kgdb: Read buffer overflow (84667d48) · Commits · 戴 / test

Roel Kluin reported an error found with Parfait. Where we want to ensure that that kgdb_info[-1] never gets accessed. Also check to ensure any negative tid does not exceed the size of the shadow CPU array, else report critical debug context because it is an internal kgdb failure. Reported-by:

Roel Kluin <roel.kluin@gmail.com> Signed-off-by:

Jason Wessel <jason.wessel@windriver.com>

kernel/kgdb.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -541,12 +541,17 @@ static struct task_struct getthread(struct pt_regs regs, int tid)
		*/
		if (tid == 0 \|\| tid == -1)
		tid = -atomic_read(&kgdb_active) - 2;
		if (tid < 0) {
		if (tid < -1 && tid > -NR_CPUS - 2) {
		if (kgdb_info[-tid - 2].task)
		return kgdb_info[-tid - 2].task;
		else
		return idle_task(-tid - 2);
		}
		if (tid <= 0) {
		printk(KERN_ERR "KGDB: Internal thread select error\n");
		dump_stack();
		return NULL;
		}

		/*
		* find_task_by_pid_ns() does not take the tasklist lock anymore

Admin message