linux-kernel - [RFC PATCH v1 11/19] powerpc/signal32: Simplify logging in handle_rt

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Message-Id: <3e2f2862e422c89739dedf2b9e9e0eedc04beb6d.1597233555.git.christophe.leroy@csgroup.eu>
Date:   Wed, 12 Aug 2020 12:06:02 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, ldv@...linux.org,
        viro@...iv.linux.org.uk
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [RFC PATCH v1 11/19] powerpc/signal32: Simplify logging in
 handle_rt_signal32()

If something is bad in the frame, there is no point in
knowing which part of the frame exactly is wrong as it
got allocated as a single block.

Always print the root address of the frame in case on
failed user access, just like handle_signal32().

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/kernel/signal_32.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index d1087dd87174..495bee1b713d 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -754,7 +754,6 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	struct rt_sigframe __user *rt_sf;
 	struct mcontext __user *frame;
 	struct mcontext __user *tm_frame = NULL;
-	void __user *addr;
 	unsigned long newsp = 0;
 	int sigret;
 	unsigned long tramp;
@@ -769,7 +768,6 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	/* Set up Signal Frame */
 	/* Put a Real Time Context onto stack */
 	rt_sf = get_sigframe(ksig, tsk, sizeof(*rt_sf), 1);
-	addr = rt_sf;
 	if (!access_ok(rt_sf, sizeof(*rt_sf)))
 		goto badframe;
 
@@ -784,7 +782,6 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 
 	/* Save user registers on the stack */
 	frame = &rt_sf->uc.uc_mcontext;
-	addr = frame;
 	if (vdso32_rt_sigtramp && tsk->mm->context.vdso_base) {
 		sigret = 0;
 		tramp = tsk->mm->context.vdso_base + vdso32_rt_sigtramp;
@@ -820,7 +817,6 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 
 	/* create a stack frame for the caller of the handler */
 	newsp = ((unsigned long)rt_sf) - (__SIGNAL_FRAMESIZE + 16);
-	addr = (void __user *)regs->gpr[1];
 	if (put_user(regs->gpr[1], (u32 __user *)newsp))
 		goto badframe;
 
@@ -837,7 +833,7 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset,
 	return 0;
 
 badframe:
-	signal_fault(tsk, regs, "handle_rt_signal32", addr);
+	signal_fault(tsk, regs, "handle_rt_signal32", rt_sf);
 
 	return 1;
 }
-- 
2.25.0