kernel/linux.git/drivers/dax, branch linux-5.9.y

dax: Fix stack overflow when mounting fsdax pmem device

2020-09-20T15:57:36+00:00

When mounting fsdax pmem device, commit 6180bb446ab6 ("dax: fix detection of dax support for non-persistent memory block devices") introduces the stack overflow [1][2]. Here is the call path for mounting ext4 file system: ext4_fill_super bdev_dax_supported __bdev_dax_supported dax_supported generic_fsdax_supported __generic_fsdax_supported bdev_dax_supported The call path leads to the infinite calling loop, so we cannot call bdev_dax_supported() in __generic_fsdax_supported(). The sanity checking of the variable 'dax_dev' is moved prior to the two bdev_dax_pgoff() checks [3][4]. [1] https://lore.kernel.org/linux-nvdimm/1420999447.1004543.1600055488770.JavaMail.zimbra@redhat.com/ [2] https://lore.kernel.org/linux-nvdimm/alpine.LRH.2.02.2009141131220.30651@file01.intranet.prod.int.rdu2.redhat.com/ [3] https://lore.kernel.org/linux-nvdimm/CA+RJvhxBHriCuJhm-D8NvJRe3h2MLM+ZMFgjeJjrRPerMRLvdg@mail.gmail.com/ [4] https://lore.kernel.org/linux-nvdimm/20200903160608.GU878166@iweiny-DESK2.sc.intel.com/ Fixes: 6180bb446ab6 ("dax: fix detection of dax support for non-persistent memory block devices") Reported-by: Yi Zhang Reported-by: Mikulas Patocka Signed-off-by: Adrian Huang Reviewed-by: Jan Kara Tested-by: Ritesh Harjani Cc: Coly Li Cc: Ira Weiny Cc: John Pittman Link: https://lore.kernel.org/r/20200917111549.6367-1-adrianhuang0701@gmail.com Signed-off-by: Dan Williams

dm: Call proper helper to determine dax support

2020-09-20T15:55:09+00:00

DM was calling generic_fsdax_supported() to determine whether a device referenced in the DM table supports DAX. However this is a helper for "leaf" device drivers so that they don't have to duplicate common generic checks. High level code should call dax_supported() helper which that calls into appropriate helper for the particular device. This problem manifested itself as kernel messages: dm-3: error: dax access failed (-95) when lvm2-testsuite run in cases where a DM device was stacked on top of another DM device. Fixes: 7bf7eac8d648 ("dax: Arrange for dax_supported check to span multiple devices") Cc: Tested-by: Adrian Huang Signed-off-by: Jan Kara Acked-by: Mike Snitzer Reported-by: kernel test robot Link: https://lore.kernel.org/r/160061715195.13131.5503173247632041975.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams

Merge tag 'libnvdimm-fix-v5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2020-09-12T19:43:58+00:00

Pull libnvdimm fix from Vishal Verma: "Fix detection of dax support for block devices. Previous fixes in this area, which only affected printing of debug messages, had an incorrect condition for detection of dax. This fix should finally do the right thing" * tag 'libnvdimm-fix-v5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: dax: fix detection of dax support for non-persistent memory block devices

Merge tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2020-09-06T16:59:27+00:00

Pull xen updates from Juergen Gross: "A small series for fixing a problem with Xen PVH guests when running as backends (e.g. as dom0). Mapping other guests' memory is now working via ZONE_DEVICE, thus not requiring to abuse the memory hotplug functionality for that purpose" * tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen: add helpers to allocate unpopulated memory memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC xen/balloon: add header guard

memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC

2020-09-04T07:59:59+00:00

This is in preparation for the logic behind MEMORY_DEVICE_DEVDAX also being used by non DAX devices. No functional change intended. Signed-off-by: Roger Pau Monné Reviewed-by: Ira Weiny Acked-by: Andrew Morton Reviewed-by: Pankaj Gupta Link: https://lore.kernel.org/r/20200901083326.21264-3-roger.pau@citrix.com Signed-off-by: Juergen Gross

