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3 daysobjtool: Handle Clang RSP musical chairsJosh Poimboeuf1-0/+14
[ Upstream commit 7fdaa640c810cb42090a182c33f905bcc47a616a ] For no apparent reason (possibly related to CONFIG_KMSAN), Clang can randomly pass the value of RSP to other registers and then back again to RSP. Handle that accordingly. Fixes the following warnings: drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: undefined stack state drivers/input/misc/uinput.o: warning: objtool: uinput_str_to_user+0x165: unknown CFA base reg -1 Reported-by: Arnd Bergmann <arnd@arndb.de> Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com Link: https://patch.msgid.link/240e6a172cc73292499334a3724d02ccb3247fc7.1772818491.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-19objtool: Fix another stack overflow in validate_branch()Josh Poimboeuf1-5/+5
[ Upstream commit 9a73f085dc91980ab7fcc5e9716f4449424b3b59 ] The insn state is getting saved on the stack twice for each recursive iteration. No need for that, once is enough. Fixes the following reported stack overflow: drivers/scsi/qla2xxx/qla_dbg.o: error: SIGSEGV: objtool stack overflow! Segmentation fault Fixes: 70589843b36f ("objtool: Add option to trace function validation") Reported-by: Arnd Bergmann <arnd@arndb.de> Closes: https://lore.kernel.org/90956545-2066-46e3-b547-10c884582eb0@app.fastmail.com Link: https://patch.msgid.link/8b97f62d083457f3b0a29a424275f7957dd3372f.1772821683.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04objtool/rust: add one more `noreturn` Rust functionMiguel Ojeda1-1/+2
[ Upstream commit c431b00ca6afc5da3133636ecc34ee7edd38d6cc ] `objtool` with Rust 1.84.0 reports: rust/kernel.o: error: objtool: _RNvXNtNtCsaRPFapPOzLs_6kernel3str9parse_intaNtNtB2_7private12FromStrRadix14from_str_radix() falls through to next function _RNvXNtNtCsaRPFapPOzLs_6kernel3str9parse_intaNtNtB2_7private12FromStrRadix16from_u64_negated() This is very similar to commit c18f35e49049 ("objtool/rust: add one more `noreturn` Rust function"), which added `from_ascii_radix_panic` for Rust 1.86.0, except that Rust 1.84.0 ends up needing `from_str_radix_panic`. Thus add it to the list to fix the warning. Cc: FUJITA Tomonori <fujita.tomonori@gmail.com> Fixes: 51d9ee90ea90 ("rust: str: add radix prefixed integer parsing functions") Reported-by: Alice Ryhl <aliceryhl@google.com> Link: https://rust-for-linux.zulipchat.com/#narrow/channel/291565/topic/x/with/572427627 Tested-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20260206204336.38462-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-02-07Merge tag 'objtool-urgent-2026-02-07' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool fixes from Ingo Molnar:: - Bump up the Clang minimum version requirements for livepatch builds, due to Clang assembler section handling bugs causing silent miscompilations - Strip livepatching symbol artifacts from non-livepatch modules - Fix livepatch build warnings when certain Clang LTO options are enabled - Fix livepatch build error when CONFIG_MEM_ALLOC_PROFILING_DEBUG=y * tag 'objtool-urgent-2026-02-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: objtool/klp: Fix unexported static call key access for manually built livepatch modules objtool/klp: Fix symbol correlation for orphaned local symbols livepatch: Free klp_{object,func}_ext data after initialization livepatch: Fix having __klp_objects relics in non-livepatch modules livepatch/klp-build: Require Clang assembler >= 20
2026-02-05objtool/klp: Fix unexported static call key access for manually built ↵Josh Poimboeuf1-1/+1
livepatch modules Enabling CONFIG_MEM_ALLOC_PROFILING_DEBUG with CONFIG_SAMPLE_LIVEPATCH results in the following error: samples/livepatch/livepatch-shadow-fix1.o: error: objtool: static_call: can't find static_call_key symbol: __SCK__WARN_trap This is caused an extra file->klp sanity check which was added by commit 164c9201e1da ("objtool: Add base objtool support for livepatch modules"). That check was intended to ensure that livepatch modules built with klp-build always have full access to their static call keys. However, it failed to account for the fact that manually built livepatch modules (i.e., not built with klp-build) might need access to unexported static call keys, for which read-only access is typically allowed for modules. While the livepatch-shadow-fix1 module doesn't explicitly use any static calls, it does have a memory allocation, which can cause CONFIG_MEM_ALLOC_PROFILING_DEBUG to insert a WARN() call. And WARN() is now an unexported static call as of commit 860238af7a33 ("x86_64/bug: Inline the UD1"). Fix it by removing the overzealous file->klp check, restoring the original behavior for manually built livepatch modules. Fixes: 164c9201e1da ("objtool: Add base objtool support for livepatch modules") Reported-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Song Liu <song@kernel.org> Tested-by: Arnd Bergmann <arnd@arndb.de> Link: https://patch.msgid.link/0bd3ae9a53c3d743417fe842b740a7720e2bcd1c.1770058775.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-02-05livepatch: Free klp_{object,func}_ext data after initializationPetr Pavlu1-1/+1
