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From: Jiri Slaby <jslaby@suse.cz>
To: mingo@redhat.com
Cc: linux-kernel@vger.kernel.org, Jiri Slaby <jslaby@suse.cz>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>
Subject: [PATCH v2 3/6] x86/stacktrace: remove STACKTRACE_DUMP_ONCE from __save_stack_trace_reliable
Date: Mon, 14 May 2018 16:06:50 +0200	[thread overview]
Message-ID: <20180514140653.23678-3-jslaby@suse.cz> (raw)
In-Reply-To: <20180514140653.23678-1-jslaby@suse.cz>

The stack unwinding can sometimes fail yet. Especially with the
generated debug info. So do not yell at users -- live patching (the only
user of this interface) will inform the user about the failure
gracefully.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
---
 arch/x86/kernel/stacktrace.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index 3a4602c2324f..e0169b128523 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -125,20 +125,16 @@ __save_stack_trace_reliable(struct stack_trace *trace,
 		 * generated code which __kernel_text_address() doesn't know
 		 * about.
 		 */
-		if (!addr) {
-			STACKTRACE_DUMP_ONCE(task);
+		if (!addr)
 			return -EINVAL;
-		}
 
 		if (save_stack_address(trace, addr, false))
 			return -EINVAL;
 	}
 
 	/* Check for stack corruption */
-	if (unwind_error(&state)) {
-		STACKTRACE_DUMP_ONCE(task);
+	if (unwind_error(&state))
 		return -EINVAL;
-	}
 
 	/* Success path for non-user tasks, i.e. kthreads and idle tasks */
 	if (!(task->flags & (PF_KTHREAD | PF_IDLE)))
-- 
2.16.3

  parent reply	other threads:[~2018-05-14 14:08 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-14 14:06 [PATCH v2 1/6] x86/stacktrace: do not unwind after user regs Jiri Slaby
2018-05-14 14:06 ` [PATCH v2 2/6] x86/stacktrace: make clear the success paths Jiri Slaby
2018-05-14 15:03   ` Josh Poimboeuf
2018-05-14 14:06 ` Jiri Slaby [this message]
2018-05-14 15:04   ` [PATCH v2 3/6] x86/stacktrace: remove STACKTRACE_DUMP_ONCE from __save_stack_trace_reliable Josh Poimboeuf
2018-05-14 14:06 ` [PATCH v2 4/6] x86/stacktrace: do not fail for ORC with regs on stack Jiri Slaby
2018-05-14 14:06 ` [PATCH v2 5/6] x86/unwind/orc: Detect the end of the stack Jiri Slaby
2018-05-14 14:06 ` [PATCH v2 6/6] x86/stacktrace: orc, mark it as reliable Jiri Slaby
2018-05-14 15:07   ` Josh Poimboeuf

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