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.

seq_print_user_ip() uses provided user pointers for vma lookups, which
can only by done with untagged pointers.

Untag user pointers in this function.

Signed-off-by: Andrey Konovalov <andreyk...@google.com>
---
 kernel/trace/trace_output.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 54373d93e251..6376bee93c84 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -370,6 +370,7 @@ static int seq_print_user_ip(struct trace_seq *s, struct 
mm_struct *mm,
 {
        struct file *file = NULL;
        unsigned long vmstart = 0;
+       unsigned long untagged_ip = untagged_addr(ip);
        int ret = 1;
 
        if (s->full)
@@ -379,7 +380,7 @@ static int seq_print_user_ip(struct trace_seq *s, struct 
mm_struct *mm,
                const struct vm_area_struct *vma;
 
                down_read(&mm->mmap_sem);
-               vma = find_vma(mm, ip);
+               vma = find_vma(mm, untagged_ip);
                if (vma) {
                        file = vma->vm_file;
                        vmstart = vma->vm_start;
@@ -388,7 +389,7 @@ static int seq_print_user_ip(struct trace_seq *s, struct 
mm_struct *mm,
                        ret = trace_seq_path(s, &file->f_path);
                        if (ret)
                                trace_seq_printf(s, "[+0x%lx]",
-                                                ip - vmstart);
+                                                untagged_ip - vmstart);
                }
                up_read(&mm->mmap_sem);
        }
-- 
2.21.0.225.g810b269d1ac-goog

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