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2023-05-31rust: task: add `Send` marker to `Task`Alice Ryhl
When a type also implements `Sync`, the meaning of `Send` is just "this type may be accessed mutably from threads other than the one it is created on". That's ok for this type. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20230531145939.3714886-5-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: specify when `ARef` is thread safeAlice Ryhl
An `ARef` behaves just like the `Arc` when it comes to thread safety, so we can reuse the thread safety comments from `Arc` here. This is necessary because without this change, the Rust compiler will assume that things are not thread safe even though they are. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20230531145939.3714886-4-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: sync: reword the `Arc` safety comment for `Sync`Alice Ryhl
The safety comment on `impl Sync for Arc` references the Send safety comment. This commit avoids that in case the two comments drift apart in the future. Suggested-by: Andreas Hindborg <a.hindborg@samsung.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20230531145939.3714886-3-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: sync: reword the `Arc` safety comment for `Send`Alice Ryhl
The safety comment on `impl Send for Arc` talks about "directly" accessing the value, when it really means "accessing the value with a mutable reference". This commit clarifies that. Suggested-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20230531145939.3714886-2-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: sync: implement `AsRef<T>` for `Arc<T>`Alice Ryhl
This trait lets you use `Arc<T>` in code that is generic over smart pointer types. The `AsRef` trait should be implemented on all smart pointers. The standard library also implements it on the ordinary `Arc`. Co-developed-by: Wedson Almeida Filho <walmeida@microsoft.com> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Link: https://lore.kernel.org/r/20230517200814.3157916-2-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: sync: add `Arc::ptr_eq`Alice Ryhl
Add a method for comparing whether two `Arc` pointers reference the same underlying object. This comparison can already be done by getting a reference to the inner values and comparing whether the references have the same address. However, writing `Arc::ptr_eq(a, b)` is generally less error-prone than doing the same check on the references, since you might otherwise accidentally compare the two `&Arc<T>` references instead, which wont work because those are pointers to pointers to the inner value, when you just want to compare the pointers to the inner value. Also, this method might optimize better because getting a reference to the inner value involves offsetting the pointer, which this method does not need to do. Co-developed-by: Wedson Almeida Filho <walmeida@microsoft.com> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Link: https://lore.kernel.org/r/20230517200814.3157916-1-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: error: add missing error codesAlice Ryhl
This adds the error codes from `include/linux/errno.h` to the list of Rust error constants. These errors were not included originally, because they are not supposed to be visible from userspace. However, they are still a perfectly valid error to use when writing a kernel driver. For example, you might want to return ERESTARTSYS if you receive a signal during a call to `schedule`. This patch inserts an annotation to skip rustfmt on the list of error codes. Without it, three of the error codes are split over several lines, which looks terribly inconsistent. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Link: https://lore.kernel.org/r/20230504064854.774820-1-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: str: add conversion from `CStr` to `CString`Alice Ryhl
These methods can be used to copy the data in a temporary c string into a separate allocation, so that it can be accessed later even if the original is deallocated. The API in this change mirrors the standard library API for the `&str` and `String` types. The `ToOwned` trait is not implemented because it assumes that allocations are infallible. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Link: https://lore.kernel.org/r/20230503141016.683634-1-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: error: allow specifying error type on `Result`Alice Ryhl
Currently, if the `kernel::error::Result` type is in scope (which is often is, since it's in the kernel's prelude), you cannot write `Result<T, SomeOtherErrorType>` when you want to use a different error type than `kernel::error::Error`. To solve this we change the error type from being hard-coded to just being a default generic parameter. This still lets you write `Result<T>` when you just want to use the `Error` error type, but also lets you write `Result<T, SomeOtherErrorType>` when necessary. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Asahi Lina <lina@asahilina.net> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20230502124015.356001-1-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: init: update macro expansion example in docsBenno Lossin
Also improve the explaining comments. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Link: https://lore.kernel.org/r/20230424081112.99890-4-benno.lossin@proton.me Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: macros: replace Self with the concrete type in #[pin_data]Benno Lossin
When using `#[pin_data]` on a struct that used `Self` in the field types, a type error would be emitted when trying to use `pin_init!`. Since an internal type would be referenced by `Self` instead of the defined struct. This patch fixes this issue by replacing all occurrences of `Self` in the `#[pin_data]` macro with the concrete type circumventing the issue. Since rust allows type definitions inside of blocks, which are expressions, the macro also checks for these and emits a compile error when it finds `trait`, `enum`, `union`, `struct` or `impl`. These keywords allow creating new `Self` contexts, which conflicts with the current implementation of replacing every `Self` ident. If these were allowed, some `Self` idents would be replaced incorrectly. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reported-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20230424081112.99890-3-benno.lossin@proton.me [ Added newline in commit message ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: macros: refactor generics parsing of `#[pin_data]` into its own functionBenno Lossin
