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[PATCH] sys_unshare: remove a broken CLONE_SIGHAND code

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sys_unshare(CLONE_SIGHAND) is broken, the code under 'if (new_sigh)' is
never executed but very wrong. Just remove it to avoid a confusion,
task_lock() has nothing to do with ->sighand changing.

Also, change the comment in unshare_sighand(). Yes, CLONE_THREAD implies
CLONE_SIGHAND, but still it looks confusing. Also, we don't need to check
current->sighand != NULL.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Oleg Nesterov 2006-12-08 02:36:09 -08:00 committed by Linus Torvalds
parent ae424ae4b5
commit dae3c5a0b7
1 changed files with 4 additions and 12 deletions
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16
kernel/fork.c
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@ -1544,15 +1544,13 @@ static int unshare_namespace(unsigned long unshare_flags, struct namespace **new
}
/*
* Unsharing of sighand for tasks created with CLONE_SIGHAND is not
* supported yet
* Unsharing of sighand is not supported yet
*/
static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp)
{
struct sighand_struct *sigh = current->sighand;
if ((unshare_flags & CLONE_SIGHAND) &&
(sigh && atomic_read(&sigh->count) > 1))
if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1)
return -EINVAL;
else
return 0;
@ -1626,7 +1624,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
int err = 0;
struct fs_struct *fs, *new_fs = NULL;
struct namespace *ns, *new_ns = NULL;
struct sighand_struct *sigh, *new_sigh = NULL;
struct sighand_struct *new_sigh = NULL;
struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL;
struct files_struct *fd, *new_fd = NULL;
struct sem_undo_list *new_ulist = NULL;
@ -1671,7 +1669,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
}
}
if (new_fs || new_ns || new_sigh || new_mm || new_fd || new_ulist ||
if (new_fs || new_ns || new_mm || new_fd || new_ulist ||
new_uts || new_ipc) {
task_lock(current);
@ -1693,12 +1691,6 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
new_ns = ns;
}
if (new_sigh) {
sigh = current->sighand;
rcu_assign_pointer(current->sighand, new_sigh);
new_sigh = sigh;
}
if (new_mm) {
mm = current->mm;
active_mm = current->active_mm;