From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>,
akpm@linux-foundation.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"K . Prasad" <prasad@linux.vnet.ibm.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
rostedt@goodmis.org, Alexei Starovoitov <ast@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Ingo Molnar <mingo@redhat.com>
Subject: [RFC PATCH 1/9] tracepoint: call vmalloc_sync_mappings() on registration
Date: Thu, 9 Apr 2020 15:35:35 -0400 [thread overview]
Message-ID: <20200409193543.18115-2-mathieu.desnoyers@efficios.com> (raw)
In-Reply-To: <20200409193543.18115-1-mathieu.desnoyers@efficios.com>
Similarly to register_die_notifier(), tracepoints register callbacks
which can be invoked from execution contexts such as the page fault
handler and NMIs which should not generate a page fault. Those callbacks
can access virtual mappings and can be implemented in modules.
Calling vmalloc_sync_mappings() before registering a tracepoint callback
ensures that the virtual mappings are synchronized within each process
page tables, thus ensuring that no page fault will be triggered by the
callback.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
---
kernel/tracepoint.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 73956eaff8a9..82191a89c72e 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -14,6 +14,7 @@
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/static_key.h>
+#include <linux/vmalloc.h>
extern tracepoint_ptr_t __start___tracepoints_ptrs[];
extern tracepoint_ptr_t __stop___tracepoints_ptrs[];
@@ -308,6 +309,7 @@ int tracepoint_probe_register_prio(struct tracepoint *tp, void *probe,
struct tracepoint_func tp_func;
int ret;
+ vmalloc_sync_mappings();
mutex_lock(&tracepoints_mutex);
tp_func.func = probe;
tp_func.data = data;
--
2.17.1
next prev parent reply other threads:[~2020-04-09 19:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-09 19:35 [RFC PATCH 0/9] Export information needed by the LTTng kernel tracer Mathieu Desnoyers
2020-04-09 19:35 ` Mathieu Desnoyers [this message]
2020-04-09 19:35 ` [RFC PATCH 2/9] bpf: allow up to 13 arguments for tracepoints Mathieu Desnoyers
2020-04-09 19:35 ` [RFC PATCH 3/9] writeback: tracing: pass global_wb_domain as tracepoint parameter Mathieu Desnoyers
2020-04-09 22:33 ` Alexei Starovoitov
2020-04-10 11:54 ` Mathieu Desnoyers
2020-04-09 19:35 ` [RFC PATCH 4/9] stacktrace: export-GPL stack_trace_save_user Mathieu Desnoyers
2020-04-12 8:31 ` Christoph Hellwig
2020-04-09 19:35 ` [RFC PATCH 5/9] sched: export-GPL task_prio Mathieu Desnoyers
2020-04-09 19:35 ` [RFC PATCH 6/9] mm: export-GPL get_pageblock_migratetype Mathieu Desnoyers
2020-04-12 8:14 ` Christoph Hellwig
2020-04-09 19:35 ` [RFC PATCH 7/9] block: genhd: export-GPL gendisk_name Mathieu Desnoyers
2020-04-09 19:35 ` [RFC PATCH 8/9] block: genhd: export-GPL generic disk device type Mathieu Desnoyers
2020-04-10 6:33 ` Greg Kroah-Hartman
2020-04-10 13:31 ` Mathieu Desnoyers
2020-04-10 15:44 ` Steven Rostedt
2020-04-11 6:45 ` Greg Kroah-Hartman
2020-04-09 19:35 ` [RFC PATCH 9/9] block: genhd: export-GPL generic disk block class Mathieu Desnoyers
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