From: Ales Novak <alnovak@suse.cz>
To: linux-kernel@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ales Novak <alnovak@suse.cz>, Jiri Kosina <jkosina@suse.cz>
Subject: [PATCH] ptrace: clear TIF_SYSCALL_TRACE on ptrace detach
Date: Thu, 1 Sep 2016 15:54:36 +0200 [thread overview]
Message-ID: <1472738076-14610-1-git-send-email-alnovak@suse.cz> (raw)
On ptrace_detach(), the TIF_SYSCALL_TRACE in thread->flags of the tracee
is not cleared up. This results in the tracehook_report_syscall_* being
called (though there's no longer a tracer listening to that) upon its
further syscalls.
Example scenario - attach "strace" to a running process and kill it (the
strace) with SIGKILL. You'll see that the syscall trace hooks are still
being called.
Signed-off-by: Ales Novak <alnovak@suse.cz>
Cc: Jiri Kosina <jkosina@suse.cz>
---
kernel/ptrace.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 1d3b766..634740f 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -85,6 +85,7 @@ void __ptrace_unlink(struct task_struct *child)
task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
task_clear_jobctl_trapping(child);
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
/*
* Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
* @child isn't dead.
--
2.7.0
next reply other threads:[~2016-09-01 13:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-01 13:54 Ales Novak [this message]
2016-09-01 16:46 ` [PATCH] ptrace: clear TIF_SYSCALL_TRACE on ptrace detach Oleg Nesterov
2016-09-01 19:50 ` Ales Novak
2016-09-01 19:51 ` Ales Novak
2016-09-02 12:25 ` Oleg Nesterov
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