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* Tracing memory leaks (slabs) in 2.6.9+ kernels?
@ 2005-03-02  8:17 Justin Schoeman
  2005-03-02  9:24 ` Andrew Morton
  2005-03-02  9:31 ` Alexander Nyberg
  0 siblings, 2 replies; 10+ messages in thread
From: Justin Schoeman @ 2005-03-02  8:17 UTC (permalink / raw)
  To: Linux Kernel Mailing List

Hi,

I am having a problem with memory leaking on a patched kernel.  In order 
to pinpoint the leak, I would like to try to trace the allocation points 
for the memory.

I have found some vague references to patches that allow the user to 
dump the caller address for slab allocations, but I cannot find the 
patch itself.

Can anybody please point me in the right direction - either for that 
patch, or any other way to track down leaking slabs?

Thank you,
Justin Schoeman

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: Tracing memory leaks (slabs) in 2.6.9+ kernels?
  2005-03-02  8:17 Tracing memory leaks (slabs) in 2.6.9+ kernels? Justin Schoeman
@ 2005-03-02  9:24 ` Andrew Morton
  2005-03-02 13:32   ` OGAWA Hirofumi
  2005-03-03 12:19   ` Justin Schoeman
  2005-03-02  9:31 ` Alexander Nyberg
  1 sibling, 2 replies; 10+ messages in thread
From: Andrew Morton @ 2005-03-02  9:24 UTC (permalink / raw)
  To: Justin Schoeman; +Cc: linux-kernel

Justin Schoeman <justin@expertron.co.za> wrote:
>
> I am having a problem with memory leaking on a patched kernel.  In order 
>  to pinpoint the leak, I would like to try to trace the allocation points 
>  for the memory.
> 
>  I have found some vague references to patches that allow the user to 
>  dump the caller address for slab allocations, but I cannot find the 
>  patch itself.
> 
>  Can anybody please point me in the right direction - either for that 
>  patch, or any other way to track down leaking slabs?


From: Manfred Spraul <manfred@colorfullife.com>

With the patch applied,

	echo "size-4096 0 0 0" > /proc/slabinfo

walks the objects in the size-4096 slab, printing out the calling address
of whoever allocated that object.

It is for leak detection.

Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 25-akpm/mm/slab.c |   40 ++++++++++++++++++++++++++++++++++++++--
 1 files changed, 38 insertions(+), 2 deletions(-)

diff -puN mm/slab.c~slab-leak-detector mm/slab.c
--- 25/mm/slab.c~slab-leak-detector	2005-02-15 21:06:44.000000000 -0800
+++ 25-akpm/mm/slab.c	2005-02-15 21:06:44.000000000 -0800
@@ -2116,6 +2116,15 @@ cache_alloc_debugcheck_after(kmem_cache_
 		*dbg_redzone1(cachep, objp) = RED_ACTIVE;
 		*dbg_redzone2(cachep, objp) = RED_ACTIVE;
 	}
+	{
+		int objnr;
+		struct slab *slabp;
+
+		slabp = GET_PAGE_SLAB(virt_to_page(objp));
+
+		objnr = (objp - slabp->s_mem) / cachep->objsize;
+		slab_bufctl(slabp)[objnr] = (unsigned long)caller;
+	}
 	objp += obj_dbghead(cachep);
 	if (cachep->ctor && cachep->flags & SLAB_POISON) {
 		unsigned long	ctor_flags = SLAB_CTOR_CONSTRUCTOR;
@@ -2179,12 +2188,14 @@ static void free_block(kmem_cache_t *cac
 		objnr = (objp - slabp->s_mem) / cachep->objsize;
 		check_slabp(cachep, slabp);
 #if DEBUG
+#if 0
 		if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
 			printk(KERN_ERR "slab: double free detected in cache '%s', objp %p.\n",
 						cachep->name, objp);
 			BUG();
 		}
 #endif
+#endif
 		slab_bufctl(slabp)[objnr] = slabp->free;
 		slabp->free = objnr;
 		STATS_DEC_ACTIVE(cachep);
@@ -2998,6 +3009,29 @@ struct seq_operations slabinfo_op = {
 	.show	= s_show,
 };
 
+static void do_dump_slabp(kmem_cache_t *cachep)
+{
+#if DEBUG
+	struct list_head *q;
+
+	check_irq_on();
+	spin_lock_irq(&cachep->spinlock);
+	list_for_each(q,&cachep->lists.slabs_full) {
+		struct slab *slabp;
+		int i;
+		slabp = list_entry(q, struct slab, list);
+		for (i = 0; i < cachep->num; i++) {
+			unsigned long sym = slab_bufctl(slabp)[i];
+
+			printk("obj %p/%d: %p", slabp, i, (void *)sym);
+			print_symbol(" <%s>", sym);
+			printk("\n");
+		}
+	}
+	spin_unlock_irq(&cachep->spinlock);
+#endif
+}
+
 #define MAX_SLABINFO_WRITE 128
 /**
  * slabinfo_write - Tuning for the slab allocator
@@ -3038,9 +3072,11 @@ ssize_t slabinfo_write(struct file *file
 			    batchcount < 1 ||
 			    batchcount > limit ||
 			    shared < 0) {
-				res = -EINVAL;
+				do_dump_slabp(cachep);
+				res = 0;
 			} else {
-				res = do_tune_cpucache(cachep, limit, batchcount, shared);
+				res = do_tune_cpucache(cachep, limit,
+							batchcount, shared);
 			}
 			break;
 		}
_


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: Tracing memory leaks (slabs) in 2.6.9+ kernels?
  2005-03-02  8:17 Tracing memory leaks (slabs) in 2.6.9+ kernels? Justin Schoeman
  2005-03-02  9:24 ` Andrew Morton
@ 2005-03-02  9:31 ` Alexander Nyberg
  1 sibling, 0 replies; 10+ messages in thread
From: Alexander Nyberg @ 2005-03-02  9:31 UTC (permalink / raw)
  To: Justin Schoeman; +Cc: Linux Kernel Mailing List

> I am having a problem with memory leaking on a patched kernel.  In order 
> to pinpoint the leak, I would like to try to trace the allocation points 
> for the memory.
> 
> I have found some vague references to patches that allow the user to 
> dump the caller address for slab allocations, but I cannot find the 
> patch itself.
> 
> Can anybody please point me in the right direction - either for that 
> patch, or any other way to track down leaking slabs?
> 

>From akpm:

Could you please use this patch?  Make sure that you enable
CONFIG_FRAME_POINTER (might not be needed for __builtin_return_address(0),
but let's be sure).  Also enable CONFIG_DEBUG_SLAB.



From: Manfred Spraul <manfred@colorfullife.com>

With the patch applied,

	echo "size-4096 0 0 0" > /proc/slabinfo

walks the objects in the size-4096 slab, printing out the calling address
of whoever allocated that object.

It is for leak detection.


diff -puN mm/slab.c~slab-leak-detector mm/slab.c
--- 25/mm/slab.c~slab-leak-detector	2005-02-15 21:06:44.000000000 -0800
+++ 25-akpm/mm/slab.c	2005-02-15 21:06:44.000000000 -0800
@@ -2116,6 +2116,15 @@ cache_alloc_debugcheck_after(kmem_cache_
 		*dbg_redzone1(cachep, objp) = RED_ACTIVE;
 		*dbg_redzone2(cachep, objp) = RED_ACTIVE;
 	}
+	{
+		int objnr;
+		struct slab *slabp;
+
+		slabp = GET_PAGE_SLAB(virt_to_page(objp));
+
+		objnr = (objp - slabp->s_mem) / cachep->objsize;
+		slab_bufctl(slabp)[objnr] = (unsigned long)caller;
+	}
 	objp += obj_dbghead(cachep);
 	if (cachep->ctor && cachep->flags & SLAB_POISON) {
 		unsigned long	ctor_flags = SLAB_CTOR_CONSTRUCTOR;
@@ -2179,12 +2188,14 @@ static void free_block(kmem_cache_t *cac
 		objnr = (objp - slabp->s_mem) / cachep->objsize;
 		check_slabp(cachep, slabp);
 #if DEBUG
+#if 0
 		if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
 			printk(KERN_ERR "slab: double free detected in cache '%s', objp %p.\n",
 						cachep->name, objp);
 			BUG();
 		}
 #endif
+#endif
 		slab_bufctl(slabp)[objnr] = slabp->free;
 		slabp->free = objnr;
 		STATS_DEC_ACTIVE(cachep);
@@ -2998,6 +3009,29 @@ struct seq_operations slabinfo_op = {
 	.show	= s_show,
 };
 
+static void do_dump_slabp(kmem_cache_t *cachep)
+{
+#if DEBUG
+	struct list_head *q;
+
+	check_irq_on();
+	spin_lock_irq(&cachep->spinlock);
+	list_for_each(q,&cachep->lists.slabs_full) {
+		struct slab *slabp;
+		int i;
+		slabp = list_entry(q, struct slab, list);
+		for (i = 0; i < cachep->num; i++) {
+			unsigned long sym = slab_bufctl(slabp)[i];
+
+			printk("obj %p/%d: %p", slabp, i, (void *)sym);
+			print_symbol(" <%s>", sym);
+			printk("\n");
+		}
+	}
+	spin_unlock_irq(&cachep->spinlock);
+#endif
+}
+
 #define MAX_SLABINFO_WRITE 128
 /**
  * slabinfo_write - Tuning for the slab allocator
@@ -3038,9 +3072,11 @@ ssize_t slabinfo_write(struct file *file
 			    batchcount < 1 ||
 			    batchcount > limit ||
 			    shared < 0) {
-				res = -EINVAL;
+				do_dump_slabp(cachep);
+				res = 0;
 			} else {
-				res = do_tune_cpucache(cachep, limit, batchcount, shared);
+				res = do_tune_cpucache(cachep, limit,
+							batchcount, shared);
 			}
 			break;
 		}
_




^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: Tracing memory leaks (slabs) in 2.6.9+ kernels?
  2005-03-02  9:24 ` Andrew Morton
@ 2005-03-02 13:32   ` OGAWA Hirofumi
  2005-03-02 16:32     ` Andrew Morton
  2005-03-03 12:19   ` Justin Schoeman
  1 sibling, 1 reply; 10+ messages in thread
From: OGAWA Hirofumi @ 2005-03-02 13:32 UTC (permalink / raw)
  To: Andrew Morton; +Cc: Justin Schoeman, linux-kernel

Andrew Morton <akpm@osdl.org> writes:

> +		slab_bufctl(slabp)[objnr] = (unsigned long)caller;

Umm... this patch looks strange..

slab_bufctl() returns "kmem_bufctl_t *", but kmem_bufctl_t is
"unsigned short".

I guess that this debug patch was broken by something else...
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: Tracing memory leaks (slabs) in 2.6.9+ kernels?
  2005-03-02 13:32   ` OGAWA Hirofumi
@ 2005-03-02 16:32     ` Andrew Morton
  2005-03-02 19:46       ` Manfred Spraul
  0 siblings, 1 reply; 10+ messages in thread
From: Andrew Morton @ 2005-03-02 16:32 UTC (permalink / raw)
  To: OGAWA Hirofumi; +Cc: justin, linux-kernel, Manfred Spraul

OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> wrote:
>
> Andrew Morton <akpm@osdl.org> writes:
> 
>  > +		slab_bufctl(slabp)[objnr] = (unsigned long)caller;
> 
>  Umm... this patch looks strange..
> 
>  slab_bufctl() returns "kmem_bufctl_t *", but kmem_bufctl_t is
>  "unsigned short".

