kernel.git/fs/kernfs, branch linux-6.7.y

fs/kernfs/dir: obey S_ISGID

2024-02-05T20:17:04Z

[ Upstream commit 5133bee62f0ea5d4c316d503cc0040cac5637601 ] Handling of S_ISGID is usually done by inode_init_owner() in all other filesystems, but kernfs doesn't use that function. In kernfs, struct kernfs_node is the primary data structure, and struct inode is only created from it on demand. Therefore, inode_init_owner() can't be used and we need to imitate its behavior. S_ISGID support is useful for the cgroup filesystem; it allows subtrees managed by an unprivileged process to retain a certain owner gid, which then enables sharing access to the subtree with another unprivileged process. -- v1 -> v2: minor coding style fix (comment) Signed-off-by: Max Kellermann Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20231208093310.297233-2-max.kellermann@ionos.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

Revert "kernfs: convert kernfs_idr_lock to an irq safe raw spinlock"

2024-01-25T23:45:09Z

commit e3977e0609a07d86406029fceea0fd40d7849368 upstream. This reverts commit dad3fb67ca1cbef87ce700e83a55835e5921ce8a. The commit converted kernfs_idr_lock to an IRQ-safe raw_spinlock because it could be acquired while holding an rq lock through bpf_cgroup_from_id(). However, kernfs_idr_lock is held while doing GPF_NOWAIT allocations which involves acquiring an non-IRQ-safe and non-raw lock leading to the following lockdep warning: ============================= [ BUG: Invalid wait context ] 6.7.0-rc5-kzm9g-00251-g655022a45b1c #578 Not tainted ----------------------------- swapper/0/0 is trying to lock: dfbcd488 (&c->lock){....}-{3:3}, at: local_lock_acquire+0x0/0xa4 other info that might help us debug this: context-{5:5} 2 locks held by swapper/0/0: #0: dfbc9c60 (lock){+.+.}-{3:3}, at: local_lock_acquire+0x0/0xa4 #1: c0c012a8 (kernfs_idr_lock){....}-{2:2}, at: __kernfs_new_node.constprop.0+0x68/0x258 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.7.0-rc5-kzm9g-00251-g655022a45b1c #578 Hardware name: Generic SH73A0 (Flattened Device Tree) unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x68/0x90 dump_stack_lvl from __lock_acquire+0x3cc/0x168c __lock_acquire from lock_acquire+0x274/0x30c lock_acquire from local_lock_acquire+0x28/0xa4 local_lock_acquire from ___slab_alloc+0x234/0x8a8 ___slab_alloc from __slab_alloc.constprop.0+0x30/0x44 __slab_alloc.constprop.0 from kmem_cache_alloc+0x7c/0x148 kmem_cache_alloc from radix_tree_node_alloc.constprop.0+0x44/0xdc radix_tree_node_alloc.constprop.0 from idr_get_free+0x110/0x2b8 idr_get_free from idr_alloc_u32+0x9c/0x108 idr_alloc_u32 from idr_alloc_cyclic+0x50/0xb8 idr_alloc_cyclic from __kernfs_new_node.constprop.0+0x88/0x258 __kernfs_new_node.constprop.0 from kernfs_create_root+0xbc/0x154 kernfs_create_root from sysfs_init+0x18/0x5c sysfs_init from mnt_init+0xc4/0x220 mnt_init from vfs_caches_init+0x6c/0x88 vfs_caches_init from start_kernel+0x474/0x528 start_kernel from 0x0 Let's rever the commit. It's undesirable to spread out raw spinlock usage anyway and the problem can be solved by protecting the lookup path with RCU instead. Signed-off-by: Tejun Heo Cc: Andrea Righi Reported-by: Geert Uytterhoeven Link: http://lkml.kernel.org/r/CAMuHMdV=AKt+mwY7svEq5gFPx41LoSQZ_USME5_MEdWQze13ww@mail.gmail.com Link: https://lore.kernel.org/r/20240109214828.252092-2-tj@kernel.org Tested-by: Andrea Righi Signed-off-by: Greg Kroah-Hartman

