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2021-10-05fs/sysfs/dir.c: replace S_IRWXU|S_IRUGO|S_IXUGO with 0755 sysfs_create_dir_ns()Luis Chamberlain1-2/+1
If one ends up expanding on this line checkpatch will complain that the combination S_IRWXU|S_IRUGO|S_IXUGO should just be replaced with the octal 0755. Do that. This makes no functional changes. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/20210927163805.808907-9-mcgrof@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-14sysfs: simplify sysfs_kf_seq_showChristoph Hellwig1-9/+6
Contrary to the comment ->show is never called from lseek for sysfs, given that sysfs does not use seq_lseek. So remove the NULL ->show case and just WARN and return an error if some future code path ends up here. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210913054121.616001-7-hch@lst.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-14sysfs: refactor sysfs_add_file_mode_nsChristoph Hellwig1-13/+14
Regroup the code so that preallocated attributes and normal attributes are handled in clearly separate blocks. Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210913054121.616001-6-hch@lst.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-09-14sysfs: split out binary attribute handling from sysfs_add_file_mode_nsChristoph Hellwig3-65/+78
Split adding binary attributes into a separate handler instead of overloading sysfs_add_file_mode_ns. Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210913054121.616001-5-hch@lst.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-06Merge tag 'sysfs_defferred_iomem_get_mapping-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core driver-core-nextGreg Kroah-Hartman1-2/+2
sysfs: Allow deferred execution of iomem_get_mapping() Tag for toerh trees/branches to pull from in order to have a stable base to build off of for the "Allow deferred execution of iomem_get_mapping()" set of sysfs changes Link: https://lore.kernel.org/r/20210729233235.1508920-1-kw@linux.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> * tag 'sysfs_defferred_iomem_get_mapping-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: sysfs: Rename struct bin_attribute member to f_mapping sysfs: Invoke iomem_get_mapping() from the sysfs open callback
2021-08-05sysfs: Rename struct bin_attribute member to f_mappingKrzysztof Wilczyński1-2/+2
There are two users of iomem_get_mapping(), the struct file and struct bin_attribute. The former has a member called "f_mapping" and the latter has a member called "mapping", and both are poniters to struct address_space. Rename struct bin_attribute member to "f_mapping" to keep both meaning and the usage consistent with other users of iomem_get_mapping(). Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Krzysztof Wilczyński <kw@linux.com> Link: https://lore.kernel.org/r/20210729233235.1508920-3-kw@linux.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-05sysfs: Invoke iomem_get_mapping() from the sysfs open callbackKrzysztof Wilczyński1-1/+1
Defer invocation of the iomem_get_mapping() to the sysfs open callback so that it can be executed as needed when the binary sysfs object has been accessed. To do that, convert the "mapping" member of the struct bin_attribute from a pointer to the struct address_space into a function pointer with a signature that requires the same return type, and then updates the sysfs_kf_bin_open() to invoke provided function should the function pointer be valid. Also, convert every invocation of iomem_get_mapping() into a function pointer assignment, therefore allowing for the iomem_get_mapping() invocation to be deferred to when the sysfs open callback runs. Thus, this change removes the need for the fs_initcalls to complete before any other sub-system that uses the iomem_get_mapping() would be able to invoke it safely without leading to a failure and an Oops related to an invalid iomem_get_mapping() access. Suggested-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Krzysztof Wilczyński <kw@linux.com> Link: https://lore.kernel.org/r/20210729233235.1508920-2-kw@linux.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-21sysfs: Use local reference in compat_only_sysfs_link_entry_to_kobj()Geert Uytterhoeven1-1/+1
As we have just obtained target_kobj->sd into a local variable, and incremented the object's reference count, it is better to use the local variable instead of the original reference. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Link: https://lore.kernel.org/r/20210714151559.2532572-1-geert@linux-m68k.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-12sysfs: Support zapping of binary attr mmapsDaniel Vetter1-0/+11
We want to be able to revoke pci mmaps so that the same access rules applies as for /dev/kmem. Revoke support for devmem was added in 3234ac664a87 ("/dev/mem: Revoke mappings when a driver claims the region"). The simplest way to achieve this is by having the same filp->f_mapping for all mappings, so that unmap_mapping_range can find them all, no matter through which file they've been created. Since this must be set at open time we need sysfs support for this. Add an optional mapping parameter bin_attr, which is only consulted when there's also an mmap callback, since without mmap support allowing to adjust the ->f_mapping makes no sense. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kees Cook <keescook@chromium.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-pci@vger.kernel.org Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Sourabh Jain <sourabhjain@linux.ibm.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Cc: Nayna Jain <nayna@linux.ibm.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20201127164131.2244124-12-daniel.vetter@ffwll.ch
