Messages in this thread | | | Subject | Re: [PATCH 4.19,v2] VFS: Fix fuseblk memory leak caused by mount concurrency | From | "chenxiaosong (A)" <> | Date | Wed, 13 Oct 2021 18:49:06 +0800 |
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在 2021/10/13 18:38, chenxiaosong (A) 写道: > 在 2021/10/13 18:11, Greg KH 写道: >> On Wed, Oct 13, 2021 at 05:51:01PM +0800, ChenXiaoSong wrote: >>> If two processes mount same superblock, memory leak occurs: >>> >>> CPU0 | CPU1 >>> do_new_mount | do_new_mount >>> fs_set_subtype | fs_set_subtype >>> kstrdup | >>> | kstrdup >>> memrory leak | >>> >>> Fix this by adding a write lock while calling fs_set_subtype. >>> >>> Linus's tree already have refactoring patchset [1], one of them can >>> fix this bug: >>> c30da2e981a7 (fuse: convert to use the new mount API) >>> >>> Since we did not merge the refactoring patchset in this branch, I >>> create this patch. >>> >>> [1] >>> https://patchwork.kernel.org/project/linux-fsdevel/patch/20190903113640.7984-3-mszeredi@redhat.com/ >>> >>> >>> Fixes: 79c0b2df79eb (add filesystem subtype support) >>> Cc: David Howells <dhowells@redhat.com> >>> Signed-off-by: ChenXiaoSong <chenxiaosong2@huawei.com> >>> --- >>> v1: Can not mount sshfs ([PATCH linux-4.19.y] VFS: Fix fuseblk memory >>> leak caused by mount concurrency) >>> v2: Use write lock while writing superblock >>> >>> fs/namespace.c | 9 ++++++--- >>> 1 file changed, 6 insertions(+), 3 deletions(-) >> >> As you are referring to a fuse-only patch above, why are you trying to >> resolve this issue in the core namespace code instead? >> >> How does fuse have anything to do with this? >> >> confused, >> >> greg k-h >> . >> > > Now, only `fuse_fs_type` and `fuseblk_fs_type` has `FS_HAS_SUBTYPE` flag > in kernel code, but maybe there is a filesystem module(`struct > file_system_type` has `FS_HAS_SUBTYPE` flag). And only mounting fuseblk > filesystem(e.g. ntfs) will occur memory leak now.
How about updating the subject as: VFS: Fix memory leak caused by mounting fs with subtype concurrency?
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