Other macros might also want to parse generics. Additionally this makes the code easier to read, as the next commit will introduce more code in `#[pin_data]`. Also add more comments to explain how parsing generics work. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Link: https://lore.kernel.org/r/20230424081112.99890-2-benno.lossin@proton.me Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: macros: fix usage of `#[allow]` in `quote!`Benno Lossin
When using `quote!` as part of an expression that was not the last one in a function, the `#[allow(clippy::vec_init_then_push)]` attribute would be present on an expression, which is not allowed. This patch refactors that part of the macro to use a statement instead. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20230424081112.99890-1-benno.lossin@proton.me Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31docs: rust: point directly to the standalone installersMiguel Ojeda
The Quick Start guide points to the Rust programming language front page when it mentions the possibility of using the standalone installers instead of `rustup`. This was done to have a hopefully stable link, but it is not too helpful: readers need to figure out how to reach the standalone installers from there. Thus point directly to the page (and anchor) with the table that contains the standalone installers (plus signing key etc.). If the link breaks in the future, we can always update it as needed. And anyway having the full link includes the domain and gives more information about where the old docs were in such a broken link case, which may help. Link: https://lore.kernel.org/linux-doc/CANiq72=gpzQyh1ExGbBWWNdgH-mTATdG5F600jKD1=NLLCn7wg@mail.gmail.com/ Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Link: https://lore.kernel.org/r/20230306220959.240235-1-ojeda@kernel.org [ Removed "install ``rustup``" ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31.gitattributes: set diff driver for Rust source code filesMiguel Ojeda
Git supports a builtin Rust diff driver [1] since v2.23.0 (2019). It improves the choice of hunk headers in some cases, such as diffs within methods, since those are indented in Rust within an `impl` block, and therefore the default diff driver would pick the outer `impl` block instead (rather than the method where the changed code is). For instance, with the default diff driver: @@ -455,6 +455,8 @@ impl fmt::Write for RawFormatter { // Amount that we can copy. `saturating_sub` ensures we get 0 if `pos` goes past `end`. let len_to_copy = core::cmp::min(pos_new, self.end).saturating_sub(self.pos); + test_diff_driver(); + if len_to_copy > 0 { // SAFETY: If `len_to_copy` is non-zero, then we know `pos` has not gone past `end` // yet, so it is valid for write per the type invariants. With the Rust diff driver: @@ -455,6 +455,8 @@ fn write_str(&mut self, s: &str) -> fmt::Result { // Amount that we can copy. `saturating_sub` ensures we get 0 if `pos` goes past `end`. let len_to_copy = core::cmp::min(pos_new, self.end).saturating_sub(self.pos); + test_diff_driver(); + if len_to_copy > 0 { // SAFETY: If `len_to_copy` is non-zero, then we know `pos` has not gone past `end` // yet, so it is valid for write per the type invariants. Thus set the `rust` diff driver for `*.rs` source files. The Rust repository also does so since 2020 [2]. Link: https://git-scm.com/docs/gitattributes#_defining_a_custom_hunk_header [1] Link: https://github.com/rust-lang/rust/pull/78882 [2] Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20230418233048.335281-1-ojeda@kernel.org [ Added link to Rust repository ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: upgrade to Rust 1.68.2Miguel Ojeda
This is the first upgrade to the Rust toolchain since the initial Rust merge, from 1.62.0 to 1.68.2 (i.e. the latest). # Context The kernel currently supports only a single Rust version [1] (rather than a minimum) given our usage of some "unstable" Rust features [2] which do not promise backwards compatibility. The goal is to reach a point where we can declare a minimum version for the toolchain. For instance, by waiting for some of the features to be stabilized. Therefore, the first minimum Rust version that the kernel will support is "in the future". # Upgrade policy Given we will eventually need to reach that minimum version, it would be ideal to upgrade the compiler from time to time to be as close as possible to that goal and find any issues sooner. In the extreme, we could upgrade as soon as a new Rust release is out. Of course, upgrading so often is in stark contrast to what one normally would need for GCC and LLVM, especially given the release schedule: 6 weeks for Rust vs. half a year for LLVM and a year for GCC. Having said that, there is no particular advantage to updating slowly either: kernel developers in "stable" distributions are unlikely to be able to use their distribution-provided Rust toolchain for the kernel anyway [3]. Instead, by routinely upgrading to the latest instead, kernel developers using Linux distributions that track the latest Rust release may be able to use those rather than Rust-provided ones, especially if their package manager allows to pin / hold back / downgrade the version for some days during windows where the version may not match. For instance, Arch, Fedora, Gentoo and openSUSE all provide and track the latest version of Rust as they get released every 6 weeks. Then, when the minimum version is reached, we will stop upgrading and decide how wide the window of support will be. For instance, a year of Rust versions. We will probably want to start small, and then widen it over time, just like the kernel did originally for LLVM, see commit 3519c4d6e08e ("Documentation: add minimum clang/llvm version"). # Unstable features stabilized This upgrade allows us to remove the following unstable features since they were stabilized: - `feature(explicit_generic_args_with_impl_trait)` (1.63). - `feature(core_ffi_c)` (1.64). - `feature(generic_associated_types)` (1.65). - `feature(const_ptr_offset_from)` (1.65, *). - `feature(bench_black_box)` (1.66, *). - `feature(pin_macro)` (1.68). The ones marked with `*` apply only to our old `rust` branch, not mainline yet, i.e. only for code that we may potentially upstream. With this patch applied, the only unstable feature allowed to be used outside the `kernel` crate is `new_uninit`, though other code to be upstreamed may increase the list. Please see [2] for details. # Other required changes Since 1.63, `rustdoc` triggers the `broken_intra_doc_links` lint for links pointing to exported (`#[macro_export]`) `macro_rules`. An issue was opened upstream [4], but it turns out it is intended behavior. For the moment, just add an explicit reference for each link. Later we can revisit this if `rustdoc` removes the compatibility measure. Nevertheless, this was helpful to discover a link that was pointing to the wrong place unintentionally. Since