Revision a4aeaa06d45e90f9b279f0b09de84bd00006e733 authored by Yang Shi on 28 October 2021, 21:36:30 UTC, committed by Linus Torvalds on 29 October 2021, 00:18:55 UTC
The read-only THP for filesystems will collapse THP for files opened readonly and mapped with VM_EXEC. The intended usecase is to avoid TLB misses for large text segments. But it doesn't restrict the file types so a THP could be collapsed for a non-regular file, for example, block device, if it is opened readonly and mapped with EXEC permission. This may cause bugs, like [1] and [2]. This is definitely not the intended usecase, so just collapse THP for regular files in order to close the attack surface. [shy828301@gmail.com: fix vm_file check [3]] Link: https://lore.kernel.org/lkml/CACkBjsYwLYLRmX8GpsDpMthagWOjWWrNxqY6ZLNQVr6yx+f5vA@mail.gmail.com/ [1] Link: https://lore.kernel.org/linux-mm/000000000000c6a82505ce284e4c@google.com/ [2] Link: https://lkml.kernel.org/r/CAHbLzkqTW9U3VvTu1Ki5v_cLRC9gHW+znBukg_ycergE0JWj-A@mail.gmail.com [3] Link: https://lkml.kernel.org/r/20211027195221.3825-1-shy828301@gmail.com Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Yang Shi <shy828301@gmail.com> Reported-by: Hao Sun <sunhao.th@gmail.com> Reported-by: syzbot+aae069be1de40fb11825@syzkaller.appspotmail.com Cc: Matthew Wilcox <willy@infradead.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Song Liu <songliubraving@fb.com> Cc: Andrea Righi <andrea.righi@canonical.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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File | Mode | Size |
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LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | -rw-r--r-- | 16.6 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.get_maintainer.ignore | -rw-r--r-- | 71 bytes |
.gitattributes | -rw-r--r-- | 62 bytes |
.gitignore | -rw-r--r-- | 1.9 KB |
.mailmap | -rw-r--r-- | 19.9 KB |
COPYING | -rw-r--r-- | 496 bytes |
CREDITS | -rw-r--r-- | 98.6 KB |
Kbuild | -rw-r--r-- | 1.3 KB |
Kconfig | -rw-r--r-- | 555 bytes |
MAINTAINERS | -rw-r--r-- | 606.1 KB |
Makefile | -rw-r--r-- | 64.0 KB |
README | -rw-r--r-- | 727 bytes |
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