The patch titled
ptrace_check_attach: remove unneeded ->signal != NULL check
has been removed from the -mm tree. Its filename was
ptrace_check_attach-remove-unneeded-signal-=-null-check.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: ptrace_check_attach: remove unneeded ->signal != NULL check
From: Oleg Nesterov <oleg@xxxxxxxxxx>
It is not possible to see the PT_PTRACED task without ->signal/sighand under
tasklist_lock, release_task() does ptrace_unlink() first. If the task was
already released before, ptrace_attach() can't succeed and set PT_PTRACED.
Remove this check.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Roland McGrath <roland@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/ptrace.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff -puN kernel/ptrace.c~ptrace_check_attach-remove-unneeded-signal-=-null-check kernel/ptrace.c
--- a/kernel/ptrace.c~ptrace_check_attach-remove-unneeded-signal-=-null-check
+++ a/kernel/ptrace.c
@@ -99,9 +99,12 @@ int ptrace_check_attach(struct task_stru
* be changed by us so it's not changing right after this.
*/
read_lock(&tasklist_lock);
- if ((child->ptrace & PT_PTRACED) && child->parent == current &&
- child->signal != NULL) {
+ if ((child->ptrace & PT_PTRACED) && child->parent == current) {
ret = 0;
+ /*
+ * child->sighand can't be NULL, release_task()
+ * does ptrace_unlink() before __exit_signal().
+ */
spin_lock_irq(&child->sighand->siglock);
if (task_is_stopped(child))
child->state = TASK_TRACED;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
revert-proc-fix-the-threaded-proc-self.patch
procfs-task-exe-symlink.patch
procfs-task-exe-symlink-fix.patch
-
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