Random kernel panic when unloading Dummynet module in multicore processor
Rasool Al-Saadi
ralsaadi at swin.edu.au
Mon Dec 14 10:40:10 UTC 2015
> On Monday, 14 December 2015 8:12, Hans Petter Selasky wrote:
>
> On 12/14/15 01:06, Rasool Al-Saadi wrote:
> > Hi everyone,
> >
> > I am not sure if this bug was reported before or not (I didn't find exact
> problem) .
> >
> > When I try to unload dummynet module (kldunload dummynet) in
> FreeBSD11-CURRENT, sometimes the system is halt or panic. I noticed that
> this only happens with multicore processor.
> > When I disable all CPU's cores except one (using hint.lapic.x.disabled=1),
> the panic does not appear.
> > I tried to reproduce the panic in a system with Intel Core 2 Due 2.33HGz
> processor and also in VirtualBox VM (I set number of processors in VM
> setting to 2), and in both cases I got system panic.
> >
> > Most of the times the panic is:
> > Fatal trap 12: page fault while in kernel mode ...
> > Stopped at callout_process+...
> >
> > Kernel version:
> > FreeBSD 11.0-CURRENT #0 r291495: Mon Nov 30 23:14:34 UTC 2015
> root at releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC amd64
> >
> > To reproduce the panic:
> > Run 'kldload dummynet && kldunload dummynet' many times (or write a
> > shell script loop to do that)
> >
> > Debug Info:
> >
> > DUMMYNET 0 with IPv6 initialized (100409) load_dn_sched dn_sched FIFO
> > loaded load_dn_sched dn_sched QFQ loaded load_dn_sched dn_sched RR
> > loaded load_dn_sched dn_sched WF2Q+ loaded load_dn_sched dn_sched
> PRIO
> > loaded unload_dn_sched dn_sched PRIO unloaded unload_dn_sched
> dn_sched
> > WF2Q+ unloaded unload_dn_sched dn_sched RR unloaded
> unload_dn_sched
> > dn_sched QFQ unloaded unload_dn_sched dn_sched FIFO unloaded
> kernel
> > trap 12 with interrupts disabled
> >
> >
> > Fatal trap 12: page fault while in kernel mode cpuid = 0; apic id = 00
> > fault virtual address = 0xffffffff82251c68
> > fault code = supervisor read data, page not present
> > instruction pointer = 0x20:0xffffffff80a36c50
> > stack pointer = 0x28:0xfffffe0116b0c710
> > frame pointer = 0x28:0xfffffe0116b0c7a0
> > code segment = base 0x0, limit 0xfffff, type 0x1b
> > = DPL 0, pres 1, long 1, def32 0, gran 1
> > processor eflags = resume, IOPL = 0
> > current process = 11 (idle: cpu0)
> >
> > Backtrace:
> >
> > #0 doadump (textdump=380682592) at pcpu.h:221
> > 221 pcpu.h: No such file or directory.
