kernel/linux.git/tools/objtool/check.c, branch v6.1.168

objtool: Fix Clang jump table detection

2026-04-11T12:16:19+00:00

[ Upstream commit 4e5019216402ad0b4a84cff457b662d26803f103 ] With Clang, there can be a conditional forward jump between the load of the jump table address and the indirect branch. Fixes the following warning: vmlinux.o: warning: objtool: ___bpf_prog_run+0x1c5: sibling call from callable instruction with modified stack frame Reported-by: Arnd Bergmann Closes: https://lore.kernel.org/a426d669-58bb-4be1-9eaa-6f3d83109e2d@app.fastmail.com Link: https://patch.msgid.link/7d8600caed08901b6679767488acd639f6df9688.1773071992.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf Signed-off-by: Sasha Levin

objtool: Properly disable uaccess validation

2025-06-04T12:40:03+00:00

[ Upstream commit e1a9dda74dbffbc3fa2069ff418a1876dc99fb14 ] If opts.uaccess isn't set, the uaccess validation is disabled, but only partially: it doesn't read the uaccess_safe_builtin list but still tries to do the validation. Disable it completely to prevent false warnings. Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/0e95581c1d2107fb5f59418edf2b26bba38b0cbb.1742852846.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin

objtool: Stop UNRET validation on UD2

2025-05-02T05:47:05+00:00

[ Upstream commit 9f9cc012c2cbac4833746a0182e06a8eec940d19 ] 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 Signed-off-by: Sasha Levin

objtool: Silence more KCOV warnings

2025-05-02T05:47:03+00:00

[ Upstream commit 6b023c7842048c4bbeede802f3cf36b96c7a8b25 ] In the past there were issues with KCOV triggering unreachable instruction warnings, which is why unreachable warnings are now disabled with CONFIG_KCOV. Now some new KCOV warnings are showing up with GCC 14: vmlinux.o: warning: objtool: cpuset_write_resmask() falls through to next function cpuset_update_active_cpus.cold() drivers/usb/core/driver.o: error: objtool: usb_deregister() falls through to next function usb_match_device() sound/soc/codecs/snd-soc-wcd934x.o: warning: objtool: .text.wcd934x_slim_irq_handler: unexpected end of section All are caused by GCC KCOV not finishing an optimization, leaving behind a never-taken conditional branch to a basic block which falls through to the next function (or end of section). At a high level this is similar to the unreachable warnings mentioned above, in that KCOV isn't fully removing dead code. Treat it the same way by adding these to the list of warnings to ignore with CONFIG_KCOV. Reported-by: Ingo Molnar Reported-by: kernel test robot Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Linus Torvalds Link: https://lore.kernel.org/r/66a61a0b65d74e072d3dc02384e395edb2adc3c5.1742852846.git.jpoimboe@kernel.org Closes: https://lore.kernel.org/Z9iTsI09AEBlxlHC@gmail.com Closes: https://lore.kernel.org/oe-kbuild-all/202503180044.oH9gyPeg-lkp@intel.com/ Signed-off-by: Sasha Levin

objtool/x86: allow syscall instruction

2024-12-19T17:08:58+00:00

commit dda014ba59331dee4f3b773a020e109932f4bd24 upstream. The syscall instruction is used in Xen PV mode for doing hypercalls. Allow syscall to be used in the kernel in case it is tagged with an unwind hint for objtool. This is part of XSA-466 / CVE-2024-53241. Reported-by: Andrew Cooper Signed-off-by: Juergen Gross Co-developed-by: Peter Zijlstra Signed-off-by: Greg Kroah-Hartman

objtool/x86: add missing embedded_insn check

2023-11-02T08:35:33+00:00

When dbf460087755 ("objtool/x86: Fixup frame-pointer vs rethunk") was backported to some stable branches, the check for dest->embedded_insn in is_special_call() was missed. The result is that the warning it was intended to suppress still appears. For example on 6.1 (on kernels before 6.1, the '-s' argument would instead be 'check'): $ tools/objtool/objtool -s arch/x86/lib/retpoline.o arch/x86/lib/retpoline.o: warning: objtool: srso_untrain_ret+0xd: call without frame pointer save/setup With this patch, the warning is correctly suppressed, and the kernel still passes the normal Google kernel developer tests. Signed-off-by: John Sperbeck Signed-off-by: Greg Kroah-Hartman

