make cgroup subsystem masks u16Tejun Heo1-26/+24
After the recent do_each_subsys_mask() conversion, there's no reason to use ulong for subsystem masks. We'll be adding more subsystem masks to persistent data structures, let's reduce its size to u16 which should be enough for now and the foreseeable future. This doesn't create any noticeable behavior differences. v2: Johannes spotted that the initial patch missed cgroup_no_v1_mask. Converted. Signed-off-by: Tejun Heo <[email protected]> Acked-by: Johannes Weiner <[email protected]>
2016-02-22cgroup: use do_each_subsys_mask() where applicableTejun Heo1-23/+12
There are several places in cgroup_subtree_control_write() which can use do_each_subsys_mask() instead of manual mask testing. Use it. No functional changes. Signed-off-by: Tejun Heo <[email protected]> Acked-by: Johannes Weiner <[email protected]>
2016-02-22cgroup: convert for_each_subsys_which() to do-while styleTejun Heo1-32/+40
for_each_subsys_which() allows iterating subsystems specified in a subsystem bitmask; unfortunately, it requires the mask to be an unsigned long l-value which can be inconvenient and makes it awkward to use a smaller type for subsystem masks. This patch converts for_each_subsy_which() to do-while style which allows it to drop the l-value requirement. The new iterator is named do_each_subsys_mask() / while_each_subsys_mask(). Signed-off-by: Tejun Heo <[email protected]> Cc: Aleksa Sarai <[email protected]> Acked-by: Johannes Weiner <[email protected]>
2016-02-22cgroup: s/child_subsys_mask/subtree_ss_mask/Tejun Heo1-24/+24
For consistency with cgroup->subtree_control. * cgroup->child_subsys_mask -> cgroup->subtree_ss_mask * cgroup_calc_child_subsys_mask() -> cgroup_calc_subtree_ss_mask() * cgroup_refresh_child_subsys_mask() -> cgroup_refresh_subtree_ss_mask() No functional changes. Signed-off-by: Tejun Heo <[email protected]> Acked-by: Johannes Weiner <[email protected]>
2016-02-22Revert "cgroup: add cgroup_subsys->css_e_css_changed()"Tejun Heo1-18/+0
This reverts commit 56c807ba4e91f0980567b6a69de239677879b17f. cgroup_subsys->css_e_css_changed() was supposed to be used by cgroup writeback support; however, the change to per-inode cgroup association made it unnecessary and the callback doesn't have any user. Remove it. Signed-off-by: Tejun Heo <[email protected]> Acked-by: Johannes Weiner <[email protected]>
2016-02-22cgroup: fix error return value of cgroup_addrm_files()Tejun Heo1-2/+2
cgroup_addrm_files() incorrectly returned 0 after add failure. Fix it. Signed-off-by: Tejun Heo <[email protected]> Acked-by: Johannes Weiner <[email protected]>
2016-02-12cgroup: provide cgroup_nov1= to disable controllers in v1 mountsJohannes Weiner1-1/+42
Testing cgroup2 can be painful with system software automatically mounting and populating all cgroup controllers in v1 mode. Sometimes they can be unmounted from rc.local, sometimes even that is too late. Provide a commandline option to disable certain controllers in v1 mounts, so that they remain available for cgroup2 mounts. Example use: cgroup_no_v1=memory,cpu cgroup_no_v1=all Disabling will be confirmed at boot-time as such: [ 0.013770] Disabling cpu control group subsystem in v1 mounts [ 0.016004] Disabling memory control group subsystem in v1 mounts Signed-off-by: Johannes Weiner <[email protected]> Signed-off-by: Tejun Heo <[email protected]>
2016-01-31kernel/Makefile: remove the useless CFLAGS_REMOVE_cgroup-debug.oLi Bin1-2/+1
The file cgroup-debug.c had been removed from commit fe6934354f8e (cgroups: move the cgroup debug subsys into cgroup.c to access internal state). Remain the CFLAGS_REMOVE_cgroup-debug.o = $(CC_FLAGS_FTRACE) useless in kernel/Makefile. Signed-off-by: Li Bin <[email protected]> Acked-by: Zefan Li <[email protected]> Signed-off-by: Tejun Heo <[email protected]>
2016-01-22cgroup: make sure a parent css isn't freed before its childrenTejun Heo1-3/+4
There are three subsystem callbacks in css shutdown path - css_offline(), css_released() and css_free(). Except for css_released(), cgroup core didn't guarantee the order of invocation. css_offline() or css_free() could be called on a parent css before its children. This behavior is unexpected and led to bugs in cpu and memory controller. The previous patch updated ordering for css_offline() which fixes the cpu controller issue. While there currently isn't a known bug caused by misordering of css_free() invocations, let's fix it too for consistency. css_free() ordering can be trivially fixed by moving putting of the parent css below css_free() invocation. Signed-off-by: Tejun Heo <[email protected]> Cc: Peter Zijlstra <[email protected]>
2016-01-22cgroup: make sure a parent css isn't offlined before its childrenTejun Heo1-5/+17
