Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 29 Aug 2020 12:38:24 +0200
From:      Michal Meloun <meloun.michal@gmail.com>
To:        Warner Losh <imp@bsdimp.com>, Mateusz Guzik <mjguzik@gmail.com>
Cc:        Warner Losh <imp@freebsd.org>, src-committers <src-committers@freebsd.org>, svn-src-all <svn-src-all@freebsd.org>, svn-src-head <svn-src-head@freebsd.org>
Subject:   Re: svn commit: r364946 - head/sys/kern
Message-ID:  <f1a67850-e9e5-d785-6562-972aeb9f1206@gmail.com>
In-Reply-To: <CANCZdfqXtKhKhh33ovFQ4_a3tiesRi8-6ZuMTp0yW%2BMzkxWLzA@mail.gmail.com>
References:  <202008290430.07T4UCM4007928@repo.freebsd.org> <CAGudoHFAkrAykin6ngH=04254J4AmhHk2NmDyGfrUE=wJcxH2A@mail.gmail.com> <CANCZdfqXtKhKhh33ovFQ4_a3tiesRi8-6ZuMTp0yW%2BMzkxWLzA@mail.gmail.com>

next in thread | previous in thread | raw e-mail | index | archive | help


On 29.08.2020 12:04, Warner Losh wrote:
> On Sat, Aug 29, 2020 at 1:09 AM Mateusz Guzik <mjguzik@gmail.com> wrote:
> 
>> This crashes on boot for me:
>>
> 
> I wasn't able to get it to crash on boot for me, but I was able to recreate
> it.
It crashed on ofw based systems where some enumerated devices have not a
suitable driver, see:
---------------------------------------
sysctl_devices: nameunit: root0, descs: System root bus, driver: root
sysctl_devices: nameunit: nexus0, descs: (null), driver: nexus
sysctl_devices: nameunit: ofwbus0, descs: Open Firmware Device Tree,
driver: ofwbus
sysctl_devices: nameunit: pcib0, descs: Nvidia Integrated PCI/PCI-E
Controller, driver: pcib
sysctl_devices: nameunit: simplebus0, descs: Flattened device tree
simple bus, driver: simplebus
sysctl_devices: nameunit: gic0, descs: ARM Generic Interrupt Controller,
driver: gic
sysctl_devices: nameunit: (null), descs: (null), driver:
sysctl_devices: nameunit: lic0, descs: (null), driver: lic
sysctl_devices: nameunit: (null), descs: (null), driver:
sysctl_devices: nameunit: car0, descs: Tegra Clock Driver, driver: car
....
----------------------------------------------------------------------
> Fixed in r364949.Confirmed.
 I think it didn't crash on boot for me because
> kldxref failed due to the segment thing so devmatch didn't run which would
> have triggered this bug. devinfo did trigger a very similar crash, and
> r364949 fixes that crash. Even a new kldxref failed due to the too many
> segments thing, so I can't confirm that's what you hit, but I'm pretty sure
> it is...
> 
But there is another issue in device_sysctl_handler() (not analyzed yet):
root@tegra210:~ # sysctl dev.cpu.
dev.cpu.3.temperature: 50.5C
dev.cpu.3panic: sbuf_clear makes no sense on sbuf 0xffff00006f21a528
with drain
cpuid = 2
time = 1598696937
KDB: stack backtrace:
db_trace_self() at db_fetch_ksymtab+0x164
         pc = 0xffff0000006787f4  lr = 0xffff000000153400
         sp = 0xffff00006f21a1b0  fp = 0xffff00006f21a3b0

db_fetch_ksymtab() at vpanic+0x198
         pc = 0xffff000000153400  lr = 0xffff00000036b274
         sp = 0xffff00006f21a3c0  fp = 0xffff00006f21a420

vpanic() at panic+0x44
         pc = 0xffff00000036b274  lr = 0xffff00000036b018
         sp = 0xffff00006f21a430  fp = 0xffff00006f21a4e0

panic() at sbuf_clear+0xa0
         pc = 0xffff00000036b018  lr = 0xffff0000003c17c8
         sp = 0xffff00006f21a4f0  fp = 0xffff00006f21a4f0

sbuf_clear() at sbuf_cpy+0x58
         pc = 0xffff0000003c17c8  lr = 0xffff0000003c1ff0
         sp = 0xffff00006f21a500  fp = 0xffff00006f21a500

sbuf_cpy() at _gone_in_dev+0x560
         pc = 0xffff0000003c1ff0  lr = 0xffff0000003a9078
         sp = 0xffff00006f21a510  fp = 0xffff00006f21a570

_gone_in_dev() at sbuf_new_for_sysctl+0x170
         pc = 0xffff0000003a9078  lr = 0xffff00000037c1a8
         sp = 0xffff00006f21a580  fp = 0xffff00006f21a5a0

sbuf_new_for_sysctl() at kernel_sysctl+0x36c
         pc = 0xffff00000037c1a8  lr = 0xffff00000037b63c
         sp = 0xffff00006f21a5b0  fp = 0xffff00006f21a630

kernel_sysctl() at userland_sysctl+0xf4
         pc = 0xffff00000037b63c  lr = 0xffff00000037bc5c
         sp = 0xffff00006f21a640  fp = 0xffff00006f21a6d0

userland_sysctl() at sys___sysctl+0x68
         pc = 0xffff00000037bc5c  lr = 0xffff00000037bb28
         sp = 0xffff00006f21a6e0  fp = 0xffff00006f21a790

sys___sysctl() at do_el0_sync+0x4e0
         pc = 0xffff00000037bb28  lr = 0xffff000000697918
         sp = 0xffff00006f21a7a0  fp = 0xffff00006f21a830

do_el0_sync() at handle_el0_sync+0x90
         pc = 0xffff000000697918  lr = 0xffff00000067aa24
         sp = 0xffff00006f21a840  fp = 0xffff00006f21a980

handle_el0_sync() at 0x4047764c
         pc = 0xffff00000067aa24  lr = 0x000000004047764c
         sp = 0xffff00006f21a990  fp = 0x0000ffffffffc250

KDB: enter: panic
[ thread pid 1263 tid 100092 ]
Stopped at      0x40477fb4:     undefined       54000042

> Warner
>

> 
>> 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@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>
>>
> 



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?f1a67850-e9e5-d785-6562-972aeb9f1206>