The klp_object_ext and klp_func_ext data, which are stored in the __klp_objects and __klp_funcs sections, respectively, are not needed after they are used to create the actual klp_object and klp_func instances. This operation is implemented by the init function in scripts/livepatch/init.c. Prefix the two sections with ".init" so they are freed after the module is initializated. Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Aaron Tomlin <atomlin@atomlin.com> Link: https://patch.msgid.link/20260123102825.3521961-3-petr.pavlu@suse.com Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2026-01-05objtool/rust: add one more `noreturn` Rust functionFUJITA Tomonori1-1/+2
Fix the following warning: rust/kernel.o: warning: objtool: _RNvXNtNtCs1ewLyjEZ7Le_6kernel3str9parse_intaNtNtB2_7private12FromStrRadix14from_str_radix() falls through to next function _RNvXNtNtCs1ewLyjEZ7Le_6kernel3str9parse_intaNtNtB2_7private12FromStrRadix16from_u64_negated() The commit 51d9ee90ea90 ("rust: str: add radix prefixed integer parsing functions") introduces u64::from_str_radix(), whose implementation contains a panic path for out-of-range radix values. The panic helper is core::num::from_ascii_radix_panic(). Note that radix is derived from strip_radix() here and is always within the valid range, so kernel never panics. Fixes: 51d9ee90ea90 ("rust: str: add radix prefixed integer parsing functions") Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20251223113538.1016078-1-fujita.tomonori@gmail.com [ Reworded typo. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-12-02objtool: Fix stack overflow in validate_branch()Josh Poimboeuf1-14/+13
On an allmodconfig kernel compiled with Clang, objtool is segfaulting in drivers/scsi/qla2xxx/qla2xxx.o due to a stack overflow in validate_branch(). Due in part to KASAN being enabled, the qla2xxx code has a large number of conditional jumps, causing objtool to go quite deep in its recursion. By far the biggest offender of stack usage is the recently added 'prev_state' stack variable in validate_insn(), coming in at 328 bytes. Move that variable (and its tracing usage) to handle_insn_ops() and make handle_insn_ops() noinline to keep its stack frame outside the recursive call chain. Reported-by: Nathan Chancellor <nathan@kernel.org> Fixes: fcb268b47a2f ("objtool: Trace instruction state changes during function validation") Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://patch.msgid.link/21bb161c23ca0d8c942a960505c0d327ca2dc7dc.1764691895.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/20251201202329.GA3225984@ax162
2025-11-21objtool: Provide access to feature and flags of group alternativesAlexandre Chartre1-0/+2
Each alternative of a group alternative depends on a specific feature and flags. Provide access to the feature/flags for each alternative as an attribute (feature) in struct alt_group. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-26-alexandre.chartre@oracle.com
2025-11-21objtool: Preserve alternatives orderAlexandre Chartre1-2/+14
Preserve the order in which alternatives are defined. Currently objtool stores alternatives in a list in reverse order. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-19-alexandre.chartre@oracle.com
2025-11-21objtool: Add the --disas=<function-pattern> actionAlexandre Chartre1-17/+21
Add the --disas=<function-pattern> actions to disassemble the specified functions. The function pattern can be a single function name (e.g. --disas foo to disassemble the function with the name "foo"), or a shell wildcard pattern (e.g. --disas foo* to disassemble all functions with a name starting with "foo"). Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-18-alexandre.chartre@oracle.com
2025-11-21objtool: Do not validate IBT for .return_sites and .call_sitesAlexandre Chartre1-0/+2
The .return_sites and .call_sites sections reference text addresses, but not with the intent to indirect branch to them, so they don't need to be validated for IBT. This is useful when running objtool on object files which already have .return_sites or .call_sites sections, for example to re-run objtool after it has reported an error or a warning. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-17-alexandre.chartre@oracle.com
2025-11-21objtool: Improve tracing of alternative instructionsAlexandre Chartre1-12/+6
When tracing function validation, improve the reporting of alternative instruction by more clearly showing the different alternatives beginning and end. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-16-alexandre.chartre@oracle.com