There are three subsystem callbacks in css shutdown path - css_offline(), css_released() and css_free(). Except for css_released(), cgroup core didn't guarantee the order of invocation. css_offline() or css_free() could be called on a parent css before its children. This behavior is unexpected and led to bugs in cpu and memory controller. This patch updates offline path so that a parent css is never offlined before its children. Each css keeps online_cnt which reaches zero iff itself and all its children are offline and offline_css() is invoked only after online_cnt reaches zero. This fixes the memory controller bug and allows the fix for cpu controller. Signed-off-by: Tejun Heo <[email protected]> Reported-and-tested-by: Christian Borntraeger <[email protected]> Reported-by: Brian Christiansen <[email protected]> Link: http://lkml.kernel.org/g/[email protected] Link: http://lkml.kernel.org/g/CAKB58ikDkzc8REt31WBkD99+hxNzjK4+FBmhkgS+NVrC9vjMSg@mail.gmail.com Cc: Heiko Carstens <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: [email protected]
2016-01-22cpuset: make mm migration asynchronousTejun Heo2-22/+51
If "cpuset.memory_migrate" is set, when a process is moved from one cpuset to another with a different memory node mask, pages in used by the process are migrated to the new set of nodes. This was performed synchronously in the ->attach() callback, which is synchronized against process management. Recently, the synchronization was changed from per-process rwsem to global percpu rwsem for simplicity and optimization. Combined with the synchronous mm migration, this led to deadlocks because mm migration could schedule a work item which may in turn try to create a new worker blocking on the process management lock held from cgroup process migration path. This heavy an operation shouldn't be performed synchronously from that deep inside cgroup migration in the first place. This patch punts the actual migration to an ordered workqueue and updates cgroup process migration and cpuset config update paths to flush the workqueue after all locks are released. This way, the operations still seem synchronous to userland without entangling mm migration with process management synchronization. CPU hotplug can also invoke mm migration but there's no reason for it to wait for mm migrations and thus doesn't synchronize against their completions. Signed-off-by: Tejun Heo <[email protected]> Reported-and-tested-by: Christian Borntraeger <[email protected]> Cc: [email protected] # v4.4+
2016-01-21Merge branch 'akpm' (patches from Andrew)Linus Torvalds14-96/+104
Merge third patch-bomb from Andrew Morton: "I'm pretty much done for -rc1 now: - the rest of MM, basically - lib/ updates - checkpatch, epoll, hfs, fatfs, ptrace, coredump, exit - cpu_mask simplifications - kexec, rapidio, MAINTAINERS etc, etc. - more dma-mapping cleanups/simplifications from hch" * emailed patches from Andrew Morton <[email protected]>: (109 commits) MAINTAINERS: add/fix git URLs for various subsystems mm: memcontrol: add "sock" to cgroup2 memory.stat mm: memcontrol: basic memory statistics in cgroup2 memory controller mm: memcontrol: do not uncharge old page in page cache replacement Documentation: cgroup: add memory.swap.{current,max} description mm: free swap cache aggressively if memcg swap is full mm: vmscan: do not scan anon pages if memcg swap limit is hit swap.h: move memcg related stuff to the end of the file mm: memcontrol: replace mem_cgroup_lruvec_online with mem_cgroup_online mm: vmscan: pass memcg to get_scan_count() mm: memcontrol: charge swap to cgroup2 mm: memcontrol: clean up alloc, online, offline, free functions mm: memcontrol: flatten struct cg_proto mm: memcontrol: rein in the CONFIG space madness net: drop tcp_memcontrol.c mm: memcontrol: introduce CONFIG_MEMCG_LEGACY_KMEM mm: memcontrol: allow to disable kmem accounting for cgroup2 mm: memcontrol: account "kmem" consumers in cgroup2 memory controller mm: memcontrol: move kmem accounting code to CONFIG_MEMCG mm: memcontrol: separate kmem code from legacy tcp accounting code ...
2016-01-21Merge tag 'pci-v4.5-changes' of ↵Linus Torvalds2-3/+6
