The commit is pushed to "branch-rh10-6.12.0-211.30.1.14.x.vz10-ovz" and will
appear at [email protected]:openvz/vzkernel.git
after rh10-6.12.0-211.30.1.14.1.vz10
------>
commit 26beb5149f57b2e16ae80ac54395c8e9f0386d57
Author: Konstantin Khorenko <[email protected]>
Date: Mon Jul 6 12:59:41 2026 +0200
fuse: also take req_lock when walking open_files in fusectl
Commit 56ef1ee0584c switched the fusectl seq-file iterator from an
unconditional spin_lock(&fcp->conn->lock) to spin_lock(fcp->req_lock),
so that each fusectl list is walked under the lock that actually
protects it. It set ->req_lock for the "pending_req" file (and the
#if 0 processing/io variants), but missed the second consumer of the
same start/next/stop callbacks: the "open_files" seq-file has its own
open handler, fuse_conn_files_open().
fuse_conn_priv is allocated with __seq_open_private() (kzalloc), so for
open_files ->req_lock stayed NULL. The first read of
/sys/fs/fuse/connections/<dev>/open_files then calls fuse_req_start()
-> spin_lock(NULL) and the kernel panics with a NULL pointer
dereference in the qspinlock slow path.
The conn_files list is added to and removed from under conn->lock
(fuse_file_alloc()/fuse_file_list_del()), so point ->req_lock at
conn->lock for the open_files file too. This restores the exact lock
that was used before 56ef1ee0584c for this path.
Fixes: 56ef1ee0584c ("fuse: lock the input-queue lock when walking
pending_req in fusectl")
Feature: vStorage
https://virtuozzo.atlassian.net/browse/VSTOR-137234
Signed-off-by: Konstantin Khorenko <[email protected]>
Acked-by: Liu Kui <[email protected]>
---
fs/fuse/control.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/fuse/control.c b/fs/fuse/control.c
index 1f5d998be23d8..6d210ac80610e 100644
--- a/fs/fuse/control.c
+++ b/fs/fuse/control.c
@@ -441,6 +441,7 @@ static int fuse_conn_files_open(struct inode *inode, struct
file *filp)
fcp->conn = conn;
fcp->req_list = &conn->conn_files;
+ fcp->req_lock = &conn->lock;
return 0;
}
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