2025-11-21objtool: Identify the different types of alternativesAlexandre Chartre1-5/+8
Alternative code, including jump table and exception table, is represented with the same struct alternative structure. But there is no obvious way to identify whether the struct represents alternative instructions, a jump table or an exception table. So add a type to struct alternative to clearly identify the type of alternative. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-14-alexandre.chartre@oracle.com
2025-11-21objtool: Trace instruction state changes during function validationAlexandre Chartre1-1/+7
During function validation, objtool maintains a per-instruction state, in particular to track call frame information. When tracing validation, print any instruction state changes. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-12-alexandre.chartre@oracle.com
2025-11-21objtool: Add option to trace function validationAlexandre Chartre1-17/+87
Add an option to trace and have information during the validation of specified functions. Functions are specified with the --trace option which can be a single function name (e.g. --trace foo to trace the function with the name "foo"), or a shell wildcard pattern (e.g. --trace foo* to trace all functions with a name starting with "foo"). Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-11-alexandre.chartre@oracle.com
2025-11-21objtool: Record symbol name max lengthAlexandre Chartre1-0/+7
Keep track of the maximum length of symbol names. This will help formatting the code flow between different functions. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-10-alexandre.chartre@oracle.com
2025-11-21objtool: Extract code to validate instruction from the validate branch loopAlexandre Chartre1-181/+205
The code to validate a branch loops through all instructions of the branch and validate each instruction. Move the code to validate an instruction to a separated function. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-9-alexandre.chartre@oracle.com
2025-11-21objtool: Disassemble instruction on warning or backtraceAlexandre Chartre1-6/+30
When an instruction warning (WARN_INSN) or backtrace (BT_INSN) is issued, disassemble the instruction to provide more context. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-8-alexandre.chartre@oracle.com
2025-11-21objtool: Print symbol during disassemblyAlexandre Chartre1-9/+0
Print symbols referenced during disassembly instead of just printing raw addresses. Also handle address relocation. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-6-alexandre.chartre@oracle.com
2025-11-21objtool: Disassemble code with libopcodes instead of running objdumpAlexandre Chartre1-5/+9
objtool executes the objdump command to disassemble code. Use libopcodes instead to have more control about the disassembly scope and output. If libopcodes is not present then objtool is built without disassembly support. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-4-alexandre.chartre@oracle.com
2025-11-21objtool: Create disassembly contextAlexandre Chartre1-1/+5
Create a structure to store information for disassembling functions. For now, it is just a wrapper around an objtool file. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-3-alexandre.chartre@oracle.com
2025-11-21objtool: Move disassembly functions to a separated fileAlexandre Chartre1-81/+0
objtool disassembles functions which have warnings. Move the code to do that to a dedicated file. The code is just moved, it is not changed. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Link: https://patch.msgid.link/20251121095340.464045-2-alexandre.chartre@oracle.com
2025-11-21Revert "objtool: Warn on functions with ambiguous -ffunction-sections ↵Josh Poimboeuf1-33/+0
section names" This reverts commit 9c7dc1dd897a1cdcade9566ea4664b03fbabf4a4. The check-function-names.sh script now provides the function name checking functionality for all architectures, making the objtool check redundant. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://patch.msgid.link/c7d549d4de8bd1490d106b99630eea5efc69a4dd.1763669451.git.jpoimboe@kernel.org
2025-11-21objtool: Remove second pass of .cold function correlationJosh Poimboeuf1-22/+1
The .cold function parent/child correlation logic has two passes: one in read_symbols() and one in add_jump_destinations(). The second pass was added with commit cd77849a69cf ("objtool: Fix GCC 8 cold subfunction detection for aliased functions") to ensure that if the parent symbol had aliases then the canonical symbol was chosen as the parent. That solution was rather clunky, not to mention incomplete due to the existence of alternatives and switch tables. Now that we have sym->alias, the canonical alias fix can be done much simpler in the first pass, making the second pass obsolete. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/bdab245a38000a5407f663a031f39e14c67a43d4.1763671318.git.jpoimboe@kernel.org
