On 04/10/2018 07:37 AM, Mike Galbraith wrote: > On Tue, 2018-04-10 at 10:59 +0200, Ingo Molnar wrote: >> * Mike Galbraith <efa...@gmx.de> wrote: >> >>> Hi Ingo, >>> >>> FYI, my i4790 box reboots immediately.. or close enough to it that you >>> see nothing at all before again meeting the bios splash. Master with >>> the ~same config works fine. I haven't poked around yet (work). >> >> Hm, so there's been a few 'dangerous' pieces of work merged yesterday-ish. >> >> Prime suspects would be: >> >> triton:~/tip> gll linus..x86/pti >> >> 0564258fb2cf: x86/pti: Leave kernel text global for !PCID >> a5df4f1f0d78: x86/pti: Never implicitly clear _PAGE_GLOBAL for kernel image >> e0bb456e3250: x86/pti: Enable global pages for shared areas >> efad2b415152: x86/mm: Do not forbid _PAGE_RW before init for __ro_after_init >> 4ddee6efdcd0: x86/mm: Comment _PAGE_GLOBAL mystery >> e71e836f463d: x86/mm: Remove extra filtering in pageattr code >> 64c80759408f: x86/mm: Do not auto-massage page protections <== WOOF >> 6baf4bec02db: x86/espfix: Document use of _PAGE_GLOBAL >> 8a57f4849f4f: x86/mm: Introduce "default" kernel PTE mask >> 606c7193d5fb: x86/mm: Undo double _PAGE_PSE clearing >> d1440b23c922: x86/mm: Factor out pageattr _PAGE_GLOBAL setting >> ee1400dda318: Merge branch 'linus' into x86/pti to pick up upstream changes >> 071ccc966ba5: x86/entry/64: Drop idtentry's manual stack switch for user >> entries >> 9820e1c3376c: x86/uapi: Fix asm/bootparam.h userspace compilation errors >> >> ... which you could test via 0564258fb2cf: if that insta-reboots too then >> 9820e1c3376c^1 is expected to work and 4 bisection steps should pinpoint the >> guilty commit ... > > Thanks. I already had a full bisect running, so ended up doing more > than 4 steps, but ended up at the above.
Just out of curiosity, can you try the following patch and see if it fixes your reboot issue: diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index c5196d2..a0a50b9 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -55,7 +55,7 @@ extern unsigned long get_cmd_line_ptr(void); /* Used by PAGE_KERN* macros: */ -pteval_t __default_kernel_pte_mask __read_mostly; +pteval_t __default_kernel_pte_mask __read_mostly = ~0; /* Simplified build-specific string for starting entropy. */ static const char build_str = UTS_RELEASE " (" LINUX_COMPILE_BY "@" Thanks, Tom > > -Mike >