This is a note to let you know that I've just added the patch titled
device-dax: implement ->split() to catch invalid munmap attempts
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
device-dax-implement-split-to-catch-invalid-munmap-attempts.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Feb 26 20:55:53 CET 2018
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Date: Fri, 23 Feb 2018 14:05:43 -0800
Subject: device-dax: implement ->split() to catch invalid munmap attempts
To: gregkh@xxxxxxxxxxxxxxxxxxx
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, stable@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx
Message-ID: <151942354379.21775.5321017414392517094.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
From: Dan Williams <dan.j.williams@xxxxxxxxx>
commit 9702cffdbf2129516db679e4467db81e1cd287da upstream.
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@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reported-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dax/dax.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- a/drivers/dax/dax.c
+++ b/drivers/dax/dax.c
@@ -453,9 +453,21 @@ static int dax_dev_pmd_fault(struct vm_a
return rc;
}
+static int dax_dev_split(struct vm_area_struct *vma, unsigned long addr)
+{
+ struct file *filp = vma->vm_file;
+ struct dax_dev *dax_dev = filp->private_data;
+ struct dax_region *dax_region = dax_dev->region;
+
+ if (!IS_ALIGNED(addr, dax_region->align))
+ return -EINVAL;
+ return 0;
+}
+
static const struct vm_operations_struct dax_dev_vm_ops = {
.fault = dax_dev_fault,
.pmd_fault = dax_dev_pmd_fault,
+ .split = dax_dev_split,
};
static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
Patches currently in stable-queue which might be from dan.j.williams@xxxxxxxxx are
queue-4.9/mm-fix-devm_memremap_pages-collision-handling.patch
queue-4.9/ib-core-disable-memory-registration-of-filesystem-dax-vmas.patch
queue-4.9/mm-avoid-spurious-bad-pmd-warning-messages.patch
queue-4.9/mm-introduce-get_user_pages_longterm.patch
queue-4.9/mm-fail-get_vaddr_frames-for-filesystem-dax-mappings.patch
queue-4.9/fs-dax.c-fix-inefficiency-in-dax_writeback_mapping_range.patch
queue-4.9/device-dax-implement-split-to-catch-invalid-munmap-attempts.patch
queue-4.9/v4l2-disable-filesystem-dax-mapping-support.patch
queue-4.9/libnvdimm-dax-fix-1gb-aligned-namespaces-vs-physical-misalignment.patch
queue-4.9/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch
queue-4.9/libnvdimm-fix-integer-overflow-static-analysis-warning.patch