mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2025-01-22 22:04:47 +08:00
55fc0d9174
Patch series "fix two bugs for file THP".
This patch (of 2):
Transparent huge page has supported read-only non-shmem files. The
file- backed THP is collapsed by khugepaged and truncated when written
(for shared libraries).
However, there is a race when multiple writers truncate the same page
cache concurrently.
In that case, subpage(s) of file THP can be revealed by find_get_entry
in truncate_inode_pages_range, which will trigger PageTail BUG_ON in
truncate_inode_page, as follows:
page:000000009e420ff2 refcount:1 mapcount:0 mapping:0000000000000000 index:0x7ff pfn:0x50c3ff
head:0000000075ff816d order:9 compound_mapcount:0 compound_pincount:0
flags: 0x37fffe0000010815(locked|uptodate|lru|arch_1|head)
raw: 37fffe0000000000 fffffe0013108001 dead000000000122 dead000000000400
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
head: 37fffe0000010815 fffffe001066bd48 ffff000404183c20 0000000000000000
head: 0000000000000600 0000000000000000 00000001ffffffff ffff000c0345a000
page dumped because: VM_BUG_ON_PAGE(PageTail(page))
------------[ cut here ]------------
kernel BUG at mm/truncate.c:213!
Internal error: Oops - BUG: 0 [#1] SMP
Modules linked in: xfs(E) libcrc32c(E) rfkill(E) ...
CPU: 14 PID: 11394 Comm: check_madvise_d Kdump: ...
Hardware name: ECS, BIOS 0.0.0 02/06/2015
pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)
Call trace:
truncate_inode_page+0x64/0x70
truncate_inode_pages_range+0x550/0x7e4
truncate_pagecache+0x58/0x80
do_dentry_open+0x1e4/0x3c0
vfs_open+0x38/0x44
do_open+0x1f0/0x310
path_openat+0x114/0x1dc
do_filp_open+0x84/0x134
do_sys_openat2+0xbc/0x164
__arm64_sys_openat+0x74/0xc0
el0_svc_common.constprop.0+0x88/0x220
do_el0_svc+0x30/0xa0
el0_svc+0x20/0x30
el0_sync_handler+0x1a4/0x1b0
el0_sync+0x180/0x1c0
Code: aa0103e0 900061e1 910ec021 9400d300 (d4210000)
This patch mainly to lock filemap when one enter truncate_pagecache(),
avoiding truncating the same page cache concurrently.
Link: https://lkml.kernel.org/r/20211025092134.18562-1-rongwei.wang@linux.alibaba.com
Link: https://lkml.kernel.org/r/20211025092134.18562-2-rongwei.wang@linux.alibaba.com
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.