that one was actually wrong, it is fixed in a previous commit independently. Another change was the addition of `cfg(no_rc)` and `cfg(no_sync)` in upstream [5], thus remove our original changes for that. Similarly, upstream now tests that it compiles successfully with `#[cfg(not(no_global_oom_handling))]` [6], which allow us to get rid of some changes, such as an `#[allow(dead_code)]`. In addition, remove another `#[allow(dead_code)]` due to new uses within the standard library. Finally, add `try_extend_trusted` and move the code in `spec_extend.rs` since upstream moved it for the infallible version. # `alloc` upgrade and reviewing There are a large amount of changes, but the vast majority of them are due to our `alloc` fork being upgraded at once. There are two kinds of changes to be aware of: the ones coming from upstream, which we should follow as closely as possible, and the updates needed in our added fallible APIs to keep them matching the newer infallible APIs coming from upstream. Instead of taking a look at the diff of this patch, an alternative approach is reviewing a diff of the changes between upstream `alloc` and the kernel's. This allows to easily inspect the kernel additions only, especially to check if the fallible methods we already have still match the infallible ones in the new version coming from upstream. Another approach is reviewing the changes introduced in the additions in the kernel fork between the two versions. This is useful to spot potentially unintended changes to our additions. To apply these approaches, one may follow steps similar to the following to generate a pair of patches that show the differences between upstream Rust and the kernel (for the subset of `alloc` we use) before and after applying this patch: # Get the difference with respect to the old version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > old.patch git -C linux restore rust/alloc # Apply this patch. git -C linux am rust-upgrade.patch # Get the difference with respect to the new version. git -C rust checkout $(linux/scripts/min-tool-version.sh rustc) git -C linux ls-tree -r --name-only HEAD -- rust/alloc | cut -d/ -f3- | grep -Fv README.md | xargs -IPATH cp rust/library/alloc/src/PATH linux/rust/alloc/PATH git -C linux diff --patch-with-stat --summary -R > new.patch git -C linux restore rust/alloc Now one may check the `new.patch` to take a look at the additions (first approach) or at the difference between those two patches (second approach). For the latter, a side-by-side tool is recommended. Link: https://rust-for-linux.com/rust-version-policy [1] Link: https://github.com/Rust-for-Linux/linux/issues/2 [2] Link: https://lore.kernel.org/rust-for-linux/CANiq72mT3bVDKdHgaea-6WiZazd8Mvurqmqegbe5JZxVyLR8Yg@mail.gmail.com/ [3] Link: https://github.com/rust-lang/rust/issues/106142 [4] Link: https://github.com/rust-lang/rust/pull/89891 [5] Link: https://github.com/rust-lang/rust/pull/98652 [6] Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-By: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-4-ojeda@kernel.org [ Removed `feature(core_ffi_c)` from `uapi` ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: arc: fix intra-doc link in `Arc<T>::init`Miguel Ojeda
`Arc<T>::init` refers to `Arc<T>::pin_init` via an intra-doc link using the text `pin_init`, rather than more explicitly, which makes `rustdoc` point it to the `pin_init!` macro instead. This is required for the compiler upgrade since the newer `rustdoc` would trigger the `broken_intra_doc_links` lint [1], but in this case the macro was not the intended target to begin with, and so the actual fix is to make it point to the right place, regardless of the upgrade. Thus make it more explicit. Fixes: 92c4a1e7e81c ("rust: init/sync: add `InPlaceInit` trait to pin-initialize smart pointers") Link: https://github.com/rust-lang/rust/issues/106142 [1] Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-3-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-31rust: alloc: clarify what is the upstream versionMiguel Ojeda
It may be unclear for readers which upstream Rust version these files are based on. They may be unaware that they are intended to match the minimum (and only, so far) supported version of Rust in the kernel. Thus clarify it. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Tested-by: Ariel Miculas <amiculas@cisco.com> Tested-by: David Gow <davidgow@google.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20230418214347.324156-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-05-28Linux 6.4-rc4v6.4-rc4Linus Torvalds
2023-05-28Merge tag 'x86-urgent-2023-05-28' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cpu fix from Thomas Gleixner: "A single fix for x86: - Prevent a bogus setting for the number of HT siblings, which is caused by the CPUID evaluation trainwreck of X86. That recomputes the value for each CPU, so the last CPU "wins". That can cause completely bogus sibling values" * tag 'x86-urgent-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/topology: Fix erroneous smp_num_siblings on Intel Hybrid platforms
2023-05-28Merge tag 'perf-urgent-2023-05-28' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Thomas Gleixner: "A small set of perf fixes: - Make the MSR-readout based CHA discovery work around broken discovery tables in some SPR firmwares. - Prevent saving PEBS configuration which has software bits set that cause a crash when restored into the relevant MSR" * tag 'perf-urgent-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/uncore: Correct the number of CHAs on SPR perf/x86/intel: Save/restore cpuc->active_pebs_data_cfg when using guest PEBS
2023-05-28Merge tag 'objtool-urgent-2023-05-28' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull unwinder fixes from Thomas Gleixner: "A set of unwinder and tooling fixes: - Ensure that the stack pointer on x86 is aligned again so that the unwinder does not read past the end of the stack - Discard .note.gnu.property section which has a pointlessly different alignment than the other note sections. That confuses tooling of all sorts including readelf, libbpf and pahole" * tag 'objtool-urgent-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/show_trace_log_lvl: Ensure stack pointer is aligned, again vmlinux.lds.h: Discard .note.gnu.property section
2023-05-28Merge tag 'core-debugobjects-2023-05-28' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull debugobjects fixes from Thomas Gleixner: "Two fixes for debugobjects: - Prevent the allocation path from waking up kswapd. That's a long standing issue due to the GFP_ATOMIC allocation flag. As debug objects can be invoked from pretty much any context waking kswapd can end up in arbitrary lock chains versus the waitqueue lock - Correct the explicit lockdep wait-type violation in debug_object_fill_pool()" * tag 'core-debugobjects-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: debugobjects: Don't wake up kswapd from fill_pool() debugobjects,locking: Annotate debug_object_fill_pool() wait type violation
