From: Catalin Marinas It makes more sense to end the stack trace with ULONG_MAX only if nr_entries < max_entries. Otherwise, we lose one entry in the long stack traces and cannot know whether the trace was complete or not. Signed-off-by: Catalin Marinas Cc: Andi Kleen Cc: Jan Beulich Signed-off-by: Andrew Morton --- arch/x86_64/kernel/stacktrace.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff -puN arch/x86_64/kernel/stacktrace.c~x86_64-do-not-always-end-the-stack-trace-with-ulong_max arch/x86_64/kernel/stacktrace.c --- a/arch/x86_64/kernel/stacktrace.c~x86_64-do-not-always-end-the-stack-trace-with-ulong_max +++ a/arch/x86_64/kernel/stacktrace.c @@ -32,7 +32,7 @@ static void save_stack_address(void *dat trace->skip--; return; } - if (trace->nr_entries < trace->max_entries - 1) + if (trace->nr_entries < trace->max_entries) trace->entries[trace->nr_entries++] = addr; } @@ -49,7 +49,8 @@ static struct stacktrace_ops save_stack_ void save_stack_trace(struct stack_trace *trace, struct task_struct *task) { dump_trace(task, NULL, NULL, &save_stack_ops, trace); - trace->entries[trace->nr_entries++] = ULONG_MAX; + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = ULONG_MAX; } EXPORT_SYMBOL(save_stack_trace); _