kernel/rust, branch linux-6.17.y

rust: Add -fno-isolate-erroneous-paths-dereference to bindgen_skip_c_flags

2025-11-24T09:37:28Z

[ Upstream commit fe4b3a34e9a9654d98d274218dac0270779db0ae ] It's used to work around an objtool issue since commit abb2a5572264 ("LoongArch: Add cflag -fno-isolate-erroneous-paths-dereference"), but it's then passed to bindgen and cause an error because Clang does not have this option. Fixes: abb2a5572264 ("LoongArch: Add cflag -fno-isolate-erroneous-paths-dereference") Acked-by: Miguel Ojeda Tested-by: Mingcong Bai Signed-off-by: Xi Ruoyao Signed-off-by: Huacai Chen Signed-off-by: Sasha Levin

rust: kbuild: treat `build_error` and `rustdoc` as kernel objects

2025-11-13T20:37:40Z

commit 16c43a56b79e2c3220b043236369a129d508c65a upstream. Even if normally `build_error` isn't a kernel object, it should still be treated as such so that we pass the same flags. Similarly, `rustdoc` targets are never kernel objects, but we need to treat them as such. Otherwise, starting with Rust 1.91.0 (released 2025-10-30), `rustc` will complain about missing sanitizer flags since `-Zsanitizer` is a target modifier too [1]: error: mixing `-Zsanitizer` will cause an ABI mismatch in crate `build_error` --> rust/build_error.rs:3:1 | 3 | //! Build-time error. | ^ | = help: the `-Zsanitizer` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zsanitizer` in this crate is incompatible with `-Zsanitizer=kernel-address` in dependency `core` = help: set `-Zsanitizer=kernel-address` in this crate or unset `-Zsanitizer` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=sanitizer` to silence this error Thus explicitly mark them as kernel objects. Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs). Link: https://github.com/rust-lang/rust/pull/138736 [1] Reviewed-by: Alice Ryhl Tested-by: Justin M. Forbes Link: https://patch.msgid.link/20251102212853.1505384-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman

rust: kbuild: workaround `rustdoc` doctests modifier bug

2025-11-13T20:37:39Z

commit fad472efab0a805dd939f017c5b8669a786a4bcf upstream. The `rustdoc` modifiers bug [1] was fixed in Rust 1.90.0 [2], for which we added a workaround in commit abbf9a449441 ("rust: workaround `rustdoc` target modifiers bug"). However, `rustdoc`'s doctest generation still has a similar issue [3], being fixed at [4], which does not affect us because we apply the workaround to both, and now, starting with Rust 1.91.0 (released 2025-10-30), `-Zsanitizer` is a target modifier too [5], which means we fail with: RUSTDOC TK rust/kernel/lib.rs error: mixing `-Zsanitizer` will cause an ABI mismatch in crate `kernel` --> rust/kernel/lib.rs:3:1 | 3 | //! The `kernel` crate. | ^ | = help: the `-Zsanitizer` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely = note: unset `-Zsanitizer` in this crate is incompatible with `-Zsanitizer=kernel-address` in dependency `core` = help: set `-Zsanitizer=kernel-address` in this crate or unset `-Zsanitizer` in `core` = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=sanitizer` to silence this error A simple way around is to add the sanitizer to the list in the existing workaround (especially if we had not started to pass the sanitizer flags in the previous commit, since in that case that would not be necessary). However, that still applies the workaround in more cases than necessary. Instead, only modify the doctests flags to ignore the check for sanitizers, so that it is more local (and thus the compiler keeps checking it for us in the normal `rustdoc` calls). Since the previous commit already treated the `rustdoc` calls as kernel objects, this should allow us in the future to easily remove this workaround when the time comes. By the way, the `-Cunsafe-allow-abi-mismatch` flag overwrites previous ones rather than appending, so it needs to be all done in the same flag. Moreover, unknown modifiers are rejected, and thus we have to gate based on the version too. Finally, `-Zsanitizer-cfi-normalize-integers` is not affected (in Rust 1.91.0), so it is not needed in the workaround for the moment. Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs). Link: https://github.com/rust-lang/rust/issues/144521 [1] Link: https://github.com/rust-lang/rust/pull/144523 [2] Link: https://github.com/rust-lang/rust/issues/146465 [3] Link: https://github.com/rust-lang/rust/pull/148068 [4] Link: https://github.com/rust-lang/rust/pull/138736 [5] Reviewed-by: Alice Ryhl Tested-by: Justin M. Forbes Link: https://patch.msgid.link/20251102212853.1505384-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman

rust: devres: fix private intra-doc link

2025-11-13T20:37:39Z

commit ff4d2ef3874773c9c6173b0f099372bf62252aaf upstream. The future move of pin-init to `syn` uncovers the following private intra-doc link: error: public documentation for `Devres` links to private item `Self::inner` --> rust/kernel/devres.rs:106:7 | 106 | /// [`Self::inner`] is guaranteed to be initialized and is always accessed read-only. | ^^^^^^^^^^^ this item is private | = note: this link will resolve properly if you pass `--document-private-items` = note: `-D rustdoc::private-intra-doc-links` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(rustdoc::private_intra_doc_links)]` Currently, when rendered, the link points to "nowhere" (an inexistent anchor for a "method"). Thus fix it. Cc: stable@vger.kernel.org Fixes: f5d3ef25d238 ("rust: devres: get rid of Devres' inner Arc") Acked-by: Danilo Krummrich Link: https://patch.msgid.link/20251029071406.324511-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman

rust: condvar: fix broken intra-doc link

2025-11-13T20:37:39Z

commit 09b1704f5b02c18dd02b21343530463fcfc92c54 upstream. The future move of pin-init to `syn` uncovers the following broken intra-doc link: error: unresolved link to `crate::pin_init` --> rust/kernel/sync/condvar.rs:39:40 | 39 | /// instances is with the [`pin_init`](crate::pin_init!) and [`new_condvar`] macros. | ^^^^^^^^^^^^^^^^ no item named `pin_init` in module `kernel` | = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(rustdoc::broken_intra_doc_links)]` Currently, when rendered, the link points to a literal `crate::pin_init!` URL. Thus fix it. Cc: stable@vger.kernel.org Fixes: 129e97be8e28 ("rust: pin-init: fix documentation links") Reviewed-by: Alice Ryhl Link: https://patch.msgid.link/20251029073344.349341-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman

rust: kunit: allow `cfg` on `test`s

2025-11-13T20:36:51Z

[ Upstream commit c652dc44192d96820d73a7ecd89d275ca7e4355d ] The `kunit_test` proc macro only checks for the `test` attribute immediately preceding a `fn`. If the function is disabled via a `cfg`, the generated code would result in a compile error referencing a non-existent function [1]. This collects attributes and specifically cherry-picks `cfg` attributes to be duplicated inside KUnit wrapper functions such that a test function disabled via `cfg` compiles and is marked as skipped in KUnit correctly. Link: https://lore.kernel.org/r/20250916021259.115578-1-ent3rm4n@gmail.com Link: https://lore.kernel.org/rust-for-linux/CANiq72==48=69hYiDo1321pCzgn_n1_jg=ez5UYXX91c+g5JVQ@mail.gmail.com/ [1] Closes: https://github.com/Rust-for-Linux/linux/issues/1185 Suggested-by: Miguel Ojeda Suggested-by: David Gow Signed-off-by: Kaibo Ma Reviewed-by: David Gow Signed-off-by: Shuah Khan Signed-off-by: Sasha Levin

rust: device: fix device context of Device::parent()

2025-10-29T13:10:22Z

commit cfec502b3d091ff7c24df6ccf8079470584315a0 upstream. Regardless of the DeviceContext of a device, we can't give any guarantees about the DeviceContext of its parent device. This is very subtle, since it's only caused by a simple typo, i.e. Self::from_raw(parent) which preserves the DeviceContext in this case, vs. Device::from_raw(parent) which discards the DeviceContext. (I should have noticed it doing the correct thing in auxiliary::Device subsequently, but somehow missed it.) Hence, fix both Device::parent() and auxiliary::Device::parent(). Cc: stable@vger.kernel.org Fixes: a4c9f71e3440 ("rust: device: implement Device::parent()") Reviewed-by: Alice Ryhl Reviewed-by: Alexandre Courbot Acked-by: Greg Kroah-Hartman Signed-off-by: Danilo Krummrich Signed-off-by: Greg Kroah-Hartman

rust: cpufreq: fix formatting

2025-10-23T14:24:38Z

[ Upstream commit 32f072d9eaf9c31c2b0527a4a3370570a731e3cc ] We do our best to keep the repository `rustfmt`-clean, thus run the tool to fix the formatting issue. Link: https://docs.kernel.org/rust/coding-guidelines.html#style-formatting Link: https://rust-for-linux.com/contributing#submit-checklist-addendum Fixes: f97aef092e19 ("cpufreq: Make drivers using CPUFREQ_ETERNAL specify transition latency") Acked-by: Viresh Kumar Reviewed-by: Benno Lossin Signed-off-by: Miguel Ojeda Signed-off-by: Sasha Levin