Good point.   This seems to work.


From: Manfred Spraul <manfred@colorfullife.com>

With the patch applied,

	echo "size-4096 0 0 0" > /proc/slabinfo

walks the objects in the size-4096 slab, printing out the calling address
of whoever allocated that object.

It is for leak detection.

Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 25-akpm/include/asm-alpha/types.h   |    2 -
 25-akpm/include/asm-arm/types.h     |    2 -
 25-akpm/include/asm-arm26/types.h   |    2 -
 25-akpm/include/asm-cris/types.h    |    2 -
 25-akpm/include/asm-frv/types.h     |    2 -
 25-akpm/include/asm-h8300/types.h   |    2 -
 25-akpm/include/asm-i386/types.h    |    2 -
 25-akpm/include/asm-ia64/types.h    |    2 -
 25-akpm/include/asm-m32r/types.h    |    2 -
 25-akpm/include/asm-m68k/types.h    |    2 -
 25-akpm/include/asm-mips/types.h    |    2 -
 25-akpm/include/asm-parisc/types.h  |    2 -
 25-akpm/include/asm-ppc/types.h     |    2 -
 25-akpm/include/asm-ppc64/types.h   |    2 -
 25-akpm/include/asm-s390/types.h    |    2 -
 25-akpm/include/asm-sh/types.h      |    2 -
 25-akpm/include/asm-sh64/types.h    |    2 -
 25-akpm/include/asm-sparc/types.h   |    2 -
 25-akpm/include/asm-sparc64/types.h |    2 -
 25-akpm/include/asm-v850/types.h    |    2 -
 25-akpm/include/asm-x86_64/types.h  |    2 -
 25-akpm/mm/slab.c                   |   40 ++++++++++++++++++++++++++++++++++--
 22 files changed, 59 insertions(+), 23 deletions(-)

diff -puN include/asm-alpha/types.h~slab-leak-detector include/asm-alpha/types.h
--- 25/include/asm-alpha/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-alpha/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -56,7 +56,7 @@ typedef unsigned long u64;
 typedef u64 dma_addr_t;
 typedef u64 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 #endif /* __KERNEL__ */
diff -puN include/asm-arm26/types.h~slab-leak-detector include/asm-arm26/types.h
--- 25/include/asm-arm26/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-arm26/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -52,7 +52,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-arm/types.h~slab-leak-detector include/asm-arm/types.h
--- 25/include/asm-arm/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-arm/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -52,7 +52,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-cris/types.h~slab-leak-detector include/asm-cris/types.h
--- 25/include/asm-cris/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-cris/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -52,7 +52,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-frv/types.h~slab-leak-detector include/asm-frv/types.h
--- 25/include/asm-frv/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-frv/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -65,7 +65,7 @@ typedef u64 u_quad_t;
 
 typedef u32 dma_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-h8300/types.h~slab-leak-detector include/asm-h8300/types.h
--- 25/include/asm-h8300/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-h8300/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -58,7 +58,7 @@ typedef u32 dma_addr_t;
 #define HAVE_SECTOR_T
 typedef u64 sector_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __KERNEL__ */
 
diff -puN include/asm-i386/types.h~slab-leak-detector include/asm-i386/types.h
--- 25/include/asm-i386/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-i386/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -63,7 +63,7 @@ typedef u64 sector_t;
 #define HAVE_SECTOR_T
 #endif
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-ia64/types.h~slab-leak-detector include/asm-ia64/types.h
--- 25/include/asm-ia64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-ia64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -67,7 +67,7 @@ typedef __u64 u64;
 
 typedef u64 dma_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 # endif /* __KERNEL__ */
 #endif /* !__ASSEMBLY__ */
diff -puN include/asm-m32r/types.h~slab-leak-detector include/asm-m32r/types.h
--- 25/include/asm-m32r/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-m32r/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -55,7 +55,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u64 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-m68k/types.h~slab-leak-detector include/asm-m68k/types.h
--- 25/include/asm-m68k/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-m68k/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -60,7 +60,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-mips/types.h~slab-leak-detector include/asm-mips/types.h
--- 25/include/asm-mips/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-mips/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -99,7 +99,7 @@ typedef u64 sector_t;
 #define HAVE_SECTOR_T
 #endif
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-parisc/types.h~slab-leak-detector include/asm-parisc/types.h
--- 25/include/asm-parisc/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-parisc/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -56,7 +56,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u64 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-ppc64/types.h~slab-leak-detector include/asm-ppc64/types.h
--- 25/include/asm-ppc64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-ppc64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -72,7 +72,7 @@ typedef struct {
 	unsigned long env;
 } func_descr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
diff -puN include/asm-ppc/types.h~slab-leak-detector include/asm-ppc/types.h
--- 25/include/asm-ppc/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-ppc/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -62,7 +62,7 @@ typedef u64 sector_t;
 #define HAVE_SECTOR_T
 #endif
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-s390/types.h~slab-leak-detector include/asm-s390/types.h
--- 25/include/asm-s390/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-s390/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -79,7 +79,7 @@ typedef unsigned  long u64;
 
 typedef u32 dma_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #ifndef __s390x__
 typedef union {
diff -puN include/asm-sh64/types.h~slab-leak-detector include/asm-sh64/types.h
--- 25/include/asm-sh64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-sh64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -65,7 +65,7 @@ typedef u32 dma_addr_t;
 #endif
 typedef u64 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-sh/types.h~slab-leak-detector include/asm-sh/types.h
--- 25/include/asm-sh/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-sh/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -58,7 +58,7 @@ typedef u64 sector_t;
 #define HAVE_SECTOR_T
 #endif
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-sparc64/types.h~slab-leak-detector include/asm-sparc64/types.h
--- 25/include/asm-sparc64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-sparc64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -56,7 +56,7 @@ typedef unsigned long u64;
 typedef u32 dma_addr_t;
 typedef u64 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-sparc/types.h~slab-leak-detector include/asm-sparc/types.h
--- 25/include/asm-sparc/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-sparc/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -54,7 +54,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-v850/types.h~slab-leak-detector include/asm-v850/types.h
--- 25/include/asm-v850/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-v850/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -59,7 +59,7 @@ typedef unsigned long long u64;
 
