Hi Geert, On Tue, 4 Dec 2018 14:53:07 +0100, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: > I found similar crashes in a report from 2006, but of course the code > has changed too much to apply the solution proposed there > (https://www.linux-mips.org/archives/linux-mips/2006-09/msg00169.html). > > Userland is Debian 8 (the last release supporting "old" MIPS). > My kernel is based on v4.20.0-rc5, but the issue happens with v4.20-rc1, > too. > > However, I noticed it works in v4.19! Hence I've bisected this, to commit > 277e4ab7d530bf28 ("SUNRPC: Simplify TCP receive code by switching to using > iterators"). > > Dropping the ",tcp" part from the nfsroot parameter also fixes the issue. > > Given RBTX4926 is little endian, just like my arm/arm64 boards, it's probably > not an endianness issue. Sparse didn't show anything suspicious before/after > the guilty commit. > > Do you have a clue? If it was a cache issue, disabling i-cache or d-cache completely might help understanding the problem. I added TXx9 specific "icdisable" and "dcdisable" kernel options for debugging long ago. I hope these options still works correctly with recent kernel but not sure. Also, disabling i-cache makes your board VERY slow, of course. --- Atsushi Nemoto
