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| author | Oleg Nesterov <oleg@redhat.com> | 2009-04-13 14:40:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-13 15:04:31 -0700 |
| commit | f1671f6d783a2385d32e11f456cbe32f0e4b4b49 (patch) | |
| tree | 3d2dd4672db69b9d3b7f35e06b0fb90ca4d8cc12 /init | |
| parent | 7b102d034c0affc6ee703b576f2496ec6cb81d79 (diff) | |
| download | lwn-f1671f6d783a2385d32e11f456cbe32f0e4b4b49.tar.gz lwn-f1671f6d783a2385d32e11f456cbe32f0e4b4b49.zip | |
ptrace: fix exit_ptrace() vs ptrace_traceme() race
Pointed out by Roland. The bug was recently introduced by me in
"forget_original_parent: split out the un-ptrace part", commit
39c626ae47c469abdfd30c6e42eff884931380d6.
Since that patch we have a window after exit_ptrace() drops tasklist and
before forget_original_parent() takes it again. In this window the child
can do ptrace(PTRACE_TRACEME) and nobody can untrace this child after
that.
Change ptrace_traceme() to not attach to the exiting ->real_parent. We
don't report the error in this case, we pretend we attach right before
->real_parent calls exit_ptrace() which should untrace us anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'init')
0 files changed, 0 insertions, 0 deletions