2023-05-28Merge tag 'irq-urgent-2023-05-28' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq fixes from Thomas Gleixner: "A set of fixes for interrupt chip drivers: - Prevent loss of state in the MIPS GIC interrupt controller - Disable pseudo NMIs on Mediatek based Chromebooks as they have firmware issues which cause instantenous chrashes and freezes wen pseudo NMIs are used - Fix the error handling path in the MBIGEN driver and a defined but not used warning in the meson-gpio interrupt chip driver" * tag 'irq-urgent-2023-05-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/mbigen: Unify the error handling in mbigen_of_create_domain() irqchip/meson-gpio: Mark OF related data as maybe unused irqchip/mips-gic: Use raw spinlock for gic_lock irqchip/mips-gic: Don't touch vl_map if a local interrupt is not routable irqchip/gic-v3: Disable pseudo NMIs on Mediatek devices w/ firmware issues dt-bindings: interrupt-controller: arm,gic-v3: Add quirk for Mediatek SoCs w/ broken FW
2023-05-28Merge tag 'mips-fixes_6.4_1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux Pull MIPS fixes from Thomas Bogendoerfer: - fixes to get alchemy platform back in shape - fix for initrd detection * tag 'mips-fixes_6.4_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: mips: Move initrd_start check after initrd address sanitisation. MIPS: Alchemy: fix dbdma2 MIPS: Restore Au1300 support MIPS: unhide PATA_PLATFORM
2023-05-27Merge tag 'powerpc-6.4-3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc fix from Michael Ellerman: - Reinstate ARCH_FORCE_MAX_ORDER ranges to fix various breakage * tag 'powerpc-6.4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/mm: Reinstate ARCH_FORCE_MAX_ORDER ranges
2023-05-27Merge tag 'for-linus-6.4-rc4-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen fixes from Juergen Gross: - a double free fix in the Xen pvcalls backend driver - a fix for a regression causing the MSI related sysfs entries to not being created in Xen PV guests - a fix in the Xen blkfront driver for handling insane input data better * tag 'for-linus-6.4-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: x86/pci/xen: populate MSI sysfs entries xen/pvcalls-back: fix double frees with pvcalls_new_active_socket() xen/blkfront: Only check REQ_FUA for writes
2023-05-27Merge tag 'char-misc-6.4-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc fixes from Greg KH: "Here are some small driver fixes for 6.4-rc4. They are just two different types: - binder fixes and reverts for reported problems and regressions in the binder "driver". - coresight driver fixes for reported problems. All of these have been in linux-next for over a week with no reported problems" * tag 'char-misc-6.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: binder: fix UAF of alloc->vma in race with munmap() binder: add lockless binder_alloc_(set|get)_vma() Revert "android: binder: stop saving a pointer to the VMA" Revert "binder_alloc: add missing mmap_lock calls when using the VMA" binder: fix UAF caused by faulty buffer cleanup coresight: perf: Release Coresight path when alloc trace id failed coresight: Fix signedness bug in tmc_etr_buf_insert_barrier_packet()
2023-05-26Merge tag 'cxl-fixes-6.4-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl Pull compute express link fixes from Dan Williams: "The 'media ready' series prevents the driver from acting on bad capacity information, and it moves some checks earlier in the init sequence which impacts topics in the queue for 6.5. Additional hotplug testing uncovered a missing enable for memory decode. A debug crash fix is also included. Summary: - Stop trusting capacity data before the "media ready" indication - Add missing HDM decoder capability enable for the cold-plug case - Fix a debug message induced crash" * tag 'cxl-fixes-6.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl: cxl: Explicitly initialize resources when media is not ready cxl/port: Fix NULL pointer access in devm_cxl_add_port() cxl: Move cxl_await_media_ready() to before capacity info retrieval cxl: Wait Memory_Info_Valid before access memory related info cxl/port: Enable the HDM decoder capability for switch ports
2023-05-26Merge tag 'arm-fixes-6.4-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc Pull ARM SoC fixes from Arnd Bergmann: "There have not been a lot of fixes for for the soc tree in 6.4, but these have been sitting here for too long. For the devicetree side, there is one minor warning fix for vexpress, the rest all all for the the NXP i.MX platforms: SoC specific bugfixes for the iMX8 clocks and its USB-3.0 gadget device, as well as board specific fixes for regulators and the phy on some of the i.MX boards. The microchip risc-v and arm32 maintainers now also add a shared maintainer file entry for the arm64 parts. The remaining fixes are all for firmware drivers, addressing mistakes in the optee, scmi and ff-a firmware driver implementation, mostly in the error handling code, incorrect use of the alloc_workqueue() interface in SCMI, and compatibility with corner cases of the firmware implementation" * tag 'arm-fixes-6.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: MAINTAINERS: update arm64 Microchip entries arm64: dts: imx8: fix USB 3.0 Gadget Failure in QM & QXPB0 at super speed dt-binding: cdns,usb3: Fix cdns,on-chip-buff-size type arm64: dts: colibri-imx8x: delete adc1 and dsp arm64: dts: colibri-imx8x: fix iris pinctrl configuration arm64: dts: colibri-imx8x: move pinctrl property from SoM to eval board arm64: dts: colibri-imx8x: fix eval board pin configuration arm64: dts: imx8mp: Fix video clock parents ARM: dts: imx6qdl-mba6: Add missing pvcie-supply regulator ARM: dts: imx6ull-dhcor: Set and limit the mode for PMIC buck 1, 2 and 3 arm64: dts: imx8mn-var-som: fix PHY detection bug by adding deassert delay arm64: dts: imx8mn: Fix video clock parents firmware: arm_ffa: Set reserved/MBZ fields to zero in the memory descriptors firmware: arm_ffa: Fix FFA device names for logical partitions firmware: arm_ffa: Fix usage of partition info get count flag firmware: arm_ffa: Check if ffa_driver remove is present before executing arm64: dts: arm: add missing cache properties ARM: dts: vexpress: add missing cache properties firmware: arm_scmi: Fix incorrect alloc_workqueue() invocation optee: fix uninited async notif value
2023-05-26Merge tag 'pci-v6.4-fixes-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci Pull PCI fix from Bjorn Helgaas: - Quirk Ice Lake Root Ports to work around DPC log size issue (Mika Westerberg) * tag 'pci-v6.4-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci: PCI/DPC: Quirk PIO log size for Intel Ice Lake Root Ports
