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SubjectRe: [PATCH v11 10/14] tracing, arm64: untag user pointers in seq_print_user_ip
On Fri, Mar 15, 2019 at 9:14 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Fri, 15 Mar 2019 20:51:34 +0100
> Andrey Konovalov <andreyknvl@google.com> 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@google.com>
> > ---
> > kernel/trace/trace_output.c | 5 +++--
> > p | 45 +++++++++++++++++++++++++++++++++++++
> > 2 files changed, 48 insertions(+), 2 deletions(-)
> > create mode 100644 p
> >
> > 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);
> > }
> > diff --git a/p b/p
> > new file mode 100644
> > index 000000000000..9d6fa5386e55
> > --- /dev/null
> > +++ b/p
> > @@ -0,0 +1,45 @@
> > +commit 1fa6fadf644859e8a6a8ecce258444b49be8c7ee
> > +Author: Andrey Konovalov <andreyknvl@google.com>
> > +Date: Mon Mar 4 17:20:32 2019 +0100
> > +
> > + kasan: fix coccinelle warnings in kasan_p*_table
> > +
> > + kasan_p4d_table, kasan_pmd_table and kasan_pud_table are declared as
> > + returning bool, but return 0 instead of false, which produces a coccinelle
> > + warning. Fix it.
> > +
> > + Fixes: 0207df4fa1a8 ("kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN")
> > + Reported-by: kbuild test robot <lkp@intel.com>
> > + Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
>
> Did you mean to append this commit to this patch?

No, did it by mistake. Will remove in v12, thanks for noticing!

>
> -- Steve
>
> > +
> > +diff --git a/mm/kasan/init.c b/mm/kasan/init.c
> > +index 45a1b5e38e1e..fcaa1ca03175 100644
> > +--- a/mm/kasan/init.c
> > ++++ b/mm/kasan/init.c
> > +@@ -42,7 +42,7 @@ static inline bool kasan_p4d_table(pgd_t pgd)
> > + #else
> > + static inline bool kasan_p4d_table(pgd_t pgd)
> > + {
> > +- return 0;
> > ++ return false;
> > + }
> > + #endif
> > + #if CONFIG_PGTABLE_LEVELS > 3
> > +@@ -54,7 +54,7 @@ static inline bool kasan_pud_table(p4d_t p4d)
> > + #else
> > + static inline bool kasan_pud_table(p4d_t p4d)
> > + {
> > +- return 0;
> > ++ return false;
> > + }
> > + #endif
> > + #if CONFIG_PGTABLE_LEVELS > 2
> > +@@ -66,7 +66,7 @@ static inline bool kasan_pmd_table(pud_t pud)
> > + #else
> > + static inline bool kasan_pmd_table(pud_t pud)
> > + {
> > +- return 0;
> > ++ return false;
> > + }
> > + #endif
> > + pte_t kasan_early_shadow_pte[PTRS_PER_PTE] __page_aligned_bss;
>

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