Re: [PATCH] megaraid: kmemleak: Track page allocation for fusion
On Thu, Sep 14, 2017 at 02:16:46PM +0800, shuw...@redhat.com wrote:
> From: Shu Wang
>
> Kmemleak reports about a thousand false positives for fusion->
> cmd_list[]. Root casue is the cmd_list objects are allocated from
> slab allocator, and stored its pointer in object allocated by page
> allocator. The fix will tell kmemleak to track and scan fusion
> object.
>
> Before patch:
> kmemleak: 1004 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
>
> unreferenced object 0x88042584e000 (size 8192):
> backtrace:
> kmemleak_alloc+0x4a/0xa0
> __kmalloc+0xec/0x220
> megasas_alloc_cmdlist_fusion+0x3e/0x140 [megaraid_sas]
> megasas_alloc_cmds_fusion+0x44/0x450 [megaraid_sas]
> megasas_init_adapter_fusion+0x21d/0x6e0 [megaraid_sas]
> megasas_init_fw+0x357/0xd30 [megaraid_sas]
> megasas_probe_one.part.34+0x5be/0x1040 [megaraid_sas]
> megasas_probe_one+0x46/0xc0 [megaraid_sas]
> local_pci_probe+0x45/0xa0
> work_for_cpu_fn+0x14/0x20
> process_one_work+0x149/0x360
> worker_thread+0x1d8/0x3c0
> kthread+0x109/0x140
> ret_from_fork+0x25/0x30
>
> Signed-off-by: Shu Wang
> ---
> drivers/scsi/megaraid/megaraid_sas_fusion.c | 9 +++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> index 11bd2e698b84..621299edd8de 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> @@ -48,6 +48,7 @@
> #include
> #include
> #include
> +#include
>
> #include
> #include
> @@ -4512,7 +4513,9 @@ megasas_alloc_fusion_context(struct megasas_instance
> *instance)
> dev_err(&instance->pdev->dev, "Failed from %s %d\n",
> __func__, __LINE__);
> return -ENOMEM;
> }
> - }
> + } else
> + kmemleak_alloc(instance->ctrl_context,
> + sizeof(struct fusion_context), 1, GFP_KERNEL);
>
> fusion = instance->ctrl_context;
>
> @@ -4548,9 +4551,11 @@ megasas_free_fusion_context(struct megasas_instance
> *instance)
>
> if (is_vmalloc_addr(fusion))
> vfree(fusion);
> - else
> + else {
> free_pages((ulong)fusion,
> instance->ctrl_context_pages);
> + kmemleak_free(fusion);
> + }
Apart from Bart's comments on braces and comment before
kmemleak_alloc(), I'd call kmemleak_free() before free_pages(),
otherwise it may not interact nicely with other tools checking for use
after free. With that:
Reviewed-by: Catalin Marinas
--
Catalin
RE: [PATCH] megaraid: kmemleak: Track page allocation for fusion
-Original Message-
From: shuw...@redhat.com [mailto:shuw...@redhat.com]
Sent: Thursday, September 14, 2017 11:47 AM
To: kashyap.de...@broadcom.com; sumit.sax...@broadcom.com;
shivasharan.srikanteshw...@broadcom.com; j...@linux.vnet.ibm.com;
martin.peter...@oracle.com
Cc: megaraidlinux@broadcom.com; linux-s...@vger.kernel.org;
linux-kernel@vger.kernel.org; catalin.mari...@arm.com; liw...@redhat.com;
ch...@redhat.com; Shu Wang
Subject: [PATCH] megaraid: kmemleak: Track page allocation for fusion
From: Shu Wang
Kmemleak reports about a thousand false positives for fusion-> cmd_list[].
Root casue is the cmd_list objects are allocated from slab allocator, and
stored its pointer in object allocated by page allocator. The fix will
tell kmemleak to track and scan fusion object.
Before patch:
kmemleak: 1004 new suspected memory leaks (see /sys/kernel/debug/kmemleak)
unreferenced object 0x88042584e000 (size 8192):
backtrace:
kmemleak_alloc+0x4a/0xa0
__kmalloc+0xec/0x220
megasas_alloc_cmdlist_fusion+0x3e/0x140 [megaraid_sas]
megasas_alloc_cmds_fusion+0x44/0x450 [megaraid_sas]
megasas_init_adapter_fusion+0x21d/0x6e0 [megaraid_sas]
megasas_init_fw+0x357/0xd30 [megaraid_sas]
megasas_probe_one.part.34+0x5be/0x1040 [megaraid_sas]
megasas_probe_one+0x46/0xc0 [megaraid_sas]
local_pci_probe+0x45/0xa0
work_for_cpu_fn+0x14/0x20
process_one_work+0x149/0x360
worker_thread+0x1d8/0x3c0
kthread+0x109/0x140
ret_from_fork+0x25/0x30
Signed-off-by: Shu Wang
---
drivers/scsi/megaraid/megaraid_sas_fusion.c | 9 +++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c
b/drivers/scsi/megaraid/megaraid_sas_fusion.c
index 11bd2e698b84..621299edd8de 100644
--- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
+++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
@@ -48,6 +48,7 @@
#include
#include
#include
+#include
#include
#include
@@ -4512,7 +4513,9 @@ megasas_alloc_fusion_context(struct megasas_instance
*instance)
dev_err(&instance->pdev->dev, "Failed from %s
%d\n", __func__, __LINE__);
return -ENOMEM;
}
- }
+ } else
+ kmemleak_alloc(instance->ctrl_context,
+ sizeof(struct fusion_context), 1, GFP_KERNEL);
fusion = instance->ctrl_context;
@@ -4548,9 +4551,11 @@ megasas_free_fusion_context(struct megasas_instance
*instance)
if (is_vmalloc_addr(fusion))
vfree(fusion);
- else
+ else {
free_pages((ulong)fusion,
instance->ctrl_context_pages);
+ kmemleak_free(fusion);
+ }
}
}
Looks good. Thanks for catching this.
Acked-by: Sumit Saxena
--
2.13.5
Re: [PATCH] megaraid: kmemleak: Track page allocation for fusion
On Thu, 2017-09-14 at 14:16 +0800, shuw...@redhat.com wrote:
> diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> index 11bd2e698b84..621299edd8de 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
> @@ -48,6 +48,7 @@
> #include
> #include
> #include
> +#include
>
> #include
> #include
> @@ -4512,7 +4513,9 @@ megasas_alloc_fusion_context(struct megasas_instance
> *instance)
> dev_err(&instance->pdev->dev, "Failed from %s %d\n",
> __func__, __LINE__);
> return -ENOMEM;
> }
> - }
> + } else
> + kmemleak_alloc(instance->ctrl_context,
> + sizeof(struct fusion_context), 1, GFP_KERNEL);
>
> fusion = instance->ctrl_context;
Thank you for having tracked this down and for having shared this patch. But
please keep braces balanced to keep checkpatch happy and please also consider
adding a comment similar to the following above the kmemleak_alloc() call:
/* Allow kmemleak to scan these pages as they contain pointers to additional
allocations. */
> @@ -4548,9 +4551,11 @@ megasas_free_fusion_context(struct megasas_instance
> *instance)
>
> if (is_vmalloc_addr(fusion))
> vfree(fusion);
> - else
> + else {
> free_pages((ulong)fusion,
> instance->ctrl_context_pages);
> + kmemleak_free(fusion);
> + }
> }
Please keep braces balanced in the above code too.
Thanks,
Bart.
