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From: Vasily Gorbik <gor@linux.ibm.com>
To: Miroslav Benes <mbenes@suse.cz>
Cc: heiko.carstens@de.ibm.com, borntraeger@de.ibm.com,
	jpoimboe@redhat.com, joe.lawrence@redhat.com,
	linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
	jikos@kernel.org, pmladek@suse.com, nstange@suse.de,
	live-patching@vger.kernel.org
Subject: [PATCH v4 1/2] s390/unwind: add stack pointer alignment sanity checks
Date: Fri, 29 Nov 2019 08:41:48 +0100
Message-ID: <patch-1.thread-a0061f.git-617139935cc4.your-ad-here.call-01575012971-ext-9115@work.hours> (raw)
In-Reply-To: <cover.thread-a0061f.your-ad-here.call-01575012971-ext-9115@work.hours>

From: Miroslav Benes <mbenes@suse.cz>

ABI requires SP to be aligned 8 bytes, report unwinding error otherwise.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
---
 arch/s390/kernel/dumpstack.c | 4 ++++
 arch/s390/kernel/unwind_bc.c | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c
index d74e21a23703..d306fe04489a 100644
--- a/arch/s390/kernel/dumpstack.c
+++ b/arch/s390/kernel/dumpstack.c
@@ -94,6 +94,10 @@ int get_stack_info(unsigned long sp, struct task_struct *task,
 	if (!sp)
 		goto unknown;
 
+	/* Sanity check: ABI requires SP to be aligned 8 bytes. */
+	if (sp & 0x7)
+		goto unknown;
+
 	/* Check per-task stack */
 	if (in_task_stack(sp, task, info))
 		goto recursion_check;
diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c
index ef42d5f77ce7..da2d4d4c5b0e 100644
--- a/arch/s390/kernel/unwind_bc.c
+++ b/arch/s390/kernel/unwind_bc.c
@@ -92,6 +92,10 @@ bool unwind_next_frame(struct unwind_state *state)
 		}
 	}
 
+	/* Sanity check: ABI requires SP to be aligned 8 bytes. */
+	if (sp & 0x7)
+		goto out_err;
+
 	ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, ip, (void *) sp);
 
 	/* Update unwind state */
-- 
2.21.0


  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-06  9:55 [PATCH v3 0/4] s390/livepatch: Implement reliable stack tracing for the consistency model Miroslav Benes
2019-11-06  9:55 ` [PATCH v3 1/4] s390/unwind: drop unnecessary code around calling ftrace_graph_ret_addr() Miroslav Benes
2019-11-28 16:51   ` Vasily Gorbik
2019-11-06  9:55 ` [PATCH v3 2/4] s390/unwind: split unwind_next_frame() to several functions Miroslav Benes
2019-11-06  9:56 ` [PATCH v3 3/4] s390/unwind: prepare the unwinding interface for reliable stack traces Miroslav Benes
2019-11-06  9:56 ` [PATCH v3 4/4] s390/livepatch: Implement reliable stack tracing for the consistency model Miroslav Benes
2019-11-29  7:41   ` Vasily Gorbik
2019-11-29  7:41     ` Vasily Gorbik [this message]
2019-11-29 18:16       ` [PATCH v4 1/2] s390/unwind: add stack pointer alignment sanity checks Miroslav Benes
2019-11-29  7:41     ` [PATCH v4 2/2] s390/livepatch: Implement reliable stack tracing for the consistency model Vasily Gorbik
2019-11-29 18:16       ` Miroslav Benes
2019-11-29 18:16     ` [PATCH v3 4/4] " Miroslav Benes

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