2020-10-02sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs outputJoe Perches1-0/+55
Output defects can exist in sysfs content using sprintf and snprintf. sprintf does not know the PAGE_SIZE maximum of the temporary buffer used for outputting sysfs content and it's possible to overrun the PAGE_SIZE buffer length. Add a generic sysfs_emit function that knows that the size of the temporary buffer and ensures that no overrun is done. Add a generic sysfs_emit_at function that can be used in multiple call situations that also ensures that no overrun is done. Validate the output buffer argument to be page aligned. Validate the offset len argument to be within the PAGE_SIZE buf. Signed-off-by: Joe Perches <joe@perches.com> Link: https://lore.kernel.org/r/884235202216d464d61ee975f7465332c86f76b2.1600285923.git.joe@perches.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-05Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdmaLinus Torvalds1-0/+1
Pull rdma updates from Jason Gunthorpe: "A more active cycle than most of the recent past, with a few large, long discussed works this time. The RNBD block driver has been posted for nearly two years now, and flowing through RDMA due to it also introducing a new ULP. The removal of FMR has been a recurring discussion theme for a long time. And the usual smattering of features and bug fixes. Summary: - Various small driver bugs fixes in rxe, mlx5, hfi1, and efa - Continuing driver cleanups in bnxt_re, hns - Big cleanup of mlx5 QP creation flows - More consistent use of src port and flow label when LAG is used and a mlx5 implementation - Additional set of cleanups for IB CM - 'RNBD' network block driver and target. This is a network block RDMA device specific to ionos's cloud environment. It brings strong multipath and resiliency capabilities. - Accelerated IPoIB for HFI1 - QP/WQ/SRQ ioctl migration for uverbs, and support for multiple async fds - Support for exchanging the new IBTA defiend ECE data during RDMA CM exchanges - Removal of the very old and insecure FMR interface from all ULPs and drivers. FRWR should be preferred for at least a decade now" * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (247 commits) RDMA/cm: Spurious WARNING triggered in cm_destroy_id() RDMA/mlx5: Return ECE DC support RDMA/mlx5: Don't rely on FW to set zeros in ECE response RDMA/mlx5: Return an error if copy_to_user fails IB/hfi1: Use free_netdev() in hfi1_netdev_free() RDMA/hns: Uninitialized variable in modify_qp_init_to_rtr() RDMA/core: Move and rename trace_cm_id_create() IB/hfi1: Fix hfi1_netdev_rx_init() error handling RDMA: Remove 'max_map_per_fmr' RDMA: Remove 'max_fmr' RDMA/core: Remove FMR device ops RDMA/rdmavt: Remove FMR memory registration RDMA/mthca: Remove FMR support for memory registration RDMA/mlx4: Remove FMR support for memory registration RDMA/i40iw: Remove FMR leftovers RDMA/bnxt_re: Remove FMR leftovers RDMA/mlx5: Remove FMR leftovers RDMA/core: Remove FMR pool API RDMA/rds: Remove FMR support for memory registration RDMA/srp: Remove support for FMR memory registration ...
2020-05-17sysfs: export sysfs_remove_file_self()Jack Wang1-0/+1
Function is going to be used in transport over RDMA module in subsequent patches, so export it to GPL modules. Link: https://lore.kernel.org/r/20200511135131.27580-2-danil.kipnis@cloud.ionos.com Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: linux-kernel@vger.kernel.org [jwang: extend the commit message] Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2020-04-20docs: filesystems: fix renamed referencesMauro Carvalho Chehab4-4/+4
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>
2020-04-05sysfs: remove redundant __compat_only_sysfs_link_entry_to_kobj fnLinus Torvalds1-16/+0
Commit 9255782f7061 ("sysfs: Wrap __compat_only_sysfs_link_entry_to_kobj function to change the symlink name") made this function a wrapper around a new non-underscored function, which is a bit odd. The normal naming convention is the other way around: the underscored function is the wrappee, and the non-underscored function is the wrapper. There's only one single user (well, two call-sites in that user) of the more limited double underscore version of this function, so just remove the oddly named wrapper entirely and just add the extra NULL argument to the user. I considered just doing that in the merge, but that tends to make history really hard to read. Link: https://lore.kernel.org/lkml/CAHk-=wgkkmNV5tMzQDmPAQuNJBuMcry--Jb+h8H1o4RA3kF7QQ@mail.gmail.com/ Cc: Sourabh Jain <sourabhjain@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-04-05Merge tag 'powerpc-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linuxLinus Torvalds1-3/+25
Pull powerpc updates from Michael Ellerman: "Slightly late as I had to rebase mid-week to insert a bug fix: - A large series from Nick for 64-bit to further rework our exception vectors, and rewrite portions of the syscall entry/exit and interrupt return in C. The result is much easier to follow code that is also faster in general. - Cleanup of our ptrace code to split various parts out that had become badly intertwined with #ifdefs over the years. - Changes to our NUMA setup under the PowerVM hypervisor which should hopefully avoid non-sensical topologies which can lead to warnings from the workqueue code and other problems. - MAINTAINERS updates to remove some of our old orphan entries and update the status of others. - Quite a few other small changes and fixes all over the map. Thanks to: Abdul Haleem, afzal mohammed, Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Balamuruhan S, Cédric Le Goater, Chen Zhou, Christophe JAILLET, Christophe Leroy, Christoph Hellwig, Clement Courbet, Daniel Axtens, David Gibson, Douglas Miller, Fabiano Rosas, Fangrui Song, Ganesh Goudar, Gautham R. Shenoy, Greg Kroah-Hartman, Greg Kurz, Gustavo Luiz Duarte, Hari Bathini, Ilie Halip, Jan Kara, Joe Lawrence, Joe Perches, Kajol Jain, Larry Finger, Laurentiu Tudor, Leonardo Bras, Libor Pechacek, Madhavan Srinivasan, Mahesh Salgaonkar, Masahiro Yamada, Masami Hiramatsu, Mauricio Faria de Oliveira, Michael Neuling, Michal Suchanek, Mike Rapoport, Nageswara R Sastry, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nick Desaulniers, Oliver O'Halloran, Po-Hsu Lin, Pratik Rajesh Sampat, Rasmus Villemoes, Ravi Bangoria, Roman Bolshakov, Sam Bobroff, Sandipan Das, Santosh S, Sedat Dilek, Segher Boessenkool, Shilpasri G Bhat, Sourabh Jain, Srikar Dronamraju, Stephen Rothwell, Tyrel Datwyler, Vaibhav Jain, YueHaibing" * tag 'powerpc-5.7-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (158 commits) powerpc: Make setjmp/longjmp signature standard powerpc/cputable: Remove unnecessary copy of cpu_spec->oprofile_type powerpc: Suppress .eh_frame generation powerpc: Drop -fno-dwarf2-cfi-asm powerpc/32: drop unused ISA_DMA_THRESHOLD powerpc/powernv: Add documentation for the opal sensor_groups sysfs interfaces selftests/powerpc: Fix try-run when source tree is not writable powerpc/vmlinux.lds: Explicitly retain .gnu.hash powerpc/ptrace: move ptrace_triggered() into hw_breakpoint.c powerpc/ptrace: create ppc_gethwdinfo() powerpc/ptrace: create ptrace_get_debugreg() powerpc/ptrace: split out ADV_DEBUG_REGS related functions. powerpc/ptrace: move register viewing functions out of ptrace.c powerpc/ptrace: split out TRANSACTIONAL_MEM related functions. powerpc/ptrace: split out SPE related functions. powerpc/ptrace: split out ALTIVEC related functions. powerpc/ptrace: split out VSX related functions. powerpc/ptrace: drop PARAMETER_SAVE_AREA_OFFSET powerpc/ptrace: drop unnecessary #ifdefs CONFIG_PPC64 powerpc/ptrace: remove unused header includes ...
2020-02-26sysfs: add sysfs_change_owner()Christian Brauner1-0/+60
Add a helper to change the owner of sysfs objects. This function will be used to correctly account for kobject ownership changes, e.g. when moving network devices between network namespaces. This mirrors how a kobject is added through driver core which in its guts is done via kobject_add_internal() which in summary creates the main directory via create_dir(), populates that directory with the groups associated with the ktype of the kobject (if any) and populates the directory with the basic attributes associated with the ktype of the kobject (if any). These are the basic steps that are associated with adding a kobject in sysfs. Any additional properties are added by the specific subsystem itself (not by driver core) after it has registered the device. So for the example of network devices, a network device will e.g. register a queue subdirectory under the basic sysfs directory for the network device and than further subdirectories within that queues subdirectory. But that is all specific to network devices and they call the corresponding sysfs functions to do that directly when they create those queue objects. So anything that a subsystem adds outside of what driver core does must also be changed by it (That's already true for removal of files it created outside of driver core.) and it's the same for ownership changes. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-26sysfs: add sysfs_group{s}_change_owner()Christian Brauner1-0/+115
Add helpers to change the owner of sysfs groups. This function will be used to correctly account for kobject ownership changes, e.g. when moving network devices between network namespaces. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-26sysfs: add sysfs_link_change_owner()Christian Brauner1-0/+41
Add a helper to change the owner of a sysfs link. This function will be used to correctly account for kobject ownership changes, e.g. when moving network devices between network namespaces. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-26sysfs: add sysfs_file_change_owner()Christian Brauner1-0/+47
Add helpers to change the owner of a sysfs files. This function will be used to correctly account for kobject ownership changes, e.g. when moving network devices between network namespaces. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-19sysfs: Wrap __compat_only_sysfs_link_entry_to_kobj function to change the symlink nameSourabh Jain1-3/+25
The __compat_only_sysfs_link_entry_to_kobj function creates a symlink to a kobject but doesn't provide an option to change the symlink file name. This patch adds a wrapper function compat_only_sysfs_link_entry_to_kobj that extends the __compat_only_sysfs_link_entry_to_kobj functionality which allows function caller to customize the symlink name. Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> [mpe: Fix compile error when CONFIG_SYSFS=n] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20191211160910.21656-3-sourabhjain@linux.ibm.com
2020-02-04treewide: remove redundant IS_ERR() before error code checkMasahiro Yamada1-1/+1
