Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux
![]() A vma with vm_pgoff large enough to overflow a loff_t type when
converted to a byte offset can be passed via the remap_file_pages system
call. The hugetlbfs mmap routine uses the byte offset to calculate
reservations and file size.
A sequence such as:
mmap(0x20a00000, 0x600000, 0, 0x66033, -1, 0);
remap_file_pages(0x20a00000, 0x600000, 0, 0x20000000000000, 0);
will result in the following when task exits/file closed,
kernel BUG at mm/hugetlb.c:749!
Call Trace:
hugetlbfs_evict_inode+0x2f/0x40
evict+0xcb/0x190
__dentry_kill+0xcb/0x150
__fput+0x164/0x1e0
task_work_run+0x84/0xa0
exit_to_usermode_loop+0x7d/0x80
do_syscall_64+0x18b/0x190
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
The overflowed pgoff value causes hugetlbfs to try to set up a mapping
with a negative range (end < start) that leaves invalid state which
causes the BUG.
The previous overflow fix to this code was incomplete and did not take
the remap_file_pages system call into account.
[mike.kravetz@oracle.com: v3]
Link: http://lkml.kernel.org/r/20180309002726.7248-1-mike.kravetz@oracle.com
[akpm@linux-foundation.org: include mmdebug.h]
[akpm@linux-foundation.org: fix -ve left shift count on sh]
Link: http://lkml.kernel.org/r/20180308210502.15952-1-mike.kravetz@oracle.com
Fixes:
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---|---|---|
arch | ||
block | ||
certs | ||
crypto | ||
Documentation | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
LICENSES | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.