From dd83c161fbcc5d8be637ab159c0de015cbff5ba4 Mon Sep 17 00:00:00 2001 From: zhongjiang Date: Mon, 10 Jul 2017 15:53:01 -0700 Subject: [PATCH] kernel/exit.c: avoid undefined behaviour when calling wait4() wait4(-2147483648, 0x20, 0, 0xdd0000) triggers: UBSAN: Undefined behaviour in kernel/exit.c:1651:9 The related calltrace is as follows: negation of -2147483648 cannot be represented in type 'int': CPU: 9 PID: 16482 Comm: zj Tainted: G B ---- ------- 3.10.0-327.53.58.71.x86_64+ #66 Hardware name: Huawei Technologies Co., Ltd. Tecal RH2285 /BC11BTSA , BIOS CTSAV036 04/27/2011 Call Trace: dump_stack+0x19/0x1b ubsan_epilogue+0xd/0x50 __ubsan_handle_negate_overflow+0x109/0x14e SyS_wait4+0x1cb/0x1e0 system_call_fastpath+0x16/0x1b Exclude the overflow to avoid the UBSAN warning. Link: http://lkml.kernel.org/r/1497264618-20212-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhongjiang Cc: Oleg Nesterov Cc: David Rientjes Cc: Aneesh Kumar K.V Cc: Kirill A. Shutemov Cc: Xishi Qiu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/exit.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/exit.c b/kernel/exit.c index 608c9775a37b..c5548faa9f37 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1639,6 +1639,10 @@ long kernel_wait4(pid_t upid, int __user *stat_addr, int options, __WNOTHREAD|__WCLONE|__WALL)) return -EINVAL; + /* -INT_MIN is not defined */ + if (upid == INT_MIN) + return -ESRCH; + if (upid == -1) type = PIDTYPE_MAX; else if (upid < 0) {