linux-stable.git/tools/objtool/check.c, branch linux-6.15.y

objtool/rust: add one more `noreturn` Rust function for Rust 1.89.0

2025-07-24T06:58:25+00:00

commit aa7b65c2a29e8b07057b13624102c6810597c0d5 upstream.

Starting with Rust 1.89.0 (expected 2025-08-07), under
`CONFIG_RUST_DEBUG_ASSERTIONS=y`, `objtool` may report:

    rust/kernel.o: warning: objtool: _R..._6kernel4pageNtB5_4Page8read_raw()
    falls through to next function _R..._6kernel4pageNtB5_4Page9write_raw()

(and many others) due to calls to the `noreturn` symbol:

    core::panicking::panic_nounwind_fmt

Thus add the mangled one to the list so that `objtool` knows it is
actually `noreturn`.

See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions")
for more details.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Cc: Josh Poimboeuf 
Cc: Peter Zijlstra 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20250712160103.1244945-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda 
Signed-off-by: Greg Kroah-Hartman

objtool: Add missing endian conversion to read_annotate()

2025-07-17T16:43:38+00:00

[ Upstream commit ccdd09e0fc0d5ce6dfc8360f0c88da9a5045b6ea ]

Trying to compile an x86 kernel on big endian results in this error:

net/ipv4/netfilter/iptable_nat.o: warning: objtool: iptable_nat_table_init+0x150: Unknown annotation type: 50331648
make[5]: *** [scripts/Makefile.build:287: net/ipv4/netfilter/iptable_nat.o] Error 255

Reason is a missing endian conversion in read_annotate().
Add the missing conversion to fix this.

Fixes: 2116b349e29a ("objtool: Generic annotation infrastructure")
Signed-off-by: Heiko Carstens 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20250630131230.4130185-1-hca@linux.ibm.com
Signed-off-by: Sasha Levin

objtool/rust: relax slice condition to cover more `noreturn` Rust functions

2025-06-19T13:41:02+00:00

commit cbeaa41dfe26b72639141e87183cb23e00d4b0dd upstream.

Developers are indeed hitting other of the `noreturn` slice symbols in
Nova [1], thus relax the last check in the list so that we catch all of
them, i.e.

    *_4core5slice5index22slice_index_order_fail
    *_4core5slice5index24slice_end_index_len_fail
    *_4core5slice5index26slice_start_index_len_fail
    *_4core5slice5index29slice_end_index_overflow_fail
    *_4core5slice5index31slice_start_index_overflow_fail

These all exist since at least Rust 1.78.0, thus backport it too.

See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions")
for more details.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later.
Cc: John Hubbard 
Cc: Timur Tabi 
Cc: Kane York 
Cc: Josh Poimboeuf 
Cc: Peter Zijlstra 
Reported-by: Joel Fernandes 
Fixes: 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions")
Closes: https://lore.kernel.org/rust-for-linux/20250513180757.GA1295002@joelnvbox/ [1]
Tested-by: Joel Fernandes 
Link: https://lore.kernel.org/r/20250520185555.825242-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda 
Signed-off-by: Greg Kroah-Hartman

objtool/rust: add one more `noreturn` Rust function for Rust 1.87.0

2025-05-06T22:08:51+00:00

Starting with Rust 1.87.0 (expected 2025-05-15), `objtool` may report:

    rust/core.o: warning: objtool: _R..._4core9panicking9panic_fmt() falls
    through to next function _R..._4core9panicking18panic_nounwind_fmt()

    rust/core.o: warning: objtool: _R..._4core9panicking18panic_nounwind_fmt()
    falls through to next function _R..._4core9panicking5panic()

The reason is that `rust_begin_unwind` is now mangled:

    _R..._7___rustc17rust_begin_unwind

Thus add the mangled one to the list so that `objtool` knows it is
actually `noreturn`.

See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions")
for more details.

Alternatively, we could remove the fixed one in `noreturn.h` and relax
this test to cover both, but it seems best to be strict as long as we can.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Cc: Josh Poimboeuf 
Cc: Peter Zijlstra 
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20250502140237.1659624-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda

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

2025-04-19T17:02:43+00:00

Pull rust fixes from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Fix missing KASAN LLVM flags on first build (and fix spurious
     rebuilds) by skipping '--target'

   - Fix Make < 4.3 build error by using '$(pound)'

   - Fix UML build error by removing 'volatile' qualifier from io
     helpers

   - Fix UML build error by adding 'dma_{alloc,free}_attrs()' helpers

   - Clean gendwarfksyms warnings by avoiding to export '__pfx' symbols

   - Clean objtool warning by adding a new 'noreturn' function for
     1.86.0

   - Disable 'needless_continue' Clippy lint due to new 1.86.0 warnings

   - Add missing 'ffi' crate to 'generate_rust_analyzer.py'

  'pin-init' crate:

   - Import a couple fixes from upstream"

