panic: sleeping in an epoch section

[Harry Schmalzbauer]

Am 09.10.2019 um 16:47 schrieb Mark Johnston:
> On Wed, Oct 09, 2019 at 04:18:34PM +0200, Hans Petter Selasky wrote:
>> On 2019-10-09 15:56, Mark Johnston wrote:
>>> On Wed, Oct 09, 2019 at 10:40:04AM +0200, Hans Petter Selasky wrote:
>>>> On 2019-10-09 06:36, Yuri Pankov wrote:
>>>>> Tried updating from r353072 to r353334 and getting the following panic
>>>>> reproducibly on boot (starting dhclient?):
>>>>>
>>>>> panic: sleeping in an epoch section
>>>>> cpuid = 5
>>>>> time = 1570591558
>>>>> KDB: stack backtrace:
>>>>> db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame
>>>>> 0xfffffe00af780140
>>>>> vpanic() at vpanic+0x19d/frame 0xfffffe00af780190
>>>>> panic() at panic+0x43/frame 0xfffffe00af7801f0
>>>>> _sleep() at _sleep+0x463/frame 0xfffffe00af780290
>>>>> pause_sbt() at pause_sbt+0x10f/frame 0xfffffe00af7802d0
>>>>> e1000_write_phy_reg_mdic() at e1000_write_phy_reg_mdic+0xee/frame
>>>>> 0xfffffe00af780310
>>>>> e1000_enable_phy_wakeup_reg_access_bm() at
>>>>> e1000_enable_phy_wakeup_reg_access_bm+0x2b/frame 0xfffffe00af780330
>>>>> e1000_update_mc_addr_list_pch2lan() at
>>>>> e1000_update_mc_addr_list_pch2lan+0x3a/frame 0xfffffe00af780370
>>>>> em_if_multi_set() at em_if_multi_set+0x1d4/frame 0xfffffe00af7803c0
>>>>> iflib_if_ioctl() at iflib_if_ioctl+0x100/frame 0xfffffe00af780430
>>>>> if_addmulti() at if_addmulti+0x2af/frame 0xfffffe00af7804d0
>>>>> in_joingroup_locked() at in_joingroup_locked+0x235/frame 0xfffffe00af780570
>>>>> in_joingroup() at in_joingroup+0x5c/frame 0xfffffe00af7805d0
>>>>> in_control() at in_control+0xadf/frame 0xfffffe00af780680
>>>>> ifioctl() at ifioctl+0x40f/frame 0xfffffe00af780750
>>>>> kern_ioctl() at kern_ioctl+0x295/frame 0xfffffe00af7807b0
>>>>> sys_ioctl() at sys_ioctl+0x15d/frame 0xfffffe00af780880
>>>>> amd64_syscall() at amd64_syscall+0x2b9/frame 0xfffffe00af7809b0
>>>>> fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe00af7809b0
>>>>> --- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x80048051a, rsp =
>>>>> 0x7fffffffe3e8, rbp = 0x7fffffffe430 ---
>>>> The SIOCADDMULTI if_ioctl() is not allowed to sleep, because it can be
>>>> called from the fast-path, so this is a bug in e1000 driver. Does the
>>>> attached patch workaround the issue?
>>> What fast path are you referring to?  The locking protocol used by the
>>> multicast code was changed specifically to allow for sleeps in driver
>>> ioctl handlers.
>> I recall a long time ago seeing that input packet processing may end up
>> calling if_ioctl's . Things may have changed since then though.
> That may be true in general, but I can't see any instances of that
> for SIOCADDMULTI or SIOCDELMULTI.  I think we should always permit ioctl
> handlers to sleep.  In particular, the panic reported above is a bug in
> r353292.

Hope you don't ming hijacking your attention to something problably 
related, but definitely not to r353292:
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=240609

Thanks,

-harry