'PTR_ERR(p) == -E*' is a stronger condition than IS_ERR(p). Hence, IS_ERR(p) is unneeded. The semantic patch that generates this commit is as follows: // <smpl> @@ expression ptr; constant error_code; @@ -IS_ERR(ptr) && (PTR_ERR(ptr) == - error_code) +PTR_ERR(ptr) == - error_code // </smpl> Link: http://lkml.kernel.org/r/20200106045833.1725-1-masahiroy@kernel.org Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Cc: Julia Lawall <julia.lawall@lip6.fr> Acked-by: Stephen Boyd <sboyd@kernel.org> [drivers/clk/clk.c] Acked-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> [GPIO] Acked-by: Wolfram Sang <wsa@the-dreams.de> [drivers/i2c] Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [acpi/scan.c] Acked-by: Rob Herring <robh@kernel.org> Cc: Eric Biggers <ebiggers@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-19Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds1-2/+1
Pull vfs mount updates from Al Viro: "The first part of mount updates. Convert filesystems to use the new mount API" * 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) mnt_init(): call shmem_init() unconditionally constify ksys_mount() string arguments don't bother with registering rootfs init_rootfs(): don't bother with init_ramfs_fs() vfs: Convert smackfs to use the new mount API vfs: Convert selinuxfs to use the new mount API vfs: Convert securityfs to use the new mount API vfs: Convert apparmorfs to use the new mount API vfs: Convert openpromfs to use the new mount API vfs: Convert xenfs to use the new mount API vfs: Convert gadgetfs to use the new mount API vfs: Convert oprofilefs to use the new mount API vfs: Convert ibmasmfs to use the new mount API vfs: Convert qib_fs/ipathfs to use the new mount API vfs: Convert efivarfs to use the new mount API vfs: Convert configfs to use the new mount API vfs: Convert binfmt_misc to use the new mount API convenience helper: get_tree_single() convenience helper get_tree_nodev() vfs: Kill sget_userns() ...
2019-06-03sysfs: Add sysfs_update_groups functionJiri Olsa1-15/+39
Adding sysfs_update_groups function to update multiple groups. sysfs_update_groups - given a directory kobject, create a bunch of attribute groups @kobj: The kobject to update the group on @groups: The attribute groups to update, NULL terminated This function update a bunch of attribute groups. If an error occurs when updating a group, all previously updated groups will be removed together with already existing (not updated) attributes. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190512155518.21468-2-jolsa@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-05-25no need to protect against put_user_ns(NULL)Al Viro1-2/+1
it's a no-op Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-05-21treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2-0/+2
Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-16Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds1-3/+5
Pull vfs mount infrastructure fix from Al Viro: "Fixup for sysfs braino. Capabilities checks for sysfs mount do include those on netns, but only if CONFIG_NET_NS is enabled. Sorry, should've caught that earlier..." * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fix sysfs_init_fs_context() in !CONFIG_NET_NS case
2019-03-16fix sysfs_init_fs_context() in !CONFIG_NET_NS caseAl Viro1-3/+5
Permission checks on current's netns should be done only when netns are enabled. Reported-by: Dominik Brodowski <linux@dominikbrodowski.net> Fixes: 23bf1b6be9c2 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-03-12Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds1-19/+54
Pull vfs mount infrastructure updates from Al Viro: "The rest of core infrastructure; no new syscalls in that pile, but the old parts are switched to new infrastructure. At that point conversions of individual filesystems can happen independently; some are done here (afs, cgroup, procfs, etc.), there's also a large series outside of that pile dealing with NFS (quite a bit of option-parsing stuff is getting used there - it's one of the most convoluted filesystems in terms of mount-related logics), but NFS bits are the next cycle fodder. It got seriously simplified since the last cycle; documentation is probably the weakest bit at the moment - I considered dropping the commit introducing Documentation/filesystems/mount_api.txt (cutting the size increase by quarter ;-), but decided that it would be better to fix it up after -rc1 instead. That pile allows to do followup work in independent branches, which should make life much easier for the next cycle. fs/super.c size increase is unpleasant; there's a followup series that allows to shrink it considerably, but I decided to leave that until the next cycle" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits) afs: Use fs_context to pass parameters over automount afs: Add fs_context support vfs: Add some logging to the core users of the fs_context log vfs: Implement logging through fs_context vfs: Provide documentation for new mount API vfs: Remove kern_mount_data() hugetlbfs: Convert to fs_context cpuset: Use fs_context kernfs, sysfs, cgroup, intel_rdt: Support fs_context cgroup: store a reference to cgroup_ns into cgroup_fs_context cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper cgroup_do_mount(): massage calling conventions cgroup: stash cgroup_root reference into cgroup_fs_context cgroup2: switch to option-by-option parsing cgroup1: switch to option-by-option parsing cgroup: take options parsing into ->parse_monolithic() cgroup: fold cgroup1_mount() into cgroup1_get_tree() cgroup: start switching to fs_context ipc: Convert mqueue fs to fs_context proc: Add fs_context support to procfs ...
