* [PATCH] libnvdimm/pmem: Fix blk_cleanup_disk() usage
@ 2021-06-07 23:31 Dan Williams
2021-06-07 23:52 ` [PATCH v2] " Dan Williams
0 siblings, 1 reply; 5+ messages in thread
From: Dan Williams @ 2021-06-07 23:31 UTC (permalink / raw)
To: axboe
Cc: Sachin Sant, Christoph Hellwig, Ulf Hansson, nvdimm, linux-block,
linuxppc-dev
The queue_to_disk() helper can not be used after del_gendisk()
communicate @disk via the pgmap->owner.
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Fixes: 87eb73b2ca7c ("nvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
Jens,
Please take or fold this into your tree after Sachin has a chance
to test it out. It's passing my tests.
drivers/nvdimm/pmem.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 31f3c4bd6f72..fc6b78dd2d24 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -337,8 +337,9 @@ static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap)
{
struct request_queue *q =
container_of(pgmap->ref, struct request_queue, q_usage_counter);
+ struct pmem_device *pmem = pgmap->owner;
- blk_cleanup_disk(queue_to_disk(q));
+ blk_cleanup_disk(pmem->disk);
}
static void pmem_release_queue(void *pgmap)
@@ -427,6 +428,7 @@ static int pmem_attach_disk(struct device *dev,
q = disk->queue;
pmem->disk = disk;
+ pmem->pgmap.owner = pmem;
pmem->pfn_flags = PFN_DEV;
pmem->pgmap.ref = &q->q_usage_counter;
if (is_nd_pfn(dev)) {
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2] libnvdimm/pmem: Fix blk_cleanup_disk() usage
2021-06-07 23:31 [PATCH] libnvdimm/pmem: Fix blk_cleanup_disk() usage Dan Williams
@ 2021-06-07 23:52 ` Dan Williams
2021-06-08 5:36 ` Christoph Hellwig
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Dan Williams @ 2021-06-07 23:52 UTC (permalink / raw)
To: axboe
Cc: Sachin Sant, Christoph Hellwig, Ulf Hansson, nvdimm, linux-block,
linuxppc-dev
The queue_to_disk() helper can not be used after del_gendisk()
communicate @disk via the pgmap->owner.
Otherwise, queue_to_disk() returns NULL resulting in the splat below.
Kernel attempted to read user page (330) - exploit attempt? (uid: 0)
BUG: Kernel NULL pointer dereference on read at 0x00000330
Faulting instruction address: 0xc000000000906344
Oops: Kernel access of bad area, sig: 11 [#1]
[..]
NIP [c000000000906344] pmem_pagemap_cleanup+0x24/0x40
LR [c0000000004701d4] memunmap_pages+0x1b4/0x4b0
Call Trace:
[c000000022cbb9c0] [c0000000009063c8] pmem_pagemap_kill+0x28/0x40 (unreliable)
[c000000022cbb9e0] [c0000000004701d4] memunmap_pages+0x1b4/0x4b0
[c000000022cbba90] [c0000000008b28a0] devm_action_release+0x30/0x50
[c000000022cbbab0] [c0000000008b39c8] release_nodes+0x2f8/0x3e0
[c000000022cbbb60] [c0000000008ac440] device_release_driver_internal+0x190/0x2b0
[c000000022cbbba0] [c0000000008a8450] unbind_store+0x130/0x170
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Fixes: 87eb73b2ca7c ("nvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk")
Link: http://lore.kernel.org/r/DFB75BA8-603F-4A35-880B-C5B23EF8FA7D@linux.vnet.ibm.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
Changes in v2 Improve the changelog.
drivers/nvdimm/pmem.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 31f3c4bd6f72..fc6b78dd2d24 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -337,8 +337,9 @@ static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap)
{
struct request_queue *q =
container_of(pgmap->ref, struct request_queue, q_usage_counter);
+ struct pmem_device *pmem = pgmap->owner;
- blk_cleanup_disk(queue_to_disk(q));
+ blk_cleanup_disk(pmem->disk);
}
static void pmem_release_queue(void *pgmap)
@@ -427,6 +428,7 @@ static int pmem_attach_disk(struct device *dev,
q = disk->queue;
pmem->disk = disk;
+ pmem->pgmap.owner = pmem;
pmem->pfn_flags = PFN_DEV;
pmem->pgmap.ref = &q->q_usage_counter;
if (is_nd_pfn(dev)) {
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v2] libnvdimm/pmem: Fix blk_cleanup_disk() usage
2021-06-07 23:52 ` [PATCH v2] " Dan Williams
@ 2021-06-08 5:36 ` Christoph Hellwig
2021-06-08 5:43 ` Sachin Sant
2021-06-08 21:26 ` Jens Axboe
2 siblings, 0 replies; 5+ messages in thread
From: Christoph Hellwig @ 2021-06-08 5:36 UTC (permalink / raw)
To: Dan Williams
Cc: axboe, Sachin Sant, Christoph Hellwig, Ulf Hansson, nvdimm,
linux-block, linuxppc-dev
Thanks Dan, this looks good to me:
Reviewed-by: Christoph Hellwig <hch@lst.de>
Jens, can you quickly pick this up?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] libnvdimm/pmem: Fix blk_cleanup_disk() usage
2021-06-07 23:52 ` [PATCH v2] " Dan Williams
2021-06-08 5:36 ` Christoph Hellwig
@ 2021-06-08 5:43 ` Sachin Sant
2021-06-08 21:26 ` Jens Axboe
2 siblings, 0 replies; 5+ messages in thread
From: Sachin Sant @ 2021-06-08 5:43 UTC (permalink / raw)
To: Dan Williams
Cc: axboe, nvdimm, Ulf Hansson, linux-block, linuxppc-dev, Christoph Hellwig
> Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
> Fixes: 87eb73b2ca7c ("nvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk")
> Link: http://lore.kernel.org/r/DFB75BA8-603F-4A35-880B-C5B23EF8FA7D@linux.vnet.ibm.com
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: Jens Axboe <axboe@kernel.dk>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
Thanks Dan. This patch fixes the reported crash for me.
Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
>
> Changes in v2 Improve the changelog.
>
> drivers/nvdimm/pmem.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 31f3c4bd6f72..fc6b78dd2d24 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -337,8 +337,9 @@ static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap)
> {
> struct request_queue *q =
> container_of(pgmap->ref, struct request_queue, q_usage_counter);
With this change variable ‘q' is no longer needed and can be removed.
drivers/nvdimm/pmem.c: In function 'pmem_pagemap_cleanup':
drivers/nvdimm/pmem.c:338:24: warning: unused variable 'q' [-Wunused-variable]
struct request_queue *q =
^
> + struct pmem_device *pmem = pgmap->owner;
>
> - blk_cleanup_disk(queue_to_disk(q));
> + blk_cleanup_disk(pmem->disk);
> }
>
> static void pmem_release_queue(void *pgmap)
> @@ -427,6 +428,7 @@ static int pmem_attach_disk(struct device *dev,
> q = disk->queue;
>
> pmem->disk = disk;
> + pmem->pgmap.owner = pmem;
> pmem->pfn_flags = PFN_DEV;
> pmem->pgmap.ref = &q->q_usage_counter;
> if (is_nd_pfn(dev)) {
>
Thanks
-Sachin
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2] libnvdimm/pmem: Fix blk_cleanup_disk() usage
2021-06-07 23:52 ` [PATCH v2] " Dan Williams
2021-06-08 5:36 ` Christoph Hellwig
2021-06-08 5:43 ` Sachin Sant
@ 2021-06-08 21:26 ` Jens Axboe
2 siblings, 0 replies; 5+ messages in thread
From: Jens Axboe @ 2021-06-08 21:26 UTC (permalink / raw)
To: Dan Williams
Cc: Sachin Sant, Christoph Hellwig, Ulf Hansson, nvdimm, linux-block,
linuxppc-dev
On 6/7/21 5:52 PM, Dan Williams wrote:
> The queue_to_disk() helper can not be used after del_gendisk()
> communicate @disk via the pgmap->owner.
>
> Otherwise, queue_to_disk() returns NULL resulting in the splat below.
>
> Kernel attempted to read user page (330) - exploit attempt? (uid: 0)
> BUG: Kernel NULL pointer dereference on read at 0x00000330
> Faulting instruction address: 0xc000000000906344
> Oops: Kernel access of bad area, sig: 11 [#1]
> [..]
> NIP [c000000000906344] pmem_pagemap_cleanup+0x24/0x40
> LR [c0000000004701d4] memunmap_pages+0x1b4/0x4b0
> Call Trace:
> [c000000022cbb9c0] [c0000000009063c8] pmem_pagemap_kill+0x28/0x40 (unreliable)
> [c000000022cbb9e0] [c0000000004701d4] memunmap_pages+0x1b4/0x4b0
> [c000000022cbba90] [c0000000008b28a0] devm_action_release+0x30/0x50
> [c000000022cbbab0] [c0000000008b39c8] release_nodes+0x2f8/0x3e0
> [c000000022cbbb60] [c0000000008ac440] device_release_driver_internal+0x190/0x2b0
> [c000000022cbbba0] [c0000000008a8450] unbind_store+0x130/0x170
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-06-08 21:26 UTC | newest]
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2021-06-07 23:31 [PATCH] libnvdimm/pmem: Fix blk_cleanup_disk() usage Dan Williams
2021-06-07 23:52 ` [PATCH v2] " Dan Williams
2021-06-08 5:36 ` Christoph Hellwig
2021-06-08 5:43 ` Sachin Sant
2021-06-08 21:26 ` Jens Axboe
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