The patch titled
Subject: mm/slub: introduce SLAB_WARN_ON_ERROR
has been added to the -mm tree. Its filename is
mm-slub-introduce-slab_warn_on_error.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-slub-introduce-slab_warn_on_error.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-slub-introduce-slab_warn_on_error.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Miles Chen <miles.chen@xxxxxxxxxxxx>
Subject: mm/slub: introduce SLAB_WARN_ON_ERROR
When debugging slab errors in slub.c, sometimes we have to trigger a panic
in order to get the coredump file. Add a debug option SLAB_WARN_ON_ERROR
to toggle WARN_ON() when the option is set.
Link: http://lkml.kernel.org/r/1548313223-17114-1-git-send-email-miles.chen@xxxxxxxxxxxx
Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx>
Cc: Christopher Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>,
Cc: David Rientjes <rientjes@xxxxxxxxxx>,
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>,
Cc: Jonathan Corbet <corbet@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/vm/slub.rst | 1 +
include/linux/slab.h | 3 +++
mm/slub.c | 34 ++++++++++++++++++++++++++++++++--
3 files changed, 36 insertions(+), 2 deletions(-)
--- a/Documentation/vm/slub.rst~mm-slub-introduce-slab_warn_on_error
+++ a/Documentation/vm/slub.rst
@@ -52,6 +52,7 @@ Possible debug options are::
A Toggle failslab filter mark for the cache
O Switch debugging off for caches that would have
caused higher minimum slab orders
+ W Toggle WARN_ON() on slab errors
- Switch all debugging off (useful if the kernel is
configured with CONFIG_SLUB_DEBUG_ON)
--- a/include/linux/slab.h~mm-slub-introduce-slab_warn_on_error
+++ a/include/linux/slab.h
@@ -109,6 +109,9 @@
#define SLAB_KASAN 0
#endif
+/* WARN_ON slab error */
+#define SLAB_WARN_ON_ERROR ((slab_flags_t __force)0x10000000U)
+
/* The following flags affect the page allocator grouping pages by mobility */
/* Objects are reclaimable */
#define SLAB_RECLAIM_ACCOUNT ((slab_flags_t __force)0x00020000U)
--- a/mm/slub.c~mm-slub-introduce-slab_warn_on_error
+++ a/mm/slub.c
@@ -684,7 +684,10 @@ static void print_trailer(struct kmem_ca
print_section(KERN_ERR, "Padding ", p + off,
size_from_object(s) - off);
- dump_stack();
+ if (unlikely(s->flags & SLAB_WARN_ON_ERROR))
+ WARN_ON(1);
+ else
+ dump_stack();
}
void object_err(struct kmem_cache *s, struct page *page,
@@ -705,7 +708,11 @@ static __printf(3, 4) void slab_err(stru
va_end(args);
slab_bug(s, "%s", buf);
print_page_info(page);
- dump_stack();
+
+ if (unlikely(s->flags & SLAB_WARN_ON_ERROR))
+ WARN_ON(1);
+ else
+ dump_stack();
}
static void init_object(struct kmem_cache *s, void *object, u8 val)
@@ -1254,6 +1261,9 @@ static int __init setup_slub_debug(char
case 'a':
slub_debug |= SLAB_FAILSLAB;
break;
+ case 'w':
+ slub_debug |= SLAB_WARN_ON_ERROR;
+ break;
case 'o':
/*
* Avoid enabling debugging on caches if its minimum
@@ -5219,6 +5229,25 @@ static ssize_t store_user_store(struct k
}
SLAB_ATTR(store_user);
+static ssize_t warn_on_error_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%d\n", !!(s->flags & SLAB_WARN_ON_ERROR));
+}
+
+static ssize_t warn_on_error_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ if (any_slab_objects(s))
+ return -EBUSY;
+
+ s->flags &= ~SLAB_WARN_ON_ERROR;
+ if (buf[0] == '1')
+ s->flags |= SLAB_WARN_ON_ERROR;
+
+ return length;
+}
+SLAB_ATTR(warn_on_error);
+
static ssize_t validate_show(struct kmem_cache *s, char *buf)
{
return 0;
@@ -5427,6 +5456,7 @@ static struct attribute *slab_attrs[] =
&validate_attr.attr,
&alloc_calls_attr.attr,
&free_calls_attr.attr,
+ &warn_on_error_attr.attr,
#endif
#ifdef CONFIG_ZONE_DMA
&cache_dma_attr.attr,
_
Patches currently in -mm which might be from miles.chen@xxxxxxxxxxxx are
mm-slub-introduce-slab_warn_on_error.patch