git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci Pull PCI updates from Bjorn Helgaas: "PCI changes for the v4.5 merge window: Enumeration: - Simplify config space size computation (Bjorn Helgaas) - Avoid iterating through ROM outside the resource window (Edward O'Callaghan) - Support PCIe devices with short cfg_size (Jason S. McMullan) - Add Netronome vendor and device IDs (Jason S. McMullan) - Limit config space size for Netronome NFP6000 family (Jason S. McMullan) - Add Netronome NFP4000 PF device ID (Simon Horman) - Limit config space size for Netronome NFP4000 (Simon Horman) - Print warnings for all invalid expansion ROM headers (Vladis Dronov) Resource management: - Fix minimum allocation address overwrite (Christoph Biedl) PCI device hotplug: - acpiphp_ibm: Fix null dereferences on null ibm_slot (Colin Ian King) - pciehp: Always protect pciehp_disable_slot() with hotplug mutex (Guenter Roeck) - shpchp: Constify hpc_ops structure (Julia Lawall) - ibmphp: Remove unneeded NULL test (Julia Lawall) Power management: - Make ASPM sysfs link_state_store() consistent with link_state_show() (Andy Lutomirski) Virtualization - Add function 1 DMA alias quirk for Lite-On/Plextor M6e/Marvell 88SS9183 (Tim Sander) MSI: - Remove empty pci_msi_init_pci_dev() (Bjorn Helgaas) - Mark PCIe/PCI (MSI) IRQ cascade handlers as IRQF_NO_THREAD (Grygorii Strashko) - Initialize MSI capability for all architectures (Guilherme G. Piccoli) - Relax msi_domain_alloc() to support parentless MSI irqdomains (Liu Jiang) ARM Versatile host bridge driver: - Remove unused pci_sys_data structures (Lorenzo Pieralisi) Broadcom iProc host bridge driver: - Hide CONFIG_PCIE_IPROC (Arnd Bergmann) - Do not use 0x in front of %pap (Dmitry V. Krivenok) - Update iProc PCIe device tree binding (Ray Jui) - Add PAXC interface support (Ray Jui) - Add iProc PCIe MSI device tree binding (Ray Jui) - Add iProc PCIe MSI support (Ray Jui) Freescale i.MX6 host bridge driver: - Use gpio_set_value_cansleep() (Fabio Estevam) - Add support for active-low reset GPIO (Petr Štetiar) HiSilicon host bridge driver: - Add support for HiSilicon Hip06 PCIe host controllers (Gabriele Paoloni) Intel VMD host bridge driver: - Export irq_domain_set_info() for module use (Keith Busch) - x86/PCI: Allow DMA ops specific to a PCI domain (Keith Busch) - Use 32 bit PCI domain numbers (Keith Busch) - Add driver for Intel Volume Management Device (VMD) (Keith Busch) Qualcomm host bridge driver: - Document PCIe devicetree bindings (Stanimir Varbanov) - Add Qualcomm PCIe controller driver (Stanimir Varbanov) - dts: apq8064: add PCIe devicetree node (Stanimir Varbanov) - dts: ifc6410: enable PCIe DT node for this board (Stanimir Varbanov) Renesas R-Car host bridge driver: - Add support for R-Car H3 to pcie-rcar (Harunobu Kurokawa) - Allow DT to override default window settings (Phil Edworthy) - Convert to DT resource parsing API (Phil Edworthy) - Revert "PCI: rcar: Build pcie-rcar.c only on ARM" (Phil Edworthy) - Remove unused pci_sys_data struct from pcie-rcar (Phil Edworthy) - Add runtime PM support to pcie-rcar (Phil Edworthy) - Add Gen2 PHY setup to pcie-rcar (Phil Edworthy) - Add gen2 fallback compatibility string for pci-rcar-gen2 (Simon Horman) - Add gen2 fallback compatibility string for pcie-rcar (Simon Horman) Synopsys DesignWare host bridge driver: - Simplify control flow (Bjorn Helgaas) - Make config accessor override checking symmetric (Bjorn Helgaas) - Ensure ATU is enabled before IO/conf space accesses (Stanimir Varbanov) Miscellaneous: - Add of_pci_get_host_bridge_resources() stub (Arnd Bergmann) - Check for PCI_HEADER_TYPE_BRIDGE equality, not bitmask (Bjorn Helgaas) - Fix all whitespace issues (Bogicevic Sasa) - x86/PCI: Simplify pci_bios_{read,write} (Geliang Tang) - Use to_pci_dev() instead of open-coding it (Geliang Tang) - Use kobj_to_dev() instead of open-coding it (Geliang Tang) - Use list_for_each_entry() to simplify code (Geliang Tang) - Fix typos in <linux/msi.h> (Thomas Petazzoni) - x86/PCI: Clarify AMD Fam10h config access restrictions comment (Tomasz Nowicki)" * tag 'pci-v4.5-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (58 commits) PCI: Add function 1 DMA alias quirk for Lite-On/Plextor M6e/Marvell 88SS9183 PCI: Limit config space size for Netronome NFP4000 PCI: Add Netronome NFP4000 PF device ID x86/PCI: Add driver for Intel Volume Management Device (VMD) PCI/AER: Use 32 bit PCI domain numbers x86/PCI: Allow DMA ops specific to a PCI domain irqdomain: Export irq_domain_set_info() for module use PCI: host: Add of_pci_get_host_bridge_resources() stub genirq/MSI: Relax msi_domain_alloc() to support parentless MSI irqdomains PCI: rcar: Add Gen2 PHY setup to pcie-rcar PCI: rcar: Add runtime PM support to pcie-rcar PCI: designware: Make config accessor override checking symmetric PCI: ibmphp: Remove unneeded NULL test ARM: dts: ifc6410: enable PCIe DT node for this board ARM: dts: apq8064: add PCIe devicetree node PCI: hotplug: Use list_for_each_entry() to simplify code PCI: rcar: Remove unused pci_sys_data struct from pcie-rcar PCI: hisi: Add support for HiSilicon Hip06 PCIe host controllers PCI: Avoid iterating through memory outside the resource window PCI: acpiphp_ibm: Fix null dereferences on null ibm_slot ...