dax: fix detection of dax support for non-persistent memory block devices

2020-09-03T18:28:03+00:00

When calling __generic_fsdax_supported(), a dax-unsupported device may not have dax_dev as NULL, e.g. the dax related code block is not enabled by Kconfig. Therefore in __generic_fsdax_supported(), to check whether a device supports DAX or not, the following order of operations should be performed: - If dax_dev pointer is NULL, it means the device driver explicitly announce it doesn't support DAX. Then it is OK to directly return false from __generic_fsdax_supported(). - If dax_dev pointer is NOT NULL, it might be because the driver doesn't support DAX and not explicitly initialize related data structure. Then bdev_dax_supported() should be called for further check. If device driver desn't explicitly set its dax_dev pointer to NULL, this is not a bug. Calling bdev_dax_supported() makes sure they can be recognized as dax-unsupported eventually. Fixes: c2affe920b0e ("dax: do not print error message for non-persistent memory block device") Cc: Jan Kara Cc: Vishal Verma Reviewed-and-tested-by: Adrian Huang Reviewed-by: Ira Weiny Reviewed-by: Mike Snitzer Reviewed-by: Pankaj Gupta Signed-off-by: Coly Li Signed-off-by: Vishal Verma Link: https://lore.kernel.org/r/20200903161625.19524-1-colyli@suse.de

dax: do not print error message for non-persistent memory block device

2020-08-20T17:43:18+00:00

Commit 231609785cbf ("dax: print error message by pr_info() in __generic_fsdax_supported()") happens to print the following error message during booting when the non-persistent memory block devices are configured by device mapper. Those error messages are caused by the variable 'dax_dev' is NULL. Users might be confused with those error messages since they do not use the persistent memory device. Moreover, users might scare about "what's wrong with my disks" because they see the 'error' and 'failed' keywords. # dmesg | grep fail sdk3: error: dax access failed (-95) sdk3: error: dax access failed (-95) sdk3: error: dax access failed (-95) sdk3: error: dax access failed (-95) sdk3: error: dax access failed (-95) sdk3: error: dax access failed (-95) sdk3: error: dax access failed (-95) sdk3: error: dax access failed (-95) sdk3: error: dax access failed (-95) sdb3: error: dax access failed (-95) sdb3: error: dax access failed (-95) sdb3: error: dax access failed (-95) sdb3: error: dax access failed (-95) sdb3: error: dax access failed (-95) sdb3: error: dax access failed (-95) sdb3: error: dax access failed (-95) sdb3: error: dax access failed (-95) sdb3: error: dax access failed (-95) # lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 1.1T 0 disk ├─sda1 8:1 0 156M 0 part ├─sda2 8:2 0 40G 0 part └─sda3 8:3 0 1.1T 0 part sdb 8:16 0 1.1T 0 disk ├─sdb1 8:17 0 600M 0 part ├─sdb2 8:18 0 1G 0 part └─sdb3 8:19 0 1.1T 0 part ├─rhel00-swap 254:3 0 4G 0 lvm ├─rhel00-home 254:4 0 1T 0 lvm └─rhel00-root 254:5 0 50G 0 lvm sdc 8:32 0 1.1T 0 disk sdd 8:48 0 1.1T 0 disk sde 8:64 0 1.1T 0 disk sdf 8:80 0 1.1T 0 disk sdg 8:96 0 1.1T 0 disk sdh 8:112 0 3.3T 0 disk ├─sdh1 8:113 0 500M 0 part /boot/efi ├─sdh2 8:114 0 40G 0 part / ├─sdh3 8:115 0 2.9T 0 part /home └─sdh4 8:116 0 314.6G 0 part [SWAP] sdi 8:128 0 1.1T 0 disk sdj 8:144 0 3.3T 0 disk ├─sdj1 8:145 0 512M 0 part └─sdj2 8:146 0 3.3T 0 part sdk 8:160 0 119.2G 0 disk ├─sdk1 8:161 0 200M 0 part ├─sdk2 8:162 0 1G 0 part └─sdk3 8:163 0 118G 0 part ├─rhel-swap 254:0 0 4G 0 lvm ├─rhel-home 254:1 0 64G 0 lvm └─rhel-root 254:2 0 50G 0 lvm sdl 8:176 0 119.2G 0 disk The call path is shown as follows: dm_table_determine_type dm_table_supports_dax device_supports_dax generic_fsdax_supported __generic_fsdax_supported With the disk configuration listing from the command 'lsblk', the member 'dev->dax_dev' of the block devices 'sdb3' and 'sdk3' (configured by device mapper) is NULL in function generic_fsdax_supported() because the member is configured in function open_table_device(). To prevent the confusing error messages in this scenario (this is normal behavior), just print those error messages by pr_debug() by checking if dax_dev is NULL and the block device does not support DAX. Link: https://lore.kernel.org/r/20200819154236.24191-1-adrianhuang0701@gmail.com Fixes: 231609785cbf ("dax: print error message by pr_info() in __generic_fsdax_supported()") Cc: Coly Li Cc: Dan Williams Cc: Alasdair Kergon Cc: Mike Snitzer Acked-by: Coly Li Signed-off-by: Adrian Huang Signed-off-by: Vishal Verma

Merge tag 'libnvdimm-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2020-08-11T17:59:19+00:00

