[HEADS UP] change in devfs path matching logic

[Jase Thew]

On 24/08/2013 21:03, Toomas Aas wrote:
> Hello!
>
> On Fri, 23 Aug 2013 Andriy Gapon <avg at FreeBSD.org> wrote:
>
>>
>> This change is about to be MFC-ed.
>>
>> on 26/07/2013 17:39 Andriy Gapon said the following:
>>>
>>> I have just committed a significant change to devfs path matching logic
>>> http://svnweb.freebsd.org/changeset/base/253677
>
> I just rebuilt my 8-STABLE i386 system to r254796 and now receive a
> kernel panic on boot. If I remove my /etc/devfs.rules file, the panic
> does not happen. Can anyone point out what is wrong with my devfs.rules
> what the new path matching logic doesn't like?
>
> $ cat /etc/devfs.rules.old
> [localrules=10]
> add path "da*" mode 0660 group operator
> add path "usb/1.2.0" mode 0660 group uucp
> add path "usb/4.3.0" mode 0660 group operator
>
>
> The panic, as transcribed from screen:
>
> Fatal trap 12: page fault while in kernel mode
> fault virtual address = 0x0
> fault code            = supervisor read, page not present
> instruction pointer   = 0x20:0xc06dde21
> stack pointer         = 0x28:0xe8690a48
> frame pointer         = 0x28:0xe8690a80
> code segment          = base 0x0, limit 0xfffff, type 0x1b
>                        = DPL 0, pres 1, def32 1, gran 1
> processor eflags      = interrupt enabled, resume, iopl = 0
> current process       = 577 (ln)
> trap number           = 12
> panic: page fault
> KDB: stack backtrace:
> #0 0xc0670ece at kdb_backtrace+0x50
> #1 0xc06449fa at panic+0x132
> #2 0xc07eb1d2 at trap_fatal+0x21e
> #3 0xc07eb4e0 at trap_pfault+0x1c2
> #4 0xc07ec251 at trap+0x3c1
> #5 0xc07d95fc at calltrap+0x6
> #6 0xc05c7001 at devfs_rule_run+0x13d
> #7 0xc05c70c3 at devfs_ruleset_applyde+0x25
> #8 0xc05c71b3 at devfs_rules_apply+0x73
> #9 0xc05cad51 at devfs_symlink+0x124
> #10 0xc080d084 at VOP_SYMLINK_APV+0x4a
> #11 0xc06d2985 at kern_symlinkat+0x38b
> #12 0xc06d29da at kern_symlink+0x2e
> #13 0xc06d2a05 at symlink+0x29
> #14 0xc07eb7c7 at syscall+0x1a1
> #15 0xc07d9661 at Xint0x80_syscall+0x21
>
>
> Thanks in advance!


I'm getting a similar panic with r254986 on stable/8 when starting up 
jails :

# cat /var/crash/version.txt
FreeBSD 8.4-STABLE #1 r254986M: Wed Aug 28 16:26:23 BST 2013
     root at jailhost.localdomain:/usr/obj/usr/src/sys/JAILHOST

# cat /etc/devfs.rules
[devfsrules_jailzfs=5]
add include $devfsrules_jail
add path 'zfs' unhide

[devfsrules_jail_tinderbox=6]
add include $devfsrules_jail
add path 'zfs' unhide
add path 'mem' unhide
add path 'kmem' unhide

# awk '/Fatal trap/,0' /var/crash/msgbuf.txt
Fatal 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     = 0x20:0xffffffff806f8e46
stack pointer           = 0x28:0xffffff812375b670
frame pointer           = 0x28:0xffffff812375b6d0
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         = 1028 (ln)
trap number             = 12
panic: page fault
cpuid = 0
KDB: stack backtrace:
db_trace_self_wrapper() at 0xffffffff8020466a = db_trace_self_wrapper+0x2a
kdb_backtrace() at 0xffffffff80684df7 = kdb_backtrace+0x37
panic() at 0xffffffff806510ce = panic+0x1ce
trap_fatal() at 0xffffffff809e8eb0 = trap_fatal+0x290
trap_pfault() at 0xffffffff809e923e = trap_pfault+0x23e
trap() at 0xffffffff809e970e = trap+0x3ce
calltrap() at 0xffffffff809cf894 = calltrap+0x8
--- trap 0xc, rip = 0xffffffff806f8e46, rsp = 0xffffff812375b670, rbp = 
0xffffff812375b6d0 ---
fnmatch() at 0xffffffff806f8e46 = fnmatch+0x66
devfs_rule_run() at 0xffffffff805d255b = devfs_rule_run+0x17b
devfs_ruleset_applyde() at 0xffffffff805d2621 = devfs_ruleset_applyde+0x31
devfs_rules_apply() at 0xffffffff805d274a = devfs_rules_apply+0x6a
devfs_symlink() at 0xffffffff805d624e = devfs_symlink+0x13e
VOP_SYMLINK_APV() at 0xffffffff80a78f58 = VOP_SYMLINK_APV+0x68
kern_symlinkat() at 0xffffffff806edc9e = kern_symlinkat+0x38e
amd64_syscall() at 0xffffffff809e8484 = amd64_syscall+0x1f4
Xfast_syscall() at 0xffffffff809cfb8c = Xfast_syscall+0xfc
--- syscall (57, FreeBSD ELF64, symlink), rip = 0x8006a08bc, rsp = 
0x7fffffffd838, rbp = 0x7fffffffed27 ---
Uptime: 2m39s


Regards,

Jase.
-- 
Jase Thew
jase at FreeBSD.org
FreeBSD Ports Committer