2016-01-20Merge tag 'pm+acpi-4.5-rc1-2' of ↵Linus Torvalds2-7/+1
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull more power management and ACPI updates from Rafael Wysocki: "This includes fixes on top of the previous batch of PM+ACPI updates and some new material as well. From the new material perspective the most significant are the driver core changes that should allow USB devices to stay suspended over system suspend/resume cycles if they have been runtime-suspended already beforehand. Apart from that, ACPICA is updated to upstream revision 20160108 (cosmetic mostly, but including one fixup on top of the previous ACPICA update) and there are some devfreq updates the didn't make it before (due to timing). A few recent regressions are fixed, most importantly in the cpuidle menu governor and in the ACPI backlight driver and some x86 platform drivers depending on it. Some more bugs are fixed and cleanups are made on top of that. Specifics: - Modify the driver core and the USB subsystem to allow USB devices to stay suspended over system suspend/resume cycles if they have been runtime-suspended already beforehand and fix some bugs on top of these changes (Tomeu Vizoso, Rafael Wysocki). - Update ACPICA to upstream revision 20160108, including updates of the ACPICA's copyright notices, a code fixup resulting from a regression fix that was necessary in the upstream code only (the regression fixed by it has never been present in Linux) and a compiler warning fix (Bob Moore, Lv Zheng). - Fix a recent regression in the cpuidle menu governor that broke it on practically all architectures other than x86 and make a couple of optimizations on top of that fix (Rafael Wysocki). - Clean up the selection of cpuidle governors depending on whether or not the kernel is configured for tickless systems (Jean Delvare). - Revert a recent commit that introduced a regression in the ACPI backlight driver, address the problem it attempted to fix in a different way and revert one more cosmetic change depending on the problematic commit (Hans de Goede). - Add two more ACPI backlight quirks (Hans de Goede). - Fix a few minor problems in the core devfreq code, clean it up a bit and update the MAINTAINERS information related to it (Chanwoo Choi, MyungJoo Ham). - Improve an error message in the ACPI fan driver (Andy Lutomirski). - Fix a recent build regression in the cpupower tool (Shreyas Prabhu)" * tag 'pm+acpi-4.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (32 commits) cpuidle: menu: Avoid pointless checks in menu_select() sched / idle: Drop default_idle_call() fallback from call_cpuidle() cpupower: Fix build error in cpufreq-info cpuidle: Don't enable all governors by default cpuidle: Default to ladder governor on ticking systems time: nohz: Expose tick_nohz_enabled ACPICA: Update version to 20160108 ACPICA: Silence a -Wbad-function-cast warning when acpi_uintptr_t is 'uintptr_t' ACPICA: Additional 2016 copyright changes ACPICA: Reduce regression fix divergence from upstream ACPICA ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Satellite R830 ACPI / video: Revert "thinkpad_acpi: Use acpi_video_handles_brightness_key_presses()" ACPI / video: Document acpi_video_handles_brightness_key_presses() a bit ACPI / video: Fix using an uninitialized mutex / list_head in acpi_video_handles_brightness_key_presses() ACPI / video: Revert "ACPI / video: driver must be registered before checking for keypresses" ACPI / fan: Improve acpi_device_update_power error message ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba Portege R700 cpuidle: menu: Fix menu_select() for CPUIDLE_DRIVER_STATE_START == 0 MAINTAINERS: Add devfreq-event entry MAINTAINERS: Add missing git repository and directory for devfreq ...
2016-01-20prctl: take mmap sem for writing to protect against othersMateusz Guzik1-10/+10
An unprivileged user can trigger an oops on a kernel with CONFIG_CHECKPOINT_RESTORE. proc_pid_cmdline_read takes mmap_sem for reading and obtains args + env start/end values. These get sanity checked as follows: BUG_ON(arg_start > arg_end); BUG_ON(env_start > env_end); These can be changed by prctl_set_mm. Turns out also takes the semaphore for reading, effectively rendering it useless. This results in: kernel BUG at fs/proc/base.c:240! invalid opcode: 0000 [#1] SMP Modules linked in: virtio_net CPU: 0 PID: 925 Comm: a.out Not tainted 4.4.0-rc8-next-20160105dupa+ #71 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff880077a68000 ti: ffff8800784d0000 task.ti: ffff8800784d0000 RIP: proc_pid_cmdline_read+0x520/0x530 RSP: 0018:ffff8800784d3db8 EFLAGS: 00010206 RAX: ffff880077c5b6b0 RBX: ffff8800784d3f18 RCX: 0000000000000000 RDX: 0000000000000002 RSI: 00007f78e8857000 RDI: 0000000000000246 RBP: ffff8800784d3e40 R08: 0000000000000008 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000050 R13: 00007f78e8857800 R14: ffff88006fcef000 R15: ffff880077c5b600 FS: 00007f78e884a740(0000) GS:ffff88007b200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007f78e8361770 CR3: 00000000790a5000 CR4: 00000000000006f0 Call Trace: __vfs_read+0x37/0x100 vfs_read+0x82/0x130 SyS_read+0x58/0xd0 entry_SYSCALL_64_fastpath+0x12/0x76 Code: 4c 8b 7d a8 eb e9 48 8b 9d 78 ff ff ff 4c 8b 7d 90 48 8b 03 48 39 45 a8 0f 87 f0 fe ff ff e9 d1 fe ff ff 4c 8b 7d 90 eb c6 0f 0b <0f> 0b 0f 0b 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 RIP proc_pid_cmdline_read+0x520/0x530 ---[ end trace 97882617ae9c6818 ]--- Turns out there are instances where the code just reads aformentioned values without locking whatsoever - namely environ_read and get_cmdline. Interestingly these functions look quite resilient against bogus values, but I don't believe this should be relied upon. The first patch gets rid of the oops bug by grabbing mmap_sem for writing. The second patch is optional and puts locking around aformentioned consumers for safety. Consumers of other fields don't seem to benefit from similar treatment and are left untouched. This patch (of 2): The code was taking the semaphore for reading, which does not protect against readers nor concurrent modifications. The problem could cause a sanity checks to fail in procfs's cmdline reader, resulting in an OOPS. Note that some functions perform an unlocked read of various mm fields, but they seem to be fine despite possible modificaton. Signed-off-by: Mateusz Guzik <[email protected]> Acked-by: Cyrill Gorcunov <[email protected]> Cc: Alexey Dobriyan <[email protected]> Cc: Jarod Wilson <[email protected]> Cc: Jan Stancek <[email protected]> Cc: Al Viro <[email protected]> Cc: Anshuman Khandual <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20kernel: printk: specify alignment for struct printk_logAndrey Ryabinin1-5/+5
