Hi, sorry to take time to back to this topic.
At Wed, 18 Mar 2015 15:29:14 -0700, Andy Lutomirski wrote: > > On Wed, Mar 18, 2015 at 3:22 PM, Jiri Kosina <jkos...@suse.cz> wrote: > > On Wed, 18 Mar 2015, Andy Lutomirski wrote: > > > >> sysret64 can only fail with #GP, and we're totally screwed if that > >> happens, > > > > But what if the GPF handler pagefaults afterwards? It'd be operating on > > user stack already. > > Good point. > > Stefan, can you try changing the first "jne > opportunistic_sysret_failed" to "jmp opportunistic_sysret_failed" in > entry_64.S and seeing if you can reproduce this? (Is it easy enough > to reproduce that this would tell us anything?) I tried this, and the same crash still happens. On my machine (a Dell desktop with IvyBridge 4-core, 8GB RAM), I could reproduce it relatively easily. Start a desktop session as usual, and start a KVM with 1GB memory 4 CPU, and start compiling a kernel on VM with make -j4. Meanwhile, start compiling a kernel with make -j8 on the host, too. So nothing too special there. The kconfig is attached below. Currently I haven't set up kdump for this machine due to the disk space. Will try to adjust somehow from now on. Takashi
.config
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