Pull libnvdimm updayes from Vishal Verma: "You'd normally receive this pull request from Dan Williams, but he's busy watching a newborn (Congrats Dan!), so I'm watching libnvdimm this cycle. This adds a new feature in libnvdimm - 'Runtime Firmware Activation', and a few small cleanups and fixes in libnvdimm and DAX. I'd originally intended to make separate topic-based pull requests - one for libnvdimm, and one for DAX, but some of the DAX material fell out since it wasn't quite ready. Summary: - add 'Runtime Firmware Activation' support for NVDIMMs that advertise the relevant capability - misc libnvdimm and DAX cleanups" * tag 'libnvdimm-for-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: libnvdimm/security: ensure sysfs poll thread woke up and fetch updated attr libnvdimm/security: the 'security' attr never show 'overwrite' state libnvdimm/security: fix a typo ACPI: NFIT: Fix ARS zero-sized allocation dax: Fix incorrect argument passed to xas_set_err() ACPI: NFIT: Add runtime firmware activate support PM, libnvdimm: Add runtime firmware activation support libnvdimm: Convert to DEVICE_ATTR_ADMIN_RO() drivers/dax: Expand lock scope to cover the use of addresses fs/dax: Remove unused size parameter dax: print error message by pr_info() in __generic_fsdax_supported() driver-core: Introduce DEVICE_ATTR_ADMIN_{RO,RW} tools/testing/nvdimm: Emulate firmware activation commands tools/testing/nvdimm: Prepare nfit_ctl_test() for ND_CMD_CALL emulation tools/testing/nvdimm: Add command debug messages tools/testing/nvdimm: Cleanup dimm index passing ACPI: NFIT: Define runtime firmware activation commands ACPI: NFIT: Move bus_dsm_mask out of generic nvdimm_bus_descriptor libnvdimm: Validate command family indices

drivers/dax: Expand lock scope to cover the use of addresses

2020-07-28T17:50:08+00:00

The addition of PKS protection to dax read lock/unlock will require that the address returned by dax_direct_access() be protected by this lock. Correct the locking by ensuring that the use of kaddr and end_kaddr are covered by the dax read lock/unlock. Link: https://lore.kernel.org/r/20200717072056.73134-12-ira.weiny@intel.com Reviewed-by: Dan Williams Signed-off-by: Ira Weiny Signed-off-by: Vishal Verma

dax: print error message by pr_info() in __generic_fsdax_supported()

2020-07-28T17:49:27+00:00

In struct dax_operations, the callback routine dax_supported() returns a bool type result. For false return value, the caller has no idea whether the device does not support dax at all, or it is just some mis- configuration issue. An example is formatting an Ext4 file system on pmem device on top of a NVDIMM namespace by, # mkfs.ext4 /dev/pmem0 If the fs block size does not match kernel space memory page size (which is possible on non-x86 platform), mount this Ext4 file system will fail, # mount -o dax /dev/pmem0 /mnt mount: /mnt: wrong fs type, bad option, bad superblock on /dev/pmem0, missing codepage or helper program, or other error. And from the dmesg output there is only the following information, [ 307.853148] EXT4-fs (pmem0): DAX unsupported by block device. The above information is quite confusing. Because definitely the pmem0 device supports dax operation, and the super block is consistent as how it was created by mkfs.ext4. Indeed the failure is from __generic_fsdax_supported() by the following code piece, if (blocksize != PAGE_SIZE) { pr_debug("%s: error: unsupported blocksize for dax\n", bdevname(bdev, buf)); return false; } It is because the Ext4 block size is 4KB and kernel page size is 8KB or 16KB. It is not simple to make dax_supported() from struct dax_operations or __generic_fsdax_supported() to return exact failure type right now. So the simplest fix is to use pr_info() to print all the error messages inside __generic_fsdax_supported(). Then users may find informative clue from the kernel message at least. Message printed by pr_debug() is very easy to be ignored by users. This patch prints error message by pr_info() in __generic_fsdax_supported(), when then mount fails, following lines can be found from dmesg output, [ 2705.500885] pmem0: error: unsupported blocksize for dax [ 2705.500888] EXT4-fs (pmem0): DAX unsupported by block device. Now the users may have idea the mount failure is from pmem driver for unsupported block size. Link: https://lore.kernel.org/r/20200725162450.95999-1-colyli@suse.de Cc: Dan Williams Cc: Anthony Iliopoulos Reported-by: Michal Suchanek Suggested-by: Jan Kara Reviewed-by: Jan Kara Reviewed-by: Ira Weiny Reviewed-by: Pankaj Gupta Signed-off-by: Coly Li Signed-off-by: Vishal Verma