On architectures that have support for efficient unaligned access struct printk_log has 4-byte alignment. Specify alignment attribute in type declaration. The whole point of this patch is to fix deadlock which happening when UBSAN detects unaligned access in printk() thus UBSAN recursively calls printk() with logbuf_lock held by top printk() call. Signed-off-by: Andrey Ryabinin <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Sasha Levin <[email protected]> Cc: Randy Dunlap <[email protected]> Cc: Rasmus Villemoes <[email protected]> Cc: Jonathan Corbet <[email protected]> Cc: Michal Marek <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Yury Gribov <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: Konstantin Khlebnikov <[email protected]> Cc: Kostya Serebryany <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20sysctl: enable strict writesKees Cook1-1/+1
SYSCTL_WRITES_WARN was added in commit f4aacea2f5d1 ("sysctl: allow for strict write position handling"), and released in v3.16 in August of 2014. Since then I can find only 1 instance of non-zero offset writing[1], and it was fixed immediately in CRIU[2]. As such, it appears safe to flip this to the strict state now. [1] https://www.google.com/search?q="when%20file%20position%20was%20not%200" [2] http://lists.openvz.org/pipermail/criu/2015-April/019819.html Signed-off-by: Kees Cook <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20kexec: move some memembers and definitions within the scope of CONFIG_KEXEC_FILEXunlei Pang2-0/+23
Move the stuff currently only used by the kexec file code within CONFIG_KEXEC_FILE (and CONFIG_KEXEC_VERIFY_SIG). Also move internal "struct kexec_sha_region" and "struct kexec_buf" into "kexec_internal.h". Signed-off-by: Xunlei Pang <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Cc: Dave Young <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20kernel/kexec_core.c: use list_for_each_entry_safe in kimage_free_page_listGeliang Tang1-5/+2
Use list_for_each_entry_safe() instead of list_for_each_safe() to simplify the code. Signed-off-by: Geliang Tang <[email protected]> Cc: Dave Young <[email protected]> Cc: Vivek Goyal <[email protected]> Acked-by: Baoquan He <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20kexec: set KEXEC_TYPE_CRASH before sanity_check_segment_list()Xunlei Pang1-5/+5
sanity_check_segment_list() checks KEXEC_TYPE_CRASH flag to ensure all the segments of the loaded crash kernel are within the kernel crash resource limits, so set the flag beforehand. Signed-off-by: Xunlei Pang <[email protected]> Acked-by: Dave Young <[email protected]> Cc: Eric Biederman <[email protected]> Cc: Vivek Goyal <[email protected]> Acked-by: Baoquan He <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20kernel/cpu.c: make set_cpu_* static inlinesRasmus Villemoes1-34/+0
Almost all callers of the set_cpu_* functions pass an explicit true or false. Making them static inline thus replaces the function calls with a simple set_bit/clear_bit, saving some .text. Signed-off-by: Rasmus Villemoes <[email protected]> Acked-by: Rusty Russell <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Michael Ellerman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20kernel/cpu.c: eliminate cpu_*_maskRasmus Villemoes1-8/+0
Replace the variables cpu_possible_mask, cpu_online_mask, cpu_present_mask and cpu_active_mask with macros expanding to expressions of the same type and value, eliminating some indirection. Signed-off-by: Rasmus Villemoes <[email protected]> Acked-by: Rusty Russell <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Michael Ellerman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20kernel/cpu.c: export __cpu_*_maskRasmus Villemoes1-5/+9
Exporting the cpumasks __cpu_possible_mask and friends will allow us to remove the extra indirection through the cpu_*_mask variables. It will also allow the set_cpu_* functions to become static inlines, which will give a .text reduction. Signed-off-by: Rasmus Villemoes <[email protected]> Acked-by: Rusty Russell <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Michael Ellerman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20kernel/cpu.c: change type of cpu_possible_bits and friendsRasmus Villemoes1-22/+22
Change cpu_possible_bits and friends (online, present, active) from being bitmaps that happen to have the right size to actually being struct cpumasks. Also rename them to __cpu_xyz_mask. This is mostly a small cleanup in preparation for exporting them and, eventually, eliminating the extra indirection through the cpu_xyz_mask variables. Signed-off-by: Rasmus Villemoes <[email protected]> Acked-by: Rusty Russell <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Michael Ellerman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20exit: remove unneeded declaration of exit_mm()Dmitry Safonov1-2/+0
Signed-off-by: Dmitry Safonov <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20ptrace: use fsuid, fsgid, effective creds for fs access checksJann Horn5-13/+36