2019-02-28kernfs, sysfs, cgroup, intel_rdt: Support fs_contextDavid Howells1-19/+54
Make kernfs support superblock creation/mount/remount with fs_context. This requires that sysfs, cgroup and intel_rdt, which are built on kernfs, be made to support fs_context also. Notes: (1) A kernfs_fs_context struct is created to wrap fs_context and the kernfs mount parameters are moved in here (or are in fs_context). (2) kernfs_mount{,_ns}() are made into kernfs_get_tree(). The extra namespace tag parameter is passed in the context if desired (3) kernfs_free_fs_context() is provided as a destructor for the kernfs_fs_context struct, but for the moment it does nothing except get called in the right places. (4) sysfs doesn't wrap kernfs_fs_context since it has no parameters to pass, but possibly this should be done anyway in case someone wants to add a parameter in future. (5) A cgroup_fs_context struct is created to wrap kernfs_fs_context and the cgroup v1 and v2 mount parameters are all moved there. (6) cgroup1 parameter parsing error messages are now handled by invalf(), which allows userspace to collect them directly. (7) cgroup1 parameter cleanup is now done in the context destructor rather than in the mount/get_tree and remount functions. Weirdies: (*) cgroup_do_get_tree() calls cset_cgroup_from_root() with locks held, but then uses the resulting pointer after dropping the locks. I'm told this is okay and needs commenting. (*) The cgroup refcount web. This really needs documenting. (*) cgroup2 only has one root? Add a suggestion from Thomas Gleixner in which the RDT enablement code is placed into its own function. [folded a leak fix from Andrey Vagin] Signed-off-by: David Howells <dhowells@redhat.com> cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> cc: Tejun Heo <tj@kernel.org> cc: Li Zefan <lizefan@huawei.com> cc: Johannes Weiner <hannes@cmpxchg.org> cc: cgroups@vger.kernel.org cc: fenghua.yu@intel.com Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-02-08sysfs: remove unused include of kernfs-internal.hOndrej Mosnacek1-1/+0
This include is not needed (fs/sysfs/file.c builds just fine without it). Remove it. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-18sysfs: fix blank line coding style warningStephen Martin1-0/+1
Fixed a coding style issue. Signed-off-by: Stephen Martin <lockwood@opperline.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-07sysfs: convert BUG_ON to WARN_ONGreg Kroah-Hartman4-5/+10
It's rude to crash the system just because the developer did something wrong, as it prevents them from usually even seeing what went wrong. So convert the few BUG_ON() calls that have snuck into the sysfs code over the years to WARN_ON() to make it more "friendly". All of these are able to be recovered from, so it makes no sense to crash. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-03sysfs: constify sysfs create/remove files harderJani Nikula1-2/+2
Let the passed in array be const (and thus placed in rodata) instead of a mutable array of const pointers. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181004143750.30880-1-jani.nikula@intel.com
2018-08-18Merge tag 'driver-core-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-coreLinus Torvalds1-8/+22
Pull driver core updates from Greg KH: "Here are all of the driver core and related patches for 4.19-rc1. Nothing huge here, just a number of small cleanups and the ability to now stop the deferred probing after init happens. All of these have been in linux-next for a while with only a merge issue reported" * tag 'driver-core-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (21 commits) base: core: Remove WARN_ON from link dependencies check drivers/base: stop new probing during shutdown drivers: core: Remove glue dirs from sysfs earlier driver core: remove unnecessary function extern declare sysfs.h: fix non-kernel-doc comment PM / Domains: Stop deferring probe at the end of initcall iommu: Remove IOMMU_OF_DECLARE iommu: Stop deferring probe at end of initcalls pinctrl: Support stopping deferred probe after initcalls dt-bindings: pinctrl: add a 'pinctrl-use-default' property driver core: allow stopping deferred probe after init driver core: add a debugfs entry to show deferred devices sysfs: Fix internal_create_group() for named group updates base: fix order of OF initialization linux/device.h: fix kernel-doc notation warning Documentation: update firmware loader fallback reference kobject: Replace strncpy with memcpy drivers: base: cacheinfo: use OF property_read_u32 instead of get_property,read_number kernfs: Replace strncpy with memcpy device: Add #define dev_fmt similar to #define pr_fmt ...
