From c66b23c2840446a82c389e4cb1a12eb2a71fa2e4 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 2 Apr 2018 23:56:44 -0400 Subject: jffs2_kill_sb(): deal with failed allocations jffs2_fill_super() might fail to allocate jffs2_sb_info; jffs2_kill_sb() must survive that. Cc: stable@kernel.org Signed-off-by: Al Viro --- fs/jffs2/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c index f60dee7faf03..87bdf0f4cba1 100644 --- a/fs/jffs2/super.c +++ b/fs/jffs2/super.c @@ -342,7 +342,7 @@ static void jffs2_put_super (struct super_block *sb) static void jffs2_kill_sb(struct super_block *sb) { struct jffs2_sb_info *c = JFFS2_SB_INFO(sb); - if (!sb_rdonly(sb)) + if (c && !sb_rdonly(sb)) jffs2_stop_garbage_collect_thread(c); kill_mtd_super(sb); kfree(c); -- cgit v1.2.3 From 659038428cb43a66e3eff71e2c845c9de3611a98 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 3 Apr 2018 00:13:17 -0400 Subject: orangefs_kill_sb(): deal with allocation failures orangefs_fill_sb() might've failed to allocate ORANGEFS_SB(s); don't oops in that case. Cc: stable@kernel.org Signed-off-by: Al Viro --- fs/orangefs/super.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'fs') diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c index 3ae5fdba0225..10796d3fe27d 100644 --- a/fs/orangefs/super.c +++ b/fs/orangefs/super.c @@ -579,6 +579,11 @@ void orangefs_kill_sb(struct super_block *sb) /* provided sb cleanup */ kill_anon_super(sb); + if (!ORANGEFS_SB(sb)) { + mutex_lock(&orangefs_request_mutex); + mutex_unlock(&orangefs_request_mutex); + return; + } /* * issue the unmount to userspace to tell it to remove the * dynamic mount info it has for this superblock -- cgit v1.2.3 From 8e04944f0ea8b838399049bdcda920ab36ae3b04 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Wed, 4 Apr 2018 19:53:07 +0900 Subject: mm,vmscan: Allow preallocating memory for register_shrinker(). syzbot is catching so many bugs triggered by commit 9ee332d99e4d5a97 ("sget(): handle failures of register_shrinker()"). That commit expected that calling kill_sb() from deactivate_locked_super() without successful fill_super() is safe, but the reality was different; some callers assign attributes which are needed for kill_sb() after sget() succeeds. For example, [1] is a report where sb->s_mode (which seems to be either FMODE_READ | FMODE_EXCL | FMODE_WRITE or FMODE_READ | FMODE_EXCL) is not assigned unless sget() succeeds. But it does not worth complicate sget() so that register_shrinker() failure path can safely call kill_block_super() via kill_sb(). Making alloc_super() fail if memory allocation for register_shrinker() failed is much simpler. Let's avoid calling deactivate_locked_super() from sget_userns() by preallocating memory for the shrinker and making register_shrinker() in sget_userns() never fail. [1] https://syzkaller.appspot.com/bug?id=588996a25a2587be2e3a54e8646728fb9cae44e7 Signed-off-by: Tetsuo Handa Reported-by: syzbot Cc: Al Viro Cc: Michal Hocko Signed-off-by: Al Viro --- fs/super.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'fs') diff --git a/fs/super.c b/fs/super.c index 5fa9a8d8d865..122c402049a2 100644 --- a/fs/super.c +++ b/fs/super.c @@ -167,6 +167,7 @@ static void destroy_unused_super(struct super_block *s) security_sb_free(s); put_user_ns(s->s_user_ns); kfree(s->s_subtype); + free_prealloced_shrinker(&s->s_shrink); /* no delays needed */ destroy_super_work(&s->destroy_work); } @@ -252,6 +253,8 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags, s->s_shrink.count_objects = super_cache_count; s->s_shrink.batch = 1024; s->s_shrink.flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE; + if (prealloc_shrinker(&s->s_shrink)) + goto fail; return s; fail: @@ -518,11 +521,7 @@ retry: hlist_add_head(&s->s_instances, &type->fs_supers); spin_unlock(&sb_lock); get_filesystem(type); - err = register_shrinker(&s->s_shrink); - if (err) { - deactivate_locked_super(s); - s = ERR_PTR(err); - } + register_shrinker_prepared(&s->s_shrink); return s; } -- cgit v1.2.3 From 16a34adb9392b2fe4195267475ab5b472e55292c Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 19 Apr 2018 22:03:08 -0400 Subject: Don't leak MNT_INTERNAL away from internal mounts We want it only for the stuff created by SB_KERNMOUNT mounts, *not* for their copies. As it is, creating a deep stack of bindings of /proc/*/ns/* somewhere in a new namespace and exiting yields a stack overflow. Cc: stable@kernel.org Reported-by: Alexander Aring Bisected-by: Kirill Tkhai Tested-by: Kirill Tkhai Tested-by: Alexander Aring Signed-off-by: Al Viro --- fs/namespace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/namespace.c b/fs/namespace.c index e398f32d7541..8634d565b858 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1089,7 +1089,8 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root, goto out_free; } - mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~(MNT_WRITE_HOLD|MNT_MARKED); + mnt->mnt.mnt_flags = old->mnt.mnt_flags; + mnt->mnt.mnt_flags &= ~(MNT_WRITE_HOLD|MNT_MARKED|MNT_INTERNAL); /* Don't allow unprivileged users to change mount flags */ if (flag & CL_UNPRIVILEGED) { mnt->mnt.mnt_flags |= MNT_LOCK_ATIME; -- cgit v1.2.3