diff options
Diffstat (limited to 'debian/patches-rt/0224-ptrace-fix-ptrace_unfreeze_traced-race-with-rt-lock.patch')
| -rw-r--r-- | debian/patches-rt/0224-ptrace-fix-ptrace_unfreeze_traced-race-with-rt-lock.patch | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/debian/patches-rt/0224-ptrace-fix-ptrace_unfreeze_traced-race-with-rt-lock.patch b/debian/patches-rt/0224-ptrace-fix-ptrace_unfreeze_traced-race-with-rt-lock.patch new file mode 100644 index 000000000..4e61137e3 --- /dev/null +++ b/debian/patches-rt/0224-ptrace-fix-ptrace_unfreeze_traced-race-with-rt-lock.patch @@ -0,0 +1,65 @@ +From 10d5d8e25cce1695bb99f7149038d97b9a160201 Mon Sep 17 00:00:00 2001 +From: Oleg Nesterov <oleg@redhat.com> +Date: Tue, 3 Nov 2020 12:39:01 +0100 +Subject: [PATCH 224/323] ptrace: fix ptrace_unfreeze_traced() race with + rt-lock +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz + +The patch "ptrace: fix ptrace vs tasklist_lock race" changed +ptrace_freeze_traced() to take task->saved_state into account, but +ptrace_unfreeze_traced() has the same problem and needs a similar fix: +it should check/update both ->state and ->saved_state. + +Reported-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com> +Fixes: "ptrace: fix ptrace vs tasklist_lock race" +Signed-off-by: Oleg Nesterov <oleg@redhat.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Cc: stable-rt@vger.kernel.org +--- + kernel/ptrace.c | 23 +++++++++++++++-------- + 1 file changed, 15 insertions(+), 8 deletions(-) + +diff --git a/kernel/ptrace.c b/kernel/ptrace.c +index 71acb6341e63..fb5d1a19507d 100644 +--- a/kernel/ptrace.c ++++ b/kernel/ptrace.c +@@ -213,8 +213,8 @@ static bool ptrace_freeze_traced(struct task_struct *task) + + static void ptrace_unfreeze_traced(struct task_struct *task) + { +- if (task->state != __TASK_TRACED) +- return; ++ unsigned long flags; ++ bool frozen = true; + + WARN_ON(!task->ptrace || task->parent != current); + +@@ -223,12 +223,19 @@ static void ptrace_unfreeze_traced(struct task_struct *task) + * Recheck state under the lock to close this race. + */ + spin_lock_irq(&task->sighand->siglock); +- if (task->state == __TASK_TRACED) { +- if (__fatal_signal_pending(task)) +- wake_up_state(task, __TASK_TRACED); +- else +- task->state = TASK_TRACED; +- } ++ ++ raw_spin_lock_irqsave(&task->pi_lock, flags); ++ if (task->state == __TASK_TRACED) ++ task->state = TASK_TRACED; ++ else if (task->saved_state == __TASK_TRACED) ++ task->saved_state = TASK_TRACED; ++ else ++ frozen = false; ++ raw_spin_unlock_irqrestore(&task->pi_lock, flags); ++ ++ if (frozen && __fatal_signal_pending(task)) ++ wake_up_state(task, __TASK_TRACED); ++ + spin_unlock_irq(&task->sighand->siglock); + } + +-- +2.43.0 + |