commit 775c5033a0d164622d9d10dd0f0a5531639ed3ed
author Amir Goldstein <amir73il@gmail.com> Thu Mar 04 11:09:12 2021 +0200
committer Miklos Szeredi <mszeredi@redhat.com> Thu Mar 04 13:36:46 2021 +0100
tree b4ad06726ea92cb085a5f6dbd1d3d9c8285735b8
parent fe07bfda2fb9cdef8a4d4008a409bb02f35f1bd8

fuse: fix live lock in fuse_iget()

Commit 5d069dbe8aaf ("fuse: fix bad inode") replaced make_bad_inode()
in fuse_iget() with a private implementation fuse_make_bad().

The private implementation fails to remove the bad inode from inode
cache, so the retry loop with iget5_locked() finds the same bad inode
and marks it bad forever.

kmsg snip:

[ ] rcu: INFO: rcu_sched self-detected stall on CPU
...
[ ]  ? bit_wait_io+0x50/0x50
[ ]  ? fuse_init_file_inode+0x70/0x70
[ ]  ? find_inode.isra.32+0x60/0xb0
[ ]  ? fuse_init_file_inode+0x70/0x70
[ ]  ilookup5_nowait+0x65/0x90
[ ]  ? fuse_init_file_inode+0x70/0x70
[ ]  ilookup5.part.36+0x2e/0x80
[ ]  ? fuse_init_file_inode+0x70/0x70
[ ]  ? fuse_inode_eq+0x20/0x20
[ ]  iget5_locked+0x21/0x80
[ ]  ? fuse_inode_eq+0x20/0x20
[ ]  fuse_iget+0x96/0x1b0

Fixes: 5d069dbe8aaf ("fuse: fix bad inode")
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/fuse_i.h

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 68cca8d..63d97a1 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -863,6 +863,7 @@ static inline u64 fuse_get_attr_version(struct fuse_conn *fc)
 
 static inline void fuse_make_bad(struct inode *inode)
 {
+	remove_inode_hash(inode);
 	set_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state);
 }