This is the commit that introduced this regression in V4.4-rc6:
commit 3822b5c2fc62e3de8a0f33806ff279fb7df92432 Author: Rainer Weikusat <rweiku...@mobileactivedefense.com> Date: Wed Dec 16 20:09:25 2015 +0000 af_unix: Revert 'lock_interruptible' in stream receive code With b3ca9b02b00704053a38bfe4c31dbbb9c13595d0, the AF_UNIX SOCK_STREAM receive code was changed from using mutex_lock(&u->readlock) to mutex_lock_interruptible(&u->readlock) to prevent signals from being delayed for an indefinite time if a thread sleeping on the mutex happened to be selected for handling the signal. But this was never a problem with the stream receive code (as opposed to its datagram counterpart) as that never went to sleep waiting for new messages with the mutex held and thus, wouldn't cause secondary readers to block on the mutex waiting for the sleeping primary reader. As the interruptible locking makes the code more complicated in exchange for no benefit, change it back to using mutex_lock. Signed-off-by: Rainer Weikusat <rweiku...@mobileactivedefense.com> Acked-by: Hannes Frederic Sowa <han...@stressinduktion.org> Signed-off-by: David S. Miller <da...@davemloft.net> -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1540731 Title: SocketMessenger::update_session_creds() fails to get client PID, causing "[ FAILED ] PromptSessionClientAPI.client_pid_is_associated_with_session" on kernel 4.4 (but kernel 4.3 works) Status in GLibC: New Status in Mir: Confirmed Status in linux package in Ubuntu: In Progress Bug description: Since updating to the 4.4.0-2 kernel recvmsg() fails SCM_CREDENTIALS request with EOPNOTSUPP. This manifests as a test failure in Mir: [ RUN ] PromptSessionClientAPI.client_pid_is_associated_with_session unknown file: Failure Test case: #include <stdlib.h> #include <stdio.h> #include <sys/socket.h> #include <sys/stat.h> #include <assert.h> #include <errno.h> #include <string.h> int main() { enum { server, client, size }; int socket_fd[size]; int const opt = 1; assert(socketpair(AF_LOCAL, SOCK_STREAM, 0, socket_fd) == 0); char const msg[] = "A random message"; send(socket_fd[client], msg, sizeof msg, MSG_DONTWAIT | MSG_NOSIGNAL); assert(setsockopt(socket_fd[server], SOL_SOCKET, SO_PASSCRED, &opt, sizeof(opt)) != -1); union { struct cmsghdr cmh; char control[CMSG_SPACE(sizeof(ucred))]; } control_un; control_un.cmh.cmsg_len = CMSG_LEN(sizeof(ucred)); control_un.cmh.cmsg_level = SOL_SOCKET; control_un.cmh.cmsg_type = SCM_CREDENTIALS; msghdr msgh; msgh.msg_name = NULL; msgh.msg_namelen = 0; msgh.msg_iov = NULL; msgh.msg_iovlen = 0; msgh.msg_control = control_un.control; msgh.msg_controllen = sizeof(control_un.control); errno = 0; if (recvmsg(socket_fd[server], &msgh, MSG_PEEK) == -1) { printf("Error: %s\n", strerror(errno)); exit(EXIT_FAILURE); } else { printf("Success!\n"); exit(EXIT_SUCCESS); } } To manage notifications about this bug go to: https://bugs.launchpad.net/glibc/+bug/1540731/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp