[PATCH v12 10/13] tracing, arm64: untag user pointers in seq_print_user_ip
From: Andrey Konovalov <hidden>
Date: 2019-03-18 17:18:53
Also in:
bpf, linux-arch, linux-arm-kernel, linux-doc, linux-kselftest, linux-mm, lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
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 <redacted> --- 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