wireguard-linux/arch/x86/kernel/kprobes, branch stable

x86/kprobes: Fix crash when probing CS CALL instructions

2026-09-17T07:48:42Z

When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

Merge tag 'x86_cpu_for_v7.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-08-19T02:09:42Z

Pull x86 cpuid updates from Borislav Petkov: - Get rid of static_cpu_has() - one less API to care about testing CPU features - Unify the handling of CPU core types (performance, efficient, etc) by mapping the vendor-specific types to Linux ones - Continuation of the work of Ahmed Darwish to centralize CPUID leaf representation * tag 'x86_cpu_for_v7.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/CPU: Rename struct cpuid_read_output to struct cpuid_output x86/cpu/scattered: Sort it properly x86/cpu: Use parsed CPUID(0x1) x86/lib: Add CPUID(0x1) family and model calculation x86/cpu: Use parsed CPUID(0x0) x86/cpu/transmeta: Rescan CPUID(0x1) after modifying capabilities x86/topology: Add TOPO_CPU_TYPE_LOW_POWER x86/topology: Name the AMD core-type values x86/topo: Map vendor CPU types to generic Linux such types x86/bugs: Don't use cpu-type matching in cpu_vuln_blacklist x86/cpu: Hide and rename static_cpu_has()

x86/alternative: Drop smp_locks glue

2026-07-13T16:23:36Z

This was there to be able to patch out locking instructions when running a SMP kernel build on a UP CPU. The times are long gone when single-CPU x86 machines were relevant so drop that machinery and simplify the code considerably. LOCK_PREFIX needs to stay for when one wants to do a UP build for whatever reason. That'll go away when CONFIG_SMP becomes unconditional. Kill a bunch of leftover, unused prototypes while at it. Signed-off-by: Borislav Petkov (AMD) Acked-by: Peter Zijlstra (Intel) Acked-by: Mike Rapoport (Microsoft) Link: https://lore.kernel.org/r/20260328081634.797552-1-rppt@kernel.org

x86/cpu: Hide and rename static_cpu_has()

2026-07-07T04:34:26Z

cpu_feature_enabled() is the one to use to test feature flags so hide the static thing which doesn't pay attention to disabled mask bits anyway. Use the following command to do the replacement: $ git grep --files-with-matches -w static_cpu_has -- ':(exclude)*cpufeature.h' \ | xargs sed -i 's/static_cpu_has(/cpu_feature_enabled\(/g' There should be no functional changes resulting from this. Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Nikolay Borisov Link: https://patch.msgid.link/20260620015041.336288-1-bp@kernel.org

Merge tag 'perf-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-12-02T04:42:01Z

Pull performance events updates from Ingo Molnar: "Callchain support: - Add support for deferred user-space stack unwinding for perf, enabled on x86. (Peter Zijlstra, Steven Rostedt) - unwind_user/x86: Enable frame pointer unwinding on x86 (Josh Poimboeuf) x86 PMU support and infrastructure: - x86/insn: Simplify for_each_insn_prefix() (Peter Zijlstra) - x86/insn,uprobes,alternative: Unify insn_is_nop() (Peter Zijlstra) Intel PMU driver: - Large series to prepare for and implement architectural PEBS support for Intel platforms such as Clearwater Forest (CWF) and Panther Lake (PTL). (Dapeng Mi, Kan Liang) - Check dynamic constraints (Kan Liang) - Optimize PEBS extended config (Peter Zijlstra) - cstates: - Remove PC3 support from LunarLake (Zhang Rui) - Add Pantherlake support (Zhang Rui) - Clearwater Forest support (Zide Chen) AMD PMU driver: - x86/amd: Check event before enable to avoid GPF (George Kennedy) Fixes and cleanups: - task_work: Fix NMI race condition (Peter Zijlstra) - perf/x86: Fix NULL event access and potential PEBS record loss (Dapeng Mi) - Misc other fixes and cleanups (Dapeng Mi, Ingo Molnar, Peter Zijlstra)" * tag 'perf-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits) perf/x86/intel: Fix and clean up intel_pmu_drain_arch_pebs() type use perf/x86/intel: Optimize PEBS extended config perf/x86/intel: Check PEBS dyn_constraints perf/x86/intel: Add a check for dynamic constraints perf/x86/intel: Add counter group support for arch-PEBS perf/x86/intel: Setup PEBS data configuration and enable legacy groups perf/x86/intel: Update dyn_constraint base on PEBS event precise level perf/x86/intel: Allocate arch-PEBS buffer and initialize PEBS_BASE MSR perf/x86/intel: Process arch-PEBS records or record fragments perf/x86/intel/ds: Factor out PEBS group processing code to functions perf/x86/intel/ds: Factor out PEBS record processing code to functions perf/x86/intel: Initialize architectural PEBS perf/x86/intel: Correct large PEBS flag check perf/x86/intel: Replace x86_pmu.drain_pebs calling with static call perf/x86: Fix NULL event access and potential PEBS record loss perf/x86: Remove redundant is_x86_event() prototype entry,unwind/deferred: Fix unwind_reset_info() placement unwind_user/x86: Fix arch=um build perf: Support deferred user unwind unwind_user/x86: Teach FP unwind about start of function ...

x86/insn: Simplify for_each_insn_prefix()

2025-10-16T09:13:48Z

Use the new-found freedom of allowing variable declarions inside for() to simplify the for_each_insn_prefix() iterator to no longer need an external temporary. Signed-off-by: Peter Zijlstra (Intel)

x86/kprobes: Remove STACK_FRAME_NON_STANDARD annotation

2025-10-14T21:45:21Z

Since commit 877b145f0f47 ("x86/kprobes: Move trampoline code into RODATA"), the optprobe template code is no longer analyzed by objtool so it doesn't need to be ignored. Acked-by: Petr Mladek Tested-by: Joe Lawrence Signed-off-by: Josh Poimboeuf

kcfi: Rename CONFIG_CFI_CLANG to CONFIG_CFI

2025-09-24T21:29:14Z

The kernel's CFI implementation uses the KCFI ABI specifically, and is not strictly tied to a particular compiler. In preparation for GCC supporting KCFI, rename CONFIG_CFI_CLANG to CONFIG_CFI (along with associated options). Use new "transitional" Kconfig option for old CONFIG_CFI_CLANG that will enable CONFIG_CFI during olddefconfig. Reviewed-by: Linus Walleij Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20250923213422.1105654-3-kees@kernel.org Signed-off-by: Kees Cook

x86/kprobes: enable EXECMEM_ROX_CACHE for kprobes allocations

2025-08-02T19:06:12Z

x86::alloc_insn_page() always allocates ROX memory. Instead of overriding this method, add EXECMEM_KPROBES entry in execmem_info with pgprot set to PAGE_KERNEL_ROX and use ROX cache when configuration and CPU features allow it. Link: https://lkml.kernel.org/r/20250713071730.4117334-8-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu (Google) Cc: Daniel Gomez Cc: Petr Pavlu Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton

x86/alternatives: Rename 'text_poke_sync()' to 'smp_text_poke_sync_each_cpu()'

2025-04-11T09:01:34Z

Unlike sync_core(), text_poke_sync() is a very heavy operation, as it sends an IPI to every online CPU in the system and waits for completion. Reflect this in the name. Signed-off-by: Ingo Molnar Cc: Juergen Gross Cc: "H . Peter Anvin" Cc: Linus Torvalds Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250411054105.2341982-41-mingo@kernel.org