https://github.com/torvalds/linux
Revision 22247efd822e6d263f3c8bd327f3f769aea9b1d9 authored by Peter Xu on 15 May 2021, 00:27:04 UTC, committed by Linus Torvalds on 15 May 2021, 02:41:32 UTC
Patch series "mm/hugetlb: Fix issues on file sealing and fork", v2. Hugh reported issue with F_SEAL_FUTURE_WRITE not applied correctly to hugetlbfs, which I can easily verify using the memfd_test program, which seems that the program is hardly run with hugetlbfs pages (as by default shmem). Meanwhile I found another probably even more severe issue on that hugetlb fork won't wr-protect child cow pages, so child can potentially write to parent private pages. Patch 2 addresses that. After this series applied, "memfd_test hugetlbfs" should start to pass. This patch (of 2): F_SEAL_FUTURE_WRITE is missing for hugetlb starting from the first day. There is a test program for that and it fails constantly. $ ./memfd_test hugetlbfs memfd-hugetlb: CREATE memfd-hugetlb: BASIC memfd-hugetlb: SEAL-WRITE memfd-hugetlb: SEAL-FUTURE-WRITE mmap() didn't fail as expected Aborted (core dumped) I think it's probably because no one is really running the hugetlbfs test. Fix it by checking FUTURE_WRITE also in hugetlbfs_file_mmap() as what we do in shmem_mmap(). Generalize a helper for that. Link: https://lkml.kernel.org/r/20210503234356.9097-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20210503234356.9097-2-peterx@redhat.com Fixes: ab3948f58ff84 ("mm/memfd: add an F_SEAL_FUTURE_WRITE seal to memfd") Signed-off-by: Peter Xu <peterx@redhat.com> Reported-by: Hugh Dickins <hughd@google.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Joel Fernandes (Google) <joel@joelfernandes.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent bd3c9cd
Tip revision: 22247efd822e6d263f3c8bd327f3f769aea9b1d9 authored by Peter Xu on 15 May 2021, 00:27:04 UTC
mm/hugetlb: fix F_SEAL_FUTURE_WRITE
mm/hugetlb: fix F_SEAL_FUTURE_WRITE
Tip revision: 22247ef
File | Mode | Size |
---|---|---|
accounting | ||
arch | ||
bootconfig | ||
bpf | ||
build | ||
cgroup | ||
debugging | ||
edid | ||
firewire | ||
firmware | ||
gpio | ||
hv | ||
iio | ||
include | ||
io_uring | ||
kvm | ||
laptop | ||
leds | ||
lib | ||
memory-model | ||
objtool | ||
pci | ||
pcmcia | ||
perf | ||
power | ||
scripts | ||
spi | ||
testing | ||
thermal | ||
time | ||
tracing | ||
usb | ||
virtio | ||
vm | ||
wmi | ||
Makefile | -rw-r--r-- | 6.2 KB |
Computing file changes ...