2018-08-15Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds1-0/+44
Pull SCSI updates from James Bottomley: "This is mostly updates to the usual drivers: mpt3sas, lpfc, qla2xxx, hisi_sas, smartpqi, megaraid_sas, arcmsr. In addition, with the continuing absence of Nic we have target updates for tcmu and target core (all with reviews and acks). The biggest observable change is going to be that we're (again) trying to switch to mulitqueue as the default (a user can still override the setting on the kernel command line). Other major core stuff is the removal of the remaining Microchannel drivers, an update of the internal timers and some reworks of completion and result handling" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (203 commits) scsi: core: use blk_mq_run_hw_queues in scsi_kick_queue scsi: ufs: remove unnecessary query(DM) UPIU trace scsi: qla2xxx: Fix issue reported by static checker for qla2x00_els_dcmd2_sp_done() scsi: aacraid: Spelling fix in comment scsi: mpt3sas: Fix calltrace observed while running IO & reset scsi: aic94xx: fix an error code in aic94xx_init() scsi: st: remove redundant pointer STbuffer scsi: qla2xxx: Update driver version to 10.00.00.08-k scsi: qla2xxx: Migrate NVME N2N handling into state machine scsi: qla2xxx: Save frame payload size from ICB scsi: qla2xxx: Fix stalled relogin scsi: qla2xxx: Fix race between switch cmd completion and timeout scsi: qla2xxx: Fix Management Server NPort handle reservation logic scsi: qla2xxx: Flush mailbox commands on chip reset scsi: qla2xxx: Fix unintended Logout scsi: qla2xxx: Fix session state stuck in Get Port DB scsi: qla2xxx: Fix redundant fc_rport registration scsi: qla2xxx: Silent erroneous message scsi: qla2xxx: Prevent sysfs access when chip is down scsi: qla2xxx: Add longer window for chip reset ...
2018-08-02scsi: sysfs: Introduce sysfs_{un,}break_active_protection()Bart Van Assche1-0/+44
Introduce these two functions and export them such that the next patch can add calls to these functions from the SCSI core. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-07-29sysfs: Fix regression when adding a file to an existing groupTyler Hicks1-1/+1
Commit 5f81880d5204 ("sysfs, kobject: allow creating kobject belonging to arbitrary users") incorrectly changed the argument passed as the parent parameter when calling sysfs_add_file_mode_ns(). This caused some sysfs attribute files to not be added correctly to certain groups. Fixes: 5f81880d5204 ("sysfs, kobject: allow creating kobject belonging to arbitrary users") Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Reported-by: Heiner Kallweit <hkallweit1@gmail.com> Tested-by: Heiner Kallweit <hkallweit1@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-20sysfs, kobject: allow creating kobject belonging to arbitrary usersDmitry Torokhov4-23/+44
Normally kobjects and their sysfs representation belong to global root, however it is not necessarily the case for objects in separate namespaces. For example, objects in separate network namespace logically belong to the container's root and not global root. This change lays groundwork for allowing network namespace objects ownership to be transferred to container's root user by defining get_ownership() callback in ktype structure and using it in sysfs code to retrieve desired uid/gid when creating sysfs objects for given kobject. Co-Developed-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-20kernfs: allow creating kernfs objects with arbitrary uid/gidDmitry Torokhov2-3/+6
This change allows creating kernfs files and directories with arbitrary uid/gid instead of always using GLOBAL_ROOT_UID/GID by extending kernfs_create_dir_ns() and kernfs_create_file_ns() with uid/gid arguments. The "simple" kernfs_create_file() and kernfs_create_dir() are left alone and always create objects belonging to the global root. When creating symlinks ownership (uid/gid) is taken from the target kernfs object. Co-Developed-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-07sysfs: Fix internal_create_group() for named group updatesRajat Jain1-7/+22
There are a couple of problems with named group updates in the code today: * sysfs_update_group() will always fail for a named group, because internal_create_group() will try to create a new sysfs directory unconditionally, which will ofcourse fail with -EEXIST. * We can leak the kernfs_node for grp->name if some one tries to: - rename a group (change grp->name), or - update a named group, to an unnamed group It appears that the whole purpose of sysfs_update_group() was to allow changing the permissions or visibility of attributes and not the names. So make it clear in the comments, and allow it to update an existing named group. Signed-off-by: Rajat Jain <rajatja@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-21unfuck sysfs_mount()Al Viro1-3/+3
