On Thu, Jan 09, 2020 at 12:01:07PM +0100, Mark Kettenis wrote:
> By splitting this out, the "retain the kernel lock" bit of the
> comment doesn't make a lot of sense anymore...
Then move the comment to the return where we retain it.
bluhm
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 9 Jan 2020 12:25:54 -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 9 Jan 2020 12:53:10 -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 +133,23 @@ static inline void verify_smap(const cha
static inline void debug_trap(struct trapframe *_frame, struct proc *_p,
long _type);
+static inline void
+fault(const char *format, ...)
+{
+ static char faultbuf[512];
+ va_list ap;
+
+ /*
+ * Save the fault info for DDB. Kernel lock protects
+ * faultbuf from being overwritten by another CPU.
+ */
+ va_start(ap, format);
+ vsnprintf(faultbuf, sizeof faultbuf, format, ap);
+ va_end(ap);
+ printf("%s\n", faultbuf);
+ faultstr = faultbuf;
+}
+
/*
* pageflttrap(frame, usermode): page fault handler
* Returns non-zero if the fault was handled (possibly by generating
@@ -160,17 +178,21 @@ 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 "
+ if (cr2 <= VM_MAXUSER_ADDRESS && frame->tf_err & PGEX_I) {
+ fault("attempt to execute user address %p "
"in supervisor mode", (void *)cr2);
+ /* retain kernel lock */
+ return 0;
+ }
/* 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 "
+ frame->tf_err & PGEX_P) {
+ fault("attempt to access user address %p "
"in supervisor mode", (void *)cr2);
+ /* retain kernel lock */
+ return 0;
+ }
/*
* It is only a kernel address space fault iff:
@@ -211,17 +233,10 @@ 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 */
+ fault("uvm_fault(%p, 0x%llx, 0, %d) -> %x",
map, cr2, ftype, error);
- printf("%s\n", faultbuf);
- faultstr = faultbuf;
+ /* retain kernel lock */
return 0;
}
} else {
@@ -395,7 +410,7 @@ 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 9 Jan 2020 12:25:54 -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 */
