lkml.org 
[lkml]   [2021]   [Jun]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH] mm/slub: Add taint after the errors are printed
    On Wed 2021-06-16 09:25 -0700, Georgi Djakov wrote:
    > When running the kernel with panic_on_taint, the usual slub debug error
    > messages are not being printed when object corruption happens. That's
    > because we panic in add_taint(), which is called before printing the
    > additional information. This is a bit unfortunate as the error messages
    > are actually very useful, especially before a panic. Let's fix this by
    > moving add_taint() after the errors are printed on the console.
    >
    > Signed-off-by: Georgi Djakov <quic_c_gdjako@quicinc.com>
    > ---
    > mm/slub.c | 5 +++--
    > 1 file changed, 3 insertions(+), 2 deletions(-)
    >
    > diff --git a/mm/slub.c b/mm/slub.c
    > index a8b0daa1a307..ce7b8e4551b5 100644
    > --- a/mm/slub.c
    > +++ b/mm/slub.c
    > @@ -719,8 +719,6 @@ static void slab_bug(struct kmem_cache *s, char *fmt, ...)
    > pr_err("=============================================================================\n");
    > pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
    > pr_err("-----------------------------------------------------------------------------\n\n");
    > -
    > - add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
    > va_end(args);
    > }
    >
    > @@ -801,6 +799,7 @@ void object_err(struct kmem_cache *s, struct page *page,
    >
    > slab_bug(s, "%s", reason);
    > print_trailer(s, page, object);
    > + add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
    > }
    >
    > static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
    > @@ -818,6 +817,7 @@ static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page,
    > slab_bug(s, "%s", buf);
    > print_page_info(page);
    > dump_stack();
    > + add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
    > }
    >
    > static void init_object(struct kmem_cache *s, void *object, u8 val)
    > @@ -869,6 +869,7 @@ static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
    > fault, end - 1, fault - addr,
    > fault[0], value);
    > print_trailer(s, page, object);
    > + add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
    >
    > skip_bug_print:
    > restore_bytes(s, what, value, fault, end);
    >

    Good catch. Thanks!

    Reviewed-by: Aaron Tomlin <atomlin@redhat.com>

    --
    Aaron Tomlin

    \
     
     \ /
      Last update: 2021-06-17 11:23    [W:3.292 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site