svn commit: r364946 - head/sys/kern

[Mateusz Guzik]

This crashes on boot for me:

atal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address	= 0x0
fault code		= supervisor read data, page not present
instruction pointer	= 0x20:0xffffffff805b0a7f
stack pointer	        = 0x28:0xfffffe002366a7f0
frame pointer	        = 0x28:0xfffffe002366a7f0
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 89 (devmatch)
trap number		= 12
panic: page fault
cpuid = 0
time = 1598692135
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe002366a4a0
vpanic() at vpanic+0x182/frame 0xfffffe002366a4f0
panic() at panic+0x43/frame 0xfffffe002366a550
trap_fatal() at trap_fatal+0x387/frame 0xfffffe002366a5b0
trap_pfault() at trap_pfault+0x4f/frame 0xfffffe002366a610
trap() at trap+0x27d/frame 0xfffffe002366a720
calltrap() at calltrap+0x8/frame 0xfffffe002366a720
--- trap 0xc, rip = 0xffffffff805b0a7f, rsp = 0xfffffe002366a7f0, rbp
= 0xfffffe002366a7f0 ---
strlen() at strlen+0x1f/frame 0xfffffe002366a7f0
sbuf_cat() at sbuf_cat+0x15/frame 0xfffffe002366a810
sysctl_devices() at sysctl_devices+0x104/frame 0xfffffe002366a8a0
sysctl_root_handler_locked() at sysctl_root_handler_locked+0x91/frame
0xfffffe002366a8f0
sysctl_root() at sysctl_root+0x249/frame 0xfffffe002366a970
userland_sysctl() at userland_sysctl+0x170/frame 0xfffffe002366aa20
sys___sysctl() at sys___sysctl+0x5f/frame 0xfffffe002366aad0
amd64_syscall() at amd64_syscall+0x10c/frame 0xfffffe002366abf0
fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe002366abf0
--- syscall (202, FreeBSD ELF64, sys___sysctl), rip = 0x80041c0ea, rsp
= 0x7fffffffda78, rbp = 0x7fffffffdab0 ---
KDB: enter: panic
[ thread pid 89 tid 100067 ]
Stopped at      kdb_enter+0x37: movq    $0,0x7e2616(%rip)


