check_unsafe_exec: s/lock_task_sighand/rcu_read_lock/

write_lock(&current->fs->lock) guarantees we can't wrongly miss
LSM_UNSAFE_SHARE, this is what we care about. Use rcu_read_lock()
instead of ->siglock to iterate over the sub-threads. We must see
all CLONE_THREAD|CLONE_FS threads which didn't pass exit_fs(), it
takes fs->lock too.

With or without this patch we can miss the freshly cloned thread
and set LSM_UNSAFE_SHARE, we don't care.

Signed-off-by: Oleg Nesterov <[email protected]>
Acked-by: Roland McGrath <[email protected]>
[ Fixed lock/unlock typo  - Hugh ]
Acked-by: Hugh Dickins <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions