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* docs: filesystems: fix renamed referencesMauro Carvalho Chehab2020-04-2045-52/+52
| | | | | | | | | | Some filesystem references got broken by a previous patch series I submitted. Address those. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Acked-by: David Sterba <dsterba@suse.com> # fs/affs/Kconfig Link: https://lore.kernel.org/r/57318c53008dbda7f6f4a5a9e5787f4d37e8565a.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* docs: fix broken references for ReST files that moved aroundMauro Carvalho Chehab2020-04-2011-13/+13
| | | | | | | | | | | Some broken references happened due to shifting files around and ReST renames. Those can't be auto-fixed by the script, so let's fix them manually. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Acked-by: Corentin Labbe <clabbe.montjoie@gmail.com> Link: https://lore.kernel.org/r/64773a12b4410aaf3e3be89e3ec7e34de2484eea.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* docs: fix broken references to text filesMauro Carvalho Chehab2020-04-2023-36/+36
| | | | | | | | | | | | | | | | | Several references got broken due to txt to ReST conversion. Several of them can be automatically fixed with: scripts/documentation-file-ref-check --fix Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> # hwtracing/coresight/Kconfig Reviewed-by: Paul E. McKenney <paulmck@kernel.org> # memory-barrier.txt Acked-by: Alex Shi <alex.shi@linux.alibaba.com> # translations/zh_CN Acked-by: Federico Vaga <federico.vaga@vaga.pv.it> # translations/it_IT Acked-by: Marc Zyngier <maz@kernel.org> # kvm/arm64 Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/6f919ddb83a33b5f2a63b6b5f0575737bb2b36aa.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* docs: dt: fix broken reference to phy-cadence-torrent.yamlMauro Carvalho Chehab2020-04-201-1/+1
| | | | | | | | | | | | | | | | | | This file was removed, and another file was added instead of it, on two separate commits. Splitting a single logical change (doc conversion) on two patches is a bad thing, as it makes harder to discover what crap happened. Anyway, this patch fixes the broken reference, making it pointing to the new location of the file. Fixes: 922003733d42 ("dt-bindings: phy: Remove Cadence MHDP PHY dt binding") Fixes: c6d8eef38b7f ("dt-bindings: phy: Add Cadence MHDP PHY bindings in YAML format.") Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/3f1cf6d74e392f3ee9f894d82cb7ee29d04c1b6d.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* MAINTAINERS: dt: fix pointers for ARM Integrator, Versatile and RealViewMauro Carvalho Chehab2020-04-201-1/+4
| | | | | | | | | | | | | | | | | | There's a conversion from a plain text binding file into 4 yaml ones. The old file got removed, causing this new warning: Warning: MAINTAINERS references a file that doesn't exist: Documentation/devicetree/bindings/arm/arm-boards Address it by replacing the old reference by the new ones Fixes: 2d483550b6d2 ("dt-bindings: arm: Drop the non-YAML bindings") Fixes: 33fbfb3eaf4e ("dt-bindings: arm: Add Integrator YAML schema") Fixes: 4b900070d50d ("dt-bindings: arm: Add Versatile YAML schema") Fixes: 7db625b9fa75 ("dt-bindings: arm: Add RealView YAML schema") Fixes: 4fb00d9066c1 ("dt-bindings: arm: Add Versatile Express and Juno YAML schema") Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/eae3440fb70c1b1666973e34fd3fd6b8ab4a3bc7.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* MAINTAINERS: dt: update display/allwinner file entryMauro Carvalho Chehab2020-04-201-1/+1
| | | | | | | | | | | | | Changeset f5a98bfe7b37 ("dt-bindings: display: Convert Allwinner display pipeline to schemas") split Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt into several files. Yet, it kept the old place at MAINTAINERS. Update it to point to the new place. Fixes: f5a98bfe7b37 ("dt-bindings: display: Convert Allwinner display pipeline to schemas") Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/1be758765272ba4c2acbc3904bdf71c863a90186.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* docs: LaTeX/PDF: drop list of documentsMauro Carvalho Chehab2020-04-201-38/+0
| | | | | | | | | | | | | | | | The building system can auto-generate a list of documents since commit: 9d42afbe6bd4 ("docs: pdf: add all Documentation/*/index.rst to PDF output"). The added logic there allows keeping the existing list, but there's not real reason to keep it. Now, the media document has gone (it was split into tree). So, it sounds about time to get rid of the manual entries, and let the script to generate it automatically instead. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/9345dba7164497dbf28578f6ec271e479379610c.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* docs: update recommended Sphinx version to 2.4.4Mauro Carvalho Chehab2020-04-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are some docs that have nested tables. While this was always part of the spec, only Sphinx version 2.4.x can translate it to LaTeX. In other words, if someone is using a Sphinx version < 2.4, the LaTeX and PDF output won't work for some of the docs. So, it seems that it is time to raise the bar again for the recommented version. The Sphinx check script is already smart enough to keep working, with older versions, warning the users that an upgrade is recommended (and explaining how): Sphinx version 1.7.9 Warning: It is recommended at least Sphinx version 2.4.4. Detected OS: Fedora release 31 (Thirty One). To upgrade Sphinx, use: /usr/bin/virtualenv sphinx_2.4.4 . sphinx_2.4.4/bin/activate pip install -r ./Documentation/sphinx/requirements.txt Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/498f701c618f7d0cf5f0a37e5889ee926f7c8bf4.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: kernel-doc: accept blank lines on parameter descriptionMauro Carvalho Chehab2020-04-201-12/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sphinx is very pedantic with respect to blank lines. Sometimes, in order to make it to properly handle something, we need to add a blank line. However, currently, any blank line inside a kernel-doc comment like: /* * @foo: bar * * foobar * * some description will be considered as if "foobar" was part of the description. This patch changes kernel-doc behavior. After it, foobar will be considered as part of the parameter text. The description will only be considered as such if it starts with: zero spaces after asterisk: *foo one space after asterisk: * foo or have a explicit Description section: * Description: Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/c07d2862792d75a2691d69c9eceb7b89a0164cc0.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: kernel-doc: accept negation like !@varMauro Carvalho Chehab2020-04-201-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | On a few places, it sometimes need to indicate a negation of a parameter, like: !@fshared This pattern happens, for example, at: kernel/futex.c and it is perfectly valid. However, kernel-doc currently transforms it into: !**fshared** This won't do what it would be expected. Fortunately, fixing the script is a simple matter of storing the "!" before "@" and adding it after the bold markup, like: **!fshared** Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/0314b47f8c3e1f9db00d5375a73dc3cddd8a21f2.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: kernel-doc: proper handle @foo->bar()Mauro Carvalho Chehab2020-04-201-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The pattern @foo->bar() is valid, as it can be used by a function pointer inside a struct passed as a parameter. Right now, it causes a warning: ./drivers/firewire/core-transaction.c:606: WARNING: Inline strong start-string without end-string. In this specific case, the kernel-doc markup is: /** * fw_core_remove_address_handler() - unregister an address handler * @handler: callback * * To be called in process context. * * When fw_core_remove_address_handler() returns, @handler->callback() is * guaranteed to not run on any CPU anymore. */ With seems valid on my eyes. So, instead of trying to hack the kernel-doc markup, let's teach it about how to handle such things. This should likely remove lots of other similar warnings as well. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/48b46426d7bf6ff7529f20e5718fbf4e9758e62c.1586881715.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: sphinx-pre-install: add support for python -m venvMauro Carvalho Chehab2020-04-201-38/+75
| | | | | | | | | | | | | | | | Since python 3.3, the recommended way to setup a virtual env is via "python -m venv". Set this as a default, if python version is compatible with such feature. While here, add more comments to it, as the script is getting more complex. So, better to add more things, to avoid accidentally breaking it while improving it. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/252cc849c79527ad496247e4c481961478adf41c.1586883286.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: sphinx-pre-install: add support for OpenMandrivaMauro Carvalho Chehab2020-04-201-4/+21
| | | | | | | | | | | | | | It seems that Mageia and OpenMandriva will reunite on a single distribution. In any case, both came from Mandriva. So, it is close enough to use the same logic. So, add support for it. Tested with OpenMandriva 4.1 and with Mageia 7.1. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/692809729c6818a0b0f75513da15970c53d5565c.1586883286.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: sphinx-pre-install: address some issues with GentooMauro Carvalho Chehab2020-04-201-3/+4
| | | | | | | | | | There are some small misdetections with Gentoo. While they don't cause too much trouble, it keeps recomending to install things that are already there. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/7f631edce102b02ccbdbfb18be1376a86b41373d.1586883286.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: sphinx-pre-install: fix a dependency hint with Ubuntu 16.04Mauro Carvalho Chehab2020-04-201-1/+2
