https://bugzilla.novell.com/show_bug.cgi?id=680113 https://bugzilla.novell.com/show_bug.cgi?id=680113#c zj jia changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |zjjia@novell.com AssignedTo|bnc-team-screening@forge.pr |vcizek@novell.com |ovo.novell.com | -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.

https://bugzilla.novell.com/show_bug.cgi?id=680113 https://bugzilla.novell.com/show_bug.cgi?id=680113#c3 Ingo Schwarze changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEEDINFO |NEW InfoProvider|ischwarze@astaro.com | --- Comment #3 from Ingo Schwarze 2011-04-18 16:12:58 UTC --- (In reply to comment #2) Oh indeed, at-3.1.8-massive_batch.patch, which didn't exist last time i looked in Debian, hides the bug - as opposed to fixing it. The variable nothing_to_do intends to avoid iteration of the spool directory each time CHECK_INTERVAL expires when it is known that last time, there were no waiting jobs, and in the meantime, the directory did not change - which does not work because the directory access time going backwards is misinterpreted as "no change". Now, with at-3.1.8-massive_batch.patch, each time at(1) adds a job to the spool directory, nothing_to_do is cleared by the signal, such that as long as at(1) is used, and signals don't get lost, checking the access time of the spool directory is rendered irrelevant by the at-3.1.8-massive_batch.patch. However, with a bit of manipulation, it is still possible to reproduce the bug: - schedule a job in 5 minutes - move the spool file to /tmp # required such that the spool dir becomes empty - set the spool dir time to the future, e.g. by one day - restart the atd # it finds the spool dir empty, sets the flag nothing_to_do, # and goes to sleep for CHECK_INTERVAL - move the spool file back to the spool dir # that sets the spool dir change time back to the correct time - wait for the scheduled job time to come and send a SIGCONT signal - NOT a SIGHUP signal, of course! - to the atd (or equivalently, just wait for the CHECK_INTERVAL to expire) # during the upcoming cycle, the atd sees that the spool dir time # is LESS than the one it remembers, hence does *not* iterate the # spool dir and goes right back to sleep, even though a job is due Here is a protocol of that test: ischwarze04:/root # rpm -q at at-3.1.8-1069.15.53 ischwarze04:/root # date Mon Apr 18 17:52:23 CEST 2011 ischwarze04:/root # echo "command" | at +5min warning: commands will be executed using /bin/sh job 10 at 2011-04-18 17:57 ischwarze04:/root # atq 10 2011-04-18 17:57 a root ischwarze04:/root # mv /var/spool/atjobs/a0000a014b67fd /tmp/ ischwarze04:/root # touch -t 04191800 /var/spool/atjobs ischwarze04:/root # ls -ld /var/spool/atjobs drwx------ 2 at at 4096 2011-04-19 18:00 /var/spool/atjobs ischwarze04:/root # /etc/init.d/atd restart Shutting down service at daemon done Starting service at daemon done ischwarze04:/root # ls -ld /var/spool/atjobs drwx------ 2 at at 4096 2011-04-19 18:00 /var/spool/atjobs ischwarze04:/root # mv /tmp/a0000a014b67fd /var/spool/atjobs/ ischwarze04:/root # ls -ld /var/spool/atjobs drwx------ 2 at at 4096 2011-04-18 17:54 /var/spool/atjobs ischwarze04:/root # atq 10 2011-04-18 17:57 a root ischwarze04:/root # date Mon Apr 18 17:54:40 CEST 2011 ischwarze04:/root # date Mon Apr 18 17:58:21 CEST 2011 ischwarze04:/root # atq 10 2011-04-18 17:57 a root ischwarze04:/root # kill -CONT 23684 ischwarze04:/root # atq 10 2011-04-18 17:57 a root Here is the associated strace snippet, showing that a run_loop is triggered by the SIGCONT, but the atd does not even try to look into the spool directory: ischwarze04:/root # strace -p 23684 Process 23684 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...> ) = ? ERESTART_RESTARTBLOCK (To be restarted) --- SIGCONT (Continued) @ 0 (0) --- restart_syscall(<... resuming interrupted call ...> The bug is now hidden so well that is no longer of much practical relevance, but it is still a bug. Changing the comparison operator from "<=" to "==" as suggested in my old patch makes sure that the atd correctly identifies a directory whose atime goes backwards as a changing directory and does not wrongly consider it as unchanged. Thanks for checking, Ingo -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.

https://bugzilla.novell.com/show_bug.cgi?id=680113 https://bugzilla.novell.com/show_bug.cgi?id=680113#c5 Vitezslav Cizek changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution| |FIXED --- Comment #5 from Vitezslav Cizek 2011-04-21 07:00:19 UTC --- Submitted the fix to factory. -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.