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Message-ID: <20250502165009.909829374@goodmis.org>
Date: Fri, 02 May 2025 12:48:01 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org,
linux-trace-kernel@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Josh Poimboeuf <jpoimboe@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
x86@...nel.org,
Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>
Subject: [PATCH v7 15/17] perf: Use current->flags & PF_KTHREAD instead of current->mm == NULL
From: Steven Rostedt <rostedt@...dmis.org>
To determine if a task is a kernel thread or not, it is more reliable to
use (current->flags & PF_KTHREAD) than to rely on current->mm being NULL.
That is because some kernel tasks (io_uring helpers) may have a mm field.
Link: https://lore.kernel.org/linux-trace-kernel/20250424163607.GE18306@noisy.programming.kicks-ass.net/
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
kernel/events/callchain.c | 6 +++---
kernel/events/core.c | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index abf258913ab6..cda145dc11bd 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -246,10 +246,10 @@ get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,
if (user) {
if (!user_mode(regs)) {
- if (current->mm)
- regs = task_pt_regs(current);
- else
+ if (current->flags & PF_KTHREAD)
regs = NULL;
+ else
+ regs = task_pt_regs(current);
}
if (regs) {
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 0bac8cae08a8..7c7d5a27c568 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7989,7 +7989,7 @@ static u64 perf_virt_to_phys(u64 virt)
* Try IRQ-safe get_user_page_fast_only first.
* If failed, leave phys_addr as 0.
*/
- if (current->mm != NULL) {
+ if (!(current->flags & PF_KTHREAD)) {
struct page *p;
pagefault_disable();
--
2.47.2
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