> Date: Thu, 9 Jan 2020 10:42:55 +0100
> From: Alexander Bluhm <alexander.bl...@gmx.net>
>
> On Thu, Dec 26, 2019 at 08:12:50PM +0100, Alexander Bluhm wrote:
> > Any more concerns or can this be commited?
>
> Any ok?
>
> > Index: arch/amd64/amd64/db_trace.c
> > ===================================================================
> > RCS file: /data/mirror/openbsd/cvs/src/sys/arch/amd64/amd64/db_trace.c,v
> > retrieving revision 1.47
> > diff -u -p -r1.47 db_trace.c
> > --- arch/amd64/amd64/db_trace.c 10 Nov 2019 10:03:33 -0000 1.47
> > +++ arch/amd64/amd64/db_trace.c 26 Dec 2019 19:08:35 -0000
> > @@ -150,7 +150,7 @@ db_stack_trace_print(db_expr_t addr, int
> > name = NULL;
> > }
> >
> > - if (lastframe == 0 && sym == NULL) {
> > + if (lastframe == 0 && sym == NULL && callpc != 0) {
> > /* Symbol not found, peek at code */
> > unsigned long instr = db_get_value(callpc, 8, 0);
> >
> > Index: arch/amd64/amd64/trap.c
> > ===================================================================
> > RCS file: /data/mirror/openbsd/cvs/src/sys/arch/amd64/amd64/trap.c,v
> > retrieving revision 1.77
> > diff -u -p -r1.77 trap.c
> > --- arch/amd64/amd64/trap.c 6 Sep 2019 12:22:01 -0000 1.77
> > +++ arch/amd64/amd64/trap.c 26 Dec 2019 19:08:35 -0000
> > @@ -77,6 +77,7 @@
> > #include <sys/signal.h>
> > #include <sys/syscall.h>
> > #include <sys/syscall_mi.h>
> > +#include <sys/stdarg.h>
> >
> > #include <uvm/uvm_extern.h>
> >
> > @@ -132,6 +133,24 @@ static inline void verify_smap(const cha
> > static inline void debug_trap(struct trapframe *_frame, struct proc *_p,
> > long _type);
> >
> > +static inline int
> > +fault(const char *format, ...)
> > +{
> > + static char faultbuf[512];
> > + va_list ap;
> > +
> > + /*
> > + * Save the fault info for DDB and retain the kernel lock to keep
> > + * faultbuf from being overwritten by another CPU.
> > + */
By splitting this out, the "retain the kernel lock" bit of the
comment doesn't make a lot of sense anymore...
> > + va_start(ap, format);
> > + vsnprintf(faultbuf, sizeof faultbuf, format, ap);
> > + va_end(ap);
> > + printf("%s\n", faultbuf);
> > + faultstr = faultbuf;
> > + return 0;
> > +}
> > +
> > /*
> > * pageflttrap(frame, usermode): page fault handler
> > * Returns non-zero if the fault was handled (possibly by generating
> > @@ -160,16 +179,14 @@ pageflttrap(struct trapframe *frame, int
> > KERNEL_LOCK();
> >
> > if (!usermode) {
> > - extern struct vm_map *kernel_map;
> > -
> > /* This will only trigger if SMEP is enabled */
> > if (cr2 <= VM_MAXUSER_ADDRESS && frame->tf_err & PGEX_I)
> > - panic("attempt to execute user address %p "
> > + return fault("attempt to execute user address %p "
> > "in supervisor mode", (void *)cr2);
> > /* This will only trigger if SMAP is enabled */
> > if (pcb->pcb_onfault == NULL && cr2 <= VM_MAXUSER_ADDRESS &&
> > frame->tf_err & PGEX_P)
> > - panic("attempt to access user address %p "
> > + return fault("attempt to access user address %p "
> > "in supervisor mode", (void *)cr2);
> >
> > /*
> > @@ -211,18 +228,9 @@ pageflttrap(struct trapframe *frame, int
> > frame->tf_rip = (u_int64_t)pcb->pcb_onfault;
> > return 1;
> > } else {
> > - /*
> > - * Bad memory access in the kernel; save the fault
> > - * info for DDB and retain the kernel lock to keep
> > - * faultbuf from being overwritten by another CPU.
> > - */
> > - static char faultbuf[512];
> > - snprintf(faultbuf, sizeof faultbuf,
> > - "uvm_fault(%p, 0x%llx, 0, %d) -> %x",
> > + /* bad memory access in the kernel */
> > + return fault("uvm_fault(%p, 0x%llx, 0, %d) -> %x",
> > map, cr2, ftype, error);
> > - printf("%s\n", faultbuf);
> > - faultstr = faultbuf;
> > - return 0;
> > }
> > } else {
> > union sigval sv;
> > @@ -395,7 +403,7 @@ trap_print(struct trapframe *frame, int
> > printf(" in %s mode\n", KERNELMODE(frame->tf_cs, frame->tf_rflags) ?
> > "supervisor" : "user");
> > printf("trap type %d code %llx rip %llx cs %llx rflags %llx cr2 "
> > - " %llx cpl %x rsp %llx\n",
> > + "%llx cpl %x rsp %llx\n",
> > type, frame->tf_err, frame->tf_rip, frame->tf_cs,
> > frame->tf_rflags, rcr2(), curcpu()->ci_ilevel, frame->tf_rsp);
> > printf("gsbase %p kgsbase %p\n",
> > Index: ddb/db_examine.c
> > ===================================================================
> > RCS file: /data/mirror/openbsd/cvs/src/sys/ddb/db_examine.c,v
> > retrieving revision 1.26
> > diff -u -p -r1.26 db_examine.c
> > --- ddb/db_examine.c 7 Nov 2019 13:16:25 -0000 1.26
> > +++ ddb/db_examine.c 26 Dec 2019 19:08:35 -0000
> > @@ -288,8 +288,10 @@ void
> > db_print_loc_and_inst(vaddr_t loc)
> > {
> > db_printsym(loc, DB_STGY_PROC, db_printf);
> > - db_printf(":\t");
> > - (void) db_disasm(loc, 0);
> > + if (loc != 0) {
> > + db_printf(":\t");
> > + db_disasm(loc, 0);
> > + }
> > }
> >
> > /* local copy is needed here so that we can trace strlcpy() in libkern */
> >
>
>