 typedef u32 dma_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* !__ASSEMBLY__ */
 
diff -puN include/asm-x86_64/types.h~slab-leak-detector include/asm-x86_64/types.h
--- 25/include/asm-x86_64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-x86_64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -51,7 +51,7 @@ typedef u64 dma_addr_t;
 typedef u64 sector_t;
 #define HAVE_SECTOR_T
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN mm/slab.c~slab-leak-detector mm/slab.c
--- 25/mm/slab.c~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/mm/slab.c	2005-03-02 08:30:59.000000000 -0800
@@ -2116,6 +2116,15 @@ cache_alloc_debugcheck_after(kmem_cache_
 		*dbg_redzone1(cachep, objp) = RED_ACTIVE;
 		*dbg_redzone2(cachep, objp) = RED_ACTIVE;
 	}
+	{
+		int objnr;
+		struct slab *slabp;
+
+		slabp = GET_PAGE_SLAB(virt_to_page(objp));
+
+		objnr = (objp - slabp->s_mem) / cachep->objsize;
+		slab_bufctl(slabp)[objnr] = (unsigned long)caller;
+	}
 	objp += obj_dbghead(cachep);
 	if (cachep->ctor && cachep->flags & SLAB_POISON) {
 		unsigned long	ctor_flags = SLAB_CTOR_CONSTRUCTOR;
@@ -2179,12 +2188,14 @@ static void free_block(kmem_cache_t *cac
 		objnr = (objp - slabp->s_mem) / cachep->objsize;
 		check_slabp(cachep, slabp);
 #if DEBUG
+#if 0
 		if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
 			printk(KERN_ERR "slab: double free detected in cache '%s', objp %p.\n",
 						cachep->name, objp);
 			BUG();
 		}
 #endif
+#endif
 		slab_bufctl(slabp)[objnr] = slabp->free;
 		slabp->free = objnr;
 		STATS_DEC_ACTIVE(cachep);
@@ -2998,6 +3009,29 @@ struct seq_operations slabinfo_op = {
 	.show	= s_show,
 };
 
+static void do_dump_slabp(kmem_cache_t *cachep)
+{
+#if DEBUG
+	struct list_head *q;
+
+	check_irq_on();
+	spin_lock_irq(&cachep->spinlock);
+	list_for_each(q,&cachep->lists.slabs_full) {
+		struct slab *slabp;
+		int i;
+		slabp = list_entry(q, struct slab, list);
+		for (i = 0; i < cachep->num; i++) {
+			unsigned long sym = slab_bufctl(slabp)[i];
+
+			printk("obj %p/%d: %p", slabp, i, (void *)sym);
+			print_symbol(" <%s>", sym);
+			printk("\n");
+		}
+	}
+	spin_unlock_irq(&cachep->spinlock);
+#endif
+}
+
 #define MAX_SLABINFO_WRITE 128
 /**
  * slabinfo_write - Tuning for the slab allocator
@@ -3038,9 +3072,11 @@ ssize_t slabinfo_write(struct file *file
 			    batchcount < 1 ||
 			    batchcount > limit ||
 			    shared < 0) {
-				res = -EINVAL;
+				do_dump_slabp(cachep);
+				res = 0;
 			} else {
-				res = do_tune_cpucache(cachep, limit, batchcount, shared);
+				res = do_tune_cpucache(cachep, limit,
+							batchcount, shared);
 			}
 			break;
 		}
_


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: Tracing memory leaks (slabs) in 2.6.9+ kernels?
  2005-03-02 16:32     ` Andrew Morton
@ 2005-03-02 19:46       ` Manfred Spraul
  0 siblings, 0 replies; 10+ messages in thread
From: Manfred Spraul @ 2005-03-02 19:46 UTC (permalink / raw)
  To: Andrew Morton; +Cc: OGAWA Hirofumi, justin, linux-kernel

[-- Attachment #1: Type: text/plain, Size: 597 bytes --]

Andrew Morton wrote:

>OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> wrote:
>  
>
>>Andrew Morton <akpm@osdl.org> writes:
>>
>> > +		slab_bufctl(slabp)[objnr] = (unsigned long)caller;
>>
>> Umm... this patch looks strange..
>>
>> slab_bufctl() returns "kmem_bufctl_t *", but kmem_bufctl_t is
>> "unsigned short".
>>    
>>
>
>Good point.   This seems to work.
>
>  
>
Two updates are needed for the leak detection in recent kernels:
- set kmem_bufctl_t back to unsigned long
- relax the check in check_slabuse, something like the attached patch.

Note that the patch is not tested.

