Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [PATCH 08/12] x86/dumpstack: Pin the target stack in save_stack_trace_tsk() | Date | Tue, 13 Sep 2016 14:29:28 -0700 |
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This will prevent a crash if the target task dies before or while dumping its stack once we start freeing task stacks early.
Signed-off-by: Andy Lutomirski <luto@kernel.org> --- arch/x86/kernel/stacktrace.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c index 4738f5e0f2ab..b3f32fbe3ba4 100644 --- a/arch/x86/kernel/stacktrace.c +++ b/arch/x86/kernel/stacktrace.c @@ -79,9 +79,14 @@ void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) { + if (!try_get_task_stack(tsk)) + return; + dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace); if (trace->nr_entries < trace->max_entries) trace->entries[trace->nr_entries++] = ULONG_MAX; + + put_task_stack(tsk); } EXPORT_SYMBOL_GPL(save_stack_trace_tsk); -- 2.7.4
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