By checking the effective credentials instead of the real UID / permitted capabilities, ensure that the calling process actually intended to use its credentials. To ensure that all ptrace checks use the correct caller credentials (e.g. in case out-of-tree code or newly added code omits the PTRACE_MODE_*CREDS flag), use two new flags and require one of them to be set. The problem was that when a privileged task had temporarily dropped its privileges, e.g. by calling setreuid(0, user_uid), with the intent to perform following syscalls with the credentials of a user, it still passed ptrace access checks that the user would not be able to pass. While an attacker should not be able to convince the privileged task to perform a ptrace() syscall, this is a problem because the ptrace access check is reused for things in procfs. In particular, the following somewhat interesting procfs entries only rely on ptrace access checks: /proc/$pid/stat - uses the check for determining whether pointers should be visible, useful for bypassing ASLR /proc/$pid/maps - also useful for bypassing ASLR /proc/$pid/cwd - useful for gaining access to restricted directories that contain files with lax permissions, e.g. in this scenario: lrwxrwxrwx root root /proc/13020/cwd -> /root/foobar drwx------ root root /root drwxr-xr-x root root /root/foobar -rw-r--r-- root root /root/foobar/secret Therefore, on a system where a root-owned mode 6755 binary changes its effective credentials as described and then dumps a user-specified file, this could be used by an attacker to reveal the memory layout of root's processes or reveal the contents of files he is not allowed to access (through /proc/$pid/cwd). [[email protected]: fix warning] Signed-off-by: Jann Horn <[email protected]> Acked-by: Kees Cook <[email protected]> Cc: Casey Schaufler <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: James Morris <[email protected]> Cc: "Serge E. Hallyn" <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Al Viro <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Cc: Willy Tarreau <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20ptrace: task_stopped_code(ptrace => true) can't see TASK_STOPPED taskOleg Nesterov1-2/+1
task_stopped_code()->task_is_stopped_or_traced() doesn't look right, the traced task must never be TASK_STOPPED. We can not add WARN_ON(task_is_stopped(p)), but this is only because do_wait() can race with PTRACE_ATTACH from another thread. [[email protected]: teeny cleanup] Signed-off-by: Oleg Nesterov <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Roland McGrath <[email protected]> Acked-by: Tejun Heo <[email protected]> Cc: Pedro Alves <[email protected]> Cc: Jan Kratochvil <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-20ptrace: make wait_on_bit(JOBCTL_TRAPPING_BIT) in ptrace_attach() killableOleg Nesterov1-2/+8
ptrace_attach() can hang waiting for STOPPED -> TRACED transition if the tracee gets frozen in between, change wait_on_bit() to use TASK_KILLABLE. This doesn't really solve the problem(s) and we probably need to fix the freezer. In particular, note that this means that pm freezer will fail if it races attach-to-stopped-task. And otoh perhaps we can just remove JOBCTL_TRAPPING_BIT altogether, it is not clear if we really need to hide this transition from debugger, WNOHANG after PTRACE_ATTACH can fail anyway if it races with SIGCONT. Signed-off-by: Oleg Nesterov <[email protected]> Reported-by: Andrey Ryabinin <[email protected]> Cc: Roland McGrath <[email protected]> Acked-by: Tejun Heo <[email protected]> Cc: Pedro Alves <[email protected]> Cc: Jan Kratochvil <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-21Merge branch 'pm-cpuidle'Rafael J. Wysocki2-7/+1
* pm-cpuidle: cpuidle: menu: Avoid pointless checks in menu_select() sched / idle: Drop default_idle_call() fallback from call_cpuidle() cpuidle: Don't enable all governors by default cpuidle: Default to ladder governor on ticking systems time: nohz: Expose tick_nohz_enabled cpuidle: menu: Fix menu_select() for CPUIDLE_DRIVER_STATE_START == 0
2016-01-19sched / idle: Drop default_idle_call() fallback from call_cpuidle()Rafael J. Wysocki1-6/+0
After commit 9c4b2867ed7c (cpuidle: menu: Fix menu_select() for CPUIDLE_DRIVER_STATE_START == 0) it is clear that menu_select() cannot return negative values. Moreover, ladder_select_state() will never return a negative value too, so make find_deepest_state() return non-negative values too and drop the default_idle_call() fallback from call_cpuidle(). This eliminates one branch from the idle loop and makes the governors and find_deepest_state() handle the case when all states have been disabled from sysfs consistently. Signed-off-by: Rafael J. Wysocki <[email protected]> Acked-by: Peter Zijlstra (Intel) <[email protected]> Acked-by: Ingo Molnar <[email protected]> Tested-by: Sudeep Holla <[email protected]>
2016-01-17Merge branch 'for-linus' of ↵Linus Torvalds3-5/+5
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: - EVM gains support for loading an x509 cert from the kernel (EVM_LOAD_X509), into the EVM trusted kernel keyring. - Smack implements 'file receive' process-based permission checking for sockets, rather than just depending on inode checks. - Misc enhancments for TPM & TPM2. - Cleanups and bugfixes for SELinux, Keys, and IMA. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (41 commits) selinux: Inode label revalidation performance fix KEYS: refcount bug fix ima: ima_write_policy() limit locking IMA: policy can be updated zero times selinux: rate-limit netlink message warnings in selinux_nlmsg_perm() selinux: export validatetrans decisions gfs2: Invalid security labels of inodes when they go invalid selinux: Revalidate invalid inode security labels security: Add hook to invalidate inode security labels selinux: Add accessor functions for inode->i_security security: Make inode argument of inode_getsecid non-const security: Make inode argument of inode_getsecurity non-const selinux: Remove unused variable in selinux_inode_init_security keys, trusted: seal with a TPM2 authorization policy keys, trusted: select hash algorithm for TPM2 chips keys, trusted: fix: *do not* allow duplicate key options tpm_ibmvtpm: properly handle interrupted packet receptions tpm_tis: Tighten IRQ auto-probing tpm_tis: Refactor the interrupt setup tpm_tis: Get rid of the duplicate IRQ probing code ...
