diff options
| author | Dan Williams <dan.j.williams@intel.com> | 2017-11-29 16:10:32 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-29 18:40:42 -0800 |
| commit | 9702cffdbf2129516db679e4467db81e1cd287da (patch) | |
| tree | 24d44102dbff126e931c1a169d2fd495980b342c /drivers | |
| parent | 31383c6865a578834dd953d9dbc88e6b19fe3997 (diff) | |
device-dax: implement ->split() to catch invalid munmap attempts
Similar to how device-dax enforces that the 'address', 'offset', and
'len' parameters to mmap() be aligned to the device's fundamental
alignment, the same constraints apply to munmap(). Implement ->split()
to fail munmap calls that violate the alignment constraint.
Otherwise, we later fail VM_BUG_ON checks in the unmap_page_range() path
with crash signatures of the form:
vma ffff8800b60c8a88 start 00007f88c0000000 end 00007f88c0e00000
next (null) prev (null) mm ffff8800b61150c0
prot 8000000000000027 anon_vma (null) vm_ops ffffffffa0091240
pgoff 0 file ffff8800b638ef80 private_data (null)
flags: 0x380000fb(read|write|shared|mayread|maywrite|mayexec|mayshare|softdirty|mixedmap|hugepage)
------------[ cut here ]------------
kernel BUG at mm/huge_memory.c:2014!
[..]
RIP: 0010:__split_huge_pud+0x12a/0x180
[..]
Call Trace:
unmap_page_range+0x245/0xa40
? __vma_adjust+0x301/0x990
unmap_vmas+0x4c/0xa0
unmap_region+0xae/0x120
? __vma_rb_erase+0x11a/0x230
do_munmap+0x276/0x410
vm_munmap+0x6a/0xa0
SyS_munmap+0x1d/0x30
Link: http://lkml.kernel.org/r/151130418681.4029.7118245855057952010.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Jeff Moyer <jmoyer@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/dax/device.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/dax/device.c b/drivers/dax/device.c index 6833ada237ab..7b0bf825c4e7 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -428,9 +428,21 @@ static int dev_dax_fault(struct vm_fault *vmf) return dev_dax_huge_fault(vmf, PE_SIZE_PTE); } +static int dev_dax_split(struct vm_area_struct *vma, unsigned long addr) +{ + struct file *filp = vma->vm_file; + struct dev_dax *dev_dax = filp->private_data; + struct dax_region *dax_region = dev_dax->region; + + if (!IS_ALIGNED(addr, dax_region->align)) + return -EINVAL; + return 0; +} + static const struct vm_operations_struct dax_vm_ops = { .fault = dev_dax_fault, .huge_fault = dev_dax_huge_fault, + .split = dev_dax_split, }; static int dax_mmap(struct file *filp, struct vm_area_struct *vma) |