| | | | | | | | | Avoid the scripts to keep asking to install fonts-noto-cjk on Ubuntu 16.04. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/912b664a8ca54e8c5c5767c3fe9171973eeddd6b.1586883286.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: sphinx-pre-install: improve openSuse Tumbleweed checkMauro Carvalho Chehab2020-04-201-1/+3
| | | | | | | | | | | | | | | | Currently, with openSUSE Tumbleweed 20200303, it keeps recommending this forever: sudo zypper install --no-recommends rsvg-view This dependency will never be fulfilled there, as the package now is named as on other distros: rsvg-convert. So, improve the detection to avoid such issue. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/c3774f72ac36c5e5b5f446ae5db5b795d1f274f4.1586883286.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: sphinx-pre-install: improve distro detection checkMauro Carvalho Chehab2020-04-201-0/+18
| | | | | | | | | | | | | | | | | | | | The Arch-linux detection is hit by catting /etc/issue, whose contents is (nowadays): Arch Linux \r (\l) It sounds a little ackward to print such string, so, instead, let's use the /etc/os-release file, with exists on lots of distributions and should provide a more reliable result. We'll keep the old tests before it, in order to avoid possible regressions with the other distros, although the new way should probably work on all the currently supported distributions. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/472924557afdf2b5492ae2a48c5ecfae216d54e2.1586883286.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts: documentation-file-ref-check: Add line break before exitTiezhu Yang2020-04-151-1/+1
| | | | | | | | | | | | | | | | | | | | | If execute ./scripts/documentation-file-ref-check in a directory which is not a git tree, it will exit without a line break, fix it. Without this patch: [loongson@localhost linux-5.7-rc1]$ ./scripts/documentation-file-ref-check Warning: can't check if file exists, as this is not a git tree[loongson@localhost linux-5.7-rc1]$ With this patch: [loongson@localhost linux-5.7-rc1]$ ./scripts/documentation-file-ref-check Warning: can't check if file exists, as this is not a git tree [loongson@localhost linux-5.7-rc1]$ Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/1586857308-2040-1-git-send-email-yangtiezhu@loongson.cn Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* scripts/kernel-doc: Add missing close-paren in c:function directivesPeter Maydell2020-04-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | When kernel-doc generates a 'c:function' directive for a function one of whose arguments is a function pointer, it fails to print the close-paren after the argument list of the function pointer argument. For instance: long work_on_cpu(int cpu, long (*fn) (void *, void * arg) in driver-api/basics.html is missing a ')' separating the "void *" of the 'fn' arguments from the ", void * arg" which is an argument to work_on_cpu(). Add the missing close-paren, so that we render the prototype correctly: long work_on_cpu(int cpu, long (*fn)(void *), void * arg) (Note that Sphinx stops rendering a space between the '(fn*)' and the '(void *)' once it gets something that's syntactically valid.) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Link: https://lore.kernel.org/r/20200414143743.32677-1-peter.maydell@linaro.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* docs: admin-guide: merge sections for the kernel.modprobe sysctlEric Biggers2020-04-151-28/+19
| | | | | | | | | | | | | Documentation for the kernel.modprobe sysctl was added both by commit 0317c5371e6a ("docs: merge debugging-modules.txt into sysctl/kernel.rst") and by commit 6e7158250625 ("docs: admin-guide: document the kernel.modprobe sysctl"), resulting in the same sysctl being documented in two places. Merge these into one place. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Stephen Kitt <steve@sk2.org> Link: https://lore.kernel.org/r/20200414172430.230293-1-ebiggers@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* docs: timekeeping: Use correct prototype for deprecated functionsChris Packham2020-04-151-3/+3
| | | | | | | | | | | | Use the correct prototypes for do_gettimeofday(), getnstimeofday() and getnstimeofday64(). All of these returned void and passed the return value by reference. This should make the documentation of their deprecation and replacements easier to search for. Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> Acked-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20200414221222.23996-1-chris.packham@alliedtelesis.co.nz Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* Linux 5.7-rc1v5.7-rc1Linus Torvalds2020-04-121-2/+2