new_sb is left uninitialized in case of early failures in kernfs_mount_ns(), and while IS_ERR(root) is true in all such cases, using IS_ERR(root) || !new_sb is not a solution - IS_ERR(root) is true in some cases when new_sb is true. Make sure new_sb is initialized (and matches the reality) in all cases and fix the condition for dropping kobj reference - we want it done precisely in those situations where the reference has not been transferred into a new super_block instance. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-03-19sysfs: symlink: export sysfs_create_link_nowarn()Grygorii Strashko1-0/+1
The sysfs_create_link_nowarn() is going to be used in phylib framework in subsequent patch which can be built as module. Hence, export sysfs_create_link_nowarn() to avoid build errors. Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Andrew Lunn <andrew@lunn.ch> Fixes: a3995460491d ("net: phy: Relax error checking on sysfs_create_link()") Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-01Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printkLinus Torvalds1-3/+2
Pull printk updates from Petr Mladek: - Add a console_msg_format command line option: The value "default" keeps the old "[time stamp] text\n" format. The value "syslog" allows to see the syslog-like "<log level>[timestamp] text" format. This feature was requested by people doing regression tests, for example, 0day robot. They want to have both filtered and full logs at hands. - Reduce the risk of softlockup: Pass the console owner in a busy loop. This is a new approach to the old problem. It was first proposed by Steven Rostedt on Kernel Summit 2017. It marks a context in which the console_lock owner calls console drivers and could not sleep. On the other side, printk() callers could detect this state and use a busy wait instead of a simple console_trylock(). Finally, the console_lock owner checks if there is a busy waiter at the end of the special context and eventually passes the console_lock to the waiter. The hand-off works surprisingly well and helps in many situations. Well, there is still a possibility of the softlockup, for example, when the flood of messages stops and the last owner still has too much to flush. There is increasing number of people having problems with printk-related softlockups. We might eventually need to get better solution. Anyway, this looks like a good start and promising direction. - Do not allow to schedule in console_unlock() called from printk(): This reverts an older controversial commit. The reschedule helped to avoid softlockups. But it also slowed down the console output. This patch is obsoleted by the new console waiter logic described above. In fact, the reschedule made the hand-off less effective. - Deprecate "%pf" and "%pF" format specifier: It was needed on ia64, ppc64 and parisc64 to dereference function descriptors and show the real function address. It is done transparently by "%ps" and "pS" format specifier now. Sergey Senozhatsky found that all the function descriptors were in a special elf section and could be easily detected. - Remove printk_symbol() API: It has been obsoleted by "%pS" format specifier, and this change helped to remove few continuous lines and a less intuitive old API. - Remove redundant memsets: Sergey removed unnecessary memset when processing printk.devkmsg command line option. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: (27 commits) printk: drop redundant devkmsg_log_str memsets printk: Never set console_may_schedule in console_trylock() printk: Hide console waiter logic into helpers printk: Add console owner and waiter logic to load balance console writes kallsyms: remove print_symbol() function checkpatch: add pF/pf deprecation warning symbol lookup: introduce dereference_symbol_descriptor() parisc64: Add .opd based function descriptor dereference powerpc64: Add .opd based function descriptor dereference ia64: Add .opd based function descriptor dereference sections: split dereference_function_descriptor() openrisc: Fix conflicting types for _exext and _stext lib: do not use print_symbol() irq debug: do not use print_symbol() sysfs: do not use print_symbol() drivers: do not use print_symbol() x86: do not use print_symbol() unicore32: do not use print_symbol() sh: do not use print_symbol() mn10300: do not use print_symbol() ...
