Date: Wed, 9 Oct 2019 16:18:34 +0200 From: Hans Petter Selasky <hps@selasky.org> To: Mark Johnston <markj@freebsd.org> Cc: Yuri Pankov <yuripv@yuripv.net>, freebsd-net <freebsd-net@freebsd.org> Subject: Re: panic: sleeping in an epoch section Message-ID: <a2075acc-243c-da14-180e-686eaf59cfd6@selasky.org> In-Reply-To: <20191009135616.GC66126@raichu> References: <86cc5d82-50d0-93eb-5900-54e8b0032a08@yuripv.net> <050ba95e-d0d5-dd1a-db6f-9a5c07142efe@selasky.org> <20191009135616.GC66126@raichu>
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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. --HPS
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