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* MAINTAINERS: sort field names for all entriesLinus Torvalds2020-04-121-1974/+1974
| | | | | | | | | | | | | | | This sorts the actual field names too, potentially causing even more chaos and confusion at merge time if you have edited the MAINTAINERS file. But the end result is a more consistent layout, and hopefully it's a one-time pain minimized by doing this just before the -rc1 release. This was entirely scripted: ./scripts/parse-maintainers.pl --input=MAINTAINERS --output=MAINTAINERS --order Requested-by: Joe Perches <joe@perches.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* MAINTAINERS: sort entries by entry nameLinus Torvalds2020-04-121-820/+820
| | | | | | | | | | | | | | | | | | | | | They are all supposed to be sorted, but people who add new entries don't always know the alphabet. Plus sometimes the entry names get edited, and people don't then re-order the entry. Let's see how painful this will be for merging purposes (the MAINTAINERS file is often edited in various different trees), but Joe claims there's relatively few patches in -next that touch this, and doing it just before -rc1 is likely the best time. Fingers crossed. This was scripted with /scripts/parse-maintainers.pl --input=MAINTAINERS --output=MAINTAINERS but then I also ended up manually upper-casing a few entry names that stood out when looking at the end result. Requested-by: Joe Perches <joe@perches.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'x86-urgent-2020-04-12' of ↵Linus Torvalds2020-04-124-9/+79
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Thomas Gleixner: "A set of three patches to fix the fallout of the newly added split lock detection feature. It addressed the case where a KVM guest triggers a split lock #AC and KVM reinjects it into the guest which is not prepared to handle it. Add proper sanity checks which prevent the unconditional injection into the guest and handles the #AC on the host side in the same way as user space detections are handled. Depending on the detection mode it either warns and disables detection for the task or kills the task if the mode is set to fatal" * tag 'x86-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: KVM: VMX: Extend VMXs #AC interceptor to handle split lock #AC in guest KVM: x86: Emulate split-lock access as a write in emulator x86/split_lock: Provide handle_guest_split_lock()
| * KVM: VMX: Extend VMXs #AC interceptor to handle split lock #AC in guestXiaoyao Li2020-04-111-3/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Two types of #AC can be generated in Intel CPUs: 1. legacy alignment check #AC 2. split lock #AC Reflect #AC back into the guest if the guest has legacy alignment checks enabled or if split lock detection is disabled. If the #AC is not a legacy one and split lock detection is enabled, then invoke handle_guest_split_lock() which will either warn and disable split lock detection for this task or force SIGBUS on it. [ tglx: Switch it to handle_guest_split_lock() and rename the misnamed helper function. ] Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Link: https://lkml.kernel.org/r/20200410115517.176308876@linutronix.de
| * KVM: x86: Emulate split-lock access as a write in emulatorXiaoyao Li2020-04-111-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Emulate split-lock accesses as writes if split lock detection is on to avoid #AC during emulation, which will result in a panic(). This should never occur for a well-behaved guest, but a malicious guest can manipulate the TLB to trigger emulation of a locked instruction[1]. More discussion can be found at [2][3]. [1] https://lkml.kernel.org/r/8c5b11c9-58df-38e7-a514-dc12d687b198@redhat.com [2] https://lkml.kernel.org/r/20200131200134.GD18946@linux.intel.com [3] https://lkml.kernel.org/r/20200227001117.GX9940@linux.intel.com Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Link: https://lkml.kernel.org/r/20200410115517.084300242@linutronix.de
| * x86/split_lock: Provide handle_guest_split_lock()Thomas Gleixner2020-04-112-5/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Without at least minimal handling for split lock detection induced #AC, VMX will just run into the same problem as the VMWare hypervisor, which was reported by Kenneth. It will inject the #AC blindly into the guest whether the guest is prepared or not. Provide a function for guest mode which acts depending on the host SLD mode. If mode == sld_warn, treat it like user space, i.e. emit a warning, disable SLD and mark the task accordingly. Otherwise force SIGBUS. [ bp: Add a !CPU_SUP_INTEL stub for handle_guest_split_lock(). ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Link: https://lkml.kernel.org/r/20200410115516.978037132@linutronix.de Link: https://lkml.kernel.org/r/20200402123258.895628824@linutronix.de
* | Merge tag 'timers-urgent-2020-04-12' of ↵Linus Torvalds2020-04-123-0/+10
