Thanks for getting back to me! 1. The crash seems to happen in a large percentage of the runs of a particular test that does a lot of rapid SSH connections to the machine. Sadly, I don’t have an exact number, but 50% probably wouldn’t be an exaggeration. It was also happening in the setup part of the test harness when it was making a large amount of parallel connections, but we spread those out a bit. 2. The connections all happen from a single test machine. I could try to test if this is repeatable when they’re spread over multiple sources, but that’s not how our test suite works.
As for the debugging information, I will first try to reproduce the crash on a throwaway machine (VM shouldn’t make a difference, I think), as to avoid any potential leaks of host keys or other sensitive information. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to openssh in Ubuntu. https://bugs.launchpad.net/bugs/2043114 Title: sshd segmentation fault on 20.04.6 (focal) Status in openssh package in Ubuntu: Confirmed Bug description: We have a physical server running Ubuntu 20.04.6 LTS (amd64) and openssh-server 1:8.2p1-4ubuntu0.9. Sometimes sshd crashes with a segmentation fault on remote login with key authentication: [193107.651745] sshd[1229630]: segfault at 5557eba6a008 ip 00007f2326a2ca53 sp 00007ffcba40c510 error 4 in libc-2.31.so[7f23269b8000+178000] We’ve changed only the following values in the stock sshd_config file: LogLevel DEBUG PasswordAuthentication no MaxStartups 100:30:100 The server is used for automated software testing, and sometimes our test suite might make a large amount of SSH connections in a short period of time, which seems to be correlated with the crashes. But at the same time, I have to note that the connection count was not near the MaxStartups limit, and we’ve had crashes before adding that setting. Since the backtrace shows the debug logging function in the stack, we’re currently experimenting with using `LogLevel INFO` to try and isolate the issue. I am attaching the backtrace. I could provide the full dump file, although I am hesitant due to the possibility of private keys or other sensitive information leaking. # apt-cache policy openssh-server openssh-server: Installed: 1:8.2p1-4ubuntu0.9 Candidate: 1:8.2p1-4ubuntu0.9 Version table: *** 1:8.2p1-4ubuntu0.9 500 500 http://mirrors.storpool.com/ubuntu/archive focal-updates/main amd64 Packages 500 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages 100 /var/lib/dpkg/status 1:8.2p1-4 500 500 http://mirrors.storpool.com/ubuntu/archive focal/main amd64 Packages To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/2043114/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