2023-05-26Merge tag 'vfio-v6.4-rc4' of https://github.com/awilliam/linux-vfioLinus Torvalds
Pull VFIO fix from Alex Williamson: - Test for and return error for invalid pfns through the pin pages interface (Yan Zhao) * tag 'vfio-v6.4-rc4' of https://github.com/awilliam/linux-vfio: vfio/type1: check pfn valid before converting to struct page
2023-05-26Merge tag 'block-6.4-2023-05-26' of git://git.kernel.dk/linuxLinus Torvalds
Pull block fixes from Jens Axboe: "A few fixes for the storage side of things: - Fix bio caching condition for passthrough IO (Anuj) - end-of-device check fix for zero sized devices (Christoph) - Update Paolo's email address - NVMe pull request via Keith with a single quirk addition - Fix regression in how wbt enablement is done (Yu) - Fix race in active queue accounting (Tian)" * tag 'block-6.4-2023-05-26' of git://git.kernel.dk/linux: NVMe: Add MAXIO 1602 to bogus nid list. block: make bio_check_eod work for zero sized devices block: fix bio-cache for passthru IO block, bfq: update Paolo's address in maintainer list blk-mq: fix race condition in active queue accounting blk-wbt: fix that wbt can't be disabled by default
2023-05-26Merge tag 'io_uring-6.4-2023-05-26' of git://git.kernel.dk/linuxLinus Torvalds
Pull io_uring fix from Jens Axboe: "Just a single fix for the conditional schedule with the SQPOLL thread, dropping the uring_lock if we do need to reschedule" * tag 'io_uring-6.4-2023-05-26' of git://git.kernel.dk/linux: io_uring: unlock sqd->lock before sq thread release CPU
2023-05-26Merge tag 'thermal-6.4-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull thermal control fix from Rafael Wysocki: "Fix a regression introduced inadvertently during the 6.3 cycle by a commit making the Intel int340x thermal driver use sysfs_emit_at() instead of scnprintf() (Srinivas Pandruvada)" * tag 'thermal-6.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: thermal: intel: int340x: Add new line for UUID display
2023-05-26Merge tag 'pm-6.4-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management fixes from Rafael Wysocki: "Fix three issues related to the ->fast_switch callback in the AMD P-state cpufreq driver (Gautham R. Shenoy and Wyes Karny)" * tag 'pm-6.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: cpufreq: amd-pstate: Update policy->cur in amd_pstate_adjust_perf() cpufreq: amd-pstate: Remove fast_switch_possible flag from active driver cpufreq: amd-pstate: Add ->fast_switch() callback
2023-05-26cxl: Explicitly initialize resources when media is not readyDave Jiang
When media is not ready do not assume that the capacity information from the identify command is valid, i.e. ->total_bytes ->partition_align_bytes ->{volatile,persistent}_only_bytes. Explicitly zero out the capacity resources and exit early. Given zero-init of those fields this patch is functionally equivalent to the prior state, but it improves readability and robustness going forward. Signed-off-by: Dave Jiang <dave.jiang@intel.com> Link: https://lore.kernel.org/r/168506118166.3004974.13523455340007852589.stgit@djiang5-mobl3 Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-05-26Merge tag 'gpio-fixes-for-v6.4-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux Pull gpio fixes from Bartosz Golaszewski: - fix incorrect output in in-tree gpio tools - fix a shell coding issue in gpio-sim selftests - correctly set the permissions for debugfs attributes exposed by gpio-mockup - fix chip name and pin count in gpio-f7188x for one of the supported models - fix numberspace pollution when using dynamically and statically allocated GPIOs together * tag 'gpio-fixes-for-v6.4-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: gpio-f7188x: fix chip name and pin count on Nuvoton chip gpiolib: fix allocation of mixed dynamic/static GPIOs gpio: mockup: Fix mode of debugfs files selftests: gpio: gpio-sim: Fix BUG: test FAILED due to recent change tools: gpio: fix debounce_period_us output of lsgpio
2023-05-26Merge tag 'for-6.4-rc3-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: - handle memory allocation error in checksumming helper (reported by syzbot) - fix lockdep splat when aborting a transaction, add NOFS protection around invalidate_inode_pages2 that could allocate with GFP_KERNEL - reduce chances to hit an ENOSPC during scrub with RAID56 profiles * tag 'for-6.4-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: use nofs when cleaning up aborted transactions btrfs: handle memory allocation failure in btrfs_csum_one_bio btrfs: scrub: try harder to mark RAID56 block groups read-only
2023-05-26Merge tag 'drm-fixes-2023-05-26' of git://anongit.freedesktop.org/drm/drmLinus Torvalds
Pull drm fixes from Dave Airlie: "This week's collection is pretty spread out, accel/qaic has a bunch of fixes, amdgpu, then lots of single fixes across a bunch of places. core: - fix drmm_mutex_init lock class mgag200: - fix gamma lut initialisation pl111: - fix FB depth on IMPD-1 framebuffer amdgpu: - Fix missing BO unlocking in KIQ error path - Avoid spurious secure display error messages - SMU13 fix - Fix an OD regression - GPU reset display IRQ warning fix - MST fix radeon: - Fix a DP regression i915: - PIPEDMC disabling fix for bigjoiner config panel: - fix aya neo air plus quirk sched: - remove redundant NULL check qaic: - fix NNC message corruption - Grab ch_lock during QAIC_ATTACH_SLICE_BO - Flush the transfer list again - Validate if BO is sliced before slicing - Validate user data before grabbing any lock - initialize ret variable to 0 - silence some uninitialized variable warnings" * tag 'drm-fixes-2023-05-26' of git://anongit.freedesktop.org/drm/drm: drm/amd/display: Have Payload Properly Created After Resume drm/amd/display: Fix warning in disabling vblank irq drm/amd/pm: Fix output of pp_od_clk_voltage drm/amd/pm: add missing NotifyPowerSource message mapping for SMU13.0.7 drm/radeon: reintroduce radeon_dp_work_func content drm/amdgpu: don't enable secure display on incompatible platforms drm:amd:amdgpu: Fix missing buffer object unlock in failure path accel/qaic: Fix NNC message corruption accel/qaic: Grab ch_lock during QAIC_ATTACH_SLICE_BO accel/qaic: Flush the transfer list again accel/qaic: Validate if BO is sliced before slicing accel/qaic: Validate user data before grabbing any lock accel/qaic: initialize ret variable to 0 drm/i915: Fix PIPEDMC disabling for a bigjoiner configuration drm: fix drmm_mutex_init() drm/sched: Remove redundant check drm: panel-orientation-quirks: Change Air's quirk to support Air Plus accel/qaic: silence some uninitialized variable warnings drm/pl111: Fix FB depth on IMPD-1 framebuffer drm/mgag200: Fix gamma lut not initialized.
