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author | Jamie Iles <jamie.iles@oracle.com> | 2017-01-11 03:57:54 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-08-11 19:30:16 +0300 |
commit | c398f3bb3ebaf25c149e12790a913d83b6d861b3 (patch) | |
tree | d9b8fa447b0bc1c34de5b81aa4173932bf15e9ba /mm | |
parent | c8535838e166ee6a66032d6ed3c68ea4bcad44ba (diff) | |
download | linux-c398f3bb3ebaf25c149e12790a913d83b6d861b3.tar.xz |
signal: protect SIGNAL_UNKILLABLE from unintentional clearing.
[ Upstream commit 2d39b3cd34e6d323720d4c61bd714f5ae202c022 ]
Since commit 00cd5c37afd5 ("ptrace: permit ptracing of /sbin/init") we
can now trace init processes. init is initially protected with
SIGNAL_UNKILLABLE which will prevent fatal signals such as SIGSTOP, but
there are a number of paths during tracing where SIGNAL_UNKILLABLE can
be implicitly cleared.
This can result in init becoming stoppable/killable after tracing. For
example, running:
while true; do kill -STOP 1; done &
strace -p 1
and then stopping strace and the kill loop will result in init being
left in state TASK_STOPPED. Sending SIGCONT to init will resume it, but
init will now respond to future SIGSTOP signals rather than ignoring
them.
Make sure that when setting SIGNAL_STOP_CONTINUED/SIGNAL_STOP_STOPPED
that we don't clear SIGNAL_UNKILLABLE.
Link: http://lkml.kernel.org/r/20170104122017.25047-1-jamie.iles@oracle.com
Signed-off-by: Jamie Iles <jamie.iles@oracle.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
0 files changed, 0 insertions, 0 deletions