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authorAdrian Huang <ahuang12@lenovo.com>2020-09-17 19:15:49 +0800
committerDan Williams <dan.j.williams@intel.com>2020-09-20 08:57:36 -0700
commitd4c5da5049ac27c6ef8f6f98548c3a1ade352d25 (patch)
treecc167f186cdc547b3f372c117692a186fe22b016 /drivers/dax/super.c
parente2ec5128254518cae320d5dc631b71b94160f663 (diff)
dax: Fix stack overflow when mounting fsdax pmem device
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 <yi.zhang@redhat.com> Reported-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Adrian Huang <ahuang12@lenovo.com> Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Ritesh Harjani <riteshh@linux.ibm.com> Cc: Coly Li <colyli@suse.de> Cc: Ira Weiny <ira.weiny@intel.com> Cc: John Pittman <jpittman@redhat.com> Link: https://lore.kernel.org/r/20200917111549.6367-1-adrianhuang0701@gmail.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/dax/super.c')
-rw-r--r--drivers/dax/super.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index b6284c5cae0a..e84070b55463 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -85,6 +85,12 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
return false;
}
+ if (!dax_dev) {
+ pr_debug("%s: error: dax unsupported by block device\n",
+ bdevname(bdev, buf));
+ return false;
+ }
+
err = bdev_dax_pgoff(bdev, start, PAGE_SIZE, &pgoff);
if (err) {
pr_info("%s: error: unaligned partition for dax\n",
@@ -100,12 +106,6 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
return false;
}
- if (!dax_dev || !bdev_dax_supported(bdev, blocksize)) {
- pr_debug("%s: error: dax unsupported by block device\n",
- bdevname(bdev, buf));
- return false;
- }
-
id = dax_read_lock();
len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);
len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);