Date: Wed, 4 May 2011 23:59:18 -0700 From: Jack Vogel <jfvogel@gmail.com> To: Arnaud Lacombe <lacombar@gmail.com> Cc: Olivier Smedts <olivier@gid0.org>, FreeBSD current mailing list <current@freebsd.org> Subject: Re: problems with em(4) since update to driver 7.2.2 Message-ID: <BANLkTikkbpW6_jE5QznGjAt4Zcpee0RagQ@mail.gmail.com> In-Reply-To: <BANLkTikehcbxm0MQtb0SQ0giSfhmkHw99A@mail.gmail.com> References: <BANLkTinrfZbO%2BMUDDuzsoaN1y-=_O8LgNA@mail.gmail.com> <4D94A354.9080903@sentex.net> <AANLkTik_XPsVWL-KqHkPic1KQ0SdCSk6u_9ykRefi3VE@mail.gmail.com> <BANLkTi=K5ASG9TWLAh5r%2Bzo9Wy1stMf9WA@mail.gmail.com> <BANLkTikPPzxZ6XRAaqrvdeXBp=Ydvz7hNg@mail.gmail.com> <BANLkTi=rhZ0dyO6Zq13jY6-NKVE8n24YyQ@mail.gmail.com> <4DC07013.9070707@gmx.net> <BANLkTi=DmQsVvJOaoxMr5GPOLkjs7sdTxQ@mail.gmail.com> <4DC078BD.9080908@gmx.net> <BANLkTin1ykoo80%2B9iWe%2Bg5ib1DXw%2B05BgQ@mail.gmail.com> <BANLkTi=STPT13-50dxMRgjLP_pyxL9Utyw@mail.gmail.com> <BANLkTikX8gs7Ln2KLZkA=MyieeCR%2BzKXzQ@mail.gmail.com> <BANLkTikj-wSOFWQX9Y_yN54Q_jk-=vD3LA@mail.gmail.com> <BANLkTin0ANtbWGv4CTr%2BO5xEL58hVRDefg@mail.gmail.com> <BANLkTikzpjxe%2BcMYiTRak0B0tnkhrW%2BBow@mail.gmail.com> <BANLkTikUJOD%2BtzYoiHCoWHrD36PxLQgN7A@mail.gmail.com> <BANLkTin2j3QzO0pwVHe9Nm-L8otEf9pcbg@mail.gmail.com> <BANLkTinmKH40yx5Mgu9zgQ2qEF2O-n6HMQ@mail.gmail.com> <BANLkTikehcbxm0MQtb0SQ0giSfhmkHw99A@mail.gmail.com>
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OK, but what this does not explain is why I do not see this if its so easily reproduced, what causes the failure case, any idea? As I said, given the code was not feasible for igb anyway I would not be unhappy about returning to the old way of doing things. Jack On Wed, May 4, 2011 at 11:03 PM, Arnaud Lacombe <lacombar@gmail.com> wrote: > Hi, > > On Thu, May 5, 2011 at 1:20 AM, Arnaud Lacombe <lacombar@gmail.com> wrote: > > Hi, > > > > On Wed, May 4, 2011 at 5:38 PM, Jack Vogel <jfvogel@gmail.com> wrote: > >> I have had my validation engineer busy all day, we have tried both > >> a 9 kernel as well as 8.2, using the code from HEAD, and we > >> cannot reproduce this problem. > >> > > Actually, it can be trivially reproduced by tainting `error'. As it is > > uninitialized in HEAD, it's value can be _anything_, so let's mark it > > as explicitly invalid. > > > > diff -u ./if_em.c /data/src/freebsd/em-7.2.2/src/if_em.c > > --- ./if_em.c 2011-02-18 01:18:23.000000000 -0500 > > +++ /data/src/freebsd/em-7.2.2/src/if_em.c 2011-05-05 > > 01:12:01.000000000 -0400 > > @@ -3912,7 +3912,7 @@ > > struct adapter *adapter = rxr->adapter; > > struct em_buffer *rxbuf; > > bus_dma_segment_t seg[1]; > > - int i, j, nsegs, error; > > + int i, j, nsegs, error = -1; > > > > The error pointed out in this thread pops up in the next boot. > > > I put a call to kdb_enter() at the beginning of the function, helped > with some textdump I got all the backtrace [0] for all the time > em_setup_receive_ring() is called. All are exactly the same: > > kdb_enter_why(0,c09f6511,f391aaa8,c09be1e2,c09f6511,...) at > kdb_enter_why+0x3b > kdb_enter(c09f6511,0,3810,ffffffff,5dc,...) at kdb_enter+0x19 > em_setup_receive_ring(c3c8d600,c3c8d7a4,c3c96004,310000fa,c3c8d600,...) > at em_setup_receive_ring+0x22 > em_setup_receive_structures(c3c96000,f15f2000,38,8100,3,...) at > em_setup_receive_structures+0x26 > em_init_locked(c3c96000,0,c09f5de5,414,10000,...) at em_init_locked+0x2f2 > em_ioctl(c3c7d000,80206934,c3ce9d00,c07b7a0b,c3f2a230,...) at > em_ioctl+0x1c3 > ifhwioctl(c3f2a230,f391ac34,c07b7a0b,c3f3e3d0,c08df1c0,...) at > ifhwioctl+0x4b8 > ifioctl(c3f3e3d0,80206934,c3ce9d00,c3f2a230,c3f2a230,...) at ifioctl+0x82 > kern_ioctl(c3f2a230,3,80206934,c3ce9d00,c3ce9d00,...) at kern_ioctl+0xa8 > ioctl(c3f2a230,f391acf8,c,c,f391ad2c,...) at ioctl+0xc5 > syscall(f391ad38) at syscall+0x17d > Xint0x80_syscall() at Xint0x80_syscall+0x20 > --- syscall (54, FreeBSD ELF32, ioctl), eip = 0x4816ee23, esp = > 0xbfbfe67c, ebp = 0xbfbfe698 --- > > This fully explain why the main loop in em_setup_receive_ring() is > never entered, as we always verify `j == rxr->next_to_check' (provided > that mbuf have been refreshed if some packet were transfered) and > return the value on the stack. As of now, beside changing the > call-site of em_setup_receive_ring() to ensure it is never re-entered, > I'd guess that the patch I sent earlier today, is the only way to > ensure that no junk is returned. > > I'd guess that the driver _is_ able to transmit, if the code was not > explicitly calling em_stop() upon em_setup_receive_structures() > failure. > > - Arnaud > > [0]: I wish that would have been as easy as in Linux, where a WARN() > call do all the job automatically, but still, I should not hope for > that much unless I am the one implementing it ... yes, free whining, > it's 2a.m. ... > > > - Arnaud > > > >> The data your netstat -m shows suggests to me that what's happening > >> is somehow setup of the receive ring is running more than once maybe?? > >> > >> You asked at one point how this could go into STABLE, well, because > >> not only here at Intel, but at lots of external customers this code has > been > >> used and tested thoroughly. > >> > >> I am not calling into question your problem, but until I understand what > it > >> is I cannot "fix" it :) > >> > >> The thing I am guessing right now is the culprit is the setup code, the > >> reason > >> is that when I ported to the igb driver I found that it did not work on > our > >> newer > >> hardware, and so I went back to the older version of setup for igb. Now, > >> even > >> though I have not seen hardware fail with em, maybe there is some. > >> > >> To help me give me a complete pciconf -lv, and if its a namebrand system > >> tell me that, including all hardware in it. > >> > >> If you like Olivier I can make a version of em for you that also reverts > the > >> setup code the way I did for igb, see if that fixes it for you? > >> > >> Thanks for your patience, > >> > >> Jack > >> _______________________________________________ > >> freebsd-current@freebsd.org mailing list > >> http://lists.freebsd.org/mailman/listinfo/freebsd-current > >> To unsubscribe, send any mail to " > freebsd-current-unsubscribe@freebsd.org" > >> > > >
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