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull time(keeping) updates from Thomas Gleixner: - Fix the time_for_children symlink in /proc/$PID/ so it properly reflects that it part of the 'time' namespace - Add the missing userns limit for the allowed number of time namespaces, which was half defined but the actual array member was not added. This went unnoticed as the array has an exessive empty member at the end but introduced a user visible regression as the output was corrupted. - Prevent further silent ucount corruption by adding a BUILD_BUG_ON() to catch half updated data. * tag 'timers-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ucount: Make sure ucounts in /proc/sys/user don't regress again time/namespace: Add max_time_namespaces ucount time/namespace: Fix time_for_children symlink
| * | ucount: Make sure ucounts in /proc/sys/user don't regress againJan Kara2020-04-071-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 769071ac9f20 "ns: Introduce Time Namespace" broke reporting of inotify ucounts (max_inotify_instances, max_inotify_watches) in /proc/sys/user because it has added UCOUNT_TIME_NAMESPACES into enum ucount_type but didn't properly update reporting in kernel/ucount.c:setup_userns_sysctls(). This problem got fixed in commit eeec26d5da82 "time/namespace: Add max_time_namespaces ucount". Add BUILD_BUG_ON to catch a similar problem in the future. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andrei Vagin <avagin@gmail.com> Link: https://lkml.kernel.org/r/20200407154643.10102-1-jack@suse.cz
| * | time/namespace: Add max_time_namespaces ucountDmitry Safonov2020-04-072-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Michael noticed that userns limit for number of time namespaces is missing. Furthermore, time namespace introduced UCOUNT_TIME_NAMESPACES, but didn't introduce an array member in user_table[]. It would make array's initialisation OOB write, but by luck the user_table array has an excessive empty member (all accesses to the array are limited with UCOUNT_COUNTS - so it silently reuses the last free member. Fixes user-visible regression: max_inotify_instances by reason of the missing UCOUNT_ENTRY() has limited max number of namespaces instead of the number of inotify instances. Fixes: 769071ac9f20 ("ns: Introduce Time Namespace") Reported-by: Michael Kerrisk (man-pages) <mtk.manpages@gmail.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andrei Vagin <avagin@gmail.com> Acked-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: stable@kernel.org Link: https://lkml.kernel.org/r/20200406171342.128733-1-dima@arista.com
| * | time/namespace: Fix time_for_children symlinkMichael Kerrisk (man-pages)2020-04-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Looking at the contents of the /proc/PID/ns/time_for_children symlink shows an anomaly: $ ls -l /proc/self/ns/* |awk '{print $9, $10, $11}' ... /proc/self/ns/pid -> pid:[4026531836] /proc/self/ns/pid_for_children -> pid:[4026531836] /proc/self/ns/time -> time:[4026531834] /proc/self/ns/time_for_children -> time_for_children:[4026531834] /proc/self/ns/user -> user:[4026531837] ... The reference for 'time_for_children' should be a 'time' namespace, just as the reference for 'pid_for_children' is a 'pid' namespace. In other words, the above time_for_children link should read: /proc/self/ns/time_for_children -> time:[4026531834] Fixes: 769071ac9f20 ("ns: Introduce Time Namespace") Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Dmitry Safonov <dima@arista.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Andrei Vagin <avagin@gmail.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/a2418c48-ed80-3afe-116e-6611cb799557@gmail.com
* | | Merge tag 'sched-urgent-2020-04-12' of ↵Linus Torvalds2020-04-125-62/+51
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes/updates from Thomas Gleixner: - Deduplicate the average computations in the scheduler core and the fair class code. - Fix a raise between runtime distribution and assignement which can cause exceeding the quota by up to 70%. - Prevent negative results in the imbalanace calculation - Remove a stale warning in the workqueue code which can be triggered since the call site was moved out of preempt disabled code. It's a false positive. - Deduplicate the print macros for procfs - Add the ucmap values to the SCHED_DEBUG procfs output for completness * tag 'sched-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/debug: Add task uclamp values to SCHED_DEBUG procfs sched/debug: Factor out printing formats into common macros sched/debug: Remove redundant macro define sched/core: Remove unused rq::last_load_update_tick workqueue: Remove the warning in wq_worker_sleeping() sched/fair: Fix negative imbalance in imbalance calculation sched/fair: Fix race between runtime distribution and assignment sched/fair: Align rq->avg_idle and rq->avg_scan_cost