2023-05-26x86: re-introduce support for ERMS copies for user space accessesLinus Torvalds
I tried to streamline our user memory copy code fairly aggressively in commit adfcf4231b8c ("x86: don't use REP_GOOD or ERMS for user memory copies"), in order to then be able to clean up the code and inline the modern FSRM case in commit 577e6a7fd50d ("x86: inline the 'rep movs' in user copies for the FSRM case"). We had reports [1] of that causing regressions earlier with blogbench, but that turned out to be a horrible benchmark for that case, and not a sufficient reason for re-instating "rep movsb" on older machines. However, now Eric Dumazet reported [2] a regression in performance that seems to be a rather more real benchmark, where due to the removal of "rep movs" a TCP stream over a 100Gbps network no longer reaches line speed. And it turns out that with the simplified the calling convention for the non-FSRM case in commit 427fda2c8a49 ("x86: improve on the non-rep 'copy_user' function"), re-introducing the ERMS case is actually fairly simple. Of course, that "fairly simple" is glossing over several missteps due to having to fight our assembler alternative code. This code really wanted to rewrite a conditional branch to have two different targets, but that made objtool sufficiently unhappy that this instead just ended up doing a choice between "jump to the unrolled loop, or use 'rep movsb' directly". Let's see if somebody finds a case where the kernel memory copies also care (see commit 68674f94ffc9: "x86: don't use REP_GOOD or ERMS for small memory copies"). But Eric does argue that the user copies are special because networking tries to copy up to 32KB at a time, if order-3 pages allocations are possible. In-kernel memory copies are typically small, unless they are the special "copy pages at a time" kind that still use "rep movs". Link: https://lore.kernel.org/lkml/202305041446.71d46724-yujie.liu@intel.com/ [1] Link: https://lore.kernel.org/lkml/CANn89iKUbyrJ=r2+_kK+sb2ZSSHifFZ7QkPLDpAtkJ8v4WUumA@mail.gmail.com/ [2] Reported-and-tested-by: Eric Dumazet <edumazet@google.com> Fixes: adfcf4231b8c ("x86: don't use REP_GOOD or ERMS for user memory copies") Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-05-26Merge tag 'nvme-6.4-2023-05-26' of git://git.infradead.org/nvme into block-6.4Jens Axboe
Pull NVMe fix from Keith: "nvme fixes for 6.4 One nvme quirk (Tatsuki)" * tag 'nvme-6.4-2023-05-26' of git://git.infradead.org/nvme: NVMe: Add MAXIO 1602 to bogus nid list.
2023-05-26NVMe: Add MAXIO 1602 to bogus nid list.Tatsuki Sugiura
HIKSEMI FUTURE M.2 SSD uses the same dummy nguid and eui64. I confirmed it with my two devices. This patch marks the controller as NVME_QUIRK_BOGUS_NID. --------------------------------------------------------- sugi@tempest:~% sudo nvme id-ctrl /dev/nvme0 NVME Identify Controller: vid : 0x1e4b ssvid : 0x1e4b sn : 30096022612 mn : HS-SSD-FUTURE 2048G fr : SN10542 rab : 0 ieee : 000000 cmic : 0 mdts : 7 cntlid : 0 ver : 0x10400 rtd3r : 0x7a120 rtd3e : 0x1e8480 oaes : 0x200 ctratt : 0x2 rrls : 0 cntrltype : 1 fguid : 00000000-0000-0000-0000-000000000000 <snip...> --------------------------------------------------------- --------------------------------------------------------- sugi@tempest:~% sudo nvme id-ns /dev/nvme0n1 NVME Identify Namespace 1: <snip...> nguid : 00000000000000000000000000000000 eui64 : 0000000000000002 lbaf 0 : ms:0 lbads:9 rp:0 (in use) --------------------------------------------------------- Signed-off-by: Tatsuki Sugiura <sugi@nemui.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Keith Busch <kbusch@kernel.org>
2023-05-26Merge tag 'ffa-fixes-6.4' of ↵Arnd Bergmann
git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/fixes Arm FF-A fixes for v6.4 Quite a few fixes to address set of assorted issues: 1. NULL pointer dereference if the ffa driver doesn't provide remove() callback as it is currently executed unconditionally 2. FF-A core probe failure on systems with v1.0 firmware as the new partition info get count flag is used unconditionally 3. Failure to register more than one logical partition or service within the same physical partition as the device name contains only VM ID which will be same for all but each will have unique UUID. 4. Rejection of certain memory interface transmissions by the receivers (secure partitions) as few MBZ fields are non-zero due to lack of explicit re-initialization of those fields * tag 'ffa-fixes-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux: firmware: arm_ffa: Set reserved/MBZ fields to zero in the memory descriptors firmware: arm_ffa: Fix FFA device names for logical partitions firmware: arm_ffa: Fix usage of partition info get count flag firmware: arm_ffa: Check if ffa_driver remove is present before executing Link: https://lore.kernel.org/r/20230509143453.1188753-1-sudeep.holla@arm.com Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2023-05-26Merge tag 'drm-misc-fixes-2023-05-24' of ↵Dave Airlie
git://anongit.freedesktop.org/drm/drm-misc into drm-fixes drm-misc-fixes for v6.4-rc4: - A few non-trivial fixes to qaic. - Fix drmm_mutex_init always using same lock class. - Fix pl111 fb depth. - Fix uninitialised gamma lut in mgag200. - Add Aya Neo Air Plus quirk. - Trivial null check removal in scheduler. Signed-off-by: Dave Airlie <airlied@redhat.com> From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/d19f748c-2c5b-8140-5b05-a8282dfef73e@linux.intel.com
2023-05-26Merge tag 'amd-drm-fixes-6.4-2023-05-24' of ↵Dave Airlie
https://gitlab.freedesktop.org/agd5f/linux into drm-fixes amd-drm-fixes-6.4-2023-05-24: amdgpu: - Fix missing BO unlocking in KIQ error path - Avoid spurious secure display error messages - SMU13 fix - Fix an OD regression - GPU reset display IRQ warning fix - MST fix radeon: - Fix a DP regression Signed-off-by: Dave Airlie <airlied@redhat.com> From: Alex Deucher <alexander.deucher@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230524211238.7749-1-alexander.deucher@amd.com