--
    Manfred

[-- Attachment #2: patch-recent-leak --]
[-- Type: text/plain, Size: 973 bytes --]

--- 2.6/mm/slab.c	2005-03-02 20:44:47.738737171 +0100
+++ build-2.6/mm/slab.c	2005-03-02 20:44:15.290618759 +0100
@@ -2645,18 +2642,10 @@
 		red1 = *dbg_redzone1(cachep, objp);
 		red2 = *dbg_redzone2(cachep, objp);
 
-		/* simplest case: marked as inactive */
-		if (red1 == RED_INACTIVE && red2 == RED_INACTIVE)
-			continue;
-
-		/* tricky case: if the bufctl value is BUFCTL_ALLOC, then
-		 * the object is either allocated or somewhere in a cpu
-		 * cache. The cpu caches are lockless and there might be
-		 * a concurrent alloc/free call, thus we must accept random
-		 * combinations of RED_ACTIVE and _INACTIVE
+		/* leak detection stores the caller address in the bufctl,
+		 * thus random combinations of active and inactive are ok
 		 */
-		if (slab_bufctl(slabp)[i] == BUFCTL_ALLOC &&
-				(red1 == RED_INACTIVE || red1 == RED_ACTIVE) &&
+		if ((red1 == RED_INACTIVE || red1 == RED_ACTIVE) &&
 				(red2 == RED_INACTIVE || red2 == RED_ACTIVE))
 			continue;
 

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: Tracing memory leaks (slabs) in 2.6.9+ kernels?
  2005-03-02  9:24 ` Andrew Morton
  2005-03-02 13:32   ` OGAWA Hirofumi
@ 2005-03-03 12:19   ` Justin Schoeman
  2005-03-03 12:26     ` Andrew Morton
  1 sibling, 1 reply; 10+ messages in thread
From: Justin Schoeman @ 2005-03-03 12:19 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-kernel

OK - I have the patch working now, but there seems to be a flaw in the 
address reporting. When I look up the reported address in 
/proc/kallsyms, then look in the objdump of the module, the reported 
adress _does_not_ point to a call.

Am I missing something simple here?

Justin

Andrew Morton wrote:
> Justin Schoeman <justin@expertron.co.za> wrote:
> 
>>I am having a problem with memory leaking on a patched kernel.  In order 
>> to pinpoint the leak, I would like to try to trace the allocation points 
>> for the memory.
>>
>> I have found some vague references to patches that allow the user to 
>> dump the caller address for slab allocations, but I cannot find the 
>> patch itself.
>>
>> Can anybody please point me in the right direction - either for that 
>> patch, or any other way to track down leaking slabs?
> 
> 
> 
> From: Manfred Spraul <manfred@colorfullife.com>
> 
> With the patch applied,
> 
> 	echo "size-4096 0 0 0" > /proc/slabinfo
> 
> walks the objects in the size-4096 slab, printing out the calling address
> of whoever allocated that object.
> 
> It is for leak detection.
...

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: Tracing memory leaks (slabs) in 2.6.9+ kernels?
  2005-03-03 12:19   ` Justin Schoeman
@ 2005-03-03 12:26     ` Andrew Morton
  2005-03-04  7:48       ` Justin Schoeman
  0 siblings, 1 reply; 10+ messages in thread
From: Andrew Morton @ 2005-03-03 12:26 UTC (permalink / raw)
  To: Justin Schoeman; +Cc: linux-kernel

Justin Schoeman <justin@expertron.co.za> wrote:
>
> OK - I have the patch working now, but there seems to be a flaw in the 
>  address reporting. When I look up the reported address in 
>  /proc/kallsyms, then look in the objdump of the module, the reported 
>  adress _does_not_ point to a call.
> 
>  Am I missing something simple here?

Use the latest version of the patch (below).  Link the module into the
kernel.  Enable CONFIG_KALLSYMS.

--- 25/include/asm-alpha/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-alpha/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -56,7 +56,7 @@ typedef unsigned long u64;
 typedef u64 dma_addr_t;
 typedef u64 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 #endif /* __KERNEL__ */
diff -puN include/asm-arm26/types.h~slab-leak-detector include/asm-arm26/types.h
--- 25/include/asm-arm26/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-arm26/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -52,7 +52,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-arm/types.h~slab-leak-detector include/asm-arm/types.h
--- 25/include/asm-arm/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-arm/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -52,7 +52,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-cris/types.h~slab-leak-detector include/asm-cris/types.h
--- 25/include/asm-cris/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-cris/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -52,7 +52,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-frv/types.h~slab-leak-detector include/asm-frv/types.h
--- 25/include/asm-frv/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-frv/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -65,7 +65,7 @@ typedef u64 u_quad_t;
 
 typedef u32 dma_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-h8300/types.h~slab-leak-detector include/asm-h8300/types.h
--- 25/include/asm-h8300/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-h8300/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -58,7 +58,7 @@ typedef u32 dma_addr_t;
 #define HAVE_SECTOR_T
 typedef u64 sector_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __KERNEL__ */
 
diff -puN include/asm-i386/types.h~slab-leak-detector include/asm-i386/types.h
--- 25/include/asm-i386/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-i386/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -63,7 +63,7 @@ typedef u64 sector_t;
 #define HAVE_SECTOR_T
 #endif
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-ia64/types.h~slab-leak-detector include/asm-ia64/types.h
--- 25/include/asm-ia64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-ia64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -67,7 +67,7 @@ typedef __u64 u64;
 
 typedef u64 dma_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 # endif /* __KERNEL__ */
 #endif /* !__ASSEMBLY__ */
diff -puN include/asm-m32r/types.h~slab-leak-detector include/asm-m32r/types.h
--- 25/include/asm-m32r/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-m32r/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -55,7 +55,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u64 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-m68k/types.h~slab-leak-detector include/asm-m68k/types.h
--- 25/include/asm-m68k/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-m68k/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -60,7 +60,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-mips/types.h~slab-leak-detector include/asm-mips/types.h
--- 25/include/asm-mips/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-mips/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -99,7 +99,7 @@ typedef u64 sector_t;
 #define HAVE_SECTOR_T
 #endif
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-parisc/types.h~slab-leak-detector include/asm-parisc/types.h
--- 25/include/asm-parisc/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-parisc/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -56,7 +56,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u64 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-ppc64/types.h~slab-leak-detector include/asm-ppc64/types.h
--- 25/include/asm-ppc64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-ppc64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -72,7 +72,7 @@ typedef struct {
 	unsigned long env;
 } func_descr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 #endif /* __ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
diff -puN include/asm-ppc/types.h~slab-leak-detector include/asm-ppc/types.h
--- 25/include/asm-ppc/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-ppc/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -62,7 +62,7 @@ typedef u64 sector_t;
 #define HAVE_SECTOR_T
 #endif
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-s390/types.h~slab-leak-detector include/asm-s390/types.h
--- 25/include/asm-s390/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-s390/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -79,7 +79,7 @@ typedef unsigned  long u64;
 
