** Description changed: Binary package hint: linux-image-2.6.24-19-generic Upon switching from Dapper to Hardy, I noticed one of my systems kept getting serial timeouts. Upon further investigation, it seems that there is a serial deadlock issue in kernels < 2.6.27, where machines with multiple processors and multiple serial devices can call the serial interrupt handler at the same time and become deadlocked. This was fixed in 2.6.27 with 4 lines of code. I have created a patch with the same four line based on the linux-source-2.6.24.tbz (from installing linux-source package), and I have tested it with many serial deives talking at once. My problems go away. Given that this is such a fundamental bug (deadlock in interrupt handlers), I feel it is necessary to apply this to the LTS kernels in Hardy. The original discussion of this bug and the patch (by the usual kernel programmers) is at: http://kerneltrap.org/mailarchive/linux-kernel/2008/7/1/2313364 Note, that the final fix in 2.6.27 keeps the lock and unlock lines as they were (the original discussion at the thread above changed them). My patch does not change them (as in the final 2.6.27 patch for this problem). + + === + + SRU Justification + + Justification: Systems with multiple serial ports on the will deadlock + losing serial output. + + Impact: Systems may lose serial output including console output, + particularly serious on servers. + + Fix Description: Cherry-picked the upstream fixes for this, which + introduces proper locking. + + Patch: + http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-hardy.git;a=commit;h=45485c71ce3099b7c7349f6c32dadc53087794cf + http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-hardy.git;a=commit;h=6dc468aa85f0cf60ab1b8897143226203510efe8 + + Risks: This has been tested by the affected users to good effect. Risk + should be low for normal use. + + TEST CASE: See bug report.
-- serial deadlock with SMP https://bugs.launchpad.net/bugs/280821 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
