The patch titled
From: Oleg Nesterov <oleg@xxxxxxxxxx>
has been added to the -mm tree. Its filename is
sys_unshare-remove-a-broken-clone_sighand-code.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: From: Oleg Nesterov <oleg@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/fork.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
diff -puN kernel/fork.c~sys_unshare-remove-a-broken-clone_sighand-code kernel/fork.c
--- a/kernel/fork.c~sys_unshare-remove-a-broken-clone_sighand-code
+++ a/kernel/fork.c
@@ -1538,15 +1538,13 @@ static int unshare_namespace(unsigned lo
}
/*
- * 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;
@@ -1620,7 +1618,7 @@ asmlinkage long sys_unshare(unsigned lon
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;
@@ -1665,7 +1663,7 @@ asmlinkage long sys_unshare(unsigned lon
}
}
- 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);
@@ -1687,12 +1685,6 @@ asmlinkage long sys_unshare(unsigned lon
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;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
tty-signal-tty-locking.patch
do_task_stat-dont-take-tty_mutex.patch
do_acct_process-dont-take-tty_mutex.patch
trivial-make-set_special_pids-static.patch
sys_unshare-remove-a-broken-clone_sighand-code.patch
pidhash-temporary-debug-checks.patch
-
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