[RFC v8 PATCH 2/5] uprobes: introduce has_uprobes helper
From: Yang Shi <hidden>
Date: 2018-08-15 18:50:30
Also in:
lkml
Subsystem:
performance events subsystem, the rest, uprobes · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds, Masami Hiramatsu, Oleg Nesterov
We need check if mm or vma has uprobes in the following patch to check if a vma could be unmapped with holding read mmap_sem. The checks and pre-conditions used by uprobe_munmap() look just suitable for this purpose. Extracting those checks into a helper function, has_uprobes(). Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <redacted> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Vlastimil Babka <redacted> Signed-off-by: Yang Shi <redacted> --- include/linux/uprobes.h | 7 +++++++ kernel/events/uprobes.c | 23 ++++++++++++++++------- 2 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 0a294e9..418764e 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h@@ -149,6 +149,8 @@ struct uprobes_state { extern bool arch_uprobe_ignore(struct arch_uprobe *aup, struct pt_regs *regs); extern void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, void *src, unsigned long len); +extern bool has_uprobes(struct vm_area_struct *vma, unsigned long start, + unsigned long end); #else /* !CONFIG_UPROBES */ struct uprobes_state { };
@@ -203,5 +205,10 @@ static inline void uprobe_copy_process(struct task_struct *t, unsigned long flag static inline void uprobe_clear_state(struct mm_struct *mm) { } +static inline bool has_uprobes(struct vm_area_struct *vma, unsigned long start, + unsgined long end) +{ + return false; +} #endif /* !CONFIG_UPROBES */ #endif /* _LINUX_UPROBES_H */
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index aed1ba5..568481c 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c@@ -1114,22 +1114,31 @@ int uprobe_mmap(struct vm_area_struct *vma) return !!n; } -/* - * Called in context of a munmap of a vma. - */ -void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end) +bool +has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long end) { if (no_uprobe_events() || !valid_vma(vma, false)) - return; + return false; if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */ - return; + return false; if (!test_bit(MMF_HAS_UPROBES, &vma->vm_mm->flags) || test_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags)) - return; + return false; if (vma_has_uprobes(vma, start, end)) + return true; + + return false; +} + +/* + * Called in context of a munmap of a vma. + */ +void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end) +{ + if (has_uprobes(vma, start, end)) set_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags); }
--
1.8.3.1