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authorTahsin Erdogan <tahsin@google.com>2017-01-12 12:04:04 -0800
committerMiklos Szeredi <mszeredi@redhat.com>2017-01-13 12:03:47 +0100
commita8a86d78d673b1c99fe9b0064739fde9e9774184 (patch)
tree12aaf53834805de16bf1cb6af09aa107695babde
parenta121103c922847ba5010819a3f250f1f7fc84ab8 (diff)
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fuse: clear FR_PENDING flag when moving requests out of pending queue
fuse_abort_conn() moves requests from pending list to a temporary list before canceling them. This operation races with request_wait_answer() which also tries to remove the request after it gets a fatal signal. It checks FR_PENDING flag to determine whether the request is still in the pending list. Make fuse_abort_conn() clear FR_PENDING flag so that request_wait_answer() does not remove the request from temporary list. This bug causes an Oops when trying to delete an already deleted list entry in end_requests(). Fixes: ee314a870e40 ("fuse: abort: no fc->lock needed for request ending") Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> # 4.2+
-rw-r--r--fs/fuse/dev.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 70ea57c7b6bb..4e06a27ed7f8 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -2025,7 +2025,6 @@ static void end_requests(struct fuse_conn *fc, struct list_head *head)
struct fuse_req *req;
req = list_entry(head->next, struct fuse_req, list);
req->out.h.error = -ECONNABORTED;
- clear_bit(FR_PENDING, &req->flags);
clear_bit(FR_SENT, &req->flags);
list_del_init(&req->list);
request_end(fc, req);
@@ -2103,6 +2102,8 @@ void fuse_abort_conn(struct fuse_conn *fc)
spin_lock(&fiq->waitq.lock);
fiq->connected = 0;
list_splice_init(&fiq->pending, &to_end2);
+ list_for_each_entry(req, &to_end2, list)
+ clear_bit(FR_PENDING, &req->flags);
while (forget_pending(fiq))
kfree(dequeue_forget(fiq, 1, NULL));
wake_up_all_locked(&fiq->waitq);