kernfs: convert kernfs_idr_lock to an irq safe raw spinlock

2024-01-25T23:45:09Z

commit c312828c37a72fe2d033a961c47c227b0767e9f8 upstream. bpf_cgroup_from_id() is basically a wrapper to cgroup_get_from_id(), that is relying on kernfs to determine the right cgroup associated to the target id. As a kfunc, it has the potential to be attached to any function through BPF, particularly in contexts where certain locks are held. However, kernfs is not using an irq safe spinlock for kernfs_idr_lock, that means any kernfs function that is acquiring this lock can be interrupted and potentially hit bpf_cgroup_from_id() in the process, triggering a deadlock. For example, it is really easy to trigger a lockdep splat between kernfs_idr_lock and rq->_lock, attaching a small BPF program to __set_cpus_allowed_ptr_locked() that just calls bpf_cgroup_from_id(): ===================================================== WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected 6.7.0-rc7-virtme #5 Not tainted ----------------------------------------------------- repro/131 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: ffffffffb2dc4578 (kernfs_idr_lock){+.+.}-{2:2}, at: kernfs_find_and_get_node_by_id+0x1d/0x80 and this task is already holding: ffff911cbecaf218 (&rq->__lock){-.-.}-{2:2}, at: task_rq_lock+0x50/0xc0 which would create a new lock dependency: (&rq->__lock){-.-.}-{2:2} -> (kernfs_idr_lock){+.+.}-{2:2} but this new dependency connects a HARDIRQ-irq-safe lock: (&rq->__lock){-.-.}-{2:2} ... which became HARDIRQ-irq-safe at: lock_acquire+0xbf/0x2b0 _raw_spin_lock_nested+0x2e/0x40 scheduler_tick+0x5d/0x170 update_process_times+0x9c/0xb0 tick_periodic+0x27/0xe0 tick_handle_periodic+0x24/0x70 __sysvec_apic_timer_interrupt+0x64/0x1a0 sysvec_apic_timer_interrupt+0x6f/0x80 asm_sysvec_apic_timer_interrupt+0x1a/0x20 memcpy+0xc/0x20 arch_dup_task_struct+0x15/0x30 copy_process+0x1ce/0x1eb0 kernel_clone+0xac/0x390 kernel_thread+0x6f/0xa0 kthreadd+0x199/0x230 ret_from_fork+0x31/0x50 ret_from_fork_asm+0x1b/0x30 to a HARDIRQ-irq-unsafe lock: (kernfs_idr_lock){+.+.}-{2:2} ... which became HARDIRQ-irq-unsafe at: ... lock_acquire+0xbf/0x2b0 _raw_spin_lock+0x30/0x40 __kernfs_new_node.isra.0+0x83/0x280 kernfs_create_root+0xf6/0x1d0 sysfs_init+0x1b/0x70 mnt_init+0xd9/0x2a0 vfs_caches_init+0xcf/0xe0 start_kernel+0x58a/0x6a0 x86_64_start_reservations+0x18/0x30 x86_64_start_kernel+0xc5/0xe0 secondary_startup_64_no_verify+0x178/0x17b other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(kernfs_idr_lock); local_irq_disable(); lock(&rq->__lock); lock(kernfs_idr_lock); lock(&rq->__lock); *** DEADLOCK *** Prevent this deadlock condition converting kernfs_idr_lock to a raw irq safe spinlock. The performance impact of this change should be negligible and it also helps to prevent similar deadlock conditions with any other subsystems that may depend on kernfs. Fixes: 332ea1f697be ("bpf: Add bpf_cgroup_from_id() kfunc") Cc: stable Signed-off-by: Andrea Righi Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20231229074916.53547-1-andrea.righi@canonical.com Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2023-11-04T01:15:47Z

Pull driver core updates from Greg KH: "Here is the set of driver core updates for 6.7-rc1. Nothing major in here at all, just a small number of changes including: - minor cleanups and updates from Andy Shevchenko - __counted_by addition - firmware_loader update for aborting loads cleaner - other minor changes, details in the shortlog - documentation update All of these have been in linux-next for a while with no reported issues" * tag 'driver-core-6.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (21 commits) firmware_loader: Abort all upcoming firmware load request once reboot triggered firmware_loader: Refactor kill_pending_fw_fallback_reqs() Documentation: security-bugs.rst: linux-distros relaxed their rules driver core: Release all resources during unbind before updating device links driver core: class: remove boilerplate code driver core: platform: Annotate struct irq_affinity_devres with __counted_by resource: Constify resource crosscheck APIs resource: Unify next_resource() and next_resource_skip_children() resource: Reuse for_each_resource() macro PCI: Implement custom llseek for sysfs resource entries kernfs: sysfs: support custom llseek method for sysfs entries debugfs: Fix __rcu type comparison warning device property: Replace custom implementation of COUNT_ARGS() drivers: base: test: Make property entry API test modular driver core: Add missing parameter description to __fwnode_link_add() device property: Clarify usage scope of some struct fwnode_handle members devres: rename the first parameter of devm_add_action(_or_reset) driver core: platform: Unify the firmware node type check driver core: platform: Use temporary variable in platform_device_add() driver core: platform: Refactor error path in a couple places ...

