linux-kernel - [PATCH 2/3] MIPS: signal: Return immediately if call fails

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Message-Id: <1639797789-3001-3-git-send-email-yangtiezhu@loongson.cn>
Date:   Sat, 18 Dec 2021 11:23:08 +0800
From:   Tiezhu Yang <yangtiezhu@...ngson.cn>
To:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Cc:     Xuefeng Li <lixuefeng@...ngson.cn>, linux-mips@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] MIPS: signal: Return immediately if call fails

When debug sigaltstack(), copy_siginfo_to_user() fails first in
setup_rt_frame() if the alternate signal stack is too small, so
it should return immediately if call fails, no need to call the
following functions.

Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
---
 arch/mips/kernel/signal.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index c1632e8..4cd3969 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -761,15 +761,28 @@ static int setup_rt_frame(void *sig_return, struct ksignal *ksig,
 		return -EFAULT;
 
 	/* Create siginfo.  */
-	err |= copy_siginfo_to_user(&frame->rs_info, &ksig->info);
+	err = copy_siginfo_to_user(&frame->rs_info, &ksig->info);
+	if (err)
+		return -EFAULT;
 
 	/* Create the ucontext.	 */
-	err |= __put_user(0, &frame->rs_uc.uc_flags);
-	err |= __put_user(NULL, &frame->rs_uc.uc_link);
-	err |= __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
-	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
-	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
+	err = __put_user(0, &frame->rs_uc.uc_flags);
+	if (err)
+		return -EFAULT;
+
+	err = __put_user(NULL, &frame->rs_uc.uc_link);
+	if (err)
+		return -EFAULT;
+
+	err = __save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
+	if (err)
+		return -EFAULT;
+
+	err = setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
+	if (err)
+		return -EFAULT;
 
+	err = __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
 	if (err)
 		return -EFAULT;
 
-- 
2.1.0