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author | Oleg Nesterov <oleg@redhat.com> | 2009-06-17 16:27:33 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-18 13:03:51 -0700 |
commit | 4b105cbbaf7c06e01c27391957dc3c446328d087 (patch) | |
tree | 4b6a65061a7bf46baea9d8867fdda0c22c8a3d45 /sound | |
parent | f2f0b00ad61d53adfecb8bdf8f3cf8f05f6ed548 (diff) | |
download | linux-4b105cbbaf7c06e01c27391957dc3c446328d087.tar.gz linux-4b105cbbaf7c06e01c27391957dc3c446328d087.tar.bz2 linux-4b105cbbaf7c06e01c27391957dc3c446328d087.zip |
ptrace: do not use task_lock() for attach
Remove the "Nasty, nasty" lock dance in ptrace_attach()/ptrace_traceme() -
from now task_lock() has nothing to do with ptrace at all.
With the recent changes nobody uses task_lock() to serialize with ptrace,
but in fact it was never needed and it was never used consistently.
However ptrace_attach() calls __ptrace_may_access() and needs task_lock()
to pin task->mm for get_dumpable(). But we can call __ptrace_may_access()
before we take tasklist_lock, ->cred_exec_mutex protects us against
do_execve() path which can change creds and MMF_DUMP* flags.
(ugly, but we can't use ptrace_may_access() because it hides the error
code, so we have to take task_lock() and use __ptrace_may_access()).
NOTE: this change assumes that LSM hooks, security_ptrace_may_access() and
security_ptrace_traceme(), can be called without task_lock() held.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Chris Wright <chrisw@sous-sol.org>
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 'sound')
0 files changed, 0 insertions, 0 deletions