| * | | sched/debug: Add task uclamp values to SCHED_DEBUG procfsValentin Schneider2020-04-081-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Requested and effective uclamp values can be a bit tricky to decipher when playing with cgroup hierarchies. Add them to a task's procfs when SCHED_DEBUG is enabled. Reviewed-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200226124543.31986-4-valentin.schneider@arm.com
| * | | sched/debug: Factor out printing formats into common macrosValentin Schneider2020-04-081-14/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The printing macros in debug.c keep redefining the same output format. Collect each output format in a single definition, and reuse that definition in the other macros. While at it, add a layer of parentheses and replace printf's with the newly introduced macros. Reviewed-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200226124543.31986-3-valentin.schneider@arm.com
| * | | sched/debug: Remove redundant macro defineValentin Schneider2020-04-081-12/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most printing macros for procfs are defined globally in debug.c, and they are re-defined (to the exact same thing) within proc_sched_show_task(). Get rid of the duplicate defines. Reviewed-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200226124543.31986-2-valentin.schneider@arm.com
| * | | sched/core: Remove unused rq::last_load_update_tickVincent Donnefort2020-04-082-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following commit: 5e83eafbfd3b ("sched/fair: Remove the rq->cpu_load[] update code") eliminated the last use case for rq->last_load_update_tick, so remove the field as well. Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/1584710495-308969-1-git-send-email-vincent.donnefort@arm.com
| * | | workqueue: Remove the warning in wq_worker_sleeping()Sebastian Andrzej Siewior2020-04-082-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel test robot triggered a warning with the following race: task-ctx A interrupt-ctx B worker -> process_one_work() -> work_item() -> schedule(); -> sched_submit_work() -> wq_worker_sleeping() -> ->sleeping = 1 atomic_dec_and_test(nr_running) __schedule(); *interrupt* async_page_fault() -> local_irq_enable(); -> schedule(); -> sched_submit_work() -> wq_worker_sleeping() -> if (WARN_ON(->sleeping)) return -> __schedule() -> sched_update_worker() -> wq_worker_running() -> atomic_inc(nr_running); -> ->sleeping = 0; -> sched_update_worker() -> wq_worker_running() if (!->sleeping) return In this context the warning is pointless everything is fine. An interrupt before wq_worker_sleeping() will perform the ->sleeping assignment (0 -> 1 > 0) twice. An interrupt after wq_worker_sleeping() will trigger the warning and nr_running will be decremented (by A) and incremented once (only by B, A will skip it). This is the case until the ->sleeping is zeroed again in wq_worker_running(). Remove the WARN statement because this condition may happen. Document that preemption around wq_worker_sleeping() needs to be disabled to protect ->sleeping and not just as an optimisation. Fixes: 6d25be5782e48 ("sched/core, workqueues: Distangle worker accounting from rq lock") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Tejun Heo <tj@kernel.org> Link: https://lkml.kernel.org/r/20200327074308.GY11705@shao2-debian
| * | | sched/fair: Fix negative imbalance in imbalance calculationAubrey Li2020-04-081-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A negative imbalance value was observed after imbalance calculation, this happens when the local sched group type is group_fully_busy, and the average load of local group is greater than the selected busiest group. Fix this problem by comparing the average load of the local and busiest group before imbalance calculation formula. Suggested-by: Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by: Phil Auld <pauld@redhat.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/1585201349-70192-1-git-send-email-aubrey.li@intel.com
| * | | sched/fair: Fix race between runtime distribution and assignmentHuaixin Chang2020-04-081-20/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, there is a potential race between distribute_cfs_runtime() and assign_cfs_rq_runtime(). Race happens when cfs_b->runtime is read, distributes without holding lock and finds out there is not enough runtime to charge against after distribution. Because assign_cfs_rq_runtime() might be called during distribution, and use cfs_b->runtime at the same time. Fibtest is the tool to test this race. Assume all gcfs_rq is throttled and cfs period timer runs, slow threads might run and sleep, returning unused cfs_rq runtime and keeping min_cfs_rq_runtime in their local pool. If all this happens sufficiently quickly, cfs_b->runtime will drop a lot. If runtime distributed is large too, over-use of runtime happens. A runtime over-using by about 70 percent of quota is seen when we test fibtest on a 96-core machine. We run fibtest with 1 fast thread and 95 slow threads in test group, configure 10ms quota for this group and see the CPU usage of fibtest is 17.0%, which is far more than the expected 10%. On a smaller machine with 32 cores, we also run fibtest with 96 threads. CPU usage is more than 12%, which is also more than expected 10%. This shows that on similar workloads, this race do affect CPU bandwidth control. Solve this by holding lock inside distribute_cfs_runtime(). Fixes: c06f04c70489 ("sched: Fix potential near-infinite distribute_cfs_runtime() loop") Reviewed-by: Ben Segall <bsegall@google.com> Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/lkml/20200325092602.22471-1-changhuaixin@linux.alibaba.com/
| * | | sched/fair: Align rq->avg_idle and rq->avg_scan_costValentin Schneider2020-04-083-11/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sched/core.c uses update_avg() for rq->avg_idle and sched/fair.c uses an open-coded version (with the exact same decay factor) for rq->avg_scan_cost. On top of that, select_idle_cpu() expects to be able to compare these two fields. The only difference between the two is that rq->avg_scan_cost is computed using a pure division rather than a shift. Turns out it actually matters, first of all because the shifted value can be negative, and the standard has this to say about it: """ The result of E1 >> E2 is E1 right-shifted E2 bit positions. [...] If E1 has a signed type and a negative value, the resulting value is implementation-defined. """ Not only this, but (arithmetic) right shifting a negative value (using 2's complement) is *not* equivalent to dividing it by the corresponding power of 2. Let's look at a few examples: -4 -> 0xF..FC -4 >> 3 -> 0xF..FF == -1 != -4 / 8 -8 -> 0xF..F8 -8 >> 3 -> 0xF..FF == -1 == -8 / 8 -9 -> 0xF..F7 -9 >> 3 -> 0xF..FE == -2 != -9 / 8 Make update_avg() use a division, and export it to the private scheduler header to reuse it where relevant. Note that this still lets compilers use a shift here, but should prevent any unwanted surprise. The disassembly of select_idle_cpu() remains unchanged on arm64, and ttwu_do_wakeup() gains 2 instructions; the diff sort of looks like this: - sub x1, x1, x0 + subs x1, x1, x0 // set condition codes + add x0, x1, #0x7 + csel x0, x0, x1, mi // x0 = x1 < 0 ? x0 : x1 add x0, x3, x0, asr #3 which does the right thing (i.e. gives us the expected result while still using an arithmetic shift) Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200330090127.16294-1-valentin.schneider@arm.com
* | | | Merge tag 'perf-urgent-2020-04-12' of ↵Linus Torvalds2020-04-124-31/+573
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Thomas Gleixner: "Three fixes/updates for perf: - Fix the perf event cgroup tracking which tries to track the cgroup even for disabled events. - Add Ice Lake server support for uncore events - Disable pagefaults when retrieving the physical address in the sampling code" * tag 'perf-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/core: Disable page faults when getting phys address perf/x86/intel/uncore: Add Ice Lake server uncore support perf/cgroup: Correct indirection in perf_less_group_idx() perf/core: Fix event cgroup tracking
| * | | | perf/core: Disable page faults when getting phys addressJiri Olsa2020-04-081-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We hit following warning when running tests on kernel compiled with CONFIG_DEBUG_ATOMIC_SLEEP=y: WARNING: CPU: 19 PID: 4472 at mm/gup.c:2381 __get_user_pages_fast+0x1a4/0x200 CPU: 19 PID: 4472 Comm: dummy Not tainted 5.6.0-rc6+ #3 RIP: 0010:__get_user_pages_fast+0x1a4/0x200 ... Call Trace: perf_prepare_sample+0xff1/0x1d90 perf_event_output_forward+0xe8/0x210 __perf_event_overflow+0x11a/0x310 __intel_pmu_pebs_event+0x657/0x850 intel_pmu_drain_pebs_nhm+0x7de/0x11d0 handle_pmi_common+0x1b2/0x650 intel_pmu_handle_irq+0x17b/0x370 perf_event_nmi_handler+0x40/0x60 nmi_handle+0x192/0x590 default_do_nmi+0x6d/0x150 do_nmi+0x2f9/0x3c0 nmi+0x8e/0xd7 While __get_user_pages_fast() is IRQ-safe, it calls access_ok(), which warns on: WARN_ON_ONCE(!in_task() && !pagefault_disabled()) Peter suggested disabling page faults around __get_user_pages_fast(), which gets rid of the warning in access_ok() call. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200407141427.3184722-1-jolsa@kernel.org
| * | | | perf/x86/intel/uncore: Add Ice Lake server uncore supportKan Liang2020-04-083-0/+522
