kernel/lib/vsprintf.c, branch linux-6.15.y

Merge tag 'printk-for-6.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

2025-04-02T17:05:55Z

Pull more printk updates from Petr Mladek: - Silence warnings about candidates for ‘gnu_print’ format attribute * tag 'printk-for-6.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: vsnprintf: Silence false positive GCC warning for va_format() vsnprintf: Drop unused const char fmt * in va_format() vsnprintf: Mark binary printing functions with __printf() attribute tracing: Mark binary printing functions with __printf() attribute seq_file: Mark binary printing functions with __printf() attribute seq_buf: Mark binary printing functions with __printf() attribute

Merge tag 'rust-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux

2025-03-31T00:03:26Z

Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Extract the 'pin-init' API from the 'kernel' crate and make it into a standalone crate. In order to do this, the contents are rearranged so that they can easily be kept in sync with the version maintained out-of-tree that other projects have started to use too (or plan to, like QEMU). This will reduce the maintenance burden for Benno, who will now have his own sub-tree, and will simplify future expected changes like the move to use 'syn' to simplify the implementation. - Add '#[test]'-like support based on KUnit. We already had doctests support based on KUnit, which takes the examples in our Rust documentation and runs them under KUnit. Now, we are adding the beginning of the support for "normal" tests, similar to those the '#[test]' tests in userspace Rust. For instance: #[kunit_tests(my_suite)] mod tests { #[test] fn my_test() { assert_eq!(1 + 1, 2); } } Unlike with doctests, the 'assert*!'s do not map to the KUnit assertion APIs yet. - Check Rust signatures at compile time for functions called from C by name. In particular, introduce a new '#[export]' macro that can be placed in the Rust function definition. It will ensure that the function declaration on the C side matches the signature on the Rust function: #[export] pub unsafe extern "C" fn my_function(a: u8, b: i32) -> usize { // ... } The macro essentially forces the compiler to compare the types of the actual Rust function and the 'bindgen'-processed C signature. These cases are rare so far. In the future, we may consider introducing another tool, 'cbindgen', to generate C headers automatically. Even then, having these functions explicitly marked may be a good idea anyway. - Enable the 'raw_ref_op' Rust feature: it is already stable, and allows us to use the new '&raw' syntax, avoiding a couple macros. After everyone has migrated, we will disallow the macros. - Pass the correct target to 'bindgen' on Usermode Linux. - Fix 'rusttest' build in macOS. 'kernel' crate: - New 'hrtimer' module: add support for setting up intrusive timers without allocating when starting the timer. Add support for 'Pin>', 'Arc<_>', 'Pin<&_>' and 'Pin<&mut _>' as pointer types for use with timer callbacks. Add support for setting clock source and timer mode. - New 'dma' module: add a simple DMA coherent allocator abstraction and a test sample driver. - 'list' module: make the linked list 'Cursor' point between elements, rather than at an element, which is more convenient to us and allows for cursors to empty lists; and document it with examples of how to perform common operations with the provided methods. - 'str' module: implement a few traits for 'BStr' as well as the 'strip_prefix()' method. - 'sync' module: add 'Arc::as_ptr'. - 'alloc' module: add 'Box::into_pin'. - 'error' module: extend the 'Result' documentation, including a few examples on different ways of handling errors, a warning about using methods that may panic, and links to external documentation. 'macros' crate: - 'module' macro: add the 'authors' key to support multiple authors. The original key will be kept until everyone has migrated. Documentation: - Add error handling sections. MAINTAINERS: - Add Danilo Krummrich as reviewer of the Rust "subsystem". - Add 'RUST [PIN-INIT]' entry with Benno Lossin as maintainer. It has its own sub-tree. - Add sub-tree for 'RUST [ALLOC]'. - Add 'DMA MAPPING HELPERS DEVICE DRIVER API [RUST]' entry with Abdiel Janulgue as primary maintainer. It will go through the sub-tree of the 'RUST [ALLOC]' entry. - Add 'HIGH-RESOLUTION TIMERS [RUST]' entry with Andreas Hindborg as maintainer. It has its own sub-tree. And a few other cleanups and improvements" * tag 'rust-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (71 commits) rust: dma: add `Send` implementation for `CoherentAllocation` rust: macros: fix `make rusttest` build on macOS rust: block: refactor to use `&raw mut` rust: enable `raw_ref_op` feature rust: uaccess: name the correct function rust: rbtree: fix comments referring to Box instead of KBox rust: hrtimer: add maintainer entry rust: hrtimer: add clocksource selection through `ClockId` rust: hrtimer: add `HrTimerMode` rust: hrtimer: implement `HrTimerPointer` for `Pin>` rust: alloc: add `Box::into_pin` rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&mut T>` rust: hrtimer: implement `UnsafeHrTimerPointer` for `Pin<&T>` rust: hrtimer: add `hrtimer::ScopedHrTimerPointer` rust: hrtimer: add `UnsafeHrTimerPointer` rust: hrtimer: allow timer restart from timer handler rust: str: implement `strip_prefix` for `BStr` rust: str: implement `AsRef` for `[u8]` and `BStr` rust: str: implement `Index` for `BStr` rust: str: implement `PartialEq` for `BStr` ...

vsnprintf: Silence false positive GCC warning for va_format()

2025-03-28T12:37:11Z

va_format() is using vsnprintf(), and GCC compiler (Debian 14.2.0-17) is not happy about this: lib/vsprintf.c:1704:9: error: function ‘va_format’ might be a candidate for ‘gnu_print ’ format attribute [-Werror=suggest-attribute=format] Fix the compilation errors (`make W=1` when CONFIG_WERROR=y, which is default) by silencing the false positive GCC warning. Suggested-by: Rasmus Villemoes Signed-off-by: Andy Shevchenko Reviewed-by: Kees Cook Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20250321144822.324050-7-andriy.shevchenko@linux.intel.com Signed-off-by: Petr Mladek

vsnprintf: Drop unused const char fmt * in va_format()

2025-03-28T12:37:11Z

va_format() doesn't use original formatting string, drop that argument as it's done elsewhere in similar cases. Suggested-by: Rasmus Villemoes Signed-off-by: Andy Shevchenko Reviewed-by: Kees Cook Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20250321144822.324050-6-andriy.shevchenko@linux.intel.com Signed-off-by: Petr Mladek

print: use new #[export] macro for rust_fmt_argument

2025-03-09T19:52:46Z

This moves the rust_fmt_argument function over to use the new #[export] macro, which will verify at compile-time that the function signature matches what is in the header file. Reviewed-by: Andreas Hindborg Reviewed-by: Tamir Duberstein Acked-by: Greg Kroah-Hartman Signed-off-by: Alice Ryhl Acked-by: Petr Mladek Link: https://lore.kernel.org/r/20250303-export-macro-v3-4-41fbad85a27f@google.com [ Removed period as requested by Andy. - Miguel ] Signed-off-by: Miguel Ojeda

rust: fix signature of rust_fmt_argument

2025-03-09T19:52:46Z

Without this change, the rest of this series will emit the following error message: error[E0308]: `if` and `else` have incompatible types --> /rust/kernel/print.rs:22:22 | 21 | #[export] | --------- expected because of this 22 | unsafe extern "C" fn rust_fmt_argument( | ^^^^^^^^^^^^^^^^^ expected `u8`, found `i8` | = note: expected fn item `unsafe extern "C" fn(*mut u8, *mut u8, *mut c_void) -> *mut u8 {bindings::rust_fmt_argument}` found fn item `unsafe extern "C" fn(*mut i8, *mut i8, *const c_void) -> *mut i8 {print::rust_fmt_argument}` The error may be different depending on the architecture. To fix this, change the void pointer argument to use a const pointer, and change the imports to use crate::ffi instead of core::ffi for integer types. Fixes: 787983da7718 ("vsprintf: add new `%pA` format specifier") Reviewed-by: Tamir Duberstein Acked-by: Greg Kroah-Hartman Signed-off-by: Alice Ryhl Acked-by: Petr Mladek Link: https://lore.kernel.org/r/20250303-export-macro-v3-1-41fbad85a27f@google.com Signed-off-by: Miguel Ojeda

