#533184 strace repeatedly dumps nullbytes when open a file with O_RDWR|O_LARGEFILE option

Package:
strace
Source:
strace
Description:
System call tracer
Submitter:
Uni Stuttgart
Date:
2010-09-07 12:36:16 UTC
Severity:
important
#533184#5
Date:
2009-06-15 13:12:07 UTC
From:
To:
When calling strace with following options:

strace -f -tt -e trace=execve,vfork,clone,chdir,open,rename,link,symlink,read -e signal=!SIGCHLD -v -s 10485760 -o log.txt make

for example to build nano (2.0.7), when a file is opened with O_RDWR|O_LARGEFILE option, strace will dump out very large numbers of nullbytes read from that file.

In the case of nano this leads to a logfile size of 100 MB, where the logfile size of strace ver. 4.5.17 only becomes 14,4 MB.

Beside of the logfile size, dumping all that nullbytes takes a lot of time, so building nano with the above strace options will take ca. 5 minutes with strace 4.5.18, while it takes a few seconds doing the same with strace 4.5.17
#533184#10
Date:
2010-09-07 12:28:27 UTC
From:
To:
It turned out, that this is not a version problem.

This problem obviously only occurs, when strace works on a file system,
which is mounted via Network File System (NFS) from another machine.

If strace (either version) works on file system mounted from a local disk
drive, the described problem does not occur.

Best regards.