objtool/x86: Fix SRSO mess

2023-08-27T19:01:31+00:00

commit 4ae68b26c3ab5a82aa271e6e9fc9b1a06e1d6b40 upstream. Objtool --rethunk does two things: - it collects all (tail) call's of __x86_return_thunk and places them into .return_sites. These are typically compiler generated, but RET also emits this same. - it fudges the validation of the __x86_return_thunk symbol; because this symbol is inside another instruction, it can't actually find the instruction pointed to by the symbol offset and gets upset. Because these two things pertained to the same symbol, there was no pressing need to separate these two separate things. However, alas, along comes SRSO and more crazy things to deal with appeared. The SRSO patch itself added the following symbol names to identify as rethunk: 'srso_untrain_ret', 'srso_safe_ret' and '__ret' Where '__ret' is the old retbleed return thunk, 'srso_safe_ret' is a new similarly embedded return thunk, and 'srso_untrain_ret' is completely unrelated to anything the above does (and was only included because of that INT3 vs UD2 issue fixed previous). Clear things up by adding a second category for the embedded instruction thing. Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230814121148.704502245@infradead.org Signed-off-by: Josh Poimboeuf Signed-off-by: Greg Kroah-Hartman

objtool/x86: Fixup frame-pointer vs rethunk

2023-08-26T11:27:00+00:00

commit dbf46008775516f7f25c95b7760041c286299783 upstream. For stack-validation of a frame-pointer build, objtool validates that every CALL instruction is preceded by a frame-setup. The new SRSO return thunks violate this with their RSB stuffing trickery. Extend the __fentry__ exception to also cover the embedded_insn case used for this. This cures: vmlinux.o: warning: objtool: srso_untrain_ret+0xd: call without frame pointer save/setup Fixes: 4ae68b26c3ab ("objtool/x86: Fix SRSO mess") Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov (AMD) Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20230816115921.GH980931@hirez.programming.kicks-ass.net Signed-off-by: Greg Kroah-Hartman

x86/retpoline,kprobes: Fix position of thunk sections with CONFIG_LTO_CLANG

2023-08-26T11:27:00+00:00

commit 79cd2a11224eab86d6673fe8a11d2046ae9d2757 upstream. The linker script arch/x86/kernel/vmlinux.lds.S matches the thunk sections ".text.__x86.*" from arch/x86/lib/retpoline.S as follows: .text { [...] TEXT_TEXT [...] __indirect_thunk_start = .; *(.text.__x86.*) __indirect_thunk_end = .; [...] } Macro TEXT_TEXT references TEXT_MAIN which normally expands to only ".text". However, with CONFIG_LTO_CLANG, TEXT_MAIN becomes ".text .text.[0-9a-zA-Z_]*" which wrongly matches also the thunk sections. The output layout is then different than expected. For instance, the currently defined range [__indirect_thunk_start, __indirect_thunk_end] becomes empty. Prevent the problem by using ".." as the first separator, for example, ".text..__x86.indirect_thunk". This pattern is utilized by other explicit section names which start with one of the standard prefixes, such as ".text" or ".data", and that need to be individually selected in the linker script. [ nathan: Fix conflicts with SRSO and fold in fix issue brought up by Andrew Cooper in post-review: https://lore.kernel.org/20230803230323.1478869-1-andrew.cooper3@citrix.com ] Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO") Signed-off-by: Petr Pavlu Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Nathan Chancellor Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230711091952.27944-2-petr.pavlu@suse.com Signed-off-by: Greg Kroah-Hartman

x86/cpu: Rename original retbleed methods

2023-08-26T11:26:59+00:00

commit d025b7bac07a6e90b6b98b487f88854ad9247c39 upstream. Rename the original retbleed return thunk and untrain_ret to retbleed_return_thunk() and retbleed_untrain_ret(). No functional changes. Suggested-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/r/20230814121148.909378169@infradead.org Signed-off-by: Greg Kroah-Hartman