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Jiajun Xie 9eab0421fa mm: fix unmap_mapping_range high bits shift bug
The bug happens when highest bit of holebegin is 1, suppose holebegin is
0x8000000111111000, after shift, hba would be 0xfff8000000111111, then
vma_interval_tree_foreach would look it up fail or leads to the wrong
result.

error call seq e.g.:
- mmap(..., offset=0x8000000111111000)
  |- syscall(mmap, ... unsigned long, off):
     |- ksys_mmap_pgoff( ... , off >> PAGE_SHIFT);

  here pgoff is correctly shifted to 0x8000000111111,
  but pass 0x8000000111111000 as holebegin to unmap
  would then cause terrible result, as shown below:

- unmap_mapping_range(..., loff_t const holebegin)
  |- pgoff_t hba = holebegin >> PAGE_SHIFT;
          /* hba = 0xfff8000000111111 unexpectedly */

The issue happens in Heterogeneous computing, where the device(e.g. 
gpu) and host share the same virtual address space.

A simple workflow pattern which hit the issue is:
        /* host */
    1. userspace first mmap a file backed VA range with specified offset.
                        e.g. (offset=0x800..., mmap return: va_a)
    2. write some data to the corresponding sys page
                         e.g. (va_a = 0xAABB)
        /* device */
    3. gpu workload touches VA, triggers gpu fault and notify the host.
        /* host */
    4. reviced gpu fault notification, then it will:
            4.1 unmap host pages and also takes care of cpu tlb
                  (use unmap_mapping_range with offset=0x800...)
            4.2 migrate sys page to device
            4.3 setup device page table and resolve device fault.
        /* device */
    5. gpu workload continued, it accessed va_a and got 0xAABB.
    6. gpu workload continued, it wrote 0xBBCC to va_a.
        /* host */
    7. userspace access va_a, as expected, it will:
            7.1 trigger cpu vm fault.
            7.2 driver handling fault to migrate gpu local page to host.
    8. userspace then could correctly get 0xBBCC from va_a
    9. done

But in step 4.1, if we hit the bug this patch mentioned, then userspace
would never trigger cpu fault, and still get the old value: 0xAABB.

Making holebegin unsigned first fixes the bug.

Link: https://lkml.kernel.org/r/20231220052839.26970-1-jiajun.xie.sh@gmail.com
Signed-off-by: Jiajun Xie <jiajun.xie.sh@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-29 11:06:48 -08:00
arch kexec: fix KEXEC_FILE dependencies 2023-12-20 13:46:19 -08:00
block block-6.7-2023-12-01 2023-12-02 06:39:30 +09:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This push fixes a regression in ahash and hides the Kconfig sub-options for the jitter RNG. 2023-11-09 17:04:58 -08:00
Documentation - Core Frameworks 2023-12-01 08:00:02 +09:00
drivers Merge branch 'master' into mm-hotfixes-stable 2023-12-06 17:03:50 -08:00
fs Merge branch 'master' into mm-hotfixes-stable 2023-12-06 17:03:50 -08:00
include mm/mglru: reclaim offlined memcgs harder 2023-12-12 17:20:20 -08:00
init As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
io_uring io_uring: use fget/fput consistently 2023-11-28 11:56:29 -07:00
ipc Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
kernel kexec: select CRYPTO from KEXEC_FILE instead of depending on it 2023-12-20 13:46:19 -08:00
lib maple_tree: do not preallocate nodes for slot stores 2023-12-20 13:46:19 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: fix unmap_mapping_range high bits shift bug 2023-12-29 11:06:48 -08:00
net wireless fixes: 2023-11-29 19:43:34 -08:00
rust Kbuild updates for v6.7 2023-11-04 08:07:19 -10:00
samples Landlock updates for v6.7-rc1 2023-11-03 09:28:53 -10:00
scripts Merge branch 'master' into mm-hotfixes-stable 2023-12-06 17:03:50 -08:00
security + Features 2023-11-03 09:48:17 -10:00
sound ALSA: hda: Disable power-save on KONTRON SinglePC 2023-11-30 16:14:21 +01:00
tools selftests: secretmem: floor the memory size to the multiple of page_size 2023-12-20 13:46:19 -08:00
usr arch: Remove Itanium (IA-64) architecture 2023-09-11 08:13:17 +00:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/ 2023-10-03 20:49:09 +09:00
.mailmap mailmap: add an old address for Naoya Horiguchi 2023-12-20 13:46:20 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
CREDITS MAINTAINERS: drop Antti Palosaari 2023-12-06 16:12:49 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch 'master' into mm-hotfixes-stable 2023-12-06 17:03:50 -08:00
Makefile Linux 6.7-rc4 2023-12-03 18:52:56 +09:00
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