From 45e30390f50fc7499a50da33525e2ec479f8c301 Mon Sep 17 00:00:00 2001 From: Li Guifu Date: Fri, 24 Jul 2020 09:38:11 +0800 Subject: [PATCH] f2fs: fix use-after-free issue [ Upstream commit 99c787cfd2bd04926f1f553b30bd7dcea2caaba1 ] During umount, f2fs_put_super() unregisters procfs entries after f2fs_destroy_segment_manager(), it may cause use-after-free issue when umount races with procfs accessing, fix it by relocating f2fs_unregister_sysfs(). [Chao Yu: change commit title/message a bit] Signed-off-by: Li Guifu Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin --- fs/f2fs/super.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index f4b882ee48ddf..fa461db696e79 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1075,6 +1075,9 @@ static void f2fs_put_super(struct super_block *sb) int i; bool dropped; + /* unregister procfs/sysfs entries in advance to avoid race case */ + f2fs_unregister_sysfs(sbi); + f2fs_quota_off_umount(sb); /* prevent remaining shrinker jobs */ @@ -1138,8 +1141,6 @@ static void f2fs_put_super(struct super_block *sb) kvfree(sbi->ckpt); - f2fs_unregister_sysfs(sbi); - sb->s_fs_info = NULL; if (sbi->s_chksum_driver) crypto_free_shash(sbi->s_chksum_driver);