On 8/29/20, Warner Losh <imp at freebsd.org> wrote:
> Author: imp
> Date: Sat Aug 29 04:30:12 2020
> New Revision: 364946
> URL: https://svnweb.freebsd.org/changeset/base/364946
>
> Log:
>   Move to using sbuf for some sysctl in newbus
>
>   Convert two different sysctl to using sbuf. First, for all the default
>   sysctls we implement for each device driver that's attached. This is a
>   pure sbuf conversion.
>
>   Second, convert sysctl_devices to fill its buffer with sbuf rather
>   than a hand-rolled crappy thing I wrote years ago.
>
>   Reviewed by: cem, markj
>   Differential Revision: https://reviews.freebsd.org/D26206
>
> Modified:
>   head/sys/kern/subr_bus.c
>
> Modified: head/sys/kern/subr_bus.c
> ==============================================================================
> --- head/sys/kern/subr_bus.c	Sat Aug 29 04:30:06 2020	(r364945)
> +++ head/sys/kern/subr_bus.c	Sat Aug 29 04:30:12 2020	(r364946)
> @@ -260,36 +260,33 @@ enum {
>  static int
>  device_sysctl_handler(SYSCTL_HANDLER_ARGS)
>  {
> +	struct sbuf sb;
>  	device_t dev = (device_t)arg1;
> -	const char *value;
> -	char *buf;
>  	int error;
>
> -	buf = NULL;
> +	sbuf_new_for_sysctl(&sb, NULL, 1024, req);
>  	switch (arg2) {
>  	case DEVICE_SYSCTL_DESC:
> -		value = dev->desc ? dev->desc : "";
> +		sbuf_cpy(&sb, dev->desc ? dev->desc : "");
>  		break;
>  	case DEVICE_SYSCTL_DRIVER:
> -		value = dev->driver ? dev->driver->name : "";
> +		sbuf_cpy(&sb, dev->driver ? dev->driver->name : "");
>  		break;
>  	case DEVICE_SYSCTL_LOCATION:
> -		value = buf = malloc(1024, M_BUS, M_WAITOK | M_ZERO);
> -		bus_child_location_str(dev, buf, 1024);
> +		bus_child_location_sb(dev, &sb);
>  		break;
>  	case DEVICE_SYSCTL_PNPINFO:
> -		value = buf = malloc(1024, M_BUS, M_WAITOK | M_ZERO);
> -		bus_child_pnpinfo_str(dev, buf, 1024);
> +		bus_child_pnpinfo_sb(dev, &sb);
>  		break;
>  	case DEVICE_SYSCTL_PARENT:
> -		value = dev->parent ? dev->parent->nameunit : "";
> +		sbuf_cpy(&sb, dev->parent ? dev->parent->nameunit : "");
>  		break;
>  	default:
> +		sbuf_delete(&sb);
>  		return (EINVAL);
>  	}
> -	error = SYSCTL_OUT_STR(req, value);
> -	if (buf != NULL)
> -		free(buf, M_BUS);
> +	error = sbuf_finish(&sb);
> +	sbuf_delete(&sb);
>  	return (error);
>  }
>
> @@ -5464,13 +5461,13 @@ SYSCTL_PROC(_hw_bus, OID_AUTO, info, CTLTYPE_STRUCT
> |
>  static int
>  sysctl_devices(SYSCTL_HANDLER_ARGS)
>  {
> +	struct sbuf		sb;
>  	int			*name = (int *)arg1;
>  	u_int			namelen = arg2;
>  	int			index;
>  	device_t		dev;
>  	struct u_device		*udev;
>  	int			error;
> -	char			*walker, *ep;
>
>  	if (namelen != 2)
>  		return (EINVAL);
> @@ -5501,34 +5498,21 @@ sysctl_devices(SYSCTL_HANDLER_ARGS)
>  	udev->dv_devflags = dev->devflags;
>  	udev->dv_flags = dev->flags;
>  	udev->dv_state = dev->state;
> -	walker = udev->dv_fields;
> -	ep = walker + sizeof(udev->dv_fields);
> -#define CP(src)						\
> -	if ((src) == NULL)				\
> -		*walker++ = '\0';			\
> -	else {						\
> -		strlcpy(walker, (src), ep - walker);	\
> -		walker += strlen(walker) + 1;		\
> -	}						\
> -	if (walker >= ep)				\
> -		break;
> -
> -	do {
> -		CP(dev->nameunit);
> -		CP(dev->desc);
> -		CP(dev->driver != NULL ? dev->driver->name : NULL);
> -		bus_child_pnpinfo_str(dev, walker, ep - walker);
> -		walker += strlen(walker) + 1;
> -		if (walker >= ep)
> -			break;
> -		bus_child_location_str(dev, walker, ep - walker);
> -		walker += strlen(walker) + 1;
> -		if (walker >= ep)
> -			break;
> -		*walker++ = '\0';
> -	} while (0);
> -#undef CP
> -	error = SYSCTL_OUT(req, udev, sizeof(*udev));
> +	sbuf_new(&sb, udev->dv_fields, sizeof(udev->dv_fields), SBUF_FIXEDLEN);
> +	sbuf_cat(&sb, dev->nameunit);
> +	sbuf_putc(&sb, '\0');
> +	sbuf_cat(&sb, dev->desc);
> +	sbuf_putc(&sb, '\0');
> +	sbuf_cat(&sb, dev->driver != NULL ? dev->driver->name : '\0');
> +	sbuf_putc(&sb, '\0');
> +	bus_child_pnpinfo_sb(dev, &sb);
> +	sbuf_putc(&sb, '\0');
> +	bus_child_location_sb(dev, &sb);
> +	sbuf_putc(&sb, '\0');
> +	error = sbuf_finish(&sb);
> +	if (error == 0)
> +		error = SYSCTL_OUT(req, udev, sizeof(*udev));
> +	sbuf_delete(&sb);
>  	free(udev, M_BUS);
>  	return (error);
>  }
>


-- 
Mateusz Guzik <mjguzik gmail.com>