https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219399
--- Comment #204 from Don Lewis <truck...@freebsd.org> --- Created attachment 185022 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=185022&action=edit program to cause Ryzen hang/reboot on tweaked FreeBSD by executing code in high memory If you modify the FreeBSD kernel to lower the shared page, but leave sv_maxuser at its original value so that a user program can mmap the page at 0x7ffffffff000, the attached program will fill that page with RET instructions and perform calls to those in a loop. I have not observed any issues with calls to the RET instructions at 0x7fffffffff3f or below. When the RET instruction at 0x7fffffffff40 is executed, my machine will typically silently reboot without a panic message, or it will sometimes hang with the screen blanked. This test is the most sensitive on core 0, which handles most interrupts, so run under "cpuset -l 0" for best results. The problem appears to be triggered when the RET instruction is interrupted. It is possible to load and execute arbitrary code for other experiments. -- You are receiving this mail because: You are the assignee for the bug. _______________________________________________ freebsd-bugs@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-bugs To unsubscribe, send any mail to "freebsd-bugs-unsubscr...@freebsd.org"