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The uncore subsystem in Ice Lake server is similar to previous server. There are some differences in config register encoding and pci device IDs. The uncore PMON units in Ice Lake server include Ubox, Chabox, IIO, IRP, M2PCIE, PCU, M2M, PCIE3 and IMC. - For CHA, filter 1 register has been removed. The filter 0 register can be used by and of CHA events to be filterd by Thread/Core-ID. To do so, the control register's tid_en bit must be set to 1. - For IIO, there are some changes on event constraints. The MSR address and MSR offsets among counters are also changed. - For IRP, the MSR address and MSR offsets among counters are changed. - For M2PCIE, the counters are accessed by MSR now. Add new MSR address and MSR offsets. Change event constraints. - To determine the number of CHAs, have to read CAPID6(Low) and CAPID7 (High) now. - For M2M, update the PCICFG address and Device ID. - For UPI, update the PCICFG address, Device ID and counter address. - For M3UPI, update the PCICFG address, Device ID, counter address and event constraints. - For IMC, update the formular to calculate MMIO BAR address, which is MMIO_BASE + specific MEM_BAR offset. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/1585842411-150452-1-git-send-email-kan.liang@linux.intel.com
| * | | | perf/cgroup: Correct indirection in perf_less_group_idx()Ian Rogers2020-04-081-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The void* in perf_less_group_idx() is to a member in the array which points at a perf_event*, as such it is a perf_event**. Reported-By: John Sperbeck <jsperbeck@google.com> Fixes: 6eef8a7116de ("perf/core: Use min_heap in visit_groups_merge()") Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200321164331.107337-1-irogers@google.com
| * | | | perf/core: Fix event cgroup trackingPeter Zijlstra2020-04-081-27/+43
| |/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Song reports that installing cgroup events is broken since: db0503e4f675 ("perf/core: Optimize perf_install_in_event()") The problem being that cgroup events try to track cpuctx->cgrp even for disabled events, which is pointless and actively harmful since the above commit. Rework the code to have explicit enable/disable hooks for cgroup events, such that we can limit cgroup tracking to active events. More specifically, since the above commit disabled events are no longer added to their context from the 'right' CPU, and we can't access things like the current cgroup for a remote CPU. Cc: <stable@vger.kernel.org> # v5.5+ Fixes: db0503e4f675 ("perf/core: Optimize perf_install_in_event()") Reported-by: Song Liu <songliubraving@fb.com> Tested-by: Song Liu <songliubraving@fb.com> Reviewed-by: Song Liu <songliubraving@fb.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200318193337.GB20760@hirez.programming.kicks-ass.net
* | | | Merge tag 'locking-urgent-2020-04-12' of ↵Linus Torvalds2020-04-123-26/+51
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Thomas Gleixner: "Three small fixes/updates for the locking core code: - Plug a task struct reference leak in the percpu rswem implementation. - Document the refcount interaction with PID_MAX_LIMIT - Improve the 'invalid wait context' data dump in lockdep so it contains all information which is required to decode the problem" * tag 'locking-urgent-2020-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/lockdep: Improve 'invalid wait context' splat locking/refcount: Document interaction with PID_MAX_LIMIT locking/percpu-rwsem: Fix a task_struct refcount
| * | | | locking/lockdep: Improve 'invalid wait context' splatPeter Zijlstra2020-04-081-20/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 'invalid wait context' splat doesn't print all the information required to reconstruct / validate the error, specifically the irq-context state is missing. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | locking/refcount: Document interaction with PID_MAX_LIMITJann Horn2020-04-081-5/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Document the circumstances under which refcount_t's saturation mechanism works deterministically. Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200303105427.260620-1-jannh@google.com
| * | | | locking/percpu-rwsem: Fix a task_struct refcountQian Cai2020-04-081-1/+2
| |/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following commit: 7f26482a872c ("locking/percpu-rwsem: Remove the embedded rwsem") introduced task_struct memory leaks due to messing up the task_struct refcount. At the beginning of percpu_rwsem_wake_function(), it calls get_task_struct(), but if the trylock failed, it will remain in the waitqueue. However, it will run percpu_rwsem_wake_function() again with get_task_struct() to increase the refcount but then only call put_task_struct() once the trylock succeeded. Fix it by adjusting percpu_rwsem_wake_function() a bit to guard against when percpu_rwsem_wait() observing !private, terminating the wait and doing a quick exit() while percpu_rwsem_wake_function() then doing wake_up_process(p) as a use-after-free. Fixes: 7f26482a872c ("locking/percpu-rwsem: Remove the embedded rwsem") Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200330213002.2374-1-cai@lca.pw
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