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Subject[PATCH v11 11/14] uprobes, arm64: untag user pointers in find_active_uprobe
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This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

find_active_uprobe() uses provided user pointer (obtained via
instruction_pointer(regs)) for vma lookups, which can only by done with
untagged pointers.

Untag the user pointer in this function.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
kernel/events/uprobes.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c5cde87329c7..d3a2716a813a 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1992,6 +1992,8 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
struct uprobe *uprobe = NULL;
struct vm_area_struct *vma;

+ bp_vaddr = untagged_addr(bp_vaddr);
+
down_read(&mm->mmap_sem);
vma = find_vma(mm, bp_vaddr);
if (vma && vma->vm_start <= bp_vaddr) {
--
2.21.0.360.g471c308f928-goog
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