2025-11-21objtool: Skip non-canonical aliased symbols in add_jump_table_alts()Josh Poimboeuf1-1/+1
If a symbol has aliases, make add_jump_table_alts() skip the non-canonical ones to avoid any surprises. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/169aa17564b9aadb74897945ea74ac2eb70c5b13.1763671318.git.jpoimboe@kernel.org
2025-11-13objtool: Warn on functions with ambiguous -ffunction-sections section namesJosh Poimboeuf1-0/+33
When compiled with -ffunction-sections, a function named startup() will be placed in .text.startup. However, .text.startup is also used by the compiler for functions with __attribute__((constructor)). That creates an ambiguity for the vmlinux linker script, which needs to differentiate those two cases. Similar naming conflicts exist for functions named exit(), split(), unlikely(), hot() and unknown(). One potential solution would be to use '#ifdef CC_USING_FUNCTION_SECTIONS' to create two distinct implementations of the TEXT_MAIN macro. However, -ffunction-sections can be (and is) enabled or disabled on a per-object basis (for example via ccflags-y or AUTOFDO_PROFILE). So the recently unified TEXT_MAIN macro (commit 1ba9f8979426 ("vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros")) is necessary. This means there's no way for the linker script to disambiguate things. Instead, use objtool to warn on any function names whose resulting section names might create ambiguity when the kernel is compiled (in whole or in part) with -ffunction-sections. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: live-patching@vger.kernel.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://patch.msgid.link/65fedea974fe14be487c8867a0b8d0e4a294ce1e.1762991150.git.jpoimboe@kernel.org
2025-11-13Merge tag 'v6.18-rc5' into objtool/core, to pick up fixesIngo Molnar1-3/+7
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-11-01objtool: Fix skip_alt_group() for non-alternative STAC/CLACJosh Poimboeuf1-1/+4
If an insn->alt points to a STAC/CLAC instruction, skip_alt_group() assumes it's part of an alternative ("alt group") as opposed to some other kind of "alt" such as an exception fixup. While that assumption may hold true in the current code base, Linus has an out-of-tree patch which breaks that assumption by replacing the STAC/CLAC alternatives with raw STAC/CLAC instructions. Make skip_alt_group() more robust by making sure it's actually an alt group before continuing. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Fixes: 2d12c6fb7875 ("objtool: Remove ANNOTATE_IGNORE_ALTERNATIVE from CLAC/STAC") Closes: https://lore.kernel.org/CAHk-=wi6goUT36sR8GE47_P-aVrd5g38=VTRHpktWARbyE-0ow@mail.gmail.com Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://patch.msgid.link/3d22415f7b8e06a64e0873b21f48389290eeaa49.1761767616.git.jpoimboe@kernel.org
2025-10-22objtool: Fix failure when being compiled on x32 systemMikulas Patocka1-2/+2
Fix compilation failure when compiling the kernel with the x32 toolchain. In file included from check.c:16: check.c: In function ¡check_abs_references¢: /usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:47:17: error: format ¡%lx¢ expects argument of type ¡long unsigned int¢, but argument 7 has type ¡u64¢ {aka ¡long long unsigned int¢} [-Werror=format=] 47 | "%s%s%s: objtool" extra ": " format "\n", \ | ^~~~~~~~~~~~~~~~~ /usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:54:9: note: in expansion of macro ¡___WARN¢ 54 | ___WARN(severity, "", format, ##__VA_ARGS__) | ^~~~~~~ /usr/src/git/linux-2.6/tools/objtool/include/objtool/warn.h:74:27: note: in expansion of macro ¡__WARN¢ 74 | #define WARN(format, ...) __WARN(WARN_STR, format, ##__VA_ARGS__) | ^~~~~~ check.c:4713:33: note: in expansion of macro ¡WARN¢ 4713 | WARN("section %s has absolute relocation at offset 0x%lx", | ^~~~ Fixes: 0d6e4563fc03 ("objtool: Add action to check for absence of absolute relocations") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://patch.msgid.link/1ac32fff-2e67-5155-f570-69aad5bf5412@redhat.com
2025-10-22objtool/rust: add one more `noreturn` Rust functionMiguel Ojeda1-0/+1
Between Rust 1.79 and 1.86, under `CONFIG_RUST_KERNEL_DOCTESTS=y`, `objtool` may report: rust/doctests_kernel_generated.o: warning: objtool: rust_doctest_kernel_alloc_kbox_rs_13() falls through to next function rust_doctest_kernel_alloc_kvec_rs_0() (as well as in rust_doctest_kernel_alloc_kvec_rs_0) due to calls to the `noreturn` symbol: core::option::expect_failed from code added in commits 779db37373a3 ("rust: alloc: kvec: implement AsPageIter for VVec") and 671618432f46 ("rust: alloc: kbox: implement AsPageIter for VBox"). Thus add the mangled one to the list so that `objtool` knows it is actually `noreturn`. This can be reproduced as well in other versions by tweaking the code, such as the latest stable Rust (1.90.0). Stable does not have code that triggers this, but it could have it in the future. Downstream forks could too. Thus tag it for backport. See commit 56d680dd23c3 ("objtool/rust: list `noreturn` Rust functions") for more details. Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Cc: stable@vger.kernel.org # Needed in 6.12.y and later. Link: https://patch.msgid.link/20251020020714.2511718-1-ojeda@kernel.org
2025-10-15objtool: Add base objtool support for livepatch modulesJosh Poimboeuf1-5/+47
In preparation for klp-build, enable "classic" objtool to work on livepatch modules: - Avoid duplicate symbol/section warnings for prefix symbols and the .static_call_sites and __mcount_loc sections which may have already been extracted by klp diff. - Add __klp_funcs to the IBT function pointer section whitelist. - Prevent KLP symbols from getting incorrectly classified as cold subfunctions. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Refactor prefix symbol creation codeJosh Poimboeuf1-12/+45
The prefix symbol creation code currently ignores all errors, presumably because some functions don't have the leading NOPs. Shuffle the code around a bit, improve the error handling and document why some errors are ignored. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool/klp: Introduce klp diff subcommand for diffing object filesJosh Poimboeuf1-14/+0
Add a new klp diff subcommand which performs a binary diff between two object files and extracts changed functions into a new object which can then be linked into a livepatch module. This builds on concepts from the longstanding out-of-tree kpatch [1] project which began in 2012 and has been used for many years to generate livepatch modules for production kernels. However, this is a complete rewrite which incorporates hard-earned lessons from 12+ years of maintaining kpatch. Key improvements compared to kpatch-build: - Integrated with objtool: Leverages objtool's existing control-flow graph analysis to help detect changed functions. - Works on vmlinux.o: Supports late-linked objects, making it compatible with LTO, IBT, and similar. - Simplified code base: ~3k fewer lines of code. - Upstream: No more out-of-tree #ifdef hacks, far less cruft. - Cleaner internals: Vastly simplified logic for symbol/section/reloc inclusion and special section extraction. - Robust __LINE__ macro handling: Avoids false positive binary diffs caused by the __LINE__ macro by introducing a fix-patch-lines script (coming in a later patch) which injects #line directives into the source .patch to preserve the original line numbers at compile time. Note the end result of this subcommand is not yet functionally complete. Livepatch needs some ELF magic which linkers don't like: - Two relocation sections (.rela*, .klp.rela*) for the same text section. - Use of SHN_LIVEPATCH to mark livepatch symbols. Unfortunately linkers tend to mangle such things. To work around that, klp diff generates a linker-compliant intermediate binary which encodes the relevant KLP section/reloc/symbol metadata. After module linking, a klp post-link step (coming soon) will clean up the mess and convert the linked .ko into a fully compliant livepatch module. Note this subcommand requires the diffed binaries to have been compiled with -ffunction-sections and -fdata-sections, and processed with 'objtool --checksum'. Those constraints will be handled by a klp-build script introduced in a later patch. Without '-ffunction-sections -fdata-sections', reliable object diffing would be infeasible due to toolchain limitations: - For intra-file+intra-section references, the compiler might occasionally generated hard-coded instruction offsets instead of relocations. - Section-symbol-based references can be ambiguous: - Overlapping or zero-length symbols create ambiguity as to which symbol is being referenced. - A reference to the end of a symbol (e.g., checking array bounds) can be misinterpreted as a reference to the next symbol, or vice versa. A potential future alternative to '-ffunction-sections -fdata-sections' would be to introduce a toolchain option that forces symbol-based (non-section) relocations. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool/klp: Add --debug-checksum=<funcs> to show per-instruction checksumsJosh Poimboeuf1-0/+42
Add a --debug-checksum=<funcs> option to the check subcommand to print the calculated checksum of each instruction in the given functions. This is useful for determining where two versions of a function begin to diverge. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool/klp: Add --checksum option to generate per-function checksumsJosh Poimboeuf1-5/+136