> > in pcpu.h
> > (kgdb) backtrace
> > #0 doadump (textdump=380682592) at pcpu.h:221
> > #1 0xffffffff8037d906 in db_fncall (dummy1=<value optimized out>,
> > dummy2=<value optimized out>, dummy3=<value optimized out>,
> > dummy4=<value optimized out>) at
> > /usr/src/sys/ddb/db_command.c:568
> > #2 0xffffffff8037d39e in db_command (cmd_table=0x0)
> > at /usr/src/sys/ddb/db_command.c:440
> > #3 0xffffffff8037d134 in db_command_loop ()
> > at /usr/src/sys/ddb/db_command.c:493
> > #4 0xffffffff8037fbcb in db_trap (type=<value optimized out>, code=0)
> > at /usr/src/sys/ddb/db_main.c:251
> > #5 0xffffffff80a5e593 in kdb_trap (type=12, code=0, tf=<value optimized
> out>)
> > at /usr/src/sys/kern/subr_kdb.c:654
> > #6 0xffffffff80e69d01 in trap_fatal (frame=0xfffffe0116b0c660,
> > eva=<value optimized out>) at /usr/src/sys/amd64/amd64/trap.c:829
> > #7 0xffffffff80e69f4d in trap_pfault (frame=0xfffffe0116b0c660,
> > usermode=<value optimized out>) at
> > /usr/src/sys/amd64/amd64/trap.c:684
> > #8 0xffffffff80e6967f in trap (frame=0xfffffe0116b0c660)
> > at /usr/src/sys/amd64/amd64/trap.c:435
> > #9 0xffffffff80e49447 in calltrap ()
> > at /usr/src/sys/amd64/amd64/exception.S:234
> > #10 0xffffffff80a36c50 in callout_process (now=307238251753)
> > at /usr/src/sys/kern/kern_timeout.c:480
> > #11 0xffffffff80f6809d in handleevents (now=307238251753, fake=0)
> > at /usr/src/sys/kern/kern_clocksource.c:212
> > #12 0xffffffff80f68725 in timercb (et=<value optimized out>,
> > arg=<value optimized out>) at
> > /usr/src/sys/kern/kern_clocksource.c:345
> > #13 0xffffffff80e6f766 in hpet_intr_single (arg=<value optimized out>)
> > at /usr/src/sys/dev/acpica/acpi_hpet.c:273
> > #14 0xffffffff80e6f819 in hpet_intr (arg=0xfffffe0000dcb000)
> > at /usr/src/sys/dev/acpica/acpi_hpet.c:291
> > #15 0xffffffff809e9f9c in intr_event_handle (ie=0xfffff80003ca1a00,
> > frame=0xfffffe0116b0c970) at /usr/src/sys/kern/kern_intr.c:1436
> > #16 0xffffffff80fa1fb8 in intr_execute_handlers (isrc=0xfffff80003cea590,
> > frame=0xfffffe0116b0c970) at
> > /usr/src/sys/x86/x86/intr_machdep.c:275
> > #17 0xffffffff80fa6a78 in lapic_handle_intr (vector=<value optimized out>,
> > frame=0xfffffe0116b0c970) at
> > /usr/src/sys/x86/x86/local_apic.c:1008
> > #18 0xffffffff80e49b27 in Xapic_isr1 () at apic_vector.S:116
> > #19 0xffffffff80f9f6b6 in acpi_cpu_c1 ()
> > at /usr/src/sys/x86/x86/cpu_machdep.c:133
> > #20 0xffffffff8039f855 in acpi_cpu_idle (sbt=<value optimized out>)
> > at /usr/src/sys/dev/acpica/acpi_cpu.c:1157
> > #21 0xffffffff80f9f99f in cpu_idle_acpi (sbt=160862)
> > at /usr/src/sys/x86/x86/cpu_machdep.c:263
> > #22 0xffffffff80f9fa47 in cpu_idle (busy=0)
> > at /usr/src/sys/x86/x86/cpu_machdep.c:415
> > #23 0xffffffff80a4c565 in sched_idletd (dummy=<value optimized out>)
> > at /usr/src/sys/kern/sched_ule.c:2688
> > #24 0xffffffff809e7714 in fork_exit (
> > callout=0xffffffff80a4c0c0 <sched_idletd>, arg=0x0,
> > frame=0xfffffe0116b0cc00) at /usr/src/sys/kern/kern_fork.c:1011
> > #25 0xffffffff80e4997e in fork_trampoline ()
> > at /usr/src/sys/amd64/amd64/exception.S:609
> > #26 0x0000000000000000 in ?? ()
> >
>
> Hi,
>
> Can you try this DIFF:
>
> https://reviews.freebsd.org/D3855
Thanks Hans!
This DIFF solved the problem perfectly.
Cheers,
Rasool
> --HPS
>
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