 typedef u32 dma_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #ifndef __s390x__
 typedef union {
diff -puN include/asm-sh64/types.h~slab-leak-detector include/asm-sh64/types.h
--- 25/include/asm-sh64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-sh64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -65,7 +65,7 @@ typedef u32 dma_addr_t;
 #endif
 typedef u64 dma64_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-sh/types.h~slab-leak-detector include/asm-sh/types.h
--- 25/include/asm-sh/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-sh/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -58,7 +58,7 @@ typedef u64 sector_t;
 #define HAVE_SECTOR_T
 #endif
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-sparc64/types.h~slab-leak-detector include/asm-sparc64/types.h
--- 25/include/asm-sparc64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-sparc64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -56,7 +56,7 @@ typedef unsigned long u64;
 typedef u32 dma_addr_t;
 typedef u64 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-sparc/types.h~slab-leak-detector include/asm-sparc/types.h
--- 25/include/asm-sparc/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-sparc/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -54,7 +54,7 @@ typedef unsigned long long u64;
 typedef u32 dma_addr_t;
 typedef u32 dma64_addr_t;
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN include/asm-v850/types.h~slab-leak-detector include/asm-v850/types.h
--- 25/include/asm-v850/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-v850/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -59,7 +59,7 @@ typedef unsigned long long u64;
 
 typedef u32 dma_addr_t;
 
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* !__ASSEMBLY__ */
 
diff -puN include/asm-x86_64/types.h~slab-leak-detector include/asm-x86_64/types.h
--- 25/include/asm-x86_64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/include/asm-x86_64/types.h	2005-03-02 08:30:59.000000000 -0800
@@ -51,7 +51,7 @@ typedef u64 dma_addr_t;
 typedef u64 sector_t;
 #define HAVE_SECTOR_T
 
-typedef unsigned short kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
 
 #endif /* __ASSEMBLY__ */
 
diff -puN mm/slab.c~slab-leak-detector mm/slab.c
--- 25/mm/slab.c~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
+++ 25-akpm/mm/slab.c	2005-03-02 08:30:59.000000000 -0800
@@ -2116,6 +2116,15 @@ cache_alloc_debugcheck_after(kmem_cache_
 		*dbg_redzone1(cachep, objp) = RED_ACTIVE;
 		*dbg_redzone2(cachep, objp) = RED_ACTIVE;
 	}
+	{
+		int objnr;
+		struct slab *slabp;
+
+		slabp = GET_PAGE_SLAB(virt_to_page(objp));
+
+		objnr = (objp - slabp->s_mem) / cachep->objsize;
+		slab_bufctl(slabp)[objnr] = (unsigned long)caller;
+	}
 	objp += obj_dbghead(cachep);
 	if (cachep->ctor && cachep->flags & SLAB_POISON) {
 		unsigned long	ctor_flags = SLAB_CTOR_CONSTRUCTOR;
@@ -2179,12 +2188,14 @@ static void free_block(kmem_cache_t *cac
 		objnr = (objp - slabp->s_mem) / cachep->objsize;
 		check_slabp(cachep, slabp);
 #if DEBUG
+#if 0
 		if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
 			printk(KERN_ERR "slab: double free detected in cache '%s', objp %p.\n",
 						cachep->name, objp);
 			BUG();
 		}
 #endif
+#endif
 		slab_bufctl(slabp)[objnr] = slabp->free;
 		slabp->free = objnr;
 		STATS_DEC_ACTIVE(cachep);
@@ -2998,6 +3009,29 @@ struct seq_operations slabinfo_op = {
 	.show	= s_show,
 };
 
+static void do_dump_slabp(kmem_cache_t *cachep)
+{
+#if DEBUG
+	struct list_head *q;
+
+	check_irq_on();
+	spin_lock_irq(&cachep->spinlock);
+	list_for_each(q,&cachep->lists.slabs_full) {
+		struct slab *slabp;
+		int i;
+		slabp = list_entry(q, struct slab, list);
+		for (i = 0; i < cachep->num; i++) {
+			unsigned long sym = slab_bufctl(slabp)[i];
+
+			printk("obj %p/%d: %p", slabp, i, (void *)sym);
+			print_symbol(" <%s>", sym);
+			printk("\n");
+		}
+	}
+	spin_unlock_irq(&cachep->spinlock);
+#endif
+}
+
 #define MAX_SLABINFO_WRITE 128
 /**
  * slabinfo_write - Tuning for the slab allocator
@@ -3038,9 +3072,11 @@ ssize_t slabinfo_write(struct file *file
 			    batchcount < 1 ||
 			    batchcount > limit ||
 			    shared < 0) {
-				res = -EINVAL;
+				do_dump_slabp(cachep);
+				res = 0;
 			} else {
-				res = do_tune_cpucache(cachep, limit, batchcount, shared);
+				res = do_tune_cpucache(cachep, limit,
+							batchcount, shared);
 			}
 			break;
 		}
_


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: Tracing memory leaks (slabs) in 2.6.9+ kernels?
  2005-03-03 12:26     ` Andrew Morton
@ 2005-03-04  7:48       ` Justin Schoeman
  2005-03-04  7:56         ` Andrew Morton
  0 siblings, 1 reply; 10+ messages in thread
From: Justin Schoeman @ 2005-03-04  7:48 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-kernel

Thanks everybody for your help.  I have at least located the site of the 
leak - now I just need to find out why the destructor is not being 
called ;-).

Will the slab debugger make it into the kernel as a standard compile 
time option?  It is a _really_ usefull tool to have around.

