Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 15/42] fuse: clear FR_PENDING flag when moving requests out of pending queue | Date | Tue, 24 Jan 2017 08:55:25 +0100 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Tahsin Erdogan <tahsin@google.com>
commit a8a86d78d673b1c99fe9b0064739fde9e9774184 upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/fuse/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -2083,7 +2083,6 @@ static void end_requests(struct fuse_con 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); @@ -2161,6 +2160,8 @@ void fuse_abort_conn(struct fuse_conn *f 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);
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