fuse: fix live lock in fuse_iget()

3 files changed, 54 insertions, 0 deletions

diff --git a/debian/changelog b/debian/changelog
index 532379434..053f8e782 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -888,6 +888,7 @@ linux (5.10.24-1) UNRELEASED; urgency=medium
   * [x86] crypto: aesni - Use TEST %reg,%reg instead of CMP $0,%reg
   * [x86] crypto: x86/aes-ni-xts - use direct calls to and 4-way stride
   * RDMA/srp: Fix support for unpopulated and unbalanced NUMA nodes
+  * fuse: fix live lock in fuse_iget()
 
   [ Wookey ]
   * [arm64] drivers/perf: Enable ARM_CMN as module (Closes: #981186)
diff --git a/debian/patches/bugfix/all/fuse-fix-live-lock-in-fuse_iget.patch b/debian/patches/bugfix/all/fuse-fix-live-lock-in-fuse_iget.patch
new file mode 100644
index 000000000..f5491e65b
--- /dev/null
+++ b/debian/patches/bugfix/all/fuse-fix-live-lock-in-fuse_iget.patch
@@ -0,0 +1,52 @@
+From 775c5033a0d164622d9d10dd0f0a5531639ed3ed Mon Sep 17 00:00:00 2001
+From: Amir Goldstein <amir73il@gmail.com>
+Date: Thu, 4 Mar 2021 11:09:12 +0200
+Subject: fuse: fix live lock in fuse_iget()
+
+From: Amir Goldstein <amir73il@gmail.com>
+
+commit 775c5033a0d164622d9d10dd0f0a5531639ed3ed upstream.
+
+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>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/fuse/fuse_i.h |    1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/fs/fuse/fuse_i.h
++++ b/fs/fuse/fuse_i.h
+@@ -862,6 +862,7 @@ static inline u64 fuse_get_attr_version(
+ 
+ static inline void fuse_make_bad(struct inode *inode)
+ {
++	remove_inode_hash(inode);
+ 	set_bit(FUSE_I_BAD, &get_fuse_inode(inode)->state);
+ }
+ 
diff --git a/debian/patches/series b/debian/patches/series
index 1cbb9581b..21a750da2 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -90,6 +90,7 @@ bugfix/all/partially-revert-usb-kconfig-using-select-for-usb_co.patch
 debian/makefile-do-not-check-for-libelf-when-building-oot-module.patch
 bugfix/all/partially-revert-net-socket-implement-64-bit-timestamps.patch
 bugfix/all/rdma-srp-fix-support-for-unpopulated-and-unbalanced-numa-nodes.patch
+bugfix/all/fuse-fix-live-lock-in-fuse_iget.patch
 
 # Miscellaneous features