vsprintf: add simple_strntoul

2025-03-08T11:13:25Z

cpio extraction currently does a memcpy to ensure that the archive hex fields are null terminated for simple_strtoul(). simple_strntoul() will allow us to avoid the memcpy. Signed-off-by: David Disseldorp Link: https://lore.kernel.org/r/20250304061020.9815-4-ddiss@suse.de Signed-off-by: Christian Brauner

vsnprintf: fix the number base for non-numeric formats

2025-01-13T16:23:28Z

Commit 8d4826cc8a8a ("vsnprintf: collapse the number format state into one single state") changed the format specification decoding to be a bit more straightforward but in the process ended up also resetting the number base to zero for formats that aren't clearly numerical. Now, the number base obviously doesn't matter for something like '%s', so this wasn't all that obvious. But some of our specialized pointer extension formatting (ie, things like "print out IPv6 address") did up depending on the default base-10 setting, and when they then tried to print out numbers in "base zero", things didn't work out so well. Most pointer formatting (including things like the default raw hex value conversion) didn't have this issue, because they used helpers that explicitly set the base. Reported-and-tested-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202501131352.e226f995-lkp@intel.com Fixes: 8d4826cc8a8a ("vsnprintf: collapse the number format state into one single state") Signed-off-by: Linus Torvalds

vsnprintf: fix up kerneldoc for argument name changes

2025-01-06T14:31:11Z

Stephen Rothwell reports that I missed fixing up the documentation when the argument names changed in commit 938df695e98d ("vsprintf: associate the format state with the format pointer"), resulting in htmldoc warnings like lib/vsprintf.c:2760: warning: Function parameter or struct member 'fmt_str' not described in 'vsnprintf' lib/vsprintf.c:2760: warning: Excess function parameter 'fmt' description in 'vsnprintf' ... which I didn't notice because the doc build takes longer than the whole "real" kernel build for me, so I never bother (and judging by the other warnings, pretty much nobody else does either). I guess the bigger issues won't be fixed until the doc build is much faster (narrator: "That isn's in the cards") but at least linux-next finds the new cases. Reported-by: Stephen Rothwell Fixes: 938df695e98d ("vsprintf: associate the format state with the format pointer") Signed-off-by: Linus Torvalds

vsprintf: don't make the 'binary' version pack small integer arguments

2024-12-23T19:52:34Z

The strange vbin_printf / bstr_printf interface used to save one- and two-byte printf numerical arguments into their packed format. That's more than a bit strange since the argument buffer is supposed to be an array of 'u32' words, and it's also very different from how the source of the data (varargs) work - which always do the normal integer type conversions, so 'char' and 'short' are always passed as int-sized anyway. This odd packing causes extra code complexity, and it really isn't worth it, since the space savings are simply not there: it only happens for formats like '%hd' (short) and '%hhd' (char), which are very rare indeed. In fact, the only other user of this interface seems to be the bpf helper code (bpf_bprintf_prepare()), and Alexei points out that that case doesn't support those truncated integer formatting options at all in the first place. As a result, bpf_bprintf_prepare() doesn't need any changes for this, and TRACE_BPRINT uses 'vbin_printf()' -> 'bstr_printf()' for the formatting and hopefully doesn't expose the odd packing any other way (knock wood). Link: https://lore.kernel.org/all/CAADnVQJy65oOubjxM-378O3wDfhuwg8TGa9hc-cTv6NmmUSykQ@mail.gmail.com/ Signed-off-by: Linus Torvalds