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 2/6] x86/stacktrace: make clear the success paths
Date: Mon, 14 May 2018 16:06:49 +0200 [thread overview]
Message-ID: <20180514140653.23678-2-jslaby@suse.cz> (raw)
In-Reply-To: <20180514140653.23678-1-jslaby@suse.cz>
Make clear which path is for user tasks and for kthreads and idle
tasks. This will allow easier plug-in of ORC unwinder in the next
patches.
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 | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index 8948b7d9c064..3a4602c2324f 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -104,16 +104,18 @@ __save_stack_trace_reliable(struct stack_trace *trace,
regs = unwind_get_entry_regs(&state, NULL);
if (regs) {
+ /* Success path for user tasks */
+ if (user_mode(regs))
+ goto success;
+
/*
* Kernel mode registers on the stack indicate an
* in-kernel interrupt or exception (e.g., preemption
* or a page fault), which can make frame pointers
* unreliable.
*/
- if (!user_mode(regs))
- return -EINVAL;
- break;
+ return -EINVAL;
}
addr = unwind_get_return_address(&state);
@@ -138,6 +140,11 @@ __save_stack_trace_reliable(struct stack_trace *trace,
return -EINVAL;
}
+ /* Success path for non-user tasks, i.e. kthreads and idle tasks */
+ if (!(task->flags & (PF_KTHREAD | PF_IDLE)))
+ return -EINVAL;
+
+success:
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
--
2.16.3
next prev 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 ` Jiri Slaby [this message]
2018-05-14 15:03 ` [PATCH v2 2/6] x86/stacktrace: make clear the success paths Josh Poimboeuf
2018-05-14 14:06 ` [PATCH v2 3/6] x86/stacktrace: remove STACKTRACE_DUMP_ONCE from __save_stack_trace_reliable Jiri Slaby
2018-05-14 15:04 ` 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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