Messages in this thread |  | | Date | Fri, 10 Oct 2014 14:17:45 -0700 | Subject | Re: kernel crash in bpf_jit on x86_64 when running nmap | From | Alexei Starovoitov <> |
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On Fri, Oct 10, 2014 at 1:44 PM, Darrick J. Wong <darrick.wong@oracle.com> wrote: > Hi everyone, > > I was running nmap on a x86_64 qemu guest and experienced the following crash: > > # nmap -sS -O -vvv 192.168.122.1 > Starting Nmap 6.40 ( http://nmap.org ) at 2014-10-10 13:14 PDT > Initiating ARP Ping Scan at 13:14 > Scanning 192.168.122.1 [1 port] > <kaboom> > > dmesg output is as follows (I set net.core.bpf_jit_enable=2 the second time): > > [ 32.376291] flen=3 proglen=82 pass=0 image=ffffffffc01ac65b > [ 32.377595] JIT code: 00000000: 55 48 89 e5 48 81 ec 28 02 00 00 48 89 9d d8 fd > [ 32.379243] JIT code: 00000010: ff ff 4c 89 ad e0 fd ff ff 4c 89 b5 e8 fd ff ff > [ 32.380984] JIT code: 00000020: 4c 89 bd f0 fd ff ff 31 c0 4d 31 ed 48 89 fb b8 > [ 32.382606] JIT code: 00000030: 00 00 00 00 48 8b 9d d8 fd ff ff 4c 8b ad e0 fd > [ 32.384280] JIT code: 00000040: ff ff 4c 8b b5 e8 fd ff ff 4c 8b bd f0 fd ff ff > [ 32.385911] JIT code: 00000050: c9 c3 > [ 32.386841] bpf_jit: proglen=265 != oldproglen=269
thanks for the report. The line above indicates that JIT tried to emit 4 byte longer program than during pre-final pass. Will look at it asap.
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