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| author | Rongwei Wang <rongwei.wang@linux.alibaba.com> | 2021-11-05 23:43:44 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-11-18 21:17:17 +0300 |
| commit | 3ea871f0d8e0008d0707763af2bcf55689994d64 (patch) | |
| tree | babe8a80e3050333948fc6e08a1123e76e359ddc /fs/open.c | |
| parent | fd8e972dc4277638ff19e7dd9c595ebb6961c5d2 (diff) | |
| download | linux-3ea871f0d8e0008d0707763af2bcf55689994d64.tar.xz | |
mm, thp: fix incorrect unmap behavior for private pages
commit 8468e937df1f31411d1e127fa38db064af051fe5 upstream.
When truncating pagecache on file THP, the private pages of a process
should not be unmapped mapping. This incorrect behavior on a dynamic
shared libraries which will cause related processes to happen core dump.
A simple test for a DSO (Prerequisite is the DSO mapped in file THP):
int main(int argc, char *argv[])
{
int fd;
fd = open(argv[1], O_WRONLY);
if (fd < 0) {
perror("open");
}
close(fd);
return 0;
}
The test only to open a target DSO, and do nothing. But this operation
will lead one or more process to happen core dump. This patch mainly to
fix this bug.
Link: https://lkml.kernel.org/r/20211025092134.18562-3-rongwei.wang@linux.alibaba.com
Fixes: eb6ecbed0aa2 ("mm, thp: relax the VM_DENYWRITE constraint on file-backed THPs")
Signed-off-by: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Tested-by: Xu Yu <xuyu@linux.alibaba.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Collin Fijalkovich <cfijalkovich@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/open.c')
| -rw-r--r-- | fs/open.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/open.c b/fs/open.c index 9ec3cfca3b1a..e0df1536eb69 100644 --- a/fs/open.c +++ b/fs/open.c @@ -857,8 +857,17 @@ static int do_dentry_open(struct file *f, */ smp_mb(); if (filemap_nr_thps(inode->i_mapping)) { + struct address_space *mapping = inode->i_mapping; + filemap_invalidate_lock(inode->i_mapping); - truncate_pagecache(inode, 0); + /* + * unmap_mapping_range just need to be called once + * here, because the private pages is not need to be + * unmapped mapping (e.g. data segment of dynamic + * shared libraries here). + */ + unmap_mapping_range(mapping, 0, 0, 0); + truncate_inode_pages(mapping, 0); filemap_invalidate_unlock(inode->i_mapping); } } |