diff options
| author | Bhasker Hariharan <bhaskerh@google.com> | 2021-09-14 14:01:36 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2021-09-14 14:09:09 -0700 |
| commit | 603f473ada5f5cacc759c8810df01f47905ba5e9 (patch) | |
| tree | dd9c05d727c494d16562f3190f2ba47fa8c3ff4f | |
| parent | 5593b8a7e6cb5fc04c1b9e23a92b880517330cd4 (diff) | |
Fix bug in RecvMMsgDispatcher.
Fixed a bug introduced in the following commit:
https://github.com/google/gvisor/commit/979d6e7d77b17e94defc29515180cc75d3560383
The commit introduced a bug which causes the recvmmsg dispatcher to never exit
as BlockingPoll is now called with two fds and poll will not return an error
anymore if one of the FD is closed. We need to explicitly check the events for
each FD to determine if the sentry FD is closed.
ReadV dispatcher does not have the same issue as Readv does not rely on sk_err
field of the underlying socket to determine if the socket is in an error
state. Recvmmsg OTOH seems to get confused and always returns EAGAIN if poll()
is called which queries the sk_err field and clears it.
PiperOrigin-RevId: 396676135
| -rw-r--r-- | pkg/tcpip/link/rawfile/blockingpoll_amd64.s | 2 | ||||
| -rw-r--r-- | pkg/tcpip/link/rawfile/blockingpoll_arm64.s | 2 | ||||
| -rw-r--r-- | pkg/tcpip/link/rawfile/rawfile_unsafe.go | 16 |
3 files changed, 17 insertions, 3 deletions
diff --git a/pkg/tcpip/link/rawfile/blockingpoll_amd64.s b/pkg/tcpip/link/rawfile/blockingpoll_amd64.s index 298bad55d..f2c230720 100644 --- a/pkg/tcpip/link/rawfile/blockingpoll_amd64.s +++ b/pkg/tcpip/link/rawfile/blockingpoll_amd64.s @@ -27,7 +27,7 @@ TEXT ·BlockingPoll(SB),NOSPLIT,$0-40 MOVQ $0x0, R10 // sigmask parameter which isn't used here MOVQ $0x10f, AX // SYS_PPOLL SYSCALL - CMPQ AX, $0xfffffffffffff001 + CMPQ AX, $0xfffffffffffff002 JLS ok MOVQ $-1, n+24(FP) NEGQ AX diff --git a/pkg/tcpip/link/rawfile/blockingpoll_arm64.s b/pkg/tcpip/link/rawfile/blockingpoll_arm64.s index b62888b93..8807586c7 100644 --- a/pkg/tcpip/link/rawfile/blockingpoll_arm64.s +++ b/pkg/tcpip/link/rawfile/blockingpoll_arm64.s @@ -27,7 +27,7 @@ TEXT ·BlockingPoll(SB),NOSPLIT,$0-40 MOVD $0x0, R3 // sigmask parameter which isn't used here MOVD $0x49, R8 // SYS_PPOLL SVC - CMP $0xfffffffffffff001, R0 + CMP $0xfffffffffffff002, R0 BLS ok MOVD $-1, R1 MOVD R1, n+24(FP) diff --git a/pkg/tcpip/link/rawfile/rawfile_unsafe.go b/pkg/tcpip/link/rawfile/rawfile_unsafe.go index e76fc55b6..87a0b9a62 100644 --- a/pkg/tcpip/link/rawfile/rawfile_unsafe.go +++ b/pkg/tcpip/link/rawfile/rawfile_unsafe.go @@ -181,7 +181,9 @@ func BlockingReadvUntilStopped(efd int, fd int, iovecs []unix.Iovec) (int, tcpip if e == 0 { return int(n), nil } - + if e != 0 && e != unix.EWOULDBLOCK { + return 0, TranslateErrno(e) + } stopped, e := BlockingPollUntilStopped(efd, fd, unix.POLLIN) if stopped { return -1, nil @@ -204,6 +206,10 @@ func BlockingRecvMMsgUntilStopped(efd int, fd int, msgHdrs []MMsgHdr) (int, tcpi return int(n), nil } + if e != 0 && e != unix.EWOULDBLOCK { + return 0, TranslateErrno(e) + } + stopped, e := BlockingPollUntilStopped(efd, fd, unix.POLLIN) if stopped { return -1, nil @@ -228,5 +234,13 @@ func BlockingPollUntilStopped(efd int, fd int, events int16) (bool, unix.Errno) }, } _, errno := BlockingPoll(&pevents[0], len(pevents), nil) + if errno != 0 { + return pevents[0].Revents&unix.POLLIN != 0, errno + } + + if pevents[1].Revents&unix.POLLHUP != 0 || pevents[1].Revents&unix.POLLERR != 0 { + errno = unix.ECONNRESET + } + return pevents[0].Revents&unix.POLLIN != 0, errno } |