Thanks again,
Justin

Andrew Morton wrote:
> Justin Schoeman <justin@expertron.co.za> wrote:
> 
>>OK - I have the patch working now, but there seems to be a flaw in the 
>> address reporting. When I look up the reported address in 
>> /proc/kallsyms, then look in the objdump of the module, the reported 
>> adress _does_not_ point to a call.
>>
>> Am I missing something simple here?
> 
> 
> Use the latest version of the patch (below).  Link the module into the
> kernel.  Enable CONFIG_KALLSYMS.
> 
> --- 25/include/asm-alpha/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-alpha/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -56,7 +56,7 @@ typedef unsigned long u64;
>  typedef u64 dma_addr_t;
>  typedef u64 dma64_addr_t;
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  #endif /* __KERNEL__ */
> diff -puN include/asm-arm26/types.h~slab-leak-detector include/asm-arm26/types.h
> --- 25/include/asm-arm26/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-arm26/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -52,7 +52,7 @@ typedef unsigned long long u64;
>  typedef u32 dma_addr_t;
>  typedef u32 dma64_addr_t;
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-arm/types.h~slab-leak-detector include/asm-arm/types.h
> --- 25/include/asm-arm/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-arm/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -52,7 +52,7 @@ typedef unsigned long long u64;
>  typedef u32 dma_addr_t;
>  typedef u32 dma64_addr_t;
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-cris/types.h~slab-leak-detector include/asm-cris/types.h
> --- 25/include/asm-cris/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-cris/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -52,7 +52,7 @@ typedef unsigned long long u64;
>  typedef u32 dma_addr_t;
>  typedef u32 dma64_addr_t;
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-frv/types.h~slab-leak-detector include/asm-frv/types.h
> --- 25/include/asm-frv/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-frv/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -65,7 +65,7 @@ typedef u64 u_quad_t;
>  
>  typedef u32 dma_addr_t;
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-h8300/types.h~slab-leak-detector include/asm-h8300/types.h
> --- 25/include/asm-h8300/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-h8300/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -58,7 +58,7 @@ typedef u32 dma_addr_t;
>  #define HAVE_SECTOR_T
>  typedef u64 sector_t;
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __KERNEL__ */
>  
> diff -puN include/asm-i386/types.h~slab-leak-detector include/asm-i386/types.h
> --- 25/include/asm-i386/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-i386/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -63,7 +63,7 @@ typedef u64 sector_t;
>  #define HAVE_SECTOR_T
>  #endif
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-ia64/types.h~slab-leak-detector include/asm-ia64/types.h
> --- 25/include/asm-ia64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-ia64/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -67,7 +67,7 @@ typedef __u64 u64;
>  
>  typedef u64 dma_addr_t;
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  # endif /* __KERNEL__ */
>  #endif /* !__ASSEMBLY__ */
> diff -puN include/asm-m32r/types.h~slab-leak-detector include/asm-m32r/types.h
> --- 25/include/asm-m32r/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-m32r/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -55,7 +55,7 @@ typedef unsigned long long u64;
>  typedef u32 dma_addr_t;
>  typedef u64 dma64_addr_t;
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-m68k/types.h~slab-leak-detector include/asm-m68k/types.h
> --- 25/include/asm-m68k/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-m68k/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -60,7 +60,7 @@ typedef unsigned long long u64;
>  typedef u32 dma_addr_t;
>  typedef u32 dma64_addr_t;
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-mips/types.h~slab-leak-detector include/asm-mips/types.h
> --- 25/include/asm-mips/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-mips/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -99,7 +99,7 @@ typedef u64 sector_t;
>  #define HAVE_SECTOR_T
>  #endif
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-parisc/types.h~slab-leak-detector include/asm-parisc/types.h
> --- 25/include/asm-parisc/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-parisc/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -56,7 +56,7 @@ typedef unsigned long long u64;
>  typedef u32 dma_addr_t;
>  typedef u64 dma64_addr_t;
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-ppc64/types.h~slab-leak-detector include/asm-ppc64/types.h
> --- 25/include/asm-ppc64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-ppc64/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -72,7 +72,7 @@ typedef struct {
>  	unsigned long env;
>  } func_descr_t;
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  #endif /* __ASSEMBLY__ */
>  
>  #endif /* __KERNEL__ */
> diff -puN include/asm-ppc/types.h~slab-leak-detector include/asm-ppc/types.h
> --- 25/include/asm-ppc/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-ppc/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -62,7 +62,7 @@ typedef u64 sector_t;
>  #define HAVE_SECTOR_T
>  #endif
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-s390/types.h~slab-leak-detector include/asm-s390/types.h
> --- 25/include/asm-s390/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-s390/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -79,7 +79,7 @@ typedef unsigned  long u64;
>  
>  typedef u32 dma_addr_t;
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #ifndef __s390x__
>  typedef union {
> diff -puN include/asm-sh64/types.h~slab-leak-detector include/asm-sh64/types.h
