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  1. 16 Jun, 2009 2 commits
    • Kay Sievers's avatar
      sched: delayed cleanup of user_struct · 3959214f
      Kay Sievers authored 
      During bootup performance tracing we see repeated occurrences of
/sys/kernel/uid/* events for the same uid, leading to a,
in this case, rather pointless userspace processing for the
same uid over and over.

This is usually caused by tools which change their uid to "nobody",
to run without privileges to read data supplied by untrusted users.

This change delays the execution of the (already existing) scheduled
work, to cleanup the uid after one second, so the allocated and announced
uid can possibly be re-used by another process.

This is the current behavior, where almost every invocation of a
binary, which changes the uid, creates two events:
  $ read START < /sys/kernel/uevent_seqnum; \
  for i in `seq 100`; do su --shell=/bin/true bin; done; \
  read END < /sys/kernel/uevent_seqnum; \
  echo $(($END - $START))
  178

With the delayed cleanup, we get only two events, and userspace finishes
a bit faster too:
  $ read START < /sys/kernel/uevent_seqnum; \
  for i in `seq 100`; do su --shell=/bin/true bin; done; \
  read END < /sys/kernel/uevent_seqnum; \
  echo $(($END - $START))
  1
Acked-by: default avatarDhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: default avatarKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      3959214f
    • Kay Sievers's avatar
      driver core: set default SYSFS_DEPRECATED=n · f6ee649f
      Kay Sievers authored 
      All recent distros depend on the non-deprecated sysfs layout, so
change the default value of the option to reflect that.
Signed-off-by: default avatarKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      f6ee649f
  3. 15 Jun, 2009 25 commits
  5. 14 Jun, 2009 13 commits
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