2023-05-26Merge tag 'drm-intel-fixes-2023-05-25' of ↵Dave Airlie
git://anongit.freedesktop.org/drm/drm-intel into drm-fixes PIPEDMC disabling fix for bigjoiner config Signed-off-by: Dave Airlie <airlied@redhat.com> From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/ZG9aROGyc947/J1l@jlahtine-mobl.ger.corp.intel.com
2023-05-25Merge tag '6.4-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6Linus Torvalds
Pull smb directory moves and client fixes from Steve French: "Four smb3 client fixes (three of which marked for stable) and three patches to move of fs/cifs and fs/ksmbd to a new common "fs/smb" parent directory - Move the client and server source directories to a common parent directory: fs/cifs -> fs/smb/client fs/ksmbd -> fs/smb/server fs/smbfs_common -> fs/smb/common - important readahead fix - important fix for SMB1 regression - fix for missing mount option ("mapchars") in mount API conversion - minor debugging improvement" * tag '6.4-rc3-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: smb3: move Documentation/filesystems/cifs to Documentation/filesystems/smb cifs: correct references in Documentation to old fs/cifs path smb: move client and server files to common directory fs/smb cifs: mapchars mount option ignored smb3: display debug information better for encryption cifs: fix smb1 mount regression cifs: Fix cifs_limit_bvec_subset() to correctly check the maxmimum size
2023-05-25Merge tag 'parisc-for-6.4-3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux Pull parisc architecture fixes from Helge Deller: "Quite a bunch of real bugfixes in here and most of them are tagged for backporting: A fix for cache flushing from irq context, a kprobes & kgdb breakpoint handling fix, and a fix in the alternative code patching function to take care of CPU hotplugging. parisc now provides LOCKDEP support and comes with a lightweight spinlock check. Both features helped me to find the cache flush bug. Additionally writing the AGP gatt has been fixed, the machine allows the user to reboot after a system halt and arch_sync_dma_for_cpu() has been optimized for PCXL PCUs. Summary: - Fix flush_dcache_page() for usage from irq context - Handle kprobes breakpoints only in kernel context - Handle kgdb breakpoints only in kernel context - Use num_present_cpus() in alternative patching code - Enable LOCKDEP support - Add lightweight spinlock checks - Flush AGP gatt writes and adjust gatt mask in parisc_agp_mask_memory() - Allow to reboot machine after system halt - Improve cache flushing for PCXL in arch_sync_dma_for_cpu()" * tag 'parisc-for-6.4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: Fix flush_dcache_page() for usage from irq context parisc: Handle kgdb breakpoints only in kernel context parisc: Handle kprobes breakpoints only in kernel context parisc: Allow to reboot machine after system halt parisc: Enable LOCKDEP support parisc: Add lightweight spinlock checks parisc: Use num_present_cpus() in alternative patching code parisc: Flush gatt writes and adjust gatt mask in parisc_agp_mask_memory() parisc: Improve cache flushing for PCXL in arch_sync_dma_for_cpu()
2023-05-25module: error out early on concurrent load of the same module fileLinus Torvalds
It turns out that udev under certain circumstances will concurrently try to load the same modules over-and-over excessively. This isn't a kernel bug, but it ends up affecting the kernel, to the point that under certain circumstances we can fail to boot, because the kernel uses a lot of memory to read all the module data all at once. Note that it isn't a memory leak, it's just basically a thundering herd problem happening at bootup with a lot of CPUs, with the worst cases then being pretty bad. Admittedly the worst situations are somewhat contrived: lots and lots of CPUs, not a lot of memory, and KASAN enabled to make it all slower and as such (unintentionally) exacerbate the problem. Luis explains: [1] "My best assessment of the situation is that each CPU in udev ends up triggering a load of duplicate set of modules, not just one, but *a lot*. Not sure what heuristics udev uses to load a set of modules per CPU." Petr Pavlu chimes in: [2] "My understanding is that udev workers are forked. An initial kmod context is created by the main udevd process but no sharing happens after the fork. It means that the mentioned memory pool logic doesn't really kick in. Multiple parallel load requests come from multiple udev workers, for instance, each handling an udev event for one CPU device and making the exactly same requests as all others are doing at the same time. The optimization idea would be to recognize these duplicate requests at the udevd/kmod level and converge them" Note that module loading has tried to mitigate this issue before, see for example commit 064f4536d139 ("module: avoid allocation if module is already present and ready"), which has a few ASCII graphs on memory use due to this same issue. However, while that noticed that the module was already loaded, and exited with an error early before spending any more time on setting up the module, it didn't handle the case of multiple concurrent module loads all being active - but not complete - at the same time. Yes, one of them will eventually win the race and finalize its copy, and the others will then notice that the module already exists and error out, but while this all happens, we have tons of unnecessary concurrent work being done. Again, the real fix is for udev to not do that (maybe it should use threads instead of fork, and have actual shared data structures and not cause duplicate work). That real fix is apparently not trivial. But it turns out that the kernel already has a pretty good model for dealing with concurrent access to