On Wed, Mar 20, 2019 at 03:51:25PM +0100, Andrey Konovalov wrote: > 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 <andreyknvl@xxxxxxxxxx> > --- > 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); > } How would we end up with a tagged address here? Does "ip" here imply instruction pointer, which we wouldn't tag? -- Catalin _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx