Re: [slab] a1fd55538c: WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:2601 trace_hardirqs_on_caller()
From: Jesper Dangaard Brouer
Date: Sun Jan 31 2016 - 13:41:25 EST
On Sun, 31 Jan 2016 13:15:06 +1100
Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
> Hi Jesper,
>
> On Sat, 30 Jan 2016 18:46:46 +0100 Jesper Dangaard Brouer <brouer@xxxxxxxxxx> wrote:
> >
> > Let me know, if the linux-next tree need's an explicit fix?
>
> It would be a good idea if you could send a fix against linux-next to
> me as Andrew is currently travelling.
My analysis before was wrong, the fix was much simpler. No need to
revert my FAILSLAB patch. Just forgot to mask flags with gfp_allowed_mask.
I expect AKPM can pickup these two small fixes to my patches.
Below is a patch for linux-next.
- -
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer
[PATCH] mm: temporary fix for SLAB in linux-next
From: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
This is only for linux-next, until AKPM pickup fixes two patches:
base url: http://ozlabs.org/~akpm/mmots/broken-out/
[1] mm-fault-inject-take-over-bootstrap-kmem_cache-check.patch
[2] slab-use-slab_pre_alloc_hook-in-slab-allocator-shared-with-slub.patch
First fix is for compiling with CONFIG_FAILSLAB. The linux-next commit
needing this fix is 074b6f53c320 ("mm: fault-inject take over
bootstrap kmem_cache check").
Second fix is for correct masking of allowed GFP flags (gfp_allowed_mask),
in SLAB allocator. This triggered a WARN, by percpu_init_late ->
pcpu_mem_zalloc invoking kzalloc with GFP_KERNEL flags. The linux-next
commit needing this fix is a1fd55538cae ("slab: use
slab_pre_alloc_hook in SLAB allocator shared with SLUB").
Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
---
mm/failslab.c | 1 +
mm/slab.c | 2 ++
2 files changed, 3 insertions(+)
diff --git a/mm/failslab.c b/mm/failslab.c
index 0c5b3f31f310..b0fac98cd938 100644
--- a/mm/failslab.c
+++ b/mm/failslab.c
@@ -1,5 +1,6 @@
#include <linux/fault-inject.h>
#include <linux/slab.h>
+#include <linux/mm.h>
#include "slab.h"
static struct {
diff --git a/mm/slab.c b/mm/slab.c
index e90d259b3242..ddd974e6b3bb 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3190,6 +3190,7 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
void *ptr;
int slab_node = numa_mem_id();
+ flags &= gfp_allowed_mask;
cachep = slab_pre_alloc_hook(cachep, flags);
if (unlikely(!cachep))
return NULL;
@@ -3268,6 +3269,7 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
unsigned long save_flags;
void *objp;
+ flags &= gfp_allowed_mask;
cachep = slab_pre_alloc_hook(cachep, flags);
if (unlikely(!cachep))
return NULL;