the same file: the i_writecount of the inode. In fact, the module loading already indirectly uses 'i_writecount' , because 'kernel_file_read()' will in fact do ret = deny_write_access(file); if (ret) return ret; ... allow_write_access(file); around the read of the file data. We do not allow concurrent writes to the file, and return -ETXTBUSY if the file was open for writing at the same time as the module data is loaded from it. And the solution to the reader concurrency problem is to simply extend this "no concurrent writers" logic to simply be "exclusive access". Note that "exclusive" in this context isn't really some absolute thing: it's only exclusion from writers and from other "special readers" that do this writer denial. So we simply introduce a variation of that "deny_write_access()" logic that not only denies write access, but also requires that this is the _only_ such access that denies write access. Which means that you can't start loading a module that is already being loaded as a module by somebody else, or you will get the same -ETXTBSY error that you would get if there were writers around. [ It also means that you can't try to load a currently executing executable as a module, for the same reason: executables do that same "deny_write_access()" thing, and that's obviously where the whole ETXTBSY logic traditionally came from. This is not a problem for kernel modules, since the set of normal executable files and kernel module files is entirely disjoint. ] This new function is called "exclusive_deny_write_access()", and the implementation is trivial, in that it's just an atomic decrement of i_writecount if it was 0 before. To use that new exclusivity check, all we then do is wrap the module loading with that exclusive_deny_write_access()() / allow_write_access() pair. The actual patch is a bit bigger than that, because we want to surround not just the "load file data" part, but the whole module setup, to get maximum exclusion. So this ends up splitting up "finit_module()" into a few helper functions to make it all very clear and legible. In Luis' test-case (bringing up 255 vcpu's in a virtual machine [3]), the "wasted vmalloc" space (ie module data read into a vmalloc'ed area in order to be loaded as a module, but then discarded because somebody else loaded the same module instead) dropped from 1.8GiB to 474kB. Yes, that's gigabytes to kilobytes. It doesn't drop completely to zero, because even with this change, you can still end up having completely serial pointless module loads, where one udev process has loaded a module fully (and thus the kernel has released that exclusive lock on the module file), and then another udev process tries to load the same module again. So while we cannot fully get rid of the fundamental bug in user space, we _can_ get rid of the excessive concurrent thundering herd effect. A couple of final side notes on this all: - This tweak only affects the "finit_module()" system call, which gives the kernel a file descriptor with the module data. You can also just feed the module data as raw data from user space with "init_module()" (note the lack of 'f' at the beginning), and obviously for that case we do _not_ have any "exclusive read" logic. So if you absolutely want to do things wrong in user space, and try to load the same module multiple times, and error out only later when the kernel ends up saying "you can't load the same module name twice", you can still do that. And in fact, some distros will do exactly that, because they will uncompress the kernel module data in user space before feeding it to the kernel (mainly because they haven't started using the new kernel side decompression yet). So this is not some absolute "you can't do concurrent loads of the same module". It's literally just a very simple heuristic that will catch it early in case you try to load the exact same module file at the same time, and in that case avoid a potentially nasty situation. - There is another user of "deny_write_access()": the verity code that enables fs-verity on a file (the FS_IOC_ENABLE_VERITY ioctl). If you use fs-verity and you care about verifying the kernel modules (which does make sense), you should do it *before* loading said kernel module. That may sound obvious, but now the implementation basically requires it. Because if you try to do it concurrently, the kernel may refuse to load the module file that is being set up by the fs-verity code. - This all will obviously mean that if you insist on loading the same module in parallel, only one module load will succeed, and the others will return with an error. That was true before too, but what is different is that the -ETXTBSY error can be returned *before* the success case of another process fully loading and instantiating the module. Again, that might sound obvious, and it is indeed the whole point of the whole change: we are much quicker to notice the whole "you're already in the process of loading this module". So it's very much intentional, but it does mean that if you just spray the kernel with "finit_module()", and expect that the module is immediately loaded afterwards without checking the return value, you are doing something horribly horribly wrong. I'd like to say that that would never happen, but the whole _reason_ for this commit is that udev is currently doing something horribly horribly wrong, so ... Link: https://lore.kernel.org/all/ZEGopJ8VAYnE7LQ2@bombadil.infradead.org/ [1] Link: https://lore.kernel.org/all/23bd0ce6-ef78-1cd8-1f21-0e706a00424a@suse.com/ [2] Link: https://lore.kernel.org/lkml/ZG%2Fa+nrt4%2FAAUi5z@bombadil.infradead.org/ [3] Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Lucas De Marchi <lucas.demarchi@intel.com> Cc: Petr Pavlu <petr.pavlu@suse.com> Tested-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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