From c93ce9b00b9aa4bae06b758223ff62ca799522c6 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Thu, 26 Jul 2018 16:13:11 +0200 Subject: [PATCH] fuse: Fix oops at process_init_reply() commit e8f3bd773d22f488724dffb886a1618da85c2966 upstream. syzbot is hitting NULL pointer dereference at process_init_reply(). This is because deactivate_locked_super() is called before response for initial request is processed. Fix this by aborting and waiting for all requests (including FUSE_INIT) before resetting fc->sb. Original patch by Tetsuo Handa . Reported-by: syzbot Fixes: e27c9d3877a0 ("fuse: fuse: add time_gran to INIT_OUT") Cc: # v3.19 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman --- fs/fuse/inode.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 9517154..4b2eb65 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -379,11 +379,6 @@ static void fuse_put_super(struct super_block *sb) { struct fuse_conn *fc = get_fuse_conn_super(sb); - fuse_send_destroy(fc); - - fuse_abort_conn(fc); - fuse_wait_aborted(fc); - mutex_lock(&fuse_mutex); list_del(&fc->entry); fuse_ctl_remove_conn(fc); @@ -1174,16 +1169,25 @@ static struct dentry *fuse_mount(struct file_system_type *fs_type, return mount_nodev(fs_type, flags, raw_data, fuse_fill_super); } -static void fuse_kill_sb_anon(struct super_block *sb) +static void fuse_sb_destroy(struct super_block *sb) { struct fuse_conn *fc = get_fuse_conn_super(sb); if (fc) { + fuse_send_destroy(fc); + + fuse_abort_conn(fc); + fuse_wait_aborted(fc); + down_write(&fc->killsb); fc->sb = NULL; up_write(&fc->killsb); } +} +static void fuse_kill_sb_anon(struct super_block *sb) +{ + fuse_sb_destroy(sb); kill_anon_super(sb); } @@ -1206,14 +1210,7 @@ static struct dentry *fuse_mount_blk(struct file_system_type *fs_type, static void fuse_kill_sb_blk(struct super_block *sb) { - struct fuse_conn *fc = get_fuse_conn_super(sb); - - if (fc) { - down_write(&fc->killsb); - fc->sb = NULL; - up_write(&fc->killsb); - } - + fuse_sb_destroy(sb); kill_block_super(sb); } -- 2.7.4