From 01462405f0c093b2f8dfddafcadcda6c9e4c5cdf Mon Sep 17 00:00:00 2001 From: Jiri Bohac Date: Wed, 19 Nov 2014 23:05:49 +0100 Subject: [PATCH] ipx: fix locking regression in ipx_sendmsg and ipx_recvmsg This fixes an old regression introduced by commit b0d0d915 (ipx: remove the BKL). When a recvmsg syscall blocks waiting for new data, no data can be sent on the same socket with sendmsg because ipx_recvmsg() sleeps with the socket locked. This breaks mars-nwe (NetWare emulator): - the ncpserv process reads the request using recvmsg - ncpserv forks and spawns nwconn - ncpserv calls a (blocking) recvmsg and waits for new requests - nwconn deadlocks in sendmsg on the same socket Commit b0d0d915 has simply replaced BKL locking with lock_sock/release_sock. Unlike now, BKL got unlocked while sleeping, so a blocking recvmsg did not block a concurrent sendmsg. Only keep the socket locked while actually working with the socket data and release it prior to calling skb_recv_datagram(). Signed-off-by: Jiri Bohac Reviewed-by: Arnd Bergmann Signed-off-by: David S. Miller --- Reading git-format-patch failed