On 11/14/2016 10:07, Andriy Gapon wrote:
On 13/11/2016 15:28, Henri Hennebert wrote:
On 11/13/2016 11:06, Andriy Gapon wrote:
On 12/11/2016 14:40, Henri Hennebert wrote:
[snip]
Could you please show 'info local' in frame 14?
I expected that 'nd' variable would be defined there and it may contain some
useful information.
No luck there:
(kgdb) fr 14
#14 0xffffffff80636838 in kern_statat (td=0xfffff80009ba0500,
flag=<value optimized out>, fd=-100, path=0x0,
pathseg=<value optimized out>, sbp=<value optimized out>,
hook=0x800e2a388) at /usr/src/sys/kern/vfs_syscalls.c:2160
2160 if ((error = namei(&nd)) != 0)
(kgdb) info local
rights = <value optimized out>
nd = <value optimized out>
error = <value optimized out>
sb = <value optimized out>
(kgdb)
I also try to get information from the execve of the other treads:
for tid 101250:
(kgdb) fr 10
#10 0xffffffff80508ccc in sys_execve (td=0xfffff800b6429000,
uap=0xfffffe010184fb80) at /usr/src/sys/kern/kern_exec.c:218
218 error = kern_execve(td, &args, NULL);
(kgdb) print *uap
$4 = {fname_l_ = 0xfffffe010184fb80 "`\220\217\002\b", fname = 0x8028f9060
<Address 0x8028f9060 out of bounds>,
fname_r_ = 0xfffffe010184fb88 "`¶ÿÿÿ\177", argv_l_ = 0xfffffe010184fb88
"`¶ÿÿÿ\177", argv = 0x7fffffffb660,
argv_r_ = 0xfffffe010184fb90 "\bÜÿÿÿ\177", envv_l_ = 0xfffffe010184fb90
"\bÜÿÿÿ\177", envv = 0x7fffffffdc08,
envv_r_ = 0xfffffe010184fb98 ""}
(kgdb)
for tid 101243:
(kgdb) f 15
#15 0xffffffff80508ccc in sys_execve (td=0xfffff800b642b500,
uap=0xfffffe010182cb80) at /usr/src/sys/kern/kern_exec.c:218
218 error = kern_execve(td, &args, NULL);
(kgdb) print *uap
$5 = {fname_l_ = 0xfffffe010182cb80 "ÀÏ\205\002\b", fname = 0x80285cfc0 <Address
0x80285cfc0 out of bounds>,
fname_r_ = 0xfffffe010182cb88 "`¶ÿÿÿ\177", argv_l_ = 0xfffffe010182cb88
"`¶ÿÿÿ\177", argv = 0x7fffffffb660,
argv_r_ = 0xfffffe010182cb90 "\bÜÿÿÿ\177", envv_l_ = 0xfffffe010182cb90
"\bÜÿÿÿ\177", envv = 0x7fffffffdc08,
envv_r_ = 0xfffffe010182cb98 ""}
(kgdb)
I think that you see garbage in those structures because they contain pointers
to userland data.
Hmm, I've just noticed another interesting thread:
Thread 668 (Thread 101245):
#0 sched_switch (td=0xfffff800b642aa00, newtd=0xfffff8000285f000, flags=<value
optimized out>) at /usr/src/sys/kern/sched_ule.c:1973
#1 0xffffffff80561ae2 in mi_switch (flags=<value optimized out>, newtd=0x0) at
/usr/src/sys/kern/kern_synch.c:455
#2 0xffffffff805ae8da in sleepq_wait (wchan=0x0, pri=0) at
/usr/src/sys/kern/subr_sleepqueue.c:646
#3 0xffffffff805614b1 in _sleep (ident=<value optimized out>, lock=<value
optimized out>, priority=<value optimized out>, wmesg=0xffffffff809c51bc
"vmpfw", sbt=0, pr=<value optimized out>, flags=<value optimized out>) at
/usr/src/sys/kern/kern_synch.c:229
#4 0xffffffff8089d1c1 in vm_page_busy_sleep (m=0xfffff800df68cd40, wmesg=<value
optimized out>) at /usr/src/sys/vm/vm_page.c:753
#5 0xffffffff8089dd4d in vm_page_sleep_if_busy (m=0xfffff800df68cd40,
msg=0xffffffff809c51bc "vmpfw") at /usr/src/sys/vm/vm_page.c:1086
#6 0xffffffff80886be9 in vm_fault_hold (map=<value optimized out>, vaddr=<value
optimized out>, fault_type=4 '\004', fault_flags=0, m_hold=0x0) at
/usr/src/sys/vm/vm_fault.c:495
#7 0xffffffff80885448 in vm_fault (map=0xfffff80011d66000, vaddr=<value
optimized out>, fault_type=4 '\004', fault_flags=<value optimized out>) at
/usr/src/sys/vm/vm_fault.c:273
#8 0xffffffff808d3c49 in trap_pfault (frame=0xfffffe0101836c00, usermode=1) at
/usr/src/sys/amd64/amd64/trap.c:741
#9 0xffffffff808d3386 in trap (frame=0xfffffe0101836c00) at
/usr/src/sys/amd64/amd64/trap.c:333
#10 0xffffffff808b7af1 in calltrap () at
/usr/src/sys/amd64/amd64/exception.S:236
This tread is another program from the news system:
668 Thread 101245 (PID=49124: innfeed) sched_switch
(td=0xfffff800b642aa00, newtd=0xfffff8000285f000, flags=<value optimized
out>) at /usr/src/sys/kern/sched_ule.c:1973
I strongly suspect that this is thread that we were looking for.
I think that it has the vnode lock in the shared mode while trying to fault in a
page.
Could you please check that by going to frame 6 and printing 'fs' and '*fs.vp'?
It'd be interesting to understand why this thread is waiting here.
So, please also print '*fs.m' and '*fs.object'.
No luck :-(
(kgdb) fr 6
#6 0xffffffff80886be9 in vm_fault_hold (map=<value optimized out>,
vaddr=<value optimized out>, fault_type=4 '\004',
fault_flags=0, m_hold=0x0) at /usr/src/sys/vm/vm_fault.c:495
495 vm_page_sleep_if_busy(fs.m,
"vmpfw");
(kgdb) print fs
Cannot access memory at address 0xffff00001fa0
(kgdb)
Henri
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