Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider: - [Medium] entry: missing __always_inline on irqentry_exit_to_kernel_mode_preempt() --
commit b2284e95ad33bdfe152568730c196eaa50875e40 Author: Karl Mehltretter <[email protected]> entry: Skip inactive IRQ-return reschedule calls This commit checks preempt_count() in irqentry_exit_to_kernel_mode_preempt() to avoid calling irqentry_exit_cond_resched() when preemption is disabled, and marks arm64's preempt_count() as __always_inline for noinstr callers. > diff --git a/include/linux/irq-entry-common.h > b/include/linux/irq-entry-common.h > index 289e308d2d46c..e1fd9155410c1 100644 > --- a/include/linux/irq-entry-common.h > +++ b/include/linux/irq-entry-common.h > @@ -503,7 +503,7 @@ static inline void > irqentry_exit_to_kernel_mode_preempt(struct pt_regs *regs, > if (regs_irqs_disabled(regs) || state.exit_rcu) > return; > > - if (IS_ENABLED(CONFIG_PREEMPTION)) > + if (IS_ENABLED(CONFIG_PREEMPTION) && !preempt_count()) > irqentry_exit_cond_resched(); > } [Severity: Medium] Should irqentry_exit_to_kernel_mode_preempt() in include/linux/irq-entry-common.h also be marked __always_inline (like its companions irqentry_enter_from_kernel_mode(), irqentry_exit_to_kernel_mode_after_preempt(), and irqentry_exit_to_kernel_mode())? On arm64, __el1_irq() and arm64_exit_to_kernel_mode() call noinstr function arm64_exit_to_kernel_mode_preempt() in arch/arm64/kernel/entry-common.c, which invokes irqentry_exit_to_kernel_mode_preempt() directly without instrumentation_begin(): static void noinstr arm64_exit_to_kernel_mode_preempt(struct pt_regs *regs, irqentry_state_t state) { irqentry_exit_to_kernel_mode_preempt(regs, state); __arm64_exit_to_kernel_mode(regs, state); } While preempt_count() in arch/arm64/include/asm/preempt.h is changed to __always_inline so Clang does not outline the new check into instrumentable text, irqentry_exit_to_kernel_mode_preempt() itself remains static inline: static inline void irqentry_exit_to_kernel_mode_preempt(struct pt_regs *regs, irqentry_state_t state) Because noinstr in include/linux/compiler_types.h strips sanitizer and profiling attributes (__no_kcsan, __no_sanitize_address, __no_profile, __no_sanitize_coverage, __no_sanitize_memory) whereas inline only adds notrace, building with Clang and CONFIG_KASAN=y, CONFIG_KCSAN=y, or CONFIG_GCOV_KERNEL=y can cause LLVM to refuse to inline a non-__always_inline callee due to mismatched attributes. If that happens, couldn't Clang inline preempt_count() into irqentry_exit_to_kernel_mode_preempt() and then outline irqentry_exit_to_kernel_mode_preempt() itself into instrumentable .text, allowing sanitizer instrumentation or kprobes to run on the noinstr return path even when state.exit_rcu or regs_irqs_disabled(regs) is true? -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=6