* tag 'rust-fixes-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux:
  rust: helpers: Add dma_alloc_attrs() and dma_free_attrs()
  rust: helpers: Remove volatile qualifier from io helpers
  rust: kbuild: use `pound` to support GNU Make < 4.3
  objtool/rust: add one more `noreturn` Rust function for Rust 1.86.0
  rust: kasan/kbuild: fix missing flags on first build
  rust: disable `clippy::needless_continue`
  rust: kbuild: Don't export __pfx symbols
  rust: pin-init: use Markdown autolinks in Rust comments
  rust: pin-init: alloc: restrict `impl ZeroableOption` for `Box` to `T: Sized`
  scripts: generate_rust_analyzer: Add ffi crate

objtool/rust: add one more `noreturn` Rust function for Rust 1.86.0

2025-04-14T15:02:49+00:00

Starting with Rust 1.86.0 (see upstream commit b151b513ba2b ("Insert null
checks for pointer dereferences when debug assertions are enabled") [1]),
under some kernel configurations with `CONFIG_RUST_DEBUG_ASSERTIONS=y`,
one may trigger a new `objtool` warning:

    rust/kernel.o: warning: objtool: _R..._6kernel9workqueue6system()
    falls through to next function _R...9workqueue14system_highpri()

due to a call to the `noreturn` symbol:

    core::panicking::panic_null_pointer_dereference

Thus add it to the list so that `objtool` knows it is actually `noreturn`.

See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions")
for more details.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Fixes: 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions")
Link: https://github.com/rust-lang/rust/commit/b151b513ba2b65c7506ec1a80f2712bbd09154d1 [1]
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20250413002338.1741593-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda

objtool: Remove ANNOTATE_IGNORE_ALTERNATIVE from CLAC/STAC

2025-04-08T20:03:51+00:00

ANNOTATE_IGNORE_ALTERNATIVE adds additional noise to the code generated
by CLAC/STAC alternatives, hurting readability for those whose read
uaccess-related code generation on a regular basis.

Remove the annotation specifically for the "NOP patched with CLAC/STAC"
case in favor of a manual check.

Leave the other uses of that annotation in place as they're less common
and more difficult to detect.

Suggested-by: Linus Torvalds 
Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Acked-by: Linus Torvalds 
Link: https://lore.kernel.org/r/fc972ba4995d826fcfb8d02733a14be8d670900b.1744098446.git.jpoimboe@kernel.org

objtool, xen: Fix INSN_SYSCALL / INSN_SYSRET semantics

2025-04-08T07:14:12+00:00

Objtool uses an arbitrary rule for INSN_SYSCALL and INSN_SYSRET that
almost works by accident: if it's in a function, control flow continues
after the instruction, otherwise it terminates.

That behavior should instead be based on the semantics of the underlying
instruction.  Change INSN_SYSCALL to always preserve control flow and
INSN_SYSRET to always terminate it.

The changed semantic for INSN_SYSCALL requires a tweak to the
!CONFIG_IA32_EMULATION version of xen_entry_SYSCALL_compat().  In Xen,
SYSCALL is a hypercall which usually returns.  But in this case it's a
hypercall to IRET which doesn't return.  Add UD2 to tell objtool to
terminate control flow, and to prevent undefined behavior at runtime.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Reviewed-by: Juergen Gross  # for the Xen part
Cc: Linus Torvalds 
Link: https://lore.kernel.org/r/19453dfe9a0431b7f016e9dc16d031cad3812a50.1744095216.git.jpoimboe@kernel.org

objtool: Stop UNRET validation on UD2

2025-04-08T07:14:11+00:00

In preparation for simplifying INSN_SYSCALL, make validate_unret()
terminate control flow on UD2 just like validate_branch() already does.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Cc: Linus Torvalds 
Link: https://lore.kernel.org/r/ce841269e7e28c8b7f32064464a9821034d724ff.1744095216.git.jpoimboe@kernel.org

objtool: Split INSN_CONTEXT_SWITCH into INSN_SYSCALL and INSN_SYSRET

2025-04-08T07:14:11+00:00

INSN_CONTEXT_SWITCH is ambiguous.  It can represent both call semantics
(SYSCALL, SYSENTER) and return semantics (SYSRET, IRET, RETS, RETU).
Those differ significantly: calls preserve control flow whereas returns
terminate it.

Objtool uses an arbitrary rule for INSN_CONTEXT_SWITCH that almost works
by accident: if in a function, keep going; otherwise stop.  It should
instead be based on the semantics of the underlying instruction.

In preparation for improving that, split INSN_CONTEXT_SWITCH into
INSN_SYCALL and INSN_SYSRET.

No functional change.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Ingo Molnar 
Cc: Linus Torvalds 
Link: https://lore.kernel.org/r/19a76c74d2c051d3bc9a775823cafc65ad267a7a.1744095216.git.jpoimboe@kernel.org