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...
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