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authorAles Novak <alnovak@suse.cz>2016-10-11 13:53:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-11 15:06:32 -0700
commit0a5bf409d3eefc1ca64cedf0bc1c0673164cacc1 (patch)
tree21c48f939afc592ecd4273ec956d8a17bf4ff1e8 /kernel/ptrace.c
parent086e774a57fba4695f14383c0818994c0b31da7c (diff)
downloadlinux-0a5bf409d3eefc1ca64cedf0bc1c0673164cacc1.tar.bz2
ptrace: clear TIF_SYSCALL_TRACE on ptrace detach
On __ptrace_detach(), called from do_exit()->exit_notify()-> forget_original_parent()->exit_ptrace(), 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. The clearing of this flag should be moved from ptrace_detach() to __ptrace_detach(). Link: http://lkml.kernel.org/r/1472759493-20554-1-git-send-email-alnovak@suse.cz Signed-off-by: Ales Novak <alnovak@suse.cz> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/ptrace.c')
-rw-r--r--kernel/ptrace.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 1d3b7665d0be..2a99027312a6 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -73,6 +73,8 @@ void __ptrace_unlink(struct task_struct *child)
{
BUG_ON(!child->ptrace);
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+
child->parent = child->real_parent;
list_del_init(&child->ptrace_entry);
@@ -489,7 +491,6 @@ static int ptrace_detach(struct task_struct *child, unsigned int data)
/* Architecture-specific hardware disable .. */
ptrace_disable(child);
- clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
write_lock_irq(&tasklist_lock);
/*