> --- 25/include/asm-sh64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-sh64/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -65,7 +65,7 @@ typedef u32 dma_addr_t;
>  #endif
>  typedef u64 dma64_addr_t;
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-sh/types.h~slab-leak-detector include/asm-sh/types.h
> --- 25/include/asm-sh/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-sh/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -58,7 +58,7 @@ typedef u64 sector_t;
>  #define HAVE_SECTOR_T
>  #endif
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-sparc64/types.h~slab-leak-detector include/asm-sparc64/types.h
> --- 25/include/asm-sparc64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-sparc64/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -56,7 +56,7 @@ typedef unsigned long u64;
>  typedef u32 dma_addr_t;
>  typedef u64 dma64_addr_t;
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-sparc/types.h~slab-leak-detector include/asm-sparc/types.h
> --- 25/include/asm-sparc/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-sparc/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -54,7 +54,7 @@ typedef unsigned long long u64;
>  typedef u32 dma_addr_t;
>  typedef u32 dma64_addr_t;
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN include/asm-v850/types.h~slab-leak-detector include/asm-v850/types.h
> --- 25/include/asm-v850/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-v850/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -59,7 +59,7 @@ typedef unsigned long long u64;
>  
>  typedef u32 dma_addr_t;
>  
> -typedef unsigned int kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* !__ASSEMBLY__ */
>  
> diff -puN include/asm-x86_64/types.h~slab-leak-detector include/asm-x86_64/types.h
> --- 25/include/asm-x86_64/types.h~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/include/asm-x86_64/types.h	2005-03-02 08:30:59.000000000 -0800
> @@ -51,7 +51,7 @@ typedef u64 dma_addr_t;
>  typedef u64 sector_t;
>  #define HAVE_SECTOR_T
>  
> -typedef unsigned short kmem_bufctl_t;
> +typedef unsigned long kmem_bufctl_t;
>  
>  #endif /* __ASSEMBLY__ */
>  
> diff -puN mm/slab.c~slab-leak-detector mm/slab.c
> --- 25/mm/slab.c~slab-leak-detector	2005-03-02 08:30:59.000000000 -0800
> +++ 25-akpm/mm/slab.c	2005-03-02 08:30:59.000000000 -0800
> @@ -2116,6 +2116,15 @@ cache_alloc_debugcheck_after(kmem_cache_
>  		*dbg_redzone1(cachep, objp) = RED_ACTIVE;
>  		*dbg_redzone2(cachep, objp) = RED_ACTIVE;
>  	}
> +	{
> +		int objnr;
> +		struct slab *slabp;
> +
> +		slabp = GET_PAGE_SLAB(virt_to_page(objp));
> +
> +		objnr = (objp - slabp->s_mem) / cachep->objsize;
> +		slab_bufctl(slabp)[objnr] = (unsigned long)caller;
> +	}
>  	objp += obj_dbghead(cachep);
>  	if (cachep->ctor && cachep->flags & SLAB_POISON) {
>  		unsigned long	ctor_flags = SLAB_CTOR_CONSTRUCTOR;
> @@ -2179,12 +2188,14 @@ static void free_block(kmem_cache_t *cac
>  		objnr = (objp - slabp->s_mem) / cachep->objsize;
>  		check_slabp(cachep, slabp);
>  #if DEBUG
> +#if 0
>  		if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
>  			printk(KERN_ERR "slab: double free detected in cache '%s', objp %p.\n",
>  						cachep->name, objp);
>  			BUG();
>  		}
>  #endif
> +#endif
>  		slab_bufctl(slabp)[objnr] = slabp->free;
>  		slabp->free = objnr;
>  		STATS_DEC_ACTIVE(cachep);
> @@ -2998,6 +3009,29 @@ struct seq_operations slabinfo_op = {
>  	.show	= s_show,
>  };
>  
> +static void do_dump_slabp(kmem_cache_t *cachep)
> +{
> +#if DEBUG
> +	struct list_head *q;
> +
> +	check_irq_on();
> +	spin_lock_irq(&cachep->spinlock);
> +	list_for_each(q,&cachep->lists.slabs_full) {
> +		struct slab *slabp;
> +		int i;
> +		slabp = list_entry(q, struct slab, list);
> +		for (i = 0; i < cachep->num; i++) {
> +			unsigned long sym = slab_bufctl(slabp)[i];
> +
> +			printk("obj %p/%d: %p", slabp, i, (void *)sym);
> +			print_symbol(" <%s>", sym);
> +			printk("\n");
> +		}
> +	}
> +	spin_unlock_irq(&cachep->spinlock);
> +#endif
> +}
> +
>  #define MAX_SLABINFO_WRITE 128
>  /**
>   * slabinfo_write - Tuning for the slab allocator
> @@ -3038,9 +3072,11 @@ ssize_t slabinfo_write(struct file *file
>  			    batchcount < 1 ||
>  			    batchcount > limit ||
>  			    shared < 0) {
> -				res = -EINVAL;
> +				do_dump_slabp(cachep);
> +				res = 0;
>  			} else {
> -				res = do_tune_cpucache(cachep, limit, batchcount, shared);
> +				res = do_tune_cpucache(cachep, limit,
> +							batchcount, shared);
>  			}
>  			break;
>  		}
> _
> 
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: Tracing memory leaks (slabs) in 2.6.9+ kernels?
  2005-03-04  7:48       ` Justin Schoeman
@ 2005-03-04  7:56         ` Andrew Morton
  0 siblings, 0 replies; 10+ messages in thread
From: Andrew Morton @ 2005-03-04  7:56 UTC (permalink / raw)
  To: Justin Schoeman; +Cc: linux-kernel

Justin Schoeman <justin@expertron.co.za> wrote:
>
> Will the slab debugger make it into the kernel as a standard compile 
>  time option?  It is a _really_ usefull tool to have around.

It has a slight downside: it unconditionally changes the type of
kmem_bufctl_t to unsigned long, which wastes two or four bytes per page of
slab.

I suppose we could fix that up with suitable use of CONFIG_DEBUG_SLAB.

^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2005-03-04  7:58 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-03-02  8:17 Tracing memory leaks (slabs) in 2.6.9+ kernels? Justin Schoeman
2005-03-02  9:24 ` Andrew Morton
2005-03-02 13:32   ` OGAWA Hirofumi
2005-03-02 16:32     ` Andrew Morton
2005-03-02 19:46       ` Manfred Spraul
2005-03-03 12:19   ` Justin Schoeman
2005-03-03 12:26     ` Andrew Morton
2005-03-04  7:48       ` Justin Schoeman
2005-03-04  7:56         ` Andrew Morton
2005-03-02  9:31 ` Alexander Nyberg

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