Date: Mon, 29 Aug 2022 18:22:23 +0000 From: bugzilla-noreply@freebsd.org To: riscv@FreeBSD.org Subject: [Bug 266103] ioctl(/dev/mem, MEM_EXTRACT_PADDR, <0x80000000>) on /dev/mem on riscv64 panics Message-ID: <bug-266103-40250@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D266103 Bug ID: 266103 Summary: ioctl(/dev/mem, MEM_EXTRACT_PADDR, <0x80000000>) on /dev/mem on riscv64 panics Product: Base System Version: CURRENT Hardware: riscv OS: Any Status: New Severity: Affects Some People Priority: --- Component: riscv Assignee: riscv@FreeBSD.org Reporter: rtm@lcs.mit.edu On qemu riscv64, the program below causes "panic: pmap_l2_to_l3: PA out of range, PA: 0x0" on an INVARIANTS kernel, and a kernel page fault without INVARIANTS. The immediate problem seems to be that the l2 PTE that pmap_extract() finds is all zeroes, but pmap_l2_to_l3() assumes it contains a valid physical address. #include <sys/ioctl.h> #include <unistd.h> #include <string.h> #include <fcntl.h> #include <sys/memrange.h> int main() { int fd =3D open("/dev/mem", 2); struct mem_extract m; memset(&m, 0, sizeof(m)); m.me_vaddr =3D 0x80000000; ioctl(fd, MEM_EXTRACT_PADDR, &m); } # uname -a FreeBSD 14.0-CURRENT FreeBSD 14.0-CURRENT #40 main-n250928-b8170f38ccc7-di= rty: Mon Aug 29 13:09:55 EDT 2022=20=20=20=20 rtm@xxx:/usr/obj/usr/rtm/symbsd/src/riscv.riscv64/sys/RTM riscv # cc x.c # ./a.out panic: Fatal page fault at 0xffffffc000618a18: 0xffffffcf80000000 panic() at panic+0x2a page_fault_handler() at page_fault_handler+0x1d6 do_trap_supervisor() at do_trap_supervisor+0x76 cpu_exception_handler_supervisor() at cpu_exception_handler_supervisor+0x70 --- exception 13, tval =3D 0xffffffcf80000000 pmap_extract() at pmap_extract+0x64 memioctl() at memioctl+0x78 devfs_ioctl() at devfs_ioctl+0xbe VOP_IOCTL_APV() at VOP_IOCTL_APV+0x30 VOP_IOCTL() at VOP_IOCTL+0x36 vn_ioctl() at vn_ioctl+0xba devfs_ioctl_f() at devfs_ioctl_f+0x20 fo_ioctl() at fo_ioctl+0xa kern_ioctl() at kern_ioctl+0x242 sys_ioctl() at sys_ioctl+0x120 syscallenter() at syscallenter+0xec ecall_handler() at ecall_handler+0x18 do_trap_user() at do_trap_user+0xea cpu_exception_handler_user() at cpu_exception_handler_user+0x72 --=20 You are receiving this mail because: You are the assignee for the bug.=
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