aboutsummaryrefslogtreecommitdiff
path: root/net/ipv6/tcp_ipv6.c
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2024-05-28 12:52:51 +0000
committerJakub Kicinski <kuba@kernel.org>2024-05-29 17:21:35 -0700
commit853c3bd7b7917670224c9fe5245bd045cac411dd (patch)
tree74e6d3420c431784c0f5715a8c267a8267c0476d /net/ipv6/tcp_ipv6.c
parent5e514f1cba090e1c8fff03e92a175eccfe46305f (diff)
downloadlinux-853c3bd7b7917670224c9fe5245bd045cac411dd.tar.gz
linux-853c3bd7b7917670224c9fe5245bd045cac411dd.tar.bz2
linux-853c3bd7b7917670224c9fe5245bd045cac411dd.zip
tcp: fix race in tcp_write_err()
I noticed flakes in a packetdrill test, expecting an epoll_wait() to return EPOLLERR | EPOLLHUP on a failed connect() attempt, after multiple SYN retransmits. It sometimes return EPOLLERR only. The issue is that tcp_write_err(): 1) writes an error in sk->sk_err, 2) calls sk_error_report(), 3) then calls tcp_done(). tcp_done() is writing SHUTDOWN_MASK into sk->sk_shutdown, among other things. Problem is that the awaken user thread (from 2) sk_error_report()) might call tcp_poll() before tcp_done() has written sk->sk_shutdown. tcp_poll() only sees a non zero sk->sk_err and returns EPOLLERR. This patch fixes the issue by making sure to call sk_error_report() after tcp_done(). tcp_write_err() also lacks an smp_wmb(). We can reuse tcp_done_with_error() to factor out the details, as Neal suggested. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Link: https://lore.kernel.org/r/20240528125253.1966136-3-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6/tcp_ipv6.c')
0 files changed, 0 insertions, 0 deletions