From: Georgi Djakov <quic_c_gdjako@xxxxxxxxxxx> Subject: mm/slub: add taint after the errors are printed 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. Link: https://lkml.kernel.org/r/1623860738-146761-1-git-send-email-quic_c_gdjako@xxxxxxxxxxx Signed-off-by: Georgi Djakov <quic_c_gdjako@xxxxxxxxxxx> Acked-by: Rafael Aquini <aquini@xxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Reviewed-by: Aaron Tomlin <atomlin@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/slub.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/mm/slub.c~mm-slub-add-taint-after-the-errors-are-printed +++ a/mm/slub.c @@ -708,8 +708,6 @@ static void slab_bug(struct kmem_cache * 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); } @@ -790,6 +788,7 @@ void object_err(struct kmem_cache *s, st 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, @@ -807,6 +806,7 @@ static __printf(3, 4) void slab_err(stru 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) @@ -858,6 +858,7 @@ static int check_bytes_and_report(struct 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); _