Merge tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-11-03T06:53:31Z

Pull non-MM updates from Andrew Morton: "As usual, lots of singleton and doubleton patches all over the tree and there's little I can say which isn't in the individual changelogs. The lengthier patch series are - 'kdump: use generic functions to simplify crashkernel reservation in arch', from Baoquan He. This is mainly cleanups and consolidation of the 'crashkernel=' kernel parameter handling - After much discussion, David Laight's 'minmax: Relax type checks in min() and max()' is here. Hopefully reduces some typecasting and the use of min_t() and max_t() - A group of patches from Oleg Nesterov which clean up and slightly fix our handling of reads from /proc/PID/task/... and which remove task_struct.thread_group" * tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (64 commits) scripts/gdb/vmalloc: disable on no-MMU scripts/gdb: fix usage of MOD_TEXT not defined when CONFIG_MODULES=n .mailmap: add address mapping for Tomeu Vizoso mailmap: update email address for Claudiu Beznea tools/testing/selftests/mm/run_vmtests.sh: lower the ptrace permissions .mailmap: map Benjamin Poirier's address scripts/gdb: add lx_current support for riscv ocfs2: fix a spelling typo in comment proc: test ProtectionKey in proc-empty-vm test proc: fix proc-empty-vm test with vsyscall fs/proc/base.c: remove unneeded semicolon do_io_accounting: use sig->stats_lock do_io_accounting: use __for_each_thread() ocfs2: replace BUG_ON() at ocfs2_num_free_extents() with ocfs2_error() ocfs2: fix a typo in a comment scripts/show_delta: add __main__ judgement before main code treewide: mark stuff as __ro_after_init fs: ocfs2: check status values proc: test /proc/${pid}/statm compiler.h: move __is_constexpr() to compiler.h ...

Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-11-03T05:38:47Z

Pull MM updates from Andrew Morton: "Many singleton patches against the MM code. The patch series which are included in this merge do the following: - Kemeng Shi has contributed some compation maintenance work in the series 'Fixes and cleanups to compaction' - Joel Fernandes has a patchset ('Optimize mremap during mutual alignment within PMD') which fixes an obscure issue with mremap()'s pagetable handling during a subsequent exec(), based upon an implementation which Linus suggested - More DAMON/DAMOS maintenance and feature work from SeongJae Park i the following patch series: mm/damon: misc fixups for documents, comments and its tracepoint mm/damon: add a tracepoint for damos apply target regions mm/damon: provide pseudo-moving sum based access rate mm/damon: implement DAMOS apply intervals mm/damon/core-test: Fix memory leaks in core-test mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval - In the series 'Do not try to access unaccepted memory' Adrian Hunter provides some fixups for the recently-added 'unaccepted memory' feature. To increase the feature's checking coverage. 'Plug a few gaps where RAM is exposed without checking if it is unaccepted memory' - In the series 'cleanups for lockless slab shrink' Qi Zheng has done some maintenance work which is preparation for the lockless slab shrinking code - Qi Zheng has redone the earlier (and reverted) attempt to make slab shrinking lockless in the series 'use refcount+RCU method to implement lockless slab shrink' - David Hildenbrand contributes some maintenance work for the rmap code in the series 'Anon rmap cleanups' - Kefeng Wang does more folio conversions and some maintenance work in the migration code. Series 'mm: migrate: more folio conversion and unification' - Matthew Wilcox has fixed an issue in the buffer_head code which was causing long stalls under some heavy memory/IO loads. Some cleanups were added on the way. Series 'Add and use bdev_getblk()' - In the series 'Use nth_page() in place of direct struct page manipulation' Zi Yan has fixed a potential issue with the direct manipulation of hugetlb page frames - In the series 'mm: hugetlb: Skip initialization of gigantic tail struct pages if freed by HVO' has improved our handling of gigantic pages in the hugetlb vmmemmep optimizaton code. This provides significant boot time improvements when significant amounts of gigantic pages are in use - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code rationalization and folio conversions in the hugetlb code - Yin Fengwei has improved mlock()'s handling of large folios in the series 'support large folio for mlock' - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has added statistics for memcg v1 users which are available (and useful) under memcg v2 - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable) prctl so that userspace may direct the kernel to not automatically propagate the denial to child processes. The series is named 'MDWE without inheritance' - Kefeng Wang has provided the series 'mm: convert numa balancing functions to use a folio' which does what it says - In the series 'mm/ksm: add fork-exec support for prctl' Stefan Roesch makes is possible for a process to propagate KSM treatment across exec() - Huang Ying has enhanced memory tiering's calculation of memory distances. This is used to permit the dax/kmem driver to use 'high bandwidth memory' in addition to Optane Data Center Persistent Memory Modules (DCPMM). The series is named 'memory tiering: calculate abstract distance based on ACPI HMAT' - In the series 'Smart scanning mode for KSM' Stefan Roesch has optimized KSM by teaching it to retain and use some historical information from previous scans - Yosry Ahmed has fixed some inconsistencies in memcg statistics in the series 'mm: memcg: fix tracking of pending stats updates values' - In the series 'Implement IOCTL to get and optionally clear info about PTEs' Peter Xu has added an ioctl to /proc//pagemap which permits us to atomically read-then-clear page softdirty state. This is mainly used by CRIU - Hugh Dickins contributed the series 'shmem,tmpfs: general maintenance', a bunch of relatively minor maintenance tweaks to this code - Matthew Wilcox has increased the use of the VMA lock over file-backed page faults in the series 'Handle more faults under the VMA lock'. Some rationalizations of the fault path became possible as a result - In the series 'mm/rmap: convert page_move_anon_rmap() to folio_move_anon_rmap()' David Hildenbrand has implemented some cleanups and folio conversions - In the series 'various improvements to the GUP interface' Lorenzo Stoakes has simplified and improved the GUP interface with an eye to providing groundwork for future improvements - Andrey Konovalov has sent along the series 'kasan: assorted fixes and improvements' which does those things - Some page allocator maintenance work from Kemeng Shi in the series 'Two minor cleanups to break_down_buddy_pages' - In thes series 'New selftest for mm' Breno Leitao has developed another MM self test which tickles a race we had between madvise() and page faults - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups and an optimization to the core pagecache code - Nhat Pham has added memcg accounting for hugetlb memory in the series 'hugetlb memcg accounting' - Cleanups and rationalizations to the pagemap code from Lorenzo Stoakes, in the series 'Abstract vma_merge() and split_vma()' - Audra Mitchell has fixed issues in the procfs page_owner code's new timestamping feature which was causing some misbehaviours. In the series 'Fix page_owner's use of free timestamps' - Lorenzo Stoakes has fixed the handling of new mappings of sealed files in the series 'permit write-sealed memfd read-only shared mappings' - Mike Kravetz has optimized the hugetlb vmemmap optimization in the series 'Batch hugetlb vmemmap modification operations' - Some buffer_head folio conversions and cleanups from Matthew Wilcox in the series 'Finish the create_empty_buffers() transition' - As a page allocator performance optimization Huang Ying has added automatic tuning to the allocator's per-cpu-pages feature, in the series 'mm: PCP high auto-tuning' - Roman Gushchin has contributed the patchset 'mm: improve performance of accounted kernel memory allocations' which improves their performance by ~30% as measured by a micro-benchmark - folio conversions from Kefeng Wang in the series 'mm: convert page cpupid functions to folios' - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about kmemleak' - Qi Zheng has improved our handling of memoryless nodes by keeping them off the allocation fallback list. This is done in the series 'handle memoryless nodes more appropriately' - khugepaged conversions from Vishal Moola in the series 'Some khugepaged folio conversions'" [ bcachefs conflicts with the dynamically allocated shrinkers have been resolved as per Stephen Rothwell in https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/ with help from Qi Zheng. The clone3 test filtering conflict was half-arsed by yours truly ] * tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits) mm/damon/sysfs: update monitoring target regions for online input commit mm/damon/sysfs: remove requested targets when online-commit inputs selftests: add a sanity check for zswap Documentation: maple_tree: fix word spelling error mm/vmalloc: fix the unchecked dereference warning in vread_iter() zswap: export compression failure stats Documentation: ubsan: drop "the" from article title mempolicy: migration attempt to match interleave nodes mempolicy: mmap_lock is not needed while migrating folios mempolicy: alloc_pages_mpol() for NUMA policy without vma mm: add page_rmappable_folio() wrapper mempolicy: remove confusing MPOL_MF_LAZY dead code mempolicy: mpol_shared_policy_init() without pseudo-vma mempolicy trivia: use pgoff_t in shared mempolicy tree mempolicy trivia: slightly more consistent naming mempolicy trivia: delete those ancient pr_debug()s mempolicy: fix migrate_pages(2) syscall return nr_failed kernfs: drop shared NUMA mempolicy hooks hugetlbfs: drop shared NUMA mempolicy pretence mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets() ...