2018-01-23sysfs: remove DEBUG definesGreg Kroah-Hartman2-3/+0
It isn't needed at all in these files, dynamic debug is the best way to enable this type of thing, if you really want it. As it is, these defines were not doing anything at all. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-23sysfs: use SPDX identifiersGreg Kroah-Hartman6-13/+6
Move the license "mark" of the sysfs files to be in SPDX form, instead of the custom text that it currently is in. This is in a quest to get rid of the 700+ different ways we say "GPLv2" in the kernel tree. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-22sysfs: turn WARN() into pr_warn()Greg Kroah-Hartman1-2/+3
It's not good to crash the machine if panic_on_warn() is set just because someone made a stupid mistake of trying to create a sysfs file with the same name of an existing one. This makes the automated testing tools a lot harder to find the real bugs in the kernel. So just print a warning out and dump the stack to get the attention of the developer that they did something foolish. Then keep on trucking, as this should not be a fatal error at all. Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-05sysfs: do not use print_symbol()Sergey Senozhatsky1-3/+2
print_symbol() is a very old API that has been obsoleted by %pS format specifier in a normal printk() call. Replace print_symbol() with a direct printk("%pS") call. Link: http://lkml.kernel.org/r/20171211125025.2270-11-sergey.senozhatsky@gmail.com To: Andrew Morton <akpm@linux-foundation.org> To: Russell King <linux@armlinux.org.uk> To: Catalin Marinas <catalin.marinas@arm.com> To: Mark Salter <msalter@redhat.com> To: Tony Luck <tony.luck@intel.com> To: David Howells <dhowells@redhat.com> To: Yoshinori Sato <ysato@users.sourceforge.jp> To: Guan Xuetao <gxt@mprc.pku.edu.cn> To: Borislav Petkov <bp@alien8.de> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org> To: Thomas Gleixner <tglx@linutronix.de> To: Peter Zijlstra <peterz@infradead.org> To: Vineet Gupta <vgupta@synopsys.com> To: Fengguang Wu <fengguang.wu@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Petr Mladek <pmladek@suse.com> Cc: LKML <linux-kernel@vger.kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-ia64@vger.kernel.org Cc: linux-am33-list@redhat.com Cc: linux-sh@vger.kernel.org Cc: linux-edac@vger.kernel.org Cc: x86@kernel.org Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> [pmladek@suse.com: updated commit message] Signed-off-by: Petr Mladek <pmladek@suse.com>
2017-12-18sysfs: Use PTR_ERR_OR_ZERO()Vasyl Gomonovych1-1/+1
Fix ptr_ret.cocci warnings: fs/sysfs/group.c:409:8-14: WARNING: PTR_ERR_OR_ZERO can be used Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR Generated by: scripts/coccinelle/api/ptr_ret.cocci Signed-off-by: Vasyl Gomonovych <gomonovych@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-27Rename superblock flags (MS_xyz -> SB_xyz)Linus Torvalds1-1/+1
This is a pure automated search-and-replace of the internal kernel superblock flags. The s_flags are now called SB_*, with the names and the values for the moment mirroring the MS_* flags that they're equivalent to. Note how the MS_xyz flags are the ones passed to the mount system call, while the SB_xyz flags are what we then use in sb->s_flags. The script to do this was: # places to look in; re security/*: it generally should *not* be # touched (that stuff parses mount(2) arguments directly), but # there are two places where we really deal with superblock flags. FILES="drivers/mtd drivers/staging/lustre fs ipc mm \ include/linux/fs.h include/uapi/linux/bfs_fs.h \ security/apparmor/apparmorfs.c security/apparmor/include/lib.h" # the list of MS_... constants SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \ DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \ POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \ I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \ ACTIVE NOUSER" SED_PROG= for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done # we want files that contain at least one of MS_..., # with fs/namespace.c and fs/pnode.c excluded. L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c') for f in $L; do sed -i $f $SED_PROG; done Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-08sysfs: be careful of error returns from ops->show()NeilBrown1-2/+4
ops->show() can return a negative error code. Commit 65da3484d9be ("sysfs: correctly handle short reads on PREALLOC attrs.") (in v4.4) caused this to be stored in an unsigned 'size_t' variable, so errors would look like large numbers. As a result, if an error is returned, sysfs_kf_read() will return the value of 'count', typically 4096. Commit 17d0774f8068 ("sysfs: correctly handle read offset on PREALLOC attrs") (in v4.8) extended this error to use the unsigned large 'len' as a size for memmove(). Consequently, if ->show returns an error, then the first read() on the sysfs file will return 4096 and could return uninitialized memory to user-space. If the application performs a subsequent read, this will trigger a memmove() with extremely large count, and is likely to crash the machine is bizarre ways. This bug can currently only be triggered by reading from an md sysfs attribute declared with __ATTR_PREALLOC() during the brief period between when mddev_put() deletes an mddev from the ->all_mddevs list, and when mddev_delayed_delete() - which is scheduled on a workqueue - completes. Before this, an error won't be returned by the ->show() After this, the ->show() won't be called. I can reproduce it reliably only by putting delay like usleep_range(500000,700000); early in mddev_delayed_delete(). Then after creating an md device md0 run echo clear > /sys/block/md0/md/array_state; cat /sys/block/md0/md/array_state The bug can be triggered without the usleep. Fixes: 65da3484d9be ("sysfs: correctly handle short reads on PREALLOC attrs.") Fixes: 17d0774f8068 ("sysfs: correctly handle read offset on PREALLOC attrs") Cc: stable@vger.kernel.org Signed-off-by: NeilBrown <neilb@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>