cpufreq: Make drivers using CPUFREQ_ETERNAL specify transition latency

2025-10-19T14:37:00Z

commit f97aef092e199c10a3da96ae79b571edd5362faa upstream. Commit a755d0e2d41b ("cpufreq: Honour transition_latency over transition_delay_us") caused platforms where cpuinfo.transition_latency is CPUFREQ_ETERNAL to get a very large transition latency whereas previously it had been capped at 10 ms (and later at 2 ms). This led to a user-observable regression between 6.6 and 6.12 as described by Shawn: "The dbs sampling_rate was 10000 us on 6.6 and suddently becomes 6442450 us (4294967295 / 1000 * 1.5) on 6.12 for these platforms because the default transition delay was dropped [...]. It slows down dbs governor's reacting to CPU loading change dramatically. Also, as transition_delay_us is used by schedutil governor as rate_limit_us, it shows a negative impact on device idle power consumption, because the device gets slightly less time in the lowest OPP." Evidently, the expectation of the drivers using CPUFREQ_ETERNAL as cpuinfo.transition_latency was that it would be capped by the core, but they may as well return a default transition latency value instead of CPUFREQ_ETERNAL and the core need not do anything with it. Accordingly, introduce CPUFREQ_DEFAULT_TRANSITION_LATENCY_NS and make all of the drivers in question use it instead of CPUFREQ_ETERNAL. Also update the related Rust binding. Fixes: a755d0e2d41b ("cpufreq: Honour transition_latency over transition_delay_us") Closes: https://lore.kernel.org/linux-pm/20250922125929.453444-1-shawnguo2@yeah.net/ Reported-by: Shawn Guo Reviewed-by: Mario Limonciello (AMD) Reviewed-by: Jie Zhan Acked-by: Viresh Kumar Cc: 6.6+ # 6.6+ Signed-off-by: Rafael J. Wysocki Link: https://patch.msgid.link/2264949.irdbgypaU6@rafael.j.wysocki [ rjw: Fix typo in new symbol name, drop redundant type cast from Rust binding ] Tested-by: Shawn Guo # with cpufreq-dt driver Reviewed-by: Qais Yousef Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

mm/ksm: fix flag-dropping behavior in ksm_madvise

2025-10-15T10:04:19Z

commit f04aad36a07cc17b7a5d5b9a2d386ce6fae63e93 upstream. syzkaller discovered the following crash: (kernel BUG) [ 44.607039] ------------[ cut here ]------------ [ 44.607422] kernel BUG at mm/userfaultfd.c:2067! [ 44.608148] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI [ 44.608814] CPU: 1 UID: 0 PID: 2475 Comm: reproducer Not tainted 6.16.0-rc6 #1 PREEMPT(none) [ 44.609635] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 44.610695] RIP: 0010:userfaultfd_release_all+0x3a8/0x460 [ 44.617726] Call Trace: [ 44.617926] [ 44.619284] userfaultfd_release+0xef/0x1b0 [ 44.620976] __fput+0x3f9/0xb60 [ 44.621240] fput_close_sync+0x110/0x210 [ 44.622222] __x64_sys_close+0x8f/0x120 [ 44.622530] do_syscall_64+0x5b/0x2f0 [ 44.622840] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 44.623244] RIP: 0033:0x7f365bb3f227 Kernel panics because it detects UFFD inconsistency during userfaultfd_release_all(). Specifically, a VMA which has a valid pointer to vma->vm_userfaultfd_ctx, but no UFFD flags in vma->vm_flags. The inconsistency is caused in ksm_madvise(): when user calls madvise() with MADV_UNMEARGEABLE on a VMA that is registered for UFFD in MINOR mode, it accidentally clears all flags stored in the upper 32 bits of vma->vm_flags. Assuming x86_64 kernel build, unsigned long is 64-bit and unsigned int and int are 32-bit wide. This setup causes the following mishap during the &= ~VM_MERGEABLE assignment. VM_MERGEABLE is a 32-bit constant of type unsigned int, 0x8000'0000. After ~ is applied, it becomes 0x7fff'ffff unsigned int, which is then promoted to unsigned long before the & operation. This promotion fills upper 32 bits with leading 0s, as we're doing unsigned conversion (and even for a signed conversion, this wouldn't help as the leading bit is 0). & operation thus ends up AND-ing vm_flags with 0x0000'0000'7fff'ffff instead of intended 0xffff'ffff'7fff'ffff and hence accidentally clears the upper 32-bits of its value. Fix it by changing `VM_MERGEABLE` constant to unsigned long, using the BIT() macro. Note: other VM_* flags are not affected: This only happens to the VM_MERGEABLE flag, as the other VM_* flags are all constants of type int and after ~ operation, they end up with leading 1 and are thus converted to unsigned long with leading 1s. Note 2: After commit 31defc3b01d9 ("userfaultfd: remove (VM_)BUG_ON()s"), this is no longer a kernel BUG, but a WARNING at the same place: [ 45.595973] WARNING: CPU: 1 PID: 2474 at mm/userfaultfd.c:2067 but the root-cause (flag-drop) remains the same. [akpm@linux-foundation.org: rust bindgen wasn't able to handle BIT(), from Miguel] Link: https://lore.kernel.org/oe-kbuild-all/202510030449.VfSaAjvd-lkp@intel.com/ Link: https://lkml.kernel.org/r/20251001090353.57523-2-acsjakub@amazon.de Fixes: 7677f7fd8be7 ("userfaultfd: add minor fault registration mode") Signed-off-by: Jakub Acs Signed-off-by: Miguel Ojeda Acked-by: David Hildenbrand Acked-by: SeongJae Park Tested-by: Alice Ryhl Tested-by: Miguel Ojeda Cc: Xu Xin Cc: Chengming Zhou Cc: Peter Xu Cc: Axel Rasmussen Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman