| Message ID | 162310994435.1571616.334551212901820961.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] libnvdimm/pmem: Fix blk_cleanup_disk() usage | expand |
Thanks Dan, this looks good to me:
Reviewed-by: Christoph Hellwig <hch@lst.de>
Jens, can you quickly pick this up?
> 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
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.
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)) {
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(-)