Investigating the issue Dirk reported [1], and after the RFC sent[2], here is now the series with my conclusions. Patch 1 fixes a real issue IMHO and is the minimal solution for backporting. Patch 2 adds some documentation. Patch 3 reduces potential race windows by letting the timer only run when we really want it. Patch 4 is a simplification because locking should be as simple as possible, right? I could trigger the code path meanwhile and did not encounter a regression. But I could not reproduce the initial report from Dirk, so I can't say this is a 100% fix. Yet, I think, we want these patches nonetheless. Dirk metioned that his system could have been shutting down. If so, patch 1 is probably the solution, but we don't know for sure. [1] https://lore.kernel.org/r/ee6c9e16-9f29-450e-81da-4a8dceaa8fc7@xxxxxxxxxxxx [2] https://lore.kernel.org/r/20240416123545.7098-4-wsa+renesas@xxxxxxxxxxxxxxxxxxxx Wolfram Sang (4): serial: sh-sci: protect invalidating RXDMA on shutdown serial: sh-sci: describe locking requirements for invalidating RXDMA serial: sh-sci: let timeout timer only run when DMA is scheduled serial: sh-sci: simplify locking when re-issuing RXDMA fails drivers/tty/serial/sh-sci.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) -- 2.43.0