2016-01-17Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/auditLinus Torvalds1-10/+7
Pull audit updates from Paul Moore: "Seven audit patches for 4.5, all very minor despite the diffstat. The diffstat churn for linux/audit.h can be attributed to needing to reshuffle the linux/audit.h header to fix the seccomp auditing issue (see the commit description for details). Besides the seccomp/audit fix, most of the fixes are around trying to improve the connection with the audit daemon and a Kconfig simplification. Nothing crazy, and everything passes our little audit-testsuite" * 'upstream' of git://git.infradead.org/users/pcmoore/audit: audit: always enable syscall auditing when supported and audit is enabled audit: force seccomp event logging to honor the audit_enabled flag audit: Delete unnecessary checks before two function calls audit: wake up threads if queue switched from limited to unlimited audit: include auditd's threads in audit_log_start() wait exception audit: remove audit_backlog_wait_overflow audit: don't needlessly reset valid wait time
2016-01-17Merge branch 'akpm' (patches from Andrew)Linus Torvalds6-75/+294
Merge second patch-bomb from Andrew Morton: - more MM stuff: - Kirill's page-flags rework - Kirill's now-allegedly-fixed THP rework - MADV_FREE implementation - DAX feature work (msync/fsync). This isn't quite complete but DAX is new and it's good enough and the guys have a handle on what needs to be done - I expect this to be wrapped in the next week or two. - some vsprintf maintenance work - various other misc bits * emailed patches from Andrew Morton <[email protected]>: (145 commits) printk: change recursion_bug type to bool lib/vsprintf: factor out %pN[F] handler as netdev_bits() lib/vsprintf: refactor duplicate code to special_hex_number() printk-formats.txt: remove unimplemented %pT printk: help pr_debug and pr_devel to optimize out arguments lib/test_printf.c: test dentry printing lib/test_printf.c: add test for large bitmaps lib/test_printf.c: account for kvasprintf tests lib/test_printf.c: add a few number() tests lib/test_printf.c: test precision quirks lib/test_printf.c: check for out-of-bound writes lib/test_printf.c: don't BUG lib/kasprintf.c: add sanity check to kvasprintf lib/vsprintf.c: warn about too large precisions and field widths lib/vsprintf.c: help gcc make number() smaller lib/vsprintf.c: expand field_width to 24 bits lib/vsprintf.c: eliminate potential race in string() lib/vsprintf.c: move string() below widen_string() lib/vsprintf.c: pull out padding code from dentry_name() printk: do cond_resched() between lines while outputting to consoles ...
2016-01-17Merge tag 'sound-4.5-rc1' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound Pull sound updates from Takashi Iwai: "We've had quite busy weeks in this cycle. Looking at ALSA core, the significant changes are a few fixes wrt timer and sequencer ioctls that have been revealed by fuzzer recently. Other than that, ASoC core got a few updates about DAI link handling, but these are rather straightforward refactoring. In drivers scene, ASoC received quite lots of new drivers in addition to bunch of updates for still ongoing Intel Skylake support and topology API. HD-audio gained a new HDMI/DP hotplug notification via component. FireWire got a pile of code refactoring/updates with SCS.1x driver integration. More highlights are shown below. [ NOTE: this contains also many commits for DRM. This is due to the pull of drm stable branch into sound tree, as the base of i915 audio component work for HD-audio. The highlights below don't contain these DRM changes, as these are supposed to be pulled via drm tree in anyway sooner or later. ] Core: - Handful fixes to harden ALSA timer and sequencer ioctls against races reported by syzkaller fuzzer - Irq description string can be unique to each card; only for HD-audio for now ASoC: - Conversion of the array of DAI links to a list for supporting dynamically adding and removing DAI links - Topology API enhancements to make everything more component based and being able to specify PCM links via topology - Some more fixes for the topology code, though it is still not final and ready for enabling in production; we really need to get to the point where that can be done - A pile of changes for Intel SkyLake drivers which hopefully deliver some useful initial functionality for systems with this chipset, though there is more work still to come - Lots of new features and cleanups for the Renesas drivers - ANC support for WM5110 - New drivers: Imagination Technologies IPs, Atmel class D speaker, Cirrus CS47L24 and WM1831, Dialog DA7128, Realtek RT5659 and RT56156, Rockchip RK3036, TI PC3168A, and AMD ACP - Rename PCM1792a driver to be generic pcm179x HD-Audio: - Use audio component for i915 HDMI/DP hotplug handling - On-demand binding with i915 driver - bdl_pos_adj parameter adjustment for Baytrail controllers - Enable power_save_node for CX20722; this shouldn't lead to regression, hopefully - Kabylake HDMI/DP codec support - Quirks for Lenovo E50-80, Dell Latitude E-series, and other Dell machines - A few code refactoring FireWire: - Lots of code cleanup and refactoring - Integrate the support of SCS.1x devices into snd-oxfw driver; snd-scs1x driver is obsoleted USB-audio: - Fix possible NULL dereference at disconnection - A regression fix for Native Instruments devices Misc: - A few code cleanups of fm801 driver" * tag 'sound-4.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (722 commits) ALSA: timer: Code cleanup ALSA: timer: Harden slave timer list handling ALSA: hda - Add fixup for Dell Latitidue E6540 ALSA: timer: Fix race among timer ioctls ALSA: hda - add codec support for Kabylake display audio codec ALSA: timer: Fix double unlink of active_list ALSA: usb-audio: Fix mixer ctl regression of Native Instrument devices ALSA: hda - fix the headset mic detection problem for a Dell laptop ALSA: hda - Fix white noise on Dell Latitude E5550 ALSA: hda_intel: add card number to irq description ALSA: seq: Fix race at timer setup and close ALSA: seq: Fix missing NULL check at remove_events ioctl ALSA: usb-audio: Avoid calling usb_autopm_put_interface() at disconnect ASoC: hdac_hdmi: remove unused hdac_hdmi_query_pin_connlist ASoC: AMD: Add missing include file ALSA: hda - Fixup inverted internal mic for Lenovo E50-80 ALSA: usb: Add native DSD support for Oppo HA-1 ASoC: Make aux_dev more like a generic component ASoC: bcm2835: cleanup includes by ordering them alphabetically ASoC: AMD: Manage ACP 2.x SRAM banks power ...
2016-01-16printk: change recursion_bug type to boolSergey Senozhatsky1-3/+3
`recursion_bug' is used as recursion_bug toggle, so make it `bool'. Signed-off-by: Sergey Senozhatsky <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-16printk: do cond_resched() between lines while outputting to consolesTejun Heo2-3/+35
@console_may_schedule tracks whether console_sem was acquired through lock or trylock. If the former, we're inside a sleepable context and console_conditional_schedule() performs cond_resched(). This allows console drivers which use console_lock for synchronization to yield while performing time-consuming operations such as scrolling. However, the actual console outputting is performed while holding irq-safe logbuf_lock, so console_unlock() clears @console_may_schedule before starting outputting lines. Also, only a few drivers call console_conditional_schedule() to begin with. This means that when a lot of lines need to be output by console_unlock(), for example on a console registration, the task doing console_unlock() may not yield for a long time on a non-preemptible kernel. If this happens with a slow console devices, for example a serial console, the outputting task may occupy the cpu for a very long time. Long enough to trigger softlockup and/or RCU stall warnings, which in turn pile more messages, sometimes enough to trigger the next cycle of warnings incapacitating the system. Fix it by making console_unlock() insert cond_resched() between lines if @console_may_schedule. Signed-off-by: Tejun Heo <[email protected]> Reported-by: Calvin Owens <[email protected]> Acked-by: Jan Kara <[email protected]> Cc: Dave Jones <[email protected]> Cc: Kyle McMartin <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-16printk: only unregister boot consoles when necessaryThierry Reding1-1/+25
Boot consoles are typically replaced by proper consoles during the boot process. This can be problematic if the boot console data is part of the init section that is reclaimed late during boot. If the proper console does not register before this point in time, the boot console will need to be removed (so that the freed memory is not accessed), leaving the system without output for some time. There are various reasons why the proper console may not register early enough, such as deferred probe or the driver being a loadable module. If that happens, there is some amount of time where no console messages are visible to the user, which in turn can mean that they won't see crashes or other potentially useful information. To avoid this situation, only remove the boot console when it resides in the init section. Code exists to replace the boot console by the proper console when it is registered, keeping a seamless transition between the boot and proper consoles. Signed-off-by: Thierry Reding <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Joe Perches <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-16kernel/stop_machine.c: remove CONFIG_SMP dependenciesAndrew Morton1-4/+0
stop_machine.o is only built if CONFIG_SMP=y, so this ifdef always evaluates to true. [[email protected]: remove now-unneeded ifdef] Reported-by: Valentin Rothberg <[email protected]> Cc: Chris Wilson <[email protected]> Cc: Ingo Molnar <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-15mm: bring in additional flag for fixup_user_fault to signal unlockDominik Dingel1-1/+1
During Jason's work with postcopy migration support for s390 a problem regarding gmap faults was discovered. The gmap code will call fixup_user_fault which will end up always in handle_mm_fault. Till now we never cared about retries, but as the userfaultfd code kind of relies on it. this needs some fix. This patchset does not take care of the futex code. I will now look closer at this. This patch (of 2): With the introduction of userfaultfd, kvm on s390 needs fixup_user_fault to pass in FAULT_FLAG_ALLOW_RETRY and give feedback if during the faulting we ever unlocked mmap_sem. This patch brings in the logic to handle retries as well as it cleans up the current documentation. fixup_user_fault was not having the same semantics as filemap_fault. It never indicated if a retry happened and so a caller wasn't able to handle that case. So we now changed the behaviour to always retry a locked mmap_sem. Signed-off-by: Dominik Dingel <[email protected]> Reviewed-by: Andrea Arcangeli <[email protected]> Cc: "Kirill A. Shutemov" <[email protected]> Cc: Martin Schwidefsky <[email protected]> Cc: Christian Borntraeger <[email protected]> Cc: "Jason J. Herne" <[email protected]> Cc: David Rientjes <[email protected]> Cc: Eric B Munson <[email protected]> Cc: Naoya Horiguchi <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Heiko Carstens <[email protected]> Cc: Dominik Dingel <[email protected]> Cc: Paolo Bonzini <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-15mm, x86: get_user_pages() for dax mappingsDan Williams1-0/+12
A dax mapping establishes a pte with _PAGE_DEVMAP set when the driver has established a devm_memremap_pages() mapping, i.e. when the pfn_t return from ->direct_access() has PFN_DEV and PFN_MAP set. Later, when encountering _PAGE_DEVMAP during a page table walk we lookup and pin a struct dev_pagemap instance to keep the result of pfn_to_page() valid until put_page(). Signed-off-by: Dan Williams <[email protected]> Tested-by: Logan Gunthorpe <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
2016-01-15mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gupDan Williams1-4/+49
get_dev_page() enables paths like get_user_pages() to pin a dynamically mapped pfn-range (devm_memremap_pages()) while the resulting struct page objects are in use. Unlike get_page() it may fail if the device is, or is in the process of being, disabled. While the initial lookup of the range may be an expensive list walk, the result is cached to speed up subsequent lookups which are likely to be in the same mapped range. devm_memremap_pages() now requires a reference counter to be specified at init time. For pmem this means moving request_queue allocation into pmem_alloc() so the existing queue usage counter can track "device pages". ZONE_DEVICE pages always have an elevated count and will never be on an lru reclaim list. That space in 'struct page' can be redirected for other uses, but for safety introduce a poison value that will always trip __list_add() to assert. This allows half of the struct list_head storage to be reclaimed with some assurance to back up the assumption that the page count never goes to zero and a list_add() is never attempted. Signed-off-by: Dan Williams <[email protected]> Tested-by: Logan Gunthorpe <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Ross Zwisler <[email protected]> Cc: Alexander Viro <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
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