In preparation for the objtool klp diff subcommand, add a command-line option to generate a unique checksum for each function. This will enable detection of functions which have changed between two versions of an object file. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Add annotype() helperJosh Poimboeuf1-4/+1
... for reading annotation types. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Refactor add_jump_destinations()Josh Poimboeuf1-113/+99
The add_jump_destinations() logic is a bit weird and convoluted after being incrementally tweaked over the years. Refactor it to hopefully be more logical and straightforward. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Resurrect --backup optionJosh Poimboeuf1-1/+3
The --backup option was removed with the following commit: aa8b3e64fd39 ("objtool: Create backup on error and print args") ... which tied the backup functionality to --verbose, and only for warnings/errors. It's a bit inelegant and out of scope to tie that to --verbose. Bring back the old --backup option, but with the new behavior: only on warnings/errors, and print the args to make it easier to recreate. Suggested-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Avoid emptying lists for duplicate sectionsJosh Poimboeuf1-4/+0
When a to-be-created section already exists, there's no point in emptying the various lists if their respective sections already exist. In fact it's better to leave them intact as they might get used later. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Simplify reloc offset calculation in unwind_read_hints()Josh Poimboeuf1-8/+1
Simplify the relocation offset calculation in unwind_read_hints(), similar to other conversions which have already been done. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Mark prefix functionsJosh Poimboeuf1-4/+1
In preparation for the objtool klp diff subcommand, introduce a flag to identify __pfx_*() and __cfi_*() functions in advance so they don't need to be manually identified every time a check is needed. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Fix weak symbol hole detection for .cold functionsJosh Poimboeuf1-41/+43
When ignore_unreachable_insn() looks for weak function holes which jump to their .cold functions, it assumes the parent function comes before the corresponding .cold function in the symbol table. That's not necessarily the case with -ffunction-sections. Mark all the holes beforehand (including .cold functions) so the ordering of the discovery doesn't matter. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Mark .cold subfunctionsJosh Poimboeuf1-8/+6
Introduce a flag to identify .cold subfunctions so they can be detected easier and faster. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Add section/symbol type helpersJosh Poimboeuf1-29/+29
Add some helper macros to improve readability. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Convert elf iterator macros to use 'struct elf'Josh Poimboeuf1-12/+12
'struct objtool_file' is specific to the check code and doesn't belong in the elf code which is supposed to be objtool_file-agnostic. Convert the elf iterator macros to use 'struct elf' instead. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Remove .parainstructions referenceJosh Poimboeuf1-1/+0
The .parainstructions section no longer exists since the following commit: 60bc276b129e ("x86/paravirt: Switch mixed paravirt/alternative calls to alternatives"). Remove the reference to it. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Clean up compiler flag usageJosh Poimboeuf1-2/+2
KBUILD_HOSTCFLAGS and KBUILD_HOSTLDFLAGS aren't defined when objtool is built standalone. Also, the EXTRA_WARNINGS flags are rather arbitrary. Make things simpler and more consistent by specifying compiler flags explicitly and tweaking the warnings. Also make a few code tweaks to make the new warnings happy. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Check for missing annotation entries in read_annotate()Josh Poimboeuf1-0/+5
Add a sanity check to make sure none of the relocations for the .discard.annotate_insn section have gone missing. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2025-10-15objtool: Fix "unexpected end of section" warning for alternativesJosh Poimboeuf1-4/+1
Due to the short circuiting logic in next_insn_to_validate(), control flow may silently transition from .altinstr_replacement to .text without a corresponding nested call to validate_branch(). As a result the validate_branch() 'sec' variable doesn't get reinitialized, which can trigger a confusing "unexpected end of section" warning which blames .altinstr_replacement rather than the offending fallthrough function. Fix that by not caching the section. There's no point in doing that anyway. Acked-by: Petr Mladek <pmladek@suse.com> Tested-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
generated by cgit v1.2.3 (git 2.39.0) at 2026-04-05 04:14:28 +0300