execve: make responsive to SIGKILL with large arguments
authorRoland McGrath <roland@redhat.com>
Wed, 8 Sep 2010 02:37:06 +0000 (19:37 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 10 Sep 2010 15:10:26 +0000 (08:10 -0700)
commit9aea5a65aa7a1af9a4236dfaeb0088f1624f9919
treec0e36c74dc511912f59e207c70893dc6bd13b543
parent7993bc1f4663c0db67bb8f0d98e6678145b387cd
execve: make responsive to SIGKILL with large arguments

An execve with a very large total of argument/environment strings
can take a really long time in the execve system call.  It runs
uninterruptibly to count and copy all the strings.  This change
makes it abort the exec quickly if sent a SIGKILL.

Note that this is the conservative change, to interrupt only for
SIGKILL, by using fatal_signal_pending().  It would be perfectly
correct semantics to let any signal interrupt the string-copying in
execve, i.e. use signal_pending() instead of fatal_signal_pending().
We'll save that change for later, since it could have user-visible
consequences, such as having a timer set too quickly make it so that
an execve can never complete, though it always happened to work before.

Signed-off-by: Roland McGrath <roland@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/exec.c