A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-06 20:03:33 -04:00
Code Issues Projects Releases Packages Wiki Activity
No description
893,140 commits 10 branches 0 tags 2.1 GiB
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Aneesh Kumar K.V 79e522101c mm/mremap: hold the rmap lock in write mode when moving page table entries. 
commit 97113eb39fa7972722ff490b947d8af023e1f6a2 upstream.

To avoid a race between rmap walk and mremap, mremap does
take_rmap_locks().  The lock was taken to ensure that rmap walk don't miss
a page table entry due to PTE moves via move_pagetables().  The kernel
does further optimization of this lock such that if we are going to find
the newly added vma after the old vma, the rmap lock is not taken.  This
is because rmap walk would find the vmas in the same order and if we don't
find the page table attached to older vma we would find it with the new
vma which we would iterate later.

As explained in commit eb66ae0308 ("mremap: properly flush TLB before
releasing the page") mremap is special in that it doesn't take ownership
of the page.  The optimized version for PUD/PMD aligned mremap also
doesn't hold the ptl lock.  This can result in stale TLB entries as show
below.

This patch updates the rmap locking requirement in mremap to handle the race condition
explained below with optimized mremap::

Optmized PMD move

    CPU 1                           CPU 2                                   CPU 3

    mremap(old_addr, new_addr)      page_shrinker/try_to_unmap_one

    mmap_write_lock_killable()

                                    addr = old_addr
                                    lock(pte_ptl)
    lock(pmd_ptl)
    pmd = *old_pmd
    pmd_clear(old_pmd)
    flush_tlb_range(old_addr)

    *new_pmd = pmd
                                                                            *new_addr = 10; and fills
                                                                            TLB with new addr
                                                                            and old pfn

    unlock(pmd_ptl)
                                    ptep_clear_flush()
                                    old pfn is free.
                                                                            Stale TLB entry

Optimized PUD move also suffers from a similar race.  Both the above race
condition can be fixed if we force mremap path to take rmap lock.

Link: https://lkml.kernel.org/r/20210616045239.370802-7-aneesh.kumar@linux.ibm.com
Fixes: 2c91bd4a4e ("mm: speed up mremap by 20x on large regions")
Fixes: c49dd3401802 ("mm: speedup mremap on 1GB or larger regions")
Link: https://lore.kernel.org/linux-mm/CAHk-=wgXVR04eBNtxQfevontWnP6FDm+oj5vauQXP3S-huwbPw@mail.gmail.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[patch rewritten for backport since the code was refactored since]
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-25 11:17:20 +02:00
arch KVM: x86: Set error code to segment selector on LLDT/LTR non-canonical #GP 2022-08-25 11:17:20 +02:00
block block: fix bio_clone_blkg_association() to associate with proper blkcg_gq 2022-06-14 18:11:50 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: drbg - make reseeding from get_random_bytes() synchronous 2022-06-22 14:11:18 +02:00
Documentation x86/speculation: Add RSB VM Exit protections 2022-08-11 12:57:53 +02:00
drivers HID: wacom: Don't register pad_input for touch switch 2022-08-25 11:17:19 +02:00
fs ntfs: fix use-after-free in ntfs_ucsncmp() 2022-08-03 11:59:37 +02:00
include add barriers to buffer_uptodate and set_buffer_uptodate 2022-08-25 11:17:18 +02:00
init random: handle latent entropy and command line from random_init() 2022-06-22 14:11:17 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-14 18:11:41 +02:00
kernel bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds() 2022-08-11 12:57:51 +02:00
lib locking/refcount: Consolidate implementations of refcount_t 2022-07-29 17:14:17 +02:00
LICENSES
mm mm/mremap: hold the rmap lock in write mode when moving page table entries. 2022-08-25 11:17:20 +02:00
net sctp: leave the err path free in sctp_stream_init to sctp_stream_free 2022-08-03 11:59:41 +02:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts modpost: fix section mismatch check for exported init/exit sections 2022-06-29 08:58:49 +02:00
security ima: remove the IMA_TEMPLATE Kconfig option 2022-07-29 17:14:16 +02:00
sound ALSA: bcd2000: Fix a UAF bug on the error path of probing 2022-08-25 11:17:17 +02:00
tools x86/speculation: Add RSB VM Exit protections 2022-08-11 12:57:53 +02:00
usr
virt KVM: Don't null dereference ops->destroy 2022-08-11 12:57:52 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: co-maintain random.c 2022-06-22 14:11:05 +02:00
Makefile Makefile: link with -z noexecstack --no-warn-rwx-segments 2022-08-25 11:17:17 +02:00
README

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.