Date: Sun, 26 Dec 2004 22:37:32 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: current@FreeBSD.org Subject: Occasional wedging entering DDB via serial break Message-ID: <Pine.NEB.3.96L.1041226223521.46391E-100000@fledge.watson.org>
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I'm seeing occasional wedging attempting to enter DDB via a serial break on a dual-Xeon box (4 logical processors). The symptoms usually look something like this: hippy# ./tmp.csh ~KDB: enter: Line break on console [thread pid 560 tid 100202 ] Stopped at kdb_enter+0x2c: leave db> show alllocks db> cont load: 0.04 cmd: super-smack 619 [runnable] 0.02u 0.51s 2% 2216k ~KDB: enter: Line break on console [thread pid 560 tid 100201 ] Stopped at kdb_enter+0x2c: leave db> show alllocks Process 560 (mysqld) Thread 0x18769 exclusive sleep mutex so_rcv r = 0 (0xc2a25bcc) locked @ kern/uipc_usrreq.c:464 exclusive sleep mutex unp r = 0 (0xc091a740) locked @ kern/uipc_usrreq.c:392 db> cont load: 0.92 cmd: super-smack 619 [runnable] 0.05u 1.36s 6% 2216k ~KDB: enter: Line break on console [thread pid 560 tid 100199 ] Stopped at kdb_enter+0x2c: leave db> show alllocks db> cont load: 2.12 cmd: super-smack 616 [running] 0.08u 2.90s 10% 2216k ~KDB: enter: Line break on console <wedge> After that point, a serial break will no longer drop to DDB, respond to pings, etc. The box is running 6.x-CURRENT from this morning. Is anyone else seeing this, or does anyone else have ideas about what might cause this? Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Principal Research Scientist, McAfee Research
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