[Kernel] [PATCH OpenHarmony-5.10 10/16] srcu: Take early exit on memory-allocation failure

From: "Paul E. McKenney" <paulmck(a)kernel.org> mainline inclusion from mainline-v5.11-rc1 commit 50edb988534c621a56ca103c0c16ac59e7399f01 category: bugfix issue: #I4LRGQ CVE: NA ------------------------------------------------------------------------- It turns out that init_srcu_struct() can be invoked from usermode tasks, and that fatal signals received by these tasks can cause memory-allocation failures. These failures are not handled well by init_srcu_struct(), so much so that NULL pointer dereferences can result. This commit therefore causes init_srcu_struct() to take an early exit upon detection of memory-allocation failure. Link: https://lore.kernel.org/lkml/20200908144306.33355-1-aik@ozlabs.ru/ Reported-by: Alexey Kardashevskiy <aik(a)ozlabs.ru> Tested-by: Alexey Kardashevskiy <aik(a)ozlabs.ru> Signed-off-by: Paul E. McKenney <paulmck(a)kernel.org> Signed-off-by: Zhen Lei <thunder.leizhen(a)huawei.com> Reviewed-by: Xie XiuQi <xiexiuqi(a)huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai(a)huawei.com> Signed-off-by: Yu Changchun <yuchangchun1(a)huawei.com> --- kernel/rcu/srcutree.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index b8821665c435..1ca734767b9d 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -180,11 +180,13 @@ static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static) INIT_DELAYED_WORK(&ssp->work, process_srcu); if (!is_static) ssp->sda = alloc_percpu(struct srcu_data); + if (!ssp->sda) + return -ENOMEM; init_srcu_struct_nodes(ssp, is_static); ssp->srcu_gp_seq_needed_exp = 0; ssp->srcu_last_gp_end = ktime_get_mono_fast_ns(); smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */ - return ssp->sda ? 0 : -ENOMEM; + return 0; } #ifdef CONFIG_DEBUG_LOCK_ALLOC -- 2.25.1