Merge tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs

2023-10-30T19:47:13Z

Pull vfs inode time accessor updates from Christian Brauner: "This finishes the conversion of all inode time fields to accessor functions as discussed on list. Changing timestamps manually as we used to do before is error prone. Using accessors function makes this robust. It does not contain the switch of the time fields to discrete 64 bit integers to replace struct timespec and free up space in struct inode. But after this, the switch can be trivially made and the patch should only affect the vfs if we decide to do it" * tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (86 commits) fs: rename inode i_atime and i_mtime fields security: convert to new timestamp accessors selinux: convert to new timestamp accessors apparmor: convert to new timestamp accessors sunrpc: convert to new timestamp accessors mm: convert to new timestamp accessors bpf: convert to new timestamp accessors ipc: convert to new timestamp accessors linux: convert to new timestamp accessors zonefs: convert to new timestamp accessors xfs: convert to new timestamp accessors vboxsf: convert to new timestamp accessors ufs: convert to new timestamp accessors udf: convert to new timestamp accessors ubifs: convert to new timestamp accessors tracefs: convert to new timestamp accessors sysv: convert to new timestamp accessors squashfs: convert to new timestamp accessors server: convert to new timestamp accessors client: convert to new timestamp accessors ...

kernfs: drop shared NUMA mempolicy hooks

2023-10-25T23:47:15Z

It seems strange that kernfs should be an outlier with a set_policy and get_policy in its kernfs_vm_ops. Ah, it dates back to v2.6.30's commit 095160aee954 ("sysfs: fix some bin_vm_ops errors"), when I had crashed on powerpc's pci_mmap_legacy_page_range() fallback to shmem_zero_setup(). Well, that was commendably thorough, to give sysfs-bin a set_policy and get_policy, just to avoid the way it was coded resulting in EINVAL from mmap when CONFIG_NUMA; but somehow feels a bit over-the-top to me now. It's easier to say that nobody should expect to manage a shmem object's shared NUMA mempolicy via some kernfs backdoor to that object: delete that code (and there's no longer an EINVAL from mmap in the NUMA case). This then leaves set_policy/get_policy as implemented only by shmem - though importantly also by SysV SHM, which has to interface with shmem which implements them, and with SHM_HUGETLB which does not. Link: https://lkml.kernel.org/r/302164-a760-4a9e-879b-6870c9b4013@google.com Signed-off-by: Hugh Dickins Reviewed-by: Matthew Wilcox (Oracle) Cc: Andi Kleen Cc: Christoph Lameter Cc: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "Huang, Ying" Cc: Kefeng Wang Cc: Mel Gorman Cc: Michal Hocko Cc: Mike Kravetz Cc: Nhat Pham Cc: Sidhartha Kumar Cc: Suren Baghdasaryan Cc: Tejun heo Cc: Vishal Moola (Oracle) Cc: Yang Shi Cc: Yosry Ahmed Signed-off-by: Andrew Morton

treewide: mark stuff as __ro_after_init

2023-10-18T21:43:23Z

__read_mostly predates __ro_after_init. Many variables which are marked __read_mostly should have been __ro_after_init from day 1. Also, mark some stuff as "const" and "__init" while I'm at it. [akpm@linux-foundation.org: revert sysctl_nr_open_min, sysctl_nr_open_max changes due to arm warning] [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/4f6bb9c0-abba-4ee4-a7aa-89265e886817@p183 Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton

kernfs: convert to new timestamp accessors

2023-10-18T12:08:23Z

Convert to using the new inode timestamp accessor functions. Signed-off-by: Jeff Layton Link: https://lore.kernel.org/r/20231004185347.80880-47-jlayton@kernel.org Signed-off-by: Christian Brauner