Re: Endless loop in udp with MSG_SPLICE_READ - Re: [syzbot] [fs?] INFO: task hung in pipe_release (4)
From: David Howells <dhowells@redhat.com>
Date: 2023-07-31 13:35:01
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bpf, linux-fsdevel, lkml
Willem de Bruijn [off-list ref] wrote:
Is the MSG_CONFIRM needed to trigger this?
It's not actually necessary. The syz test was doing it.
Is this indeed trivially sidestepped if downgrading from splicing to regular copying with fragmentation?
That works. The logging looks like: ==>splice_to_socket() 5535 udp_sendmsg(8,8) __ip_append_data(copy=-1,len=8, mtu=8192 skblen=8189 maxfl=8188) copy 8 = 9 - 0 - 1 - 0 length 8 -= 8 + 0 <==splice_to